I've had an Airthings meter in my older Virginia house for about a year now. Nobody mentioned radon when I moved in almost 10 years ago. I was averaging around 4-6 pCi/L initially, which dropped to 2-4 after I opened the crawl space vents. I almost bought a home test kit, but settled on the meter since it was a one-time cost that let's me re-measure different rooms, during different seasons, and after various mitigation steps like opening windows and sealing gaps.
Radon fans should NOT be in the basement, when passive systems are installed around here there is an outlet installed near the pipe in the ATTIC where potentially needed fan can be plugged in. Thus the suction pipe never has POSITIVE pressure while passing through a livable space. With a retrofit system, this is why the fan is always located OUTSIDE. As a Home Inspector in Ohio, I'm asked to test about 2/3 of the properties I inspect. I commonly see 10-20 pCi/l readings, my highest was 254.2 pCi/l. Big HEAD'S UP: I also test houses with operating mitigation systems, of those I tested last year, 40% were above 4.0 pCi/l WITH AN OPERATING SYSTEM! Maintenance and repairs can't be neglected.
Same, all pipework inside the house should be negative pressure. If you have a split in that pipe on it's way to the roof your pumping the radon from the soil into your 2nd floor or attic.
Yup, fan should be installed outside of the living area so there is never a chance of radon being pumped into the house. Attic is a good spot as long as it is properly ventilated itself. Retrofit radon systems generally pop through the basement wall as quickly as possible (near grade) and the fan is installed outside. This is the best place for the fan, completely outside the house envelope.
@@Critters As long as the attic is properly ventilated and is outside of the living envelope (not a conditioned space) then a small leak should not be an issue. Radon is heavier than air but even a little bit of airflow will dissipate it quickly and not allow it to accumulate. If the attic isn't ventilated properly it could definitely be an issue. This of course is only referring to if there is a crack or leak in the pressure side of the piping, after the fan. A normally operating radon system will have no leaks.
Exactly, you cannot believe all the mis-information there is out there. I had a home inspection today and I asked the inspector about an alarm on the system and he said no. I asked how would you know it isnt working. His response was you can hear the fan running when you get near it. How's That??. EPA says an obvious alarm must be installed A second question was about the stack being uncapped, I read the pipe should be like a candy cane with a sort of screen cap on it, so water and snow wont go in, birds. etc His response was oh its blows quite alot of air nothing could go in. I' m floored by his responses.
My mother, stepfather, and brother all died from various forms of cancer within a 10 year period and I believe Radon had a lot to do with it. Mother had storm windows added many years earlier and the house was virtually never opened up. Combined with a full basement in a sloped hillside and an incredible humidity problem in the basement requiring a permanent always-on dehumidifier we should have known. My brother socialized with them a lot so he spent a lot of time over there. After mother died he discovered he had cancer so took time off of work and filled his days repairing and updating her house. I was out of state so it didn't affect me. When he went to sell the house a buyer was required to do a radon test and POW! "Really bad" was how he described it to me. A passive system was installed in the basement under the slab. Retest showed little improvement. A second trench was dug and an outside fan added and now the tests passed. We didn't talk about it much because he knew as well as I that despite the different cancers they probably all got it the same way. He died just a couple of years later. If it's a rocky area, if you have any ground penetration beyond normal surface footings, if you have a ground related humidity problem inside - GET TESTED!
Moved several times in the last 6 years, my realtor made sure we knew about Radon danger and mitigation systems, as well as testing after installation. Hats off to knowledgeable people.
Radon is a scam. They couldn't possibly know that Radon is the number 1 cause of lung cancer next to smoking. The person who died of lung cancer may not have admitted to smoking, or perhaps they breathed in enough cat dander to finally cause their lungs to give in. Who knows? Hospitals don't routinely go about testing the homes of their lung cancer victims for Radon, if ever! Indigenous people have lived with radon in their wigwams for millennia and there's no history of lung cancer until the advent of industrial technology. People need to stop driving this mass hysteria.
Back in January of 2019, I came across a similar discussion to this. I bought a monitor and discovered that my basement office was measuring 12 picocuries/liter. My house is basically prehistoric. Rubble stone foundation with lime grout. The slab could only loosely be called a monolithic slab. I was fortunate to have an abandoned coal bin under the slab as it was. A good volume of air to draw from. I opted to install my fan in the cellar (common practice in Canada). I had read plenty of stories of frozen/frosted vents in winter (worse time of year for radon due to stack effect). And non-working, outta-site, outta-mind attic fans. Logistically, getting the pipe through the sill or foundation would have been tough. I did have an abandoned chimney though. My installation is simple, 18” of 4” pvc from the slab to the fan, 18” more to the chimney. In the chimney I used triple wall for the vent. I can easily monitor its function and the fan should last forever out of the elements. If I ever have to sell the place, I can relocate the fan to the top of the chimney where it’s legal but not practical to monitor. Since the chimney is surrounded by a warm house, theres natural convection that would help draft anything that may leak… at the end of the day, I achieved a three year average of 1.1 picocuries/liter down from 12.
Another benefit I saw with an active radon system in my house was lower moisture levels in the basement. It draws air through and out the drain tile in the basement. Keeps my humidity levels below 50 all year round. Don't need a dehumidifier anymore.
When we bought our Indianapolis 1913 home a few years ago it did not have a radon system in it. Last summer we grabbed one of the Airthings sensors you show in the video and saw it read about 12-14. OMG. Sealing off our crawlspaces, sealing basement walls, and installing the active system dropped us to 1-3 regularly. We're very happy with the results and feel a lot better about the home and our health. We definitely do have levels about 0.5-1 in the summers and upwards 2-3 in the winter.
I realize Texas is considered a "low risk area", but ever since that event, have you considered installing, or at least offering, a passive radon system as a standard part of the "package", whether slab on grade or crawlspace?
When doing home inspections I'm my area Radon is always a hot topic. People are worried more about radon and radon in well water than anything elce.4 Picl is the recommend limit for radon in most areas but does vary. Basements and other factors make a huge diffence.
Great Video. I bought a meter to actively measure the Radon in my basement. It hovered around 4 most of the time, but an adjacent space was as high as 9. I put in my own system to remove it and got it down to 0.5-1.0. DIY is a great option if you're willing to learn the basics to ensure your system is built properly and delivering the results needed.
Valuable education video and communication tool to raise public awareness and save lives. A “big” thanks to you, Matt, and your team for making this video possible - priceless!
Have 2 airthings in my house. And here (Norway) is considered a low radon area BUT my readings is often 3 times the limit in my basement. The living spaces is mostly under but sometimes over
We're in a zone in central WA that is not known to have Radon issues. Tested in June last year and we had 30+ pCi/l in areas of the building. Testing this winter levels rose to 80+ pCi/l. Going to be a big system to mitigate 40k sqft building.
In modern homes, as long as you hit a gravel base or porous substrate under the slab it's a straightforward setup with a basic fan. Can be homeowner friendly if they follow the EPA guidelines. In older homes with poor dense substrate or multiple slabs/crawlspaces It certainly gets challenging quickly.
Wow. I wonder how your customers would feel that you charged them more to do one test than they would have paid if they bought the device themselves. I would be royally pissed if I paid for a professional Radon test to be given a less accurate residential test. I bought my AirThings Radon Detector new on ebay for $44. My last Radon test I paid for wad $160.
@@realtyrocks1969 lol. You don’t have anything better to do than troll 8 month old comments on RUclips 😆😆 The professional Corentium Pro devices are $1399 btw
In central WI, new house construction with basement that had sump pump pit drainage installed. I bought both the Airthings devices (View Plus and Wave Plus). Found levels at around 5.0+. I installed a sealed sump pit cover to put a pipe in to vent out. Installed the Aprilaire fan to vent out. Now with the fan running all the time, the levels are at 0.5. I have the fan plugged into a smart plug. The smart plug can tie into the Airthings app, so I could program it to power the fan off when levels are low and turn on when it hits a higher level.
Hi Matt, I live in the UK and I have never heard of this problem, as far as I know Radon is not a problem. I have seen pipes at dumpsites and they are often lit at the top but that is for another gas that can accumulate and cause an explosion that is caused by the build-up of rotting material. I have just done a search and found a map of the UK and from the info; my area is considered a very low area with less than one percent of radon gas per KM. this map and information comes from the government so I have sent off for one of the tests to find out for myself. If I find out that, I am not, in this low area, I will be taking action to correct this and I will also be letting my neighbours know as well
I put a passive system in and tested it 25 years later. Found in the basement the level was average of 3.7 Then after installing a fan in the radon exhaust pipe it dropped to an average .9 long term. The levels dropped about 1 for each floor level above ground. Good advice on this video.
I really do like your show and sometimes mock your intro Matt, not out of jealousy, but from envy. Show I do want to thank you for the taking some time to bringing this issue to light.
Thanks for the video! After watching this I got the SafetySiren electronic detector and got a reading of 8 pCi/L. I will confirm with test kits but I expect that I will have to install a sub slab system. I tested for radon before I bought my house but this was in the summer and I took Matt’s advice to test in January. I think the energy efficiency measures done to my house would have increased radon levels. In addition to air sealing, I changed from using a natural gas powered boiler and hot water heater that used basement air for combustion to a high efficiency combi boiler that gets combustion air from outside.
3:35 I just learned that the "hockey puck" was actually a piece of cr-39 bullet proof plastic. The alpha and beta particles would actually make tiny little holes that are then analyzed under a microscope. 🤯
We put in an active system in when we built in 2020 and still had a reading around 8-9. So once I sealed the sump pit and all of the expansion cracks, it dropped to around 2. You should do this before you finish your basement.
Ha, once again another video where I learn about something I had no idea. I live in Tasmania, Australia and Radon levels in Australia are considered low. However I have never come across Radon as a thing in all my time as a builder. Very interesting.
is it good idea to get a builder to spray insulation on the basement floor before pouring a concrete slab on top? for added insulation? or a waste of money?
Matt has a lot of videos on this. Insulating under the slab is commonly done for net zero or passive houses that seek to greatly reduce their energy losses. Most builders will use pre-manufactured EPS foam boards for this purpose. At least you will know what thickness and material quality you are getting with EPS, versus a foam sprayed in the field and quickly covered up.
Hey Matt! Just wondering, can you just put in a vapor barrier tarp under a new build foundation? Why not? Would it not stop all radon and vapor from entering house?
I believe a barrier is commonly put under basement slabs and have been for a while now in most new construction. Unfortunately there are still some penetrations for plumbing fixtures, the edge of the slab may not be perfectly sealed, and it's always possible cracks will occur and damage or degradation of the barrier can allow radon to seep through. My house was built in 74 and their idea of radon mitigation was "what's that" so I decided to get a system put in and bought a case of caulk to seal up the edges of the slab and every crack I could find in the unfinished portions of the floor. The suction from the radon mitigation system can travel also, I took a 1/4" tube and used it as a stethoscope and found suction leaks all over the place, including some on the garden level foundation a ways away from the system slab penetration point.
@@hrlsswndr3938 That makes sense. If there is any radon present, then there are 2 types of radon foundations. Those that leak radon. That's that are going to leak radon . 😂
Mitigating radon gas in homes is a very controversial subject. The level determined to require mitigating was derived by the EPA using a no threshold linear model. Many scientists do not agree with the EPA’s model. Mitigation is a large industry so tail may be wagging the dog. Radon at very high levels, like can be found in some mines, is certainly dangerous.
ruclips.net/video/TYZglUjLE0Y/видео.html His videos on the subject are very enlightening. I work on x-ray devices and radiation is all about dose. The way we measure Radon in homes is in no way an indicator of potential dose. We just closed on a house and had the owner install a mitigating system before we closed. After we had it installed I found his videos and felt like even though we didn’t pay for the mitigation system, maybe we shouldn’t have had one installed.
More likely that radon actually protects the lungs. It stimulates DNA repair and leads to a person being healthier. There is plenty of evidence to support this. But, we certainly cannot follow the real science when it does not support the narrative and profits.
I'm a nuclear engineer by training. Funny thing, Radon was the most annoying for us at the plant I worked at. It is highly charged so it would stick to your clothes and hair as you walked around the plant. Made it difficult to detect when you were contaminated with the important stuff. Low pressure days were the worst. As it would easily come out of the granite the plant was built on. Which makes we think if you are venting your house to get rid of this bogeyman, then you are creating a low pressure atmosphere which would draw it out of the ground even more. It's all a ridiculous scam.
I bought the wave a couple days ago. Moved into this basement house in New York four years ago and in April. I had very nice radon readings with the two vile test from Pro Lab. I ran it again this year in February and I had one reading in the twos and one in the eighth so that concerned me.
Hi from Australia. Didn’t know this was something to be concerned about… then I Googled what the levels were in my area, proceeded to freak out as the levels charted for my area were 9!!! But different unit of measurement. We seem to measure in Bq/m3 where 1 pCi/L is equal to 37 Bq/m3, so we’re doin fine over here. Good luck guys.
I was in the same position just last week, I’m selling my home and the new buyers did a radon inspection and they found elevated levels. My home was built with a passive system into the sump pit so it wasn’t very costly to have it retrofitted but I should have had it inspected more often while I owned the home.
I have an Airthing monitor running in my home here in Canada since late November. So far, the average reading is just above 100Bq/m3 with some individual spikes as much as 170bq/m3. Canada's guidelines are for a maximum of 200Bq/m3 (5.4pCi/L) , whereas in Europe its only 100 Bq/m3(2.7pCi/L). This is in the middle of our winter heating season I'll probably check the average up until June or July before deciding if I should take any further action.
Canada is lacking with just having "guidance levels" IMO 200 Bg/m3 seems high. I'm in BC and we tested 59 Bq/m3 in 2018. But that was a 90 day test, I'm interested in getting an Airthing monitor to see the R/T long term stats. Like that the new monitors have all the sensors - though the $350+ price is kind of a shocker
@@BryceCampbell how airtight is your home? If it's extremely airtight or you live in the basement most of the day, then you've got something to start to worry about. 2nd case, then take that money for the sensor and spend it instead on an HRV or Erv. Nothing fancy, just have it hooked up to your central air. Even a modicum of make-up air will completely suppress.
Bought an Air Things Wave Plus. Found my levels going up to 2.5 in the winter. Installed a radon system, dropped to 1.1 in winter. Spray foamed the entire basement foundation, it dropped down to 0.1-0.3. The Air Things will tell me within 24 hours if my fan stops running as well.
I got one of those Air Things plus devices. I got it back in July and all of a sudden the radon spiked in my house despite having an active mitigation system. After having an average rating above 6 I called the installer and they came out and checked it out. Looks like the drains to the system in the basement weren't properly sealed and so far things are looking much better. I suspect it was pushing all the air under the foundation into the basement because the grills to the system were exposed. A long term testing device is great for that just in case the system starts acting weird you have a way to know immediately.
I installed a fan for my radon system in the attic of my garage. The builders had an electrical box already in place but never installed a fan. My levels went from 2-4 down to .3-.5 in the winter and .2 avg in the summer.
In my experience, ERV's/HRV's reduce the radon levels but the efficiency varies greatly. When a soil depressurization system like Matt mentioned is not suitable we usually design them specifically for basements and our rule of thumb is up to a 50% reduction when targeting the radon at its source. A whole-home system may not be as effective unless you can change pressures between the basement/first floor and prevent the radon from rising. The poly sheet and sealants on the market you may see increase the efficiency of a passive or active ASD system. The radon needs a new path to exit and usually cannot be blocked alone.
A neighbor cleared a lot behind mine of huge pine trees, and left the stumps in the ground, and built a home on it. Ten years later after the occupants had all kinds of weird sicknesses and cancer they tore it down completely and dug the contaminated ground up and rebuilt a new home on that. They added Radon fans to the first home but it wasnt enough to make it safe.
Thanks Matt for the video I don't live in a high risk area of Michigan , but that probably has been to my putting it off . Good time to have this reminder when it's 15° in Michigan to know what is actually going on from our below grade basement. Thanks
I use a Certainteed product called form-a-drain. Automatically for a few hundred dollars extra, I get a passive radon vent. This can be upgraded if need be to an active system.
Thanks Matt (& the Build Show Team). Great info here. BIG QUESTIONS: 1. If we are building with a well sealed/taped 20mil vapor/water barrier under our basement slabs, will that effectively mitigate/eliminate the need for a sub-slab radon venting system? 2. Can we look at how this venting system might work with our well sealed, blower-door tested buildings?
@@chantelm9255 Some of the entry points, per US gov: cracks and crevices in the foundation and walls, and where pipes and wires enter (without sufficient seal around them). I would use a professional - - and verify their training level. They will be on top of new techniques and issues, but a homeowner likely won't have access to that info.
A barrier (sheet) under the foundation is NOT enough! Here is a good gov article: epa . gov, "Radon-Resistant Construction Basics and Techniques" Bits from the article: Gravel: Use a 4-inch layer of clean, coarse gravel below the “slab,” also called the foundation. Alternatives are allowed, such as a perforated pipe or a collection mat. See Building Radon Out (PDF) pages 35-40 for more information. Plastic Sheeting or Vapor Retarder: Place heavy duty plastic sheeting (6 mil. polyethylene) or a vapor retarder on top of the gravel to prevent the soil gases from entering the house. The sheeting also keeps the concrete from clogging the gravel layer when the slab is poured. A Vent Pipe: .....This pipe should be labeled "Radon System." Your plumber or a certified radon professional can do this. *For more information visit:* the National Radon Proficiency Program, or NRPP the National Radon Safety Board, or NRSB or your state radon coordinator for service providers in your area. Sealing and Caulking: Seal all openings, cracks, and crevices in the concrete foundation floor *(including the slab perimeter crack) and walls* with *polyurethane caulk* to prevent radon and other soil gases from entering the home. Junction Box: Install an electrical junction box (outlet) in the attic for use with a vent fan, should, after testing for radon, a more robust system be needed.
active & passive system may be able to help with polution, when I was a kid half of my small town had to be evacuated when a gas station fuel tank ruptured and the vapors were traveling through the ground water and coming up through the soil into peoples homes
Just installed an airthings radon detector in my basement. First reading was 9, seen it vary from that to 31 (!!!). I've got a professional test scheduled for monday...
@@ccvideotech ya it's been about a week now, readings are still crazy high. I honestly think it might be a faulty sensor, or at least I hope it is. My basement is pretty damn leaky (which I'm going to work on soon enough), I'd think that any heavy gasses wouldn't have a hard time flowing out. We'll see I guess
@@MrRenneck Yea, those numbers are high for sure. Could be the sensor I suppose. Have you contacted product support. I guess the expert you bring in can do their own test too to confirm. Good luck!
Is Radon mitigated by closed cell foam under slab and up interior walls? What about other basement/crawlspace/slab air and vapor solutions you've promoted? Do they block radon without separate mitigation infrastructure?
I was JUST asking if my friends who are home owners have ever tested for radon. Because we’re in CA, the answer was no. I’m going to order a test soon.
Venting the slab underneath the insulation also allows moisture to escape and should always be installed regardless of radon level if you have a basement. My neighbour lives 250 ft away and he needs a dehumidifier in the basement to keep the humidity level at a confortahbe 45% otherwise it goes up in the 80+%. I do not have any humidity problem nor do I need to dehumidify, my HVAC system keeps the humidity at 45% all year long. (air exchanger and humidifier).
Great content. Thanks for reminding us about radon. As an alternative can we set up ventilator/erv in basement’s that will run every 20mins? In this way we will always replace the air with fresh outside air
That is exactly what I would do. Attempting to extract the radon gases from below the slab, with out crushed rock and perforated pipes throughout the floor, but instead having compacted sand, will not eliminate all of the radon. A good ventilation system will eliminate the radon, plus it will remove toxins from the air that a radon mitigation system will not.
Good job, other contractors should benefit from this experience. I have made use of that long term Airthings device to detect changes over time, to correlate with other type of time specific event data.
The state of Maryland offers free tests. I just got mine and sent it off for testing. I got the results back in about three days. Interesting thing is that the level when I bought the house was 3 and now it's 1.7 with no mitigation. I did finish the basement with sheet rock and a rug, but at the time I didn't know I should seal off cracks. Someone mentioned that the construction materials could be a source of radon. I wonder if that's what happened in my case. Perhaps the radon dissipated and now it's lower. I plan to seal the sump pump area next.
I live in Maryland also and the state offers free tests for radon. Check it out. I just ran the test this past month and received my results about three days later. Interesting side note. The results were lower, by almost half than when I first moved into the brand new house. I have done no mitigation, other than to finish the basement with sheetrock and a rug flooring. I suspect the higher level might have been caused by the construction materials that were used to build it. I really don't know, but I'm glad the level went down. Sealing the sump pump area is next. Good luck.
I live West of Chicago. The rock here is all limestone, and now I know that means Radon. The house is a split level with a finished crawl space under the front half. After we had been here maybe 3 years we had the entire crawl interior concrete walls shot with closed cell foam 3" thick, since there was no insulation at all on the exterior walls of the crawl. We were in this house for 12 years or so before I bought one of the home tests and put it in the finished crawl space. Came back over 400. Ouch. I hired a mitigation company to come and do a test and they got roughly the same number. I had a system installed right away, and the install included patching a couple of cracks in the concrete floor of the crawl, and a sealed cover for the sump which never had water in it. The fan is outside the house and the vent runs up to just past the eave. This solved our problem and got the number down to below 2. So, everything I did to tighten up the house and reduce air infiltration made the problem a whole lot worse. I'm certain the open sump hole was the main contributor, since it rarely had any water in it. I have them come back and run a test every 2 years just to make sure there isn't a problem, since if we ever move that will certainly be an inspection item. I was the first one on my street to have a system now everyone has one.
I noticed in your presentation you said people in our area could still have high Radon numbers I watched a couple more presentations, I noticed a lot of the basements we're bare concrete, If you sealed walls and floors would it make any difference in radon levels, Davis Heat &Air Ada Okla. David Davis I really enjoy your show thanks in advance.
I rent a townhouse in Concord,Ca. A area where Radon is basically nothing. I bought a VOC/Radon air monitor for work. Brought it in my townhouse to update the firmware. The sensor detects RADON after letting it run. I have 12 pCi/l. Been here a few years and so upset. All places need to be check!
Buy an AirThings over the one-time use chemical tests. The reason is that while it is more expensive, if you have to remediate, you will need a bunch of tests anyway which will equate to the cost of the permanent, digital monitor. You also get the side benefit of the other things the device monitors (humidity, VOC, etc).
I tried to diy with levels just averaging 3, but got to 5 and 6 sometimes. I first just added it to sump pump and it raised levels. Needed to buy an airtight lid and learned it’s not about flushing radon out. It’s all about creating negative pressure. Needs to be airtight
Exactly! We tend to spend more time indoors in winter when air is more heated and airflow is more stagnant, which increases the risk of radon exposure. But now with the global pandemic, we spend even more time inside - so it has never been more important to ensure the indoor air quality is healthy and safe.
Matt, would a house built in 1962, with a crawl space dirt floor (two lengths of footing supports) be something to consider testing? I got the sense from your video it was focused mainly on full slab foundations. Thanks for keeping us safe and in the know!! Great subject matter.
You've got probably one of the safest houses in terms of radon gas by definition. Old houses leak like mad and you're off the ground. Tornado etc is a much, much more likely to do damage to you, and that's where you probably should put your money.
Thanks for this video Matt! I tested my basement after watching this video. Radon is hovering around 4pCi/L. I had no idea. It's an old house so this was not considered when it was built. I'm in the process of installing a radon fan right now. I'm hoping to get those levels way down.
Is there any way to test the ground for radon before a new build? Or should one just assume radon could occure in the future? Since radon is radioactive, perhaps we could turn it into energy? :D
That's a really great question. Radon is one of the decay products of Uranium, which is present in soil and rock all over the world. Most of these decay products are solid, so they stay in the soil, but Radon is a gas. Usually, it emerges from the soil in the outdoors and blows away in the wind, so it's not a problem. But random pathways in the soil can bring the gas up beneath your home, and then entry points like cracks in your foundation and drains can allow it to enter the home. Lower air pressure inside your home compared to the air pressure below the foundation can also increase the likelihood of Radon entry. Once inside your home, it can become concentrated instead of blowing off into the atmosphere. TLDR; Measuring the soil won't tell you how your house will interact with soil conditions once it is built. You simply have to test your home to know for sure, and levels can change over time.
@@bethriddick36 Thank you Beth. Intuitively I would not think a positive air pressure would be enough but it logically would help. Now I have to read up on how to install these in a new build. Thanks again!
2 question. 1). Planning to shop for a new home in NJ in the spring. Is this something I can work into the purchase where the buyer performs a radon test and is this something I can sue the seller for the cost to hire a professional for not disclosing this to me during the sale after we close on the property if they provided false reads? 2). If the basement has the height, rather than chopping the concrete can the pvc piping be be place under a subfloor comprised of sleeper studs, subfloor decking with full perimeter continuous sealant onto the sleepers, and a finish floor if the subfloor is fully sealed with a continuous membrane that goes up the perimeter wall framing and another membrane on top of the concrete slab that runs continuous and up the foundation wall? This way the piping is in betweeen 2 sealed surfaces. One concern that comes to mind is creating a vapor barrier on the perimeter walls which can cause mold in regions that don’t require vapor barriers which I saw on one of your episodes.
It is very common in VA where I do radon testing to include a radon contingency clause in the purchase contract; in that case, the radon test is part of the home inspection. If the level is found to be high, mitigation can be done at seller's expense. Your realtor will know about laws in NJ and whether or not you can put that in a contract. If you have this done as part of the home inspection, expect it to cost more than a home test. It should be done by someone with certification to do the measurement.
There is more to the radon story. Around 1993 I took an original course in radon taught by the developers of the original study for the EPA. According to them. Statistically it is not nearly as problematic for nonsmokers as it is for smokers. The 4.0 number was reportedly a compromise between HUD and the EPA. Radon is in outside air which we breath every day. The original university study recommended taking smokers out of the population study for a more accurate representation of risk without inflating the numbers... the EPA said to leave them in to show higher risk... this is what we ended up with.
That's consistent w what I heard a few years back. I'd like to see more studies, and data on the risks. I just read that radon contributes to 13% lung cancer deaths annually for non smokers.
literally every pollutant limit in air and water established by the epa (federal and/or state) are compromises between the cost to remediate and minimizing risk to individuals at extremely low levels of said pollutant. in my experience, it is often ideal to reduce well past the epa limit to the extent possible/affordable.
I just found out my level is 13.3 + 2%. I tested the level over a period of one year. How quickly must I move to correct this problem? We have lived here for 4 yrs. My three adult children sleep on the lower floor of our home. Must I take everything out of my cellar to work on the issue? Approx. how much does it cost to fix the problem?
Hi Matt, been watching your show forever on RUclips. We have a house built in 2006. We purchased the house in 2011 and found an elevated radon level (between 14 & 25) . It's been tested a number of times and we currently have the same digital testing device you showed in your video. We have a working Radon system and fan but it certainly isn't helping. We've had several companies come out and look with no results. Any advice??? Maybe it would be a good video, trying to help figure this out!!! 🙂
Is radon only an issue in houses with bonafide basements? Or, can it be an issue in a house with only a crawlspace too? If it can be an issue in a house with just a crawlspace do you need to check both the crawlspace and the living area above for radon? If you only have elevated radon levels in the crawlspace, is that an issue? Since you're not going to spend much time in the crawlspace, would any likely exposure time in the crawlspace be sufficient to justify the cost of mitigation?
Elevated levels of radon can be found in buildings with every foundation type. The protocol is to test the lowest livable level of the home, not the crawlspace.
Isn't there another way during construction outside of laying tubing to prevent radon seepage...I thought there might be a blanket of plastic or something laid on the ground before pouring the cement..any comments?
That's a good question. I'm also interested in whether you can determine potential radon levels at a specific site prior to any construction. Having gone through some soil science classes, this was never something that was brought up; we mainly talked about how to mitigate radon in existing structures.
Here in Canada, its become code to install a poly sheet material similar to vapor barrier under the concrete slab of all new home builds and also 'rough in' a plastic vent pipe for a future radon extraction fan.
At least in CT, laying poly plastic sheeting before a concrete floor pour is code to help deflect radon, but I don't see how that's very effective & it's hard to enforce since the guys doing the concrete work usually want to remove it because it adds hours onto the finishing job since the water in the concrete can't soak into the ground, only slowly evaporate from the top.
@@dew-drop There are soil tests that can give you the radon level in the soil before construction, but the correlation between these levels and what the levels may be in the completed building are difficult to surmise.
When we sold our last home, we got dinged at the "take action" level on the radon inspection and had to install one of these fans. That fixed the problem. Unfortunately, I worked out of our basement for 10 years with these elevated levels and never knew about it. No lung cancer yet!
How can a perfect wall , roof or floor be built on a off grid weekend cabin on sonotubes in the northeast where the only source of heat is a woodstove ? You created a very helpful channel , thank you.
Hey Matt, have you ever heard of a chemical product called RadonShield? It is sprayed onto the concrete and is supposed to soak into it a couple inches reacting with the free alkalides or some such in the concrete,. The idea is that it turns the top couple inches of the concrete non porous, thus blocking radon gas from passing through. Aa a side benefit, it should also block moisture from coming up through the concrete as well. I would be very interested to hear your thoughts on this.
In the UK, I used tanking slurry to waterproof under the house. It's not a basement, just the gap between foundations and floor so I was doing it to block moisture and make it nicer to crawl around. Sounds very similar to your branded product, I wonder if they are actually the same thing and that's being sold at a premium?
Sealing alone usually doesn't reduce the radon significantly. It does however increase the effectiveness of a passive or active system already in place.
Just received a notice in the mail to do a test. I assume it came from the government although it doesn’t actually say. Wasn’t going to bother but after watching this video I’m seriously reconsidering. I live in Canada by the way.
@@lovema21 I remember getting one about 10 years ago or so. Wasn’t too worried about it then. Haven’t gotten another one till now. Not sure if it’s sent to every homeowner every year. They may only send to certain areas on a rotating schedule.
Actually, no, you never test in a crawl space. It should be placed in the lowest livable space. This includes any space that could be finished in the future as well. Hope that helps!
If you have a crawl space under your entire house I wouldn't even worry about this issue. It's only becomes a problem if you're in a modern house with very airtight sealing on a slab or with a basement.
@@rcmrcm3370 Houses with all types of foundations can have elevated radon, airtight or not. As far as testing in the crawlspace, Robert is right. Test in the lowest livable area, or any area that could be a livable space in the future in the case of real estate transactions.
Love it but we no longer vent a radon system through a roof it now has to run through the outside of the home. They make it look like an upside down downspout
People in some areas of Ramsar, a city in northern Iran, receive an annual radiation absorbed dose from background radiation that is up to 260 mSv y(-1), substantially higher than the 20 mSv y(-1) that is permitted for radiation workers. yet they are fine Visitors enter Montana mines filled with radon as a therapy for their ills
Ok, so I’m a homebuilder who finds value in practical solutions. I even have a radon mitigation system in my own home. However, the home we currently live in is a 100yr+ old family farm house that my grandparents, dad, aunts/uncles all grew up in. I got curious and had it tested. It was off the charts. Higher than any other home I have built in the last 20 years. Anecdotally my grandparents lived into their late 90’s. My aunts and uncles are all in their late 80’s now. Not one of them has had any health issues related to radon. Many of them had bedrooms in the basement. I kind of feel like it has been hyped up to be something that it is not. Almost something hyped up by real estate agents to be used as a bargaining chip during price negotiations. I have also had issues with homes in clay soils with a radon mitigation system drawing water under the basement slabs. Because they create an area of low pressure and clay soil holds a lot of moisture, it draws that moisture to under the slab area. It has caused heaving in some soil conditions and caused massive cracking in basement slabs. Soil engineers in the area say that if a sub slab system is to be installed, they want an additional 2-3 feet of over excavation under basement slabs and 3/4 gravel installed to replace it. Quite a process. Just my thoughts.
Not everyone who smokes gets lung cancer. Not everyone who drives will die in a car accident. With rare events like this don't go by your feelings but by the numbers.
What can we do if we have an empty lot that we plan to build on? Is there any kind of testing to determine any levels of radon before the concrete is poured?
nothing. as matt indicated the concentration is a factor of the type of foundation system you have (slab, crawlspace, basement, etc.). So install the passive system (pvc pipe is cheap and easy to put in before concrete is cast), once constructed run the test, and if the test is elevated, convert the passive system to an active system with a radon fan
I've had an Airthings meter in my older Virginia house for about a year now. Nobody mentioned radon when I moved in almost 10 years ago. I was averaging around 4-6 pCi/L initially, which dropped to 2-4 after I opened the crawl space vents. I almost bought a home test kit, but settled on the meter since it was a one-time cost that let's me re-measure different rooms, during different seasons, and after various mitigation steps like opening windows and sealing gaps.
Radon fans should NOT be in the basement, when passive systems are installed around here there is an outlet installed near the pipe in the ATTIC where potentially needed fan can be plugged in. Thus the suction pipe never has POSITIVE pressure while passing through a livable space. With a retrofit system, this is why the fan is always located OUTSIDE. As a Home Inspector in Ohio, I'm asked to test about 2/3 of the properties I inspect. I commonly see 10-20 pCi/l readings, my highest was 254.2 pCi/l. Big HEAD'S UP: I also test houses with operating mitigation systems, of those I tested last year, 40% were above 4.0 pCi/l WITH AN OPERATING SYSTEM! Maintenance and repairs can't be neglected.
Same, all pipework inside the house should be negative pressure. If you have a split in that pipe on it's way to the roof your pumping the radon from the soil into your 2nd floor or attic.
Yup, fan should be installed outside of the living area so there is never a chance of radon being pumped into the house. Attic is a good spot as long as it is properly ventilated itself. Retrofit radon systems generally pop through the basement wall as quickly as possible (near grade) and the fan is installed outside. This is the best place for the fan, completely outside the house envelope.
@@ultimate1576 Radon is heavier than air though right? So a leak in the attic would be... an issue?
@@Critters As long as the attic is properly ventilated and is outside of the living envelope (not a conditioned space) then a small leak should not be an issue. Radon is heavier than air but even a little bit of airflow will dissipate it quickly and not allow it to accumulate. If the attic isn't ventilated properly it could definitely be an issue. This of course is only referring to if there is a crack or leak in the pressure side of the piping, after the fan. A normally operating radon system will have no leaks.
Exactly, you cannot believe all the mis-information there is out there. I had a home inspection today and I asked the inspector about an alarm on the system and he said no. I asked how would you know it isnt working. His response was you can hear the fan running when you get near it. How's That??. EPA says an obvious alarm must be installed A second question was about the stack being uncapped, I read the pipe should be like a candy cane with a sort of screen cap on it, so water and snow wont go in, birds. etc His response was oh its blows quite alot of air nothing could go in. I' m floored by his responses.
I saw this episode last year and got the Air Things View Plus. My Radon levels on my build house were over 20. So glad I checked! Thanks, Matt!
My mother, stepfather, and brother all died from various forms of cancer within a 10 year period and I believe Radon had a lot to do with it. Mother had storm windows added many years earlier and the house was virtually never opened up. Combined with a full basement in a sloped hillside and an incredible humidity problem in the basement requiring a permanent always-on dehumidifier we should have known. My brother socialized with them a lot so he spent a lot of time over there. After mother died he discovered he had cancer so took time off of work and filled his days repairing and updating her house. I was out of state so it didn't affect me. When he went to sell the house a buyer was required to do a radon test and POW! "Really bad" was how he described it to me. A passive system was installed in the basement under the slab. Retest showed little improvement. A second trench was dug and an outside fan added and now the tests passed. We didn't talk about it much because he knew as well as I that despite the different cancers they probably all got it the same way. He died just a couple of years later.
If it's a rocky area, if you have any ground penetration beyond normal surface footings, if you have a ground related humidity problem inside - GET TESTED!
The ONLY cancer proven to be related to radon is lung cancer. So the “different” cancers were simply not caused by it.
Moved several times in the last 6 years, my realtor made sure we knew about Radon danger and mitigation systems, as well as testing after installation. Hats off to knowledgeable people.
Radon is a scam. They couldn't possibly know that Radon is the number 1 cause of lung cancer next to smoking. The person who died of lung cancer may not have admitted to smoking, or perhaps they breathed in enough cat dander to finally cause their lungs to give in. Who knows? Hospitals don't routinely go about testing the homes of their lung cancer victims for Radon, if ever! Indigenous people have lived with radon in their wigwams for millennia and there's no history of lung cancer until the advent of industrial technology. People need to stop driving this mass hysteria.
Back in January of 2019, I came across a similar discussion to this. I bought a monitor and discovered that my basement office was measuring 12 picocuries/liter. My house is basically prehistoric. Rubble stone foundation with lime grout. The slab could only loosely be called a monolithic slab. I was fortunate to have an abandoned coal bin under the slab as it was. A good volume of air to draw from. I opted to install my fan in the cellar (common practice in Canada). I had read plenty of stories of frozen/frosted vents in winter (worse time of year for radon due to stack effect). And non-working, outta-site, outta-mind attic fans. Logistically, getting the pipe through the sill or foundation would have been tough. I did have an abandoned chimney though. My installation is simple, 18” of 4” pvc from the slab to the fan, 18” more to the chimney. In the chimney I used triple wall for the vent. I can easily monitor its function and the fan should last forever out of the elements. If I ever have to sell the place, I can relocate the fan to the top of the chimney where it’s legal but not practical to monitor. Since the chimney is surrounded by a warm house, theres natural convection that would help draft anything that may leak… at the end of the day, I achieved a three year average of 1.1 picocuries/liter down from 12.
Excellent work. Excellent solution. Excellent thinking.
Another benefit I saw with an active radon system in my house was lower moisture levels in the basement. It draws air through and out the drain tile in the basement. Keeps my humidity levels below 50 all year round. Don't need a dehumidifier anymore.
When we bought our Indianapolis 1913 home a few years ago it did not have a radon system in it. Last summer we grabbed one of the Airthings sensors you show in the video and saw it read about 12-14. OMG. Sealing off our crawlspaces, sealing basement walls, and installing the active system dropped us to 1-3 regularly. We're very happy with the results and feel a lot better about the home and our health. We definitely do have levels about 0.5-1 in the summers and upwards 2-3 in the winter.
I realize Texas is considered a "low risk area", but ever since that event, have you considered installing, or at least offering, a passive radon system as a standard part of the "package", whether slab on grade or crawlspace?
When doing home inspections I'm my area Radon is always a hot topic. People are worried more about radon and radon in well water than anything elce.4 Picl is the recommend limit for radon in most areas but does vary. Basements and other factors make a huge diffence.
Great Video. I bought a meter to actively measure the Radon in my basement. It hovered around 4 most of the time, but an adjacent space was as high as 9. I put in my own system to remove it and got it down to 0.5-1.0. DIY is a great option if you're willing to learn the basics to ensure your system is built properly and delivering the results needed.
Valuable education video and communication tool to raise public awareness and save lives. A “big” thanks to you, Matt, and your team for making this video possible - priceless!
Have 2 airthings in my house.
And here (Norway) is considered a low radon area BUT my readings is often 3 times the limit in my basement.
The living spaces is mostly under but sometimes over
We're in a zone in central WA that is not known to have Radon issues. Tested in June last year and we had 30+ pCi/l in areas of the building. Testing this winter levels rose to 80+ pCi/l. Going to be a big system to mitigate 40k sqft building.
I have a airthings monitor for 5 years in my house and im very happy. I also installed a fan to depressurised my underslab
So glad homeowners can purchase those fans and guages. Saved $2,000 installing 3in PVC myself.
Me too! About to install one in a house I just bought, levels at 4.8
In modern homes, as long as you hit a gravel base or porous substrate under the slab it's a straightforward setup with a basic fan. Can be homeowner friendly if they follow the EPA guidelines.
In older homes with poor dense substrate or multiple slabs/crawlspaces It certainly gets challenging quickly.
Great video! I’m a home inspector in CT and I use the Airthings Corentium Pro devices for testing and they are awesome.
Wow. I wonder how your customers would feel that you charged them more to do one test than they would have paid if they bought the device themselves. I would be royally pissed if I paid for a professional Radon test to be given a less accurate residential test. I bought my AirThings Radon Detector new on ebay for $44. My last Radon test I paid for wad $160.
@@realtyrocks1969 lol. You don’t have anything better to do than troll 8 month old comments on RUclips 😆😆
The professional Corentium Pro devices are $1399 btw
@@jonnykromps9836 If you're still scamming customers for the last 8 months it's still valid.
@@jonnykromps9836 and no they aren't. Amazon has them for $950. And home depot is about $1000
@@realtyrocks1969 that’s retail. I paid $800/ea buying them in bulk.
I thought you said they were $40 😂
Move along bro
Just ordered the Airthings meter. I can also test my shop and family members' houses, too with it. The test kit is a pain and a one time deal.
In central WI, new house construction with basement that had sump pump pit drainage installed. I bought both the Airthings devices (View Plus and Wave Plus). Found levels at around 5.0+. I installed a sealed sump pit cover to put a pipe in to vent out. Installed the Aprilaire fan to vent out. Now with the fan running all the time, the levels are at 0.5. I have the fan plugged into a smart plug. The smart plug can tie into the Airthings app, so I could program it to power the fan off when levels are low and turn on when it hits a higher level.
Hi Matt, I live in the UK and I have never heard of this problem, as far as I know Radon is not a problem. I have seen pipes at dumpsites and they are often lit at the top but that is for another gas that can accumulate and cause an explosion that is caused by the build-up of rotting material. I have just done a search and found a map of the UK and from the info; my area is considered a very low area with less than one percent of radon gas per KM. this map and information comes from the government so I have sent off for one of the tests to find out for myself. If I find out that, I am not, in this low area, I will be taking action to correct this and I will also be letting my neighbours know as well
I put a passive system in and tested it 25 years later. Found in the basement the level was average of 3.7 Then after installing a fan in the radon exhaust pipe it dropped to an average .9 long term. The levels dropped about 1 for each floor level above ground. Good advice on this video.
I really do like your show and sometimes mock your intro Matt, not out of jealousy, but from envy. Show I do want to thank you for the taking some time to bringing this issue to light.
Thanks for the video! After watching this I got the SafetySiren electronic detector and got a reading of 8 pCi/L. I will confirm with test kits but I expect that I will have to install a sub slab system. I tested for radon before I bought my house but this was in the summer and I took Matt’s advice to test in January. I think the energy efficiency measures done to my house would have increased radon levels. In addition to air sealing, I changed from using a natural gas powered boiler and hot water heater that used basement air for combustion to a high efficiency combi boiler that gets combustion air from outside.
3:35 I just learned that the "hockey puck" was actually a piece of cr-39 bullet proof plastic. The alpha and beta particles would actually make tiny little holes that are then analyzed under a microscope. 🤯
We put in an active system in when we built in 2020 and still had a reading around 8-9. So once I sealed the sump pit and all of the expansion cracks, it dropped to around 2. You should do this before you finish your basement.
Thanks, I like that idea. I've read that some of these radon systems don't work as well as some claim.
Ha, once again another video where I learn about something I had no idea. I live in Tasmania, Australia and Radon levels in Australia are considered low. However I have never come across Radon as a thing in all my time as a builder. Very interesting.
Oh wow, I was just researching this yesterday. Great timing on this vid man 😆
is it good idea to get a builder to spray insulation on the basement floor before pouring a concrete slab on top? for added insulation? or a waste of money?
Matt has a lot of videos on this. Insulating under the slab is commonly done for net zero or passive houses that seek to greatly reduce their energy losses. Most builders will use pre-manufactured EPS foam boards for this purpose. At least you will know what thickness and material quality you are getting with EPS, versus a foam sprayed in the field and quickly covered up.
@@MorryB Slab should have a 6 mil polyethylene vapor barrier over 4" of gravel by code.
I have the airwave plus. I think it's worth the extra money. I think it's interesting the CO2 goes into yellow when I'm doing cardio.
Hey Matt! Just wondering, can you just put in a vapor barrier tarp under a new build foundation? Why not? Would it not stop all radon and vapor from entering house?
I believe a barrier is commonly put under basement slabs and have been for a while now in most new construction. Unfortunately there are still some penetrations for plumbing fixtures, the edge of the slab may not be perfectly sealed, and it's always possible cracks will occur and damage or degradation of the barrier can allow radon to seep through. My house was built in 74 and their idea of radon mitigation was "what's that" so I decided to get a system put in and bought a case of caulk to seal up the edges of the slab and every crack I could find in the unfinished portions of the floor. The suction from the radon mitigation system can travel also, I took a 1/4" tube and used it as a stethoscope and found suction leaks all over the place, including some on the garden level foundation a ways away from the system slab penetration point.
@@hrlsswndr3938 That makes sense. If there is any radon present, then there are 2 types of radon foundations. Those that leak radon. That's that are going to leak radon . 😂
I think bout this all the time.. thanks for sharing? I haven't seen that most recent device they sell, very cool. Thanks for sharing!
Mitigating radon gas in homes is a very controversial subject. The
level determined to require mitigating was derived by the EPA using a no threshold linear model. Many scientists do not agree with the EPA’s model. Mitigation is a large industry so tail may be wagging the dog. Radon at very high levels, like can be found in some mines, is certainly dangerous.
ruclips.net/video/TYZglUjLE0Y/видео.html
His videos on the subject are very enlightening. I work on x-ray devices and radiation is all about dose. The way we measure Radon in homes is in no way an indicator of potential dose. We just closed on a house and had the owner install a mitigating system before we closed. After we had it installed I found his videos and felt like even though we didn’t pay for the mitigation system, maybe we shouldn’t have had one installed.
More likely that radon actually protects the lungs. It stimulates DNA repair and leads to a person being healthier. There is plenty of evidence to support this. But, we certainly cannot follow the real science when it does not support the narrative and profits.
Lisa, always encouraging to find another independent thinker that doesn’t just follow the narrative.
I'm a nuclear engineer by training.
Funny thing, Radon was the most annoying for us at the plant I worked at. It is highly charged so it would stick to your clothes and hair as you walked around the plant. Made it difficult to detect when you were contaminated with the important stuff. Low pressure days were the worst. As it would easily come out of the granite the plant was built on.
Which makes we think if you are venting your house to get rid of this bogeyman, then you are creating a low pressure atmosphere which would draw it out of the ground even more.
It's all a ridiculous scam.
@@LisaKnobel
My good friends son died from lung cancer. The claim was that he got cancer from radon gas because he lived in a basement for 15 years.
I bought the wave a couple days ago. Moved into this basement house in New York four years ago and in April. I had very nice radon readings with the two vile test from Pro Lab. I ran it again this year in February and I had one reading in the twos and one in the eighth so that concerned me.
Hi from Australia. Didn’t know this was something to be concerned about… then I Googled what the levels were in my area, proceeded to freak out as the levels charted for my area were 9!!! But different unit of measurement. We seem to measure in Bq/m3 where 1 pCi/L is equal to 37 Bq/m3, so we’re doin fine over here. Good luck guys.
I was in the same position just last week, I’m selling my home and the new buyers did a radon inspection and they found elevated levels. My home was built with a passive system into the sump pit so it wasn’t very costly to have it retrofitted but I should have had it inspected more often while I owned the home.
Had house professionally tested. 48 hr average came back to 91.5! Will be getting system installed. I assume 91 is horribly bad?
I have an Airthing monitor running in my home here in Canada since late November. So far, the average reading is just above 100Bq/m3 with some individual spikes as much as 170bq/m3. Canada's guidelines are for a maximum of 200Bq/m3 (5.4pCi/L) , whereas in Europe its only 100 Bq/m3(2.7pCi/L). This is in the middle of our winter heating season I'll probably check the average up until June or July before deciding if I should take any further action.
Canada is lacking with just having "guidance levels"
IMO 200 Bg/m3 seems high. I'm in BC and we tested 59 Bq/m3 in 2018. But that was a 90 day test, I'm interested in getting an Airthing monitor to see the R/T long term stats. Like that the new monitors have all the sensors - though the $350+ price is kind of a shocker
@@BryceCampbell how airtight is your home? If it's extremely airtight or you live in the basement most of the day, then you've got something to start to worry about.
2nd case, then take that money for the sensor and spend it instead on an HRV or Erv. Nothing fancy, just have it hooked up to your central air. Even a modicum of make-up air will completely suppress.
Same monitor here; huge spike this summer at 170 now at average 60
Bought an Air Things Wave Plus. Found my levels going up to 2.5 in the winter. Installed a radon system, dropped to 1.1 in winter. Spray foamed the entire basement foundation, it dropped down to 0.1-0.3.
The Air Things will tell me within 24 hours if my fan stops running as well.
I got one of those Air Things plus devices. I got it back in July and all of a sudden the radon spiked in my house despite having an active mitigation system. After having an average rating above 6 I called the installer and they came out and checked it out. Looks like the drains to the system in the basement weren't properly sealed and so far things are looking much better.
I suspect it was pushing all the air under the foundation into the basement because the grills to the system were exposed.
A long term testing device is great for that just in case the system starts acting weird you have a way to know immediately.
Great Stuff - the map and other info was very useful. Testing now.
I installed a fan for my radon system in the attic of my garage. The builders had an electrical box already in place but never installed a fan. My levels went from 2-4 down to .3-.5 in the winter and .2 avg in the summer.
1. Would An ERV reduce the radon?
2. Would poly sheet under slab reduce the radon?
In my experience, ERV's/HRV's reduce the radon levels but the efficiency varies greatly. When a soil depressurization system like Matt mentioned is not suitable we usually design them specifically for basements and our rule of thumb is up to a 50% reduction when targeting the radon at its source. A whole-home system may not be as effective unless you can change pressures between the basement/first floor and prevent the radon from rising.
The poly sheet and sealants on the market you may see increase the efficiency of a passive or active ASD system. The radon needs a new path to exit and usually cannot be blocked alone.
Poly under slab is code where I live for new construction. As is passive radon.
A neighbor cleared a lot behind mine of huge pine trees, and left the stumps in the ground, and built a home on it. Ten years later after the occupants had all kinds of weird sicknesses and cancer they tore it down completely and dug the contaminated ground up and rebuilt a new home on that. They added Radon fans to the first home but it wasnt enough to make it safe.
Thanks Matt for the video
I don't live in a high risk area of Michigan , but that probably has been to my putting it off . Good time to have this reminder when it's 15° in Michigan to know what is actually going on from our below grade basement.
Thanks
I use a Certainteed product called
form-a-drain. Automatically for a few hundred dollars extra, I get a passive radon vent. This can be upgraded if need be to an active system.
Thanks Matt (& the Build Show Team). Great info here.
BIG QUESTIONS:
1. If we are building with a well sealed/taped 20mil vapor/water barrier under our basement slabs, will that effectively mitigate/eliminate the need for a sub-slab radon venting system?
2. Can we look at how this venting system might work with our well sealed, blower-door tested buildings?
I'm interested to know these too. A related question: What's the usual entry point of radon into a house?
@@chantelm9255 Some of the entry points, per US gov: cracks and crevices in the foundation and walls, and where pipes and wires enter (without sufficient seal around them). I would use a professional - - and verify their training level. They will be on top of new techniques and issues, but a homeowner likely won't have access to that info.
A barrier (sheet) under the foundation is NOT enough! Here is a good gov article: epa . gov, "Radon-Resistant Construction Basics and Techniques" Bits from the article:
Gravel: Use a 4-inch layer of clean, coarse gravel below the “slab,” also called the foundation. Alternatives are allowed, such as a perforated pipe or a collection mat.
See Building Radon Out (PDF) pages 35-40 for more information.
Plastic Sheeting or Vapor Retarder: Place heavy duty plastic sheeting (6 mil. polyethylene) or a vapor retarder on top of the gravel to prevent the soil gases from entering the house. The sheeting also keeps the concrete from clogging the gravel layer when the slab is poured.
A Vent Pipe: .....This pipe should be labeled "Radon System." Your plumber or a certified radon professional can do this.
*For more information visit:*
the National Radon Proficiency Program, or NRPP
the National Radon Safety Board, or NRSB
or your state radon coordinator for service providers in your area.
Sealing and Caulking: Seal all openings, cracks, and crevices in the concrete foundation floor *(including the slab perimeter crack) and walls* with *polyurethane caulk* to prevent radon and other soil gases from entering the home.
Junction Box: Install an electrical junction box (outlet) in the attic for use with a vent fan, should, after testing for radon, a more robust system be needed.
active & passive system may be able to help with polution, when I was a kid half of my small town had to be evacuated when a gas station fuel tank ruptured and the vapors were traveling through the ground water and coming up through the soil into peoples homes
Just installed an airthings radon detector in my basement. First reading was 9, seen it vary from that to 31 (!!!). I've got a professional test scheduled for monday...
Wasting money
@@mikemaloney1289 can you explain why?
You said that you "just installed it". Did you give the meter a week or so to normalize as per the instructions?
@@ccvideotech ya it's been about a week now, readings are still crazy high. I honestly think it might be a faulty sensor, or at least I hope it is. My basement is pretty damn leaky (which I'm going to work on soon enough), I'd think that any heavy gasses wouldn't have a hard time flowing out. We'll see I guess
@@MrRenneck Yea, those numbers are high for sure. Could be the sensor I suppose. Have you contacted product support. I guess the expert you bring in can do their own test too to confirm. Good luck!
Is Radon mitigated by closed cell foam under slab and up interior walls? What about other basement/crawlspace/slab air and vapor solutions you've promoted? Do they block radon without separate mitigation infrastructure?
thank you for the info I forgot about this, I'm getting a test done.
Thank you I never knew about this and I just moved to a high risk area
I was JUST asking if my friends who are home owners have ever tested for radon. Because we’re in CA, the answer was no. I’m going to order a test soon.
Here in NYC the public buildings, public schools, community centers etc are all built with SSDS, sub slab depressurization systems.
Would a vapor barrier installed beneath the basement slab be an effective alternative to a passive radon system? Doing a basement in North Texas.
Most foundations have a 6 mil polyethylene vapor barrier over 4" of gravel below the slab.
Venting the slab underneath the insulation also allows moisture to escape and should always be installed regardless of radon level if you have a basement. My neighbour lives 250 ft away and he needs a dehumidifier in the basement to keep the humidity level at a confortahbe 45% otherwise it goes up in the 80+%. I do not have any humidity problem nor do I need to dehumidify, my HVAC system keeps the humidity at 45% all year long. (air exchanger and humidifier).
Great content. Thanks for reminding us about radon. As an alternative can we set up ventilator/erv in basement’s that will run every 20mins? In this way we will always replace the air with fresh outside air
That is exactly what I would do. Attempting to extract the radon gases from below the slab, with out crushed rock and perforated pipes throughout the floor, but instead having compacted sand, will not eliminate all of the radon. A good ventilation system will eliminate the radon, plus it will remove toxins from the air that a radon mitigation system will not.
@@starspa1 : can’t agree more. Also I see cracks in the basement concrete floor that will defeat the purpose of the entire pipe and roof Fan setup
Good job, other contractors should benefit from this experience.
I have made use of that long term Airthings device to detect changes over time, to correlate with other type of time specific event data.
The state of Maryland offers free tests. I just got mine and sent it off for testing. I got the results back in about three days. Interesting thing is that the level when I bought the house was 3 and now it's 1.7 with no mitigation. I did finish the basement with sheet rock and a rug, but at the time I didn't know I should seal off cracks. Someone mentioned that the construction materials could be a source of radon. I wonder if that's what happened in my case. Perhaps the radon dissipated and now it's lower. I plan to seal the sump pump area next.
How would you test radon on a new build site? Before or after breaking ground?
How would you mitigate if you had an encapsulated crawlspace with no slab? That is, just a dirt floor with vapor barrier.
Create a vacuum under the vapor barrier. Exhaust out of the structure.
Thanks I’ll now do this test. I live in Maryland and my house was built in 1998.
I live in Maryland also and the state offers free tests for radon. Check it out. I just ran the test this past month and received my results about three days later. Interesting side note. The results were lower, by almost half than when I first moved into the brand new house. I have done no mitigation, other than to finish the basement with sheetrock and a rug flooring. I suspect the higher level might have been caused by the construction materials that were used to build it. I really don't know, but I'm glad the level went down. Sealing the sump pump area is next. Good luck.
I live West of Chicago. The rock here is all limestone, and now I know that means Radon. The house is a split level with a finished crawl space under the front half. After we had been here maybe 3 years we had the entire crawl interior concrete walls shot with closed cell foam 3" thick, since there was no insulation at all on the exterior walls of the crawl. We were in this house for 12 years or so before I bought one of the home tests and put it in the finished crawl space. Came back over 400. Ouch. I hired a mitigation company to come and do a test and they got roughly the same number. I had a system installed right away, and the install included patching a couple of cracks in the concrete floor of the crawl, and a sealed cover for the sump which never had water in it. The fan is outside the house and the vent runs up to just past the eave. This solved our problem and got the number down to below 2. So, everything I did to tighten up the house and reduce air infiltration made the problem a whole lot worse. I'm certain the open sump hole was the main contributor, since it rarely had any water in it. I have them come back and run a test every 2 years just to make sure there isn't a problem, since if we ever move that will certainly be an inspection item. I was the first one on my street to have a system now everyone has one.
Here in Phoenix, never heard of a radon system
We also very really do basements too. Extreme hard ground and think granite mountains.
Yes!! Here in PA, it's always high. Get a system put in.
I noticed in your presentation you said people in our area could still have high Radon numbers I watched a couple more presentations, I noticed a lot of the basements we're bare concrete, If you sealed walls and floors would it make any difference in radon levels, Davis Heat &Air Ada Okla. David Davis I really enjoy your show thanks in advance.
I rent a townhouse in Concord,Ca. A area where Radon is basically nothing. I bought a VOC/Radon air monitor for work. Brought it in my townhouse to update the firmware. The sensor detects RADON after letting it run. I have 12 pCi/l. Been here a few years and so upset. All places need to be check!
Buy an AirThings over the one-time use chemical tests. The reason is that while it is more expensive, if you have to remediate, you will need a bunch of tests anyway which will equate to the cost of the permanent, digital monitor. You also get the side benefit of the other things the device monitors (humidity, VOC, etc).
I tried to diy with levels just averaging 3, but got to 5 and 6 sometimes. I first just added it to sump pump and it raised levels. Needed to buy an airtight lid and learned it’s not about flushing radon out. It’s all about creating negative pressure. Needs to be airtight
Considering that we are at home a lot more now because of COVID - this is a good time to test.
Exactly! We tend to spend more time indoors in winter when air is more heated and airflow is more stagnant, which increases the risk of radon exposure. But now with the global pandemic, we spend even more time inside - so it has never been more important to ensure the indoor air quality is healthy and safe.
I am in MA. Tested without the fan, 1.9 short term, then tested with fan running short term below 1.1 and long term 0.4
Matt, would a house built in 1962, with a crawl space dirt floor (two lengths of footing supports) be something to consider testing? I got the sense from your video it was focused mainly on full slab foundations. Thanks for keeping us safe and in the know!! Great subject matter.
You've got probably one of the safest houses in terms of radon gas by definition. Old houses leak like mad and you're off the ground. Tornado etc is a much, much more likely to do damage to you, and that's where you probably should put your money.
You should certainly test, the type of foundation does not matter.
@@theradonpros testing is cheap insurance and peace of mind!
In Pa I have found elevated readings in a Trailer home as well as slab on grade.
Elevated radon levels are found in all sorts of buildings, regardless of age and foundation type.
July would be a much better time to test. I currently have my windows open because it's so nice here in Florida.
I knew it! I saw that map and looked up how many basements are in Texas! Too coincidental! Same might even be true in Florida!
Thanks for this video Matt! I tested my basement after watching this video. Radon is hovering around 4pCi/L. I had no idea. It's an old house so this was not considered when it was built. I'm in the process of installing a radon fan right now. I'm hoping to get those levels way down.
Matt at his best.
In Denmark we put plastic under the concrete that keeps the radon out of the building.
Is there any way to test the ground for radon before a new build? Or should one just assume radon could occure in the future? Since radon is radioactive, perhaps we could turn it into energy? :D
That's a really great question. Radon is one of the decay products of Uranium, which is present in soil and rock all over the world. Most of these decay products are solid, so they stay in the soil, but Radon is a gas. Usually, it emerges from the soil in the outdoors and blows away in the wind, so it's not a problem. But random pathways in the soil can bring the gas up beneath your home, and then entry points like cracks in your foundation and drains can allow it to enter the home. Lower air pressure inside your home compared to the air pressure below the foundation can also increase the likelihood of Radon entry. Once inside your home, it can become concentrated instead of blowing off into the atmosphere.
TLDR; Measuring the soil won't tell you how your house will interact with soil conditions once it is built. You simply have to test your home to know for sure, and levels can change over time.
@@bethriddick36 Thank you Beth. Intuitively I would not think a positive air pressure would be enough but it logically would help. Now I have to read up on how to install these in a new build. Thanks again!
My house was reading 14 , put it a dehumidifier and a few days later it was down to 2.4
Toby you’re the silent killer.
2 question. 1). Planning to shop for a new home in NJ in the spring. Is this something I can work into the purchase where the buyer performs a radon test and is this something I can sue the seller for the cost to hire a professional for not disclosing this to me during the sale after we close on the property if they provided false reads? 2). If the basement has the height, rather than chopping the concrete can the pvc piping be be place under a subfloor comprised of sleeper studs, subfloor decking with full perimeter continuous sealant onto the sleepers, and a finish floor if the subfloor is fully sealed with a continuous membrane that goes up the perimeter wall framing and another membrane on top of the concrete slab that runs continuous and up the foundation wall? This way the piping is in betweeen 2 sealed surfaces. One concern that comes to mind is creating a vapor barrier on the perimeter walls which can cause mold in regions that don’t require vapor barriers which I saw on one of your episodes.
It is very common in VA where I do radon testing to include a radon contingency clause in the purchase contract; in that case, the radon test is part of the home inspection. If the level is found to be high, mitigation can be done at seller's expense. Your realtor will know about laws in NJ and whether or not you can put that in a contract. If you have this done as part of the home inspection, expect it to cost more than a home test. It should be done by someone with certification to do the measurement.
@@bethriddick36 thanks so much for your reply and advice!! Good stuff!!
There is more to the radon story. Around 1993 I took an original course in radon taught by the developers of the original study for the EPA. According to them. Statistically it is not nearly as problematic for nonsmokers as it is for smokers. The 4.0 number was reportedly a compromise between HUD and the EPA. Radon is in outside air which we breath every day. The original university study recommended taking smokers out of the population study for a more accurate representation of risk without inflating the numbers... the EPA said to leave them in to show higher risk... this is what we ended up with.
That's consistent w what I heard a few years back. I'd like to see more studies, and data on the risks. I just read that radon contributes to 13% lung cancer deaths annually for non smokers.
literally every pollutant limit in air and water established by the epa (federal and/or state) are compromises between the cost to remediate and minimizing risk to individuals at extremely low levels of said pollutant. in my experience, it is often ideal to reduce well past the epa limit to the extent possible/affordable.
What about putting something down like Stego Wrap prior to the pour?
I just found out my level is 13.3 + 2%. I tested the level over a period of one year. How quickly must I move to correct this problem? We have lived here for 4 yrs. My three adult children sleep on the lower floor of our home. Must I take everything out of my cellar to work on the issue? Approx. how much does it cost to fix the problem?
Also some areas have more radon. It depends on how much uranium is in the bedrock below your house
Hi Matt, been watching your show forever on RUclips. We have a house built in 2006. We purchased the house in 2011 and found an elevated radon level (between 14 & 25) . It's been tested a number of times and we currently have the same digital testing device you showed in your video. We have a working Radon system and fan but it certainly isn't helping. We've had several companies come out and look with no results. Any advice??? Maybe it would be a good video, trying to help figure this out!!! 🙂
I wonder if you could just blow air out from the basement through a window?
if the basement if unfinished, consider using some Sani-Tred products to seal it up.
Is radon only an issue in houses with bonafide basements? Or, can it be an issue in a house with only a crawlspace too? If it can be an issue in a house with just a crawlspace do you need to check both the crawlspace and the living area above for radon? If you only have elevated radon levels in the crawlspace, is that an issue? Since you're not going to spend much time in the crawlspace, would any likely exposure time in the crawlspace be sufficient to justify the cost of mitigation?
Elevated levels of radon can be found in buildings with every foundation type. The protocol is to test the lowest livable level of the home, not the crawlspace.
Isn't there another way during construction outside of laying tubing to prevent radon seepage...I thought there might be a blanket of plastic or something laid on the ground before pouring the cement..any comments?
That's a good question. I'm also interested in whether you can determine potential radon levels at a specific site prior to any construction. Having gone through some soil science classes, this was never something that was brought up; we mainly talked about how to mitigate radon in existing structures.
Here in Canada, its become code to install a poly sheet material similar to vapor barrier under the concrete slab of all new home builds and also 'rough in' a plastic vent pipe for a future radon extraction fan.
At least in CT, laying poly plastic sheeting before a concrete floor pour is code to help deflect radon, but I don't see how that's very effective & it's hard to enforce since the guys doing the concrete work usually want to remove it because it adds hours onto the finishing job since the water in the concrete can't soak into the ground, only slowly evaporate from the top.
@@dew-drop There are soil tests that can give you the radon level in the soil before construction, but the correlation between these levels and what the levels may be in the completed building are difficult to surmise.
Thanks Matt
What do you do when you have radon & your home is a concrete slab foundation?
Great video Matt, thank you.
When we sold our last home, we got dinged at the "take action" level on the radon inspection and had to install one of these fans. That fixed the problem. Unfortunately, I worked out of our basement for 10 years with these elevated levels and never knew about it. No lung cancer yet!
if you don't smoke, you prolly have nothing to worry about.
How can a perfect wall , roof or floor be built on a off grid weekend cabin on sonotubes in the northeast where the only source of heat is a woodstove ? You created a very helpful channel , thank you.
Hey Matt, have you ever heard of a chemical product called RadonShield? It is sprayed onto the concrete and is supposed to soak into it a couple inches reacting with the free alkalides or some such in the concrete,. The idea is that it turns the top couple inches of the concrete non porous, thus blocking radon gas from passing through. Aa a side benefit, it should also block moisture from coming up through the concrete as well. I would be very interested to hear your thoughts on this.
In the UK, I used tanking slurry to waterproof under the house.
It's not a basement, just the gap between foundations and floor so I was doing it to block moisture and make it nicer to crawl around.
Sounds very similar to your branded product, I wonder if they are actually the same thing and that's being sold at a premium?
I'm sorry, but that product just sounds like snake oil.
Sealing alone usually doesn't reduce the radon significantly. It does however increase the effectiveness of a passive or active system already in place.
Just received a notice in the mail to do a test. I assume it came from the government although it doesn’t actually say. Wasn’t going to bother but after watching this video I’m seriously reconsidering. I live in Canada by the way.
I believe Health Canada sends out notices every winter asking people to test. This has been going on for at least the past few years.
@@lovema21 I remember getting one about 10 years ago or so. Wasn’t too worried about it then. Haven’t gotten another one till now. Not sure if it’s sent to every homeowner every year. They may only send to certain areas on a rotating schedule.
SO would you put the test kit in a crawl space (if you have one) since it's outside the conditioned space, but can accumulate?
Actually, no, you never test in a crawl space. It should be placed in the lowest livable space. This includes any space that could be finished in the future as well. Hope that helps!
If you have a crawl space under your entire house I wouldn't even worry about this issue. It's only becomes a problem if you're in a modern house with very airtight sealing on a slab or with a basement.
@@rcmrcm3370 I get elevated levels from crawl space foundations all the time. I'm in NW Indiana, maybe it's different where you are.
@@Ops376 oh yes I forgot, a lot of people call sub-basement crawl spaces.
@@rcmrcm3370 Houses with all types of foundations can have elevated radon, airtight or not. As far as testing in the crawlspace, Robert is right. Test in the lowest livable area, or any area that could be a livable space in the future in the case of real estate transactions.
Love it but we no longer vent a radon system through a roof it now has to run through the outside of the home. They make it look like an upside down downspout
People in some areas of Ramsar, a city in northern Iran, receive an annual radiation absorbed dose from background radiation that is up to 260 mSv y(-1), substantially higher than the 20 mSv y(-1) that is permitted for radiation workers. yet they are fine
Visitors enter Montana mines filled with radon as a therapy for their ills
Ok, so I’m a homebuilder who finds value in practical solutions. I even have a radon mitigation system in my own home. However, the home we currently live in is a 100yr+ old family farm house that my grandparents, dad, aunts/uncles all grew up in. I got curious and had it tested. It was off the charts. Higher than any other home I have built in the last 20 years. Anecdotally my grandparents lived into their late 90’s. My aunts and uncles are all in their late 80’s now. Not one of them has had any health issues related to radon. Many of them had bedrooms in the basement. I kind of feel like it has been hyped up to be something that it is not. Almost something hyped up by real estate agents to be used as a bargaining chip during price negotiations.
I have also had issues with homes in clay soils with a radon mitigation system drawing water under the basement slabs. Because they create an area of low pressure and clay soil holds a lot of moisture, it draws that moisture to under the slab area. It has caused heaving in some soil conditions and caused massive cracking in basement slabs. Soil engineers in the area say that if a sub slab system is to be installed, they want an additional 2-3 feet of over excavation under basement slabs and 3/4 gravel installed to replace it. Quite a process. Just my thoughts.
Not everyone who smokes gets lung cancer. Not everyone who drives will die in a car accident. With rare events like this don't go by your feelings but by the numbers.
Where can i get one of the build production hats?
What can we do if we have an empty lot that we plan to build on? Is there any kind of testing to determine any levels of radon before the concrete is poured?
That was exactly my question
Pitch a tent and install the kit in it for a week?
nothing. as matt indicated the concentration is a factor of the type of foundation system you have (slab, crawlspace, basement, etc.). So install the passive system (pvc pipe is cheap and easy to put in before concrete is cast), once constructed run the test, and if the test is elevated, convert the passive system to an active system with a radon fan
Oh no, all those hikers are breathing radon out in nature.
What's next, building code for tents too ?
Good question, I'm sure theres a way you can test without a structure in place. Or you could just install a passive system.