@@dastokene30og I don’t agree. Matt Risinger’s videos are all about sharing techniques and details. I’m guessing they didn’t realize what was going on and couldn’t get to the shot fast enough. Hard to do I guess when something isn’t scripted. If it was then bad on them.
What category is a shed?aFrom the start, Ryan was very helpful and is continuing to be helpful about his ruclips.net/user/postUgkxGqOCINHE0Z0E5gxzSdNi9NWGugRY5Hm2 Plans . Also, they have answered all the questions I have asked & I got outstanding support from his My Shed Plans full package.
@@JobeStroud I encapsulated my crawl space on my 1870s era all brick home. The details were extremely important- air conditioned with ac/heat/dehumidifier. Air sealed the limestone foundation walls with closed cell foam. Very careful to make it airtight from the outside in. Then, air sealed the 1st floor as airtight as can be with rockwool insulation as well. Was not particularly expensive, just labor to get the details right. Smells great, no mold, no high humidity. etc. It can be done.
The builder we work for has been foaming under his slabs for years. We are in Canada and do full basements. The houses are raised bungalows and we have alot of bedrock. Helps keep the frost out
Matt and Wade, your suggestions are absolutely excellent! A few years ago, I had the privilege of assisting in the construction of something very few people presently hear about;: a "mechanical basement (MB)". Mechanical basements are neither crawl spaces, nor are they entire basements, but they do have simulations. A conventional crawlspace is 4 feet tall, whereas MB is 5 to 6 feet tall, allowing homeowners and tradespeople to easily access systems or store items. A great example is a root cellar, which is just made a lot better - it's made out of concrete instead of dirt or bricks! Hey, some people do use them for storm or fallout shelters.
Living in a hot, humid coastal area, sealing my crawlspace is the best improvement I made to our house. I didn't do a full encapsulation, but had a company remove all existing vapor barrier and floor insulation. New 10 mil vapor barrier with joints overlapped and sealed, going up the foundation and piers 18"+, also sealed the vents with foam blocks and spray foam, then installed a Santa-Fe dehumidifier. Been installed for 3 years, couldn't be happier with the results.
@@DaManDaMythDaLegnd - Lower humidity. All 3 of my thermostats have built in humidistats, previously the 2 downstairs thermostats were showing 58%-60% on very humid days, now the downstairs averages 51%-52% year round. Living on NC coast, this morning weather is showing 100% humidity, dropping to 90% at 9am. I have the dehumidifier set at 50% RH. Indoors seems to maintain 51%-52%. My crawlspace is approx. 2500 SF, think the total cost to have the new vapor barrier installed, foam block the vents and install the dehumidifier was around $2800. That was after I removed the existing vapor barrier and floor insulation. I ran the electrical to dehumidifier, so that was deducted from total installation cost. Sounds expensive but the dehumidifier cost for me to purchase was $1100 at that time.
I’ve never seen a floor system that is completely inside the crawl space, that’s a interesting way to do it and let your subfloor sit on the sill. It’s interesting to see the difference on building around the country
Excellent information. I have a very problematic crawl space on my small home. Similar environment with a very high water table. None of the previous owners completed a curtain drain at the back of the property so the water comes through the property rather than skirting it. I have no intention of putting in a full basement ever...but would love to go from a disgusting, rodent filled, dirt floor crawlspace that is not well done AT ALL to a sealed and conditioned crawl space that is essentially a short basement. That being said...this has a ton of problems now. So, drainage on the property first I guess then need to assess what all needs to be replaced on the building in terms of structure due to damage. There are definitely sagging floors....I feel pretty overwhelmed...but this video, and videos like these help me to feel less confused and more focused. Thankfully this is s small home to deal with....there is that. The only thing in this video is that I could not see what you were pointing to with the top of the concrete walls and sealing there. The cameras needed to be angled to see it.
One day I will build a custom single story home with a 4 foot crawlspace or an unfinished basement! You always want a nice crawlspace or attic to run wires, electrical, ductwork, or plumbing, for future changes!!
Hey Gene just a tip…. I have done this three builds now and we use a 2x6 for what Matt calls a mud sill and then we nail down a 2x4 on top of that. That 2x4 is the bottom of plywood subfloor, then when you frame a 2x6 wall on top you have an 1 1/2 gap for two inches that you can slip your wiring out into the crawlspace area. It works really well. As for the plumbing we just brought water up through the bottom of the cabinets if they were on an outside wall and the plumbers chipped out a spot to hug the DWV so that the PVC got up into the wall cavity before it was above the toe space in the cabinets
Beemer a subscriber for 4+ years. Great informational videos and products. Matt...please work to let your guests speak and finish their sentences without interrupting.
Very nice and clean...thanks. It would also be good if you talked about how to incorporate the water and drain lines into the slab, and what the heating plans were for the crawl space and house.
For Educational purposes, can you explain the reason why or what the advantage is of having the concrete foundation crawlspace to begin with? I totally understand the reason behind the 'can't do a basement because of high water table, etc" ... but why wouldn't you just simply do the crushed gravel, closed-cell spray foam and then concrete on slab construction? I'm just trying to justify in my mind why you need a concrete crawlspace at all in this situation. Love everything else and all the fantastic engineering details associated with this build. Thanks Matt!!! Great video!!
That is a great question. The only reason I expect they are adding a concrete slab instead of just a crushed base and a vapor barrier is for added moisture barrier. I am located in the mountains and we do crawl spaces. Our typical detail has a gravel floor with vapor barrier, insulation on the walls, and we insulation in floor joists. A small amount of air flow from our HVAC system to the crawl is in there too so to not get stagnant air.
Thanks everyone! Appreciate the comments! Makes sense. I live on a crawlspace and looking at this build, I presume there will be an ‘easy’ access point to readily and easily get into the crawlspace. My access is in the garage and it is a very tight squeeze to get in. I would also add a reinforced tornado shelter (because I live in a tornado zone in the Midwest) or a panic room in that crawl space too if I were going to the expense of this type of crawlspace. I do love the design for sure.
I was wondering the same thing. We do encapsulated conditioned crawl spaces but don’t do the slab. It honestly would knock us out if pricing in a time where we are already doing more than most contractors in our area, foam, zip, etc. I probably would do these things as well if I had a RUclips channel to make up the difference that we lost.
to dehumidify the basement, just use it as the final return "space" for the whole house AC / dehumidification unit.. (or ERV - Y - -off from bathroom exhaust...)..
Hello Matt, I really appreciate the videos that you bring out. Me and my wife are going to start pretty soon building our new house. We are leaving Las Vegas and moving to eastern Kentucky. I’m torn on whether or not I should do a concrete slab on Grade or a conditioned crawlspace. My brother who lives there mentioned that every house that’s out there even new build ones are typically all built with crawlspace versus the concrete slab. The main concern with the concrete slab is the plumbing underneath the slab in the work it would take to fix a problem, if something was to happen. What are your recommendations considering the type of area and climate I would be in. It’s about 40 miles east of Lexington.
Closed cell spray foam is a really versatile product. Just keep in mind that is among the most damaging of foam insulation products when it comes to greenhouse warming potential. Foams such as EPS and PIR are much less problematic. So do consider them as an alternative when possible.
In a new addition with a crawlspace, Is it worth it to spray closed cell foam on the walls and thick poly on the floors? Or I was thinking would it be better to just foam the floors as well ? It has piping set up for a some baseboard radiators, and I was thinking of an Aprilaire or SantaFe dehumidifier for summer months. On Long Island. Thanks
Great to pass on the knowledge to the people doing the work so they understand why, and hopefully will care a little more to get it done correctly rather than "close enough" I hate those two words
This video wasn't about the structural design. But I think we can reasonably assume the concrete slab was thickened at the point loads. With insulation capable of 25 psi you can carry 3600 pounds on a square foot. So it would be easy enough to accommodate large point loads.
Does anyone know the approximate cost difference between this "Short Basement" and a regular basement? It doesn't seem like it would be that much different, and yet a full basement would offer more. Tradeoffs ? 🤔
I bet it’s so much more. Think about all that concrete…rebar…additional insulation…water proofing…a full basement should def have a French drain…probably a larger footer…additional excavation…plus you have to calc HVAC for a basement…
Costs vary so much by location. I couldn't begin to predict. But if you're thinking why not make a full height space so you can use it, I agree it's an interesting idea. Probably it would be cheaper to build a 3 foot deep "crawlspace" like this and then frame knee walls up another 5 feet, in effect a semi-basement. Then your first floor would be above that. This would avoid the expense of a lot of excavation and especially a lot of concrete. It would also make it easy to incorporate windows so that you could get the best use of the space. If you're building on a site with a slope of 3-5' you could also plan it as a "walk-out" basement this way. In most places the cheapest way to go, however, is a simple concrete slab on grade with no crawlspace or basement at all.
Hello Matt I have a 28x80 moble home would like to raise it and put a foundation basement under it do you know any that would interested pinnacle NC thanks
Ok why not do rigid up to the floor joist? Tape seams or foam adhesive. Way less money and you could get the roofing foam with OSB and have it as storage.
OK I missed some of that explanation so went back. You really need to do a sandwich wall/floor as the next step. Look up thermomass, I'm loving it in my place. Trying to make it standard in my houses.
I have no idea if it is or isn't in this location. But it's easily handled in a situation like this. As the gravel goes down, before the insulation and slab, bury a network of perforated pipes in the gravel, with a riser at a convenient spot. As the house is framed this riser will carry up an interior wall all the way up to the roof and vent any radon out high up where it can do no harm.
The worst foundation is a plenum slab . I prefer a slab with the soil graded Away. I’m 50 years in this home with no issues . Got a high water table, than yes, a conditioned crawlspaces or encapsulated PROPERLY. Don’t use a company unless they’ve been around 15 years. I’m a contractor. 1/5 of all our jobs starts by ripping out the failed system out.
I like to see better ways to build homes but to add an additional 20,000 to the cost of a home with a concrete slab for a crawlspace? I agree, looks great but a properly installed encapsulated crawlspace is much cheaper. Am I missing something? Cost of a build must be considered or it would be unaffordable to most folks. As an inspector I can really appreciate a clean crawlspace. Just some of my thoughts.
The footers only need to be as large as required by the loads they carry. Certainly an engineer was involved in the design of this house. With insulation rated at 25psi you can carry 3600 pounds per square foot. It wouldn't take much footer area to accommodate any normal residential load. A 3'x3' footer would carry 32,400 pounds.
Pennsylvania wants three times the size of the post... So at 6x6 has to sit on an 18-in diameter footer that runs 36 in deep... And you were talking about laying the foundation and compacting the stone but you didn't mention anything about how you treated the areas underneath where the footers were going to go and since you were talking about building a bulletproof crawl space I kind of thought it might make sense for them to have included some details about how they did that whole monolithic spray foam thing while also digging down and putting footing Piers underneath the column supports... Which would kind of negate the monolithic spray foam thing. If they're going to detail they bulletproof method of a better crawlspace, would be nice if they gave all the details
A great crawl space needs to be raked out of all debris and be smooth with proper slopes for drainage. Nothing worse than laying on your back on top of concrete spillage from a sloppy pour of the pads.
I agree about having a full basement because of very little extra costs and would probably advise against building on what looks to me to be a flood plain.
You guys crack me up. Basements are NOT cheap (at least not in upstate New York), and please do try your best to convince people from moving to the gulf coast from wherever you build basements. We need a break from the deluge of humanity. Perhaps you can warn them that the people here are freaks who say “hello” and “good morning” to strangers and expect reciprocation. 😂🤣
The build show has grown to a point that most of these build methods are unattainable for the average person. I wish Matt would feature some smaller high end projects. I don’t see how I could ever afford to build a house to these standards.
Stone, closed cell sprayfoam covering stone and up the wall a bit to be continued later, then concrete. Its just disconnected slab from ground contact.
Question on this type of crawlspace: If the plywood/OSB decking is flush with the top plate, then how are utilities (plumbing/electrical/etc.) getting up from the crawlspace into an exterior wall? In traditional framing the floor joists are sitting on top of the sill plate, so there is space accessible to create a path. I like the fact that a rim joist is eliminated in such a design (if I am mentally picturing this build detail correctly).
A couple of possibilities. Electrical can easily be brought up an inside wall and the routed from there to exterior walls. Plumbing is a bit more of an issue. But in the more energy conscious designs for cold climates it's best to avoid plumbing in exterior walls anyway. Sometimes what is done, especially in bathrooms that have fixtures against an exterior wall is to frame a double wall, furr out the inner face of the exterior wall. This way the plumbing doesn't disrupt the insulation and it also places the plumbing inside of the foundation plate. Good planning from the start of design makes all the difference. I rarely need to put plumbing in an exterior wall in my designs.
I have done this three builds now and we use a 2x6 for what Matt calls a mud sill and then we nail down a 2x4 on top of that. That 2x4 is the bottom of plywood subfloor, then when you frame a 2x6 wall on top you have an 1 1/2 gap for two inches that you can slip your wiring out into the crawlspace area. It works really well. As for the plumbing we just brought water up through the bottom of the cabinets if they were on an outside wall and the plumbers chipped out a spot to hug the DWV so that the PVC got up into the wall cavity before it was above the toe space in the cabinets
As one who has inspected hundreds of crawl spaces I appreciate how you are building this crawl space. Curious as to whether access to the crawl space will be from inside or outside.
Mine is similar and I'd bet money on inside access only. Just due to the fact that an outside door has the possibility to leak and let in bugs mice etc. Mine is accessed from the utility room. Same with my attic access.
@@justinballard7242 I would want interior only access to avoid issues you identified. However. I know some people do not want to give up interior floor space required for interior access.
YOu know you have a problem when mice traps are on your Amazon auto reorder list. As someone who has trapped over 100 mice and a dozen snakes from a crawl space within 18 months, I reccomend if you are going to have a exterior access door to your crawl space make sure the door has secure lock that holds the door agaist the jams and that is reinforced by magnets (kinda like cabinet), fully sealed, and all four sides of the door need to close against a jam. Anything short of this, mice are going to do a congo line around your door. Additionally, insist on any utility entering your crawl space to be installed through access ports seperate from crawl space vents. Any hole made in crawl space vent will also act as access location for critters to get inside. Lastly, investigate your house to see if there are any direct open locations that lead directly into your crawl space. I found a 4" x 16" gap into my crawlspace in my garage. It was covered by some steps so it was actually missed by 3 different inspectors. I trapped more than 50 mice in this location. The gap is now closed by a metal angle and foam sealed.
Suggestion….put the access for the crawl space from the corner area of garage floor. Works well….no cold weather,snow or rain to worry about when you do have to be in the crawl space.
The real tip from this Pro is to stop putting all that time and money into a termite floor that is also less stable and pour a monolithic concrete slab with PEX tubing in it for perfectly even heating system at a very low cost.
Hey Matt. I'm tearing down my first brand new spec home in the fort worth area if you want to use it for some content. This is a 500k + home, 3500+ Sq ft under roof.
@suspicionofdeceit there was an old blanket easement from the 60s on a big parcel. A portion of that property was purchased and split up into a few one acre lots. Since the blanket easement was created a pipeline was installed. When it was replatted it was limited to 30ft. Well the pipeline owner has been planning a new line within that easement and needs it to be 100ft wide to allow enough space for an additional line, but they hadn't broken ground on these properties or adjacent properties, so the old blanket easement, still didn't prevent us from building. When they realized a house was built they had their attorneys reach out to everyone. Since it's just a spec home and not under contract with a future owner, I offered it to them unfinished at a discount. We got the exterior finished and had sheetrock done and were just about to start cabinets when this all started. So we paused it while we finished the negotiation. I got a good deal on the house and then they asked if I could demo the house. A lot of this I learned as I got into it. I knew there was a pipeline, I got title insurance, and everything on our end was by the book, it just happened to get a little bit messy, but at the end I'm selling it for a good price and I get to tear it down which sounds fun to be honest.
In cases of high water table or when basement are not an option for sound technical reasons, I agree crawl spaces are the proper foundations. THe crawl space shown here is a giant leap from the typical crawl space design. I would not trust this crawl space will stay dry on its own, I would add a dehumidifer to assure conditions would not support mold growth. Worst thing that can happen is the dehumifier will get really bored, so leave some cross word puzzles behind. I am assuming this house will be blower door worthy. It would be a shame to have a Radon mitigation system installed post build yanking out air after much time/effort was made to make this drum tight so I hope there is some subslab mitigation is already builti in. The typical crawl space designs are ones that involve bare ground facing the floor deck which is supposely protected by fiber glass batting, which has been proven time and time again to be worthless and ineffective. Dare I say the typical crawl space is as inferior as the cardboard siding. The typical crawlspace design should be banned.. codes should focus on either slab or basement, and implement enough incentives to make basements more financially sensable. Crawl spaces should be the exception, but if you have to... use this crawl space design as your starting point and adjust to fit your local codes, lot dimensions and housing footprint.
My thoughts went immediately to radon mitigation options. I would hope that you could install a passive system before pouring the foundation, then if needed just install a fan if required.
@@codyhuber The traditional (open soil) crawl space is obsolete. Depending on your location and condition of your home it might be equivalent or close to the costs to encapsulate your crawl space rather than reinsulate because both should address water damage, mold, and rodent issues before installation. If your crawl space has mold, water damage, and evidence of rodents, replacing the insulation will not correct any of these issues and likely make the problems worse if insulation is applied over them. If your crawl space has these problems, work with a respectable crawl space company that specializes in encapsulation. These companies have standard practices including the proper insulation that also complies with local building codes. If you are encapsulating the crawlspace request your installed use rockwool comfortbatts to be used on knee walls in the crawlspace. This insulation installs easily, maintains its r-value, bugs hate it, mice hate it, its water proof, dampens sound, and is moisture permeable.
@@bricelangston8634 thanks for the thoughtful reply! Do you have any info or links on what people will see inside their homes before and after doing this work? We had serious water issues down there before installing correct sump pump pit and footer drains around foundation. Just basic vapor barrier and water damaged insulation remain currently.
If you're building in a flood plane the whole house strategy needs to be reconsidered. If you're only dealing with high ground water, like here, then a good "french drain" around the outside perimeter should be enough. One danger people overlook is simple plumbing leaks inside the house. If a pipe bursts or a washing machine breaks, you can have a considerable amount of water. One thing people do is creating a small sump in one spot of the crawlspace slab, where it drops perhaps 1 foot (30cm). This gives a place for the water to go. Then they put a small sump pump in there that goes on automatically and also sounds an alarm, so that the occupants can know there is a problem.
Is foaming under the floating slab necessary down here in the Deep South? I love the idea of a conditioned crawl space but it would be elevated above grade to provide extra protection against potential flooding.
The foam does 2 things here. It insulates of course. But it also blocks the passage of water vapor and moisture upwards from the ground into the house. In the south you _may_ not need the insulation. But you still need to block the water vapor. So something like a polyethylene plastic sheet is typical. Ten mils thickness is considered the minimum. If you don't insulate the crawlspace you need to insulate the floor above, in all climate zones. I'm concerned about the possibility that if the floor above is insulated and the unventilated crawlspace is not you may end up with large temperature differentials. This could cause humidity problems. I wouldn't do it. Really, the best way to go is to insulate the perimeter of the crawlspace, which they did in this video but didn't show. Then make sure the air in the crawlspace is linked to the house above. You can simply do this with a few floor registers. This way the air in the crawlspace is heated or cooled just like in the house. The area of perimeter insulation is less than the floor area so you'll save money this way. I have a question. When you say your crawlspace would be elevated above grade, do you mean that the floor of the crawlspace would be near ground level, or that the floor of the house above would be raised more? If it's the first, then you're basically creating a concrete slab on grade and making your ground floor a "crawlspace". That's certainly acceptable and a good solution in a lot of areas. Traditionally this was done in the south routinely until the mid-20th century. But often the space was left completely open on all sides, with the house elevated on piers. This was a great strategy for protecting the house from termites, as well as decoupling it from ground moisture. If you meant that the crawlspace floor would be a few feet below grade but that the first floor above would be elevated a few feet, then what you have is a semi-basement. That's got advantages as well since you can even get full headroom and use it as living space. It's an ideal solution for sites that slope 3-5 feet. Then you can have a walk-out basement. To learn a lot more of the techniques and options I suggest you go to the "Build America Center" at the Dept. of Energy website. It's a great resource for this stuff. I can't post links but you should be able to search "build america center department of energy" and it will be near the top of your search results.
@@HistoricHomePlans thanks for the in-depth reply and explanation. Yes I was referring to where the floating slab would be ground level (or maybe lower depending on the water table) and stem walls would extend 2-3 feet above ground level and then the first floor of the house would sit on top of that. A semi-basement would be nice, especially if I can dig 3-4 feet below grade without hitting water, but living in southern Louisiana, that’s gonna be difficult. Now granted, the property is on solid land well above sea level and not on the deposit plain of the Mississippi where New Orleans and the southern parishes now sit. All that land below Lake Pontchartrain was created by sediment from the river. A lot of new construction that I see here in New Orleans are built on raised slabs. They drive down pilings, construct stem wall foundation, fill it in with dirt and gravel and then pour a slab on top. My current house here in the city is about 120 years old and was built in piers, my crawl space is wide open to the elements and the critters-had to drag out a dead opossum one time which was smelling pretty ripe, not fun!! Before I moved in, there was no insulation and no subfloor. I can literally see daylight through the floor boards. I had about 2 inches of closed cell spray foam applied to the under side of my floor and 5 inches of open cell under my roof deck. It helps but this house is still an old shotgun-style house. It doesn’t even have sheathing on the exterior wall, just horizontal lap boards!
A cheaper option would be to put down a poly membrane and a couple of layers of EPS foam sheets, and then pour a thin concrete slab over the foam. Carry the foam up the inside walls of the crawlspace. Some jurisdictions might require the foam be covered for fire protection. That varies by locality. An even cheaper approach would be to insulate with EPS outside the foundation. And then just put down a 10mil poly membrane and slab right over it. If the foundations are insulated around their perimeter on the exterior side you don't need any insulation at all inside the crawlspace. This is the approach I detail out on the projects I design. The spray applied closed cell foam is certainly practical. But it is expensive and it is among the worst foam insulations in terms of environmental damage. I avoid it.
There is a flood plain in our area that they got permits to build on. The garage and play room are on the first floor with concrete slab and a drain hole. It floods like every 5 years. So people only put lawn furniture down there. Or they take the time to move everything upstairs right before it floods. The front door has a full staircase. I have no idea what people do with their car when it floods.
Don't see why it needs to be any different than a basement, dig a 4' hole out of the slab and suck air to the outside. Gravel existing under the slab will be key.
Probably because the whole floor is sealed off with the spray foam with no perforations compared to a traditional concrete floor with expansion crasks and volunteer cracks.
Note to camera person: when you hear the word detail, shoot it please. 😂
Lol
they definitely did that on purpose. i dont blame them not showing it... cant give out all the secret sauce lol
@@dastokene30og I don’t agree. Matt Risinger’s videos are all about sharing techniques and details. I’m guessing they didn’t realize what was going on and couldn’t get to the shot fast enough. Hard to do I guess when something isn’t scripted. If it was then bad on them.
@@robertrusso877 he’s usually good about it but this isnt his personal (business) site. you know how the business is sometimes.
What category is a shed?aFrom the start, Ryan was very helpful and is continuing to be helpful about his ruclips.net/user/postUgkxGqOCINHE0Z0E5gxzSdNi9NWGugRY5Hm2 Plans . Also, they have answered all the questions I have asked & I got outstanding support from his My Shed Plans full package.
Would love to see a video on an existing crawl space being renovated to that level.
Considering how difficult that would be, it is also a huge waste of money.
@@JobeStroud I encapsulated my crawl space on my 1870s era all brick home. The details were extremely important- air conditioned with ac/heat/dehumidifier. Air sealed the limestone foundation walls with closed cell foam. Very careful to make it airtight from the outside in. Then, air sealed the 1st floor as airtight as can be with rockwool insulation as well. Was not particularly expensive, just labor to get the details right. Smells great, no mold, no high humidity. etc. It can be done.
The builder we work for has been foaming under his slabs for years. We are in Canada and do full basements. The houses are raised bungalows and we have alot of bedrock. Helps keep the frost out
my access is in our walk in closet.
Matt and Wade, your suggestions are absolutely excellent! A few years ago, I had the privilege of assisting in the construction of something very few people presently hear about;: a "mechanical basement (MB)". Mechanical basements are neither crawl spaces, nor are they entire basements, but they do have simulations. A conventional crawlspace is 4 feet tall, whereas MB is 5 to 6 feet tall, allowing homeowners and tradespeople to easily access systems or store items. A great example is a root cellar, which is just made a lot better - it's made out of concrete instead of dirt or bricks! Hey, some people do use them for storm or fallout shelters.
Living in a hot, humid coastal area, sealing my crawlspace is the best improvement I made to our house. I didn't do a full encapsulation, but had a company remove all existing vapor barrier and floor insulation. New 10 mil vapor barrier with joints overlapped and sealed, going up the foundation and piers 18"+, also sealed the vents with foam blocks and spray foam, then installed a Santa-Fe dehumidifier. Been installed for 3 years, couldn't be happier with the results.
what improvements did you see in the living area?
@@DaManDaMythDaLegnd - Lower humidity. All 3 of my thermostats have built in humidistats, previously the 2 downstairs thermostats were showing 58%-60% on very humid days, now the downstairs averages 51%-52% year round. Living on NC coast, this morning weather is showing 100% humidity, dropping to 90% at 9am. I have the dehumidifier set at 50% RH. Indoors seems to maintain 51%-52%.
My crawlspace is approx. 2500 SF, think the total cost to have the new vapor barrier installed, foam block the vents and install the dehumidifier was around $2800. That was after I removed the existing vapor barrier and floor insulation. I ran the electrical to dehumidifier, so that was deducted from total installation cost. Sounds expensive but the dehumidifier cost for me to purchase was $1100 at that time.
Sure would have been nice to see some camera footage of those details they are describing. Really low effort from the camera crew in this one
Why didn't the camera show the details at the end of the video? Would have been nice to visually see what you were describing.
I live nearbyy and I am soo excited and pleased to see this home being built by Wade...This is Island Park section of Portsmouth RI
Thanks for the information on sealing the mudsills to the foundation walls. Sounds like a great way to work it.
I’ve never seen a floor system that is completely inside the crawl space, that’s a interesting way to do it and let your subfloor sit on the sill. It’s interesting to see the difference on building around the country
Outstanding mini-"basement"
Please consider taking a few minutes and B Roll images of the sealing method. That added visual would be most helpful in explaining the process.
Camera man needs to be fired. Don’t even know what y’all pointing out.
Excellent information. I have a very problematic crawl space on my small home. Similar environment with a very high water table. None of the previous owners completed a curtain drain at the back of the property so the water comes through the property rather than skirting it. I have no intention of putting in a full basement ever...but would love to go from a disgusting, rodent filled, dirt floor crawlspace that is not well done AT ALL to a sealed and conditioned crawl space that is essentially a short basement. That being said...this has a ton of problems now. So, drainage on the property first I guess then need to assess what all needs to be replaced on the building in terms of structure due to damage. There are definitely sagging floors....I feel pretty overwhelmed...but this video, and videos like these help me to feel less confused and more focused. Thankfully this is s small home to deal with....there is that.
The only thing in this video is that I could not see what you were pointing to with the top of the concrete walls and sealing there. The cameras needed to be angled to see it.
One day I will build a custom single story home with a 4 foot crawlspace or an unfinished basement! You always want a nice crawlspace or attic to run wires, electrical, ductwork, or plumbing, for future changes!!
Very timely for my next project. Thanks Matt....
Hey Gene just a tip….
I have done this three builds now and we use a 2x6 for what Matt calls a mud sill and then we nail down a 2x4 on top of that.
That 2x4 is the bottom of plywood subfloor, then when you frame a 2x6 wall on top you have an 1 1/2 gap for two inches that you can slip your wiring out into the crawlspace area.
It works really well.
As for the plumbing we just brought water up through the bottom of the cabinets if they were on an outside wall and the plumbers chipped out a spot to hug the DWV so that the PVC got up into the wall cavity before it was above the toe space in the cabinets
@@jesseherman2453 Thanks Jesse. I appreciate it.
Beemer a subscriber for 4+ years. Great informational videos and products.
Matt...please work to let your guests speak and finish their sentences without interrupting.
Very nice and clean...thanks. It would also be good if you talked about how to incorporate the water and drain lines into the slab, and what the heating plans were for the crawl space and house.
I love this , it’s great. Mechanics Creeper!!! Quick question: Are the floor posts on the floating slab? Or is there peers under those posts?
Nice smooth floor means you can get around on a mechanic's crawler if you need to. Big win.
For Educational purposes, can you explain the reason why or what the advantage is of having the concrete foundation crawlspace to begin with? I totally understand the reason behind the 'can't do a basement because of high water table, etc" ... but why wouldn't you just simply do the crushed gravel, closed-cell spray foam and then concrete on slab construction? I'm just trying to justify in my mind why you need a concrete crawlspace at all in this situation. Love everything else and all the fantastic engineering details associated with this build. Thanks Matt!!! Great video!!
We have mechanicals in that space, and when done properly you can use it as storage too.
That is a great question. The only reason I expect they are adding a concrete slab instead of just a crushed base and a vapor barrier is for added moisture barrier. I am located in the mountains and we do crawl spaces. Our typical detail has a gravel floor with vapor barrier, insulation on the walls, and we insulation in floor joists. A small amount of air flow from our HVAC system to the crawl is in there too so to not get stagnant air.
Thanks everyone! Appreciate the comments! Makes sense. I live on a crawlspace and looking at this build, I presume there will be an ‘easy’ access point to readily and easily get into the crawlspace. My access is in the garage and it is a very tight squeeze to get in. I would also add a reinforced tornado shelter (because I live in a tornado zone in the Midwest) or a panic room in that crawl space too if I were going to the expense of this type of crawlspace. I do love the design for sure.
I was wondering the same thing. We do encapsulated conditioned crawl spaces but don’t do the slab. It honestly would knock us out if pricing in a time where we are already doing more than most contractors in our area, foam, zip, etc. I probably would do these things as well if I had a RUclips channel to make up the difference that we lost.
@@zlmdragon. mine is conditioned with a concrete floor and my HVAC lives down there where its in the nice conditioned space
to dehumidify the basement, just use it as the final return "space" for the whole house AC / dehumidification unit.. (or ERV - Y - -off from bathroom exhaust...)..
Yes, a conditioned crawlspace needs to be linked to the house interior anyway. So that makes a lot of sense.
Camera on the wrong side of the wall. We couldn’t see any of the details you were pointing out.
Hello Matt, I really appreciate the videos that you bring out. Me and my wife are going to start pretty soon building our new house. We are leaving Las Vegas and moving to eastern Kentucky. I’m torn on whether or not I should do a concrete slab on Grade or a conditioned crawlspace. My brother who lives there mentioned that every house that’s out there even new build ones are typically all built with crawlspace versus the concrete slab. The main concern with the concrete slab is the plumbing underneath the slab in the work it would take to fix a problem, if something was to happen. What are your recommendations considering the type of area and climate I would be in. It’s about 40 miles east of Lexington.
Closed cell spray foam is a really versatile product. Just keep in mind that is among the most damaging of foam insulation products when it comes to greenhouse warming potential. Foams such as EPS and PIR are much less problematic. So do consider them as an alternative when possible.
In a new addition with a crawlspace, Is it worth it to spray closed cell foam on the walls and thick poly on the floors? Or I was thinking would it be better to just foam the floors as well ? It has piping set up for a some baseboard radiators, and I was thinking of an Aprilaire or SantaFe dehumidifier for summer months. On Long Island.
Thanks
Any air conditioning in an unvented, unsealed crawlspace? Or does it rely only on leaks through subfloor?
Great to pass on the knowledge to the people doing the work so they understand why, and hopefully will care a little more to get it done correctly rather than "close enough" I hate those two words
Can someone explain why the northern builds usually will have two sills plates. But the South usually only has one sill plate
Would this kind of crawl space work for a Midwest home in a cold climate?
Why the sil-seal sandwich?
Why not just big stretch adhering the sill to the foundation?
what is the steel support and do they come in 4 feets
Are those pier/columns on a footing? I wouldn't think they're supported by foam ultimately being a point load.
Good point
This video wasn't about the structural design. But I think we can reasonably assume the concrete slab was thickened at the point loads. With insulation capable of 25 psi you can carry 3600 pounds on a square foot. So it would be easy enough to accommodate large point loads.
I so wish that were my crawl space. In mine you have to scoot your belly in the dirt, you can't even crawl. I have to replace piers.
Does anyone know the approximate cost difference between this "Short Basement" and a regular basement? It doesn't seem like it would be that much different, and yet a full basement would offer more. Tradeoffs ? 🤔
I bet it’s so much more. Think about all that concrete…rebar…additional insulation…water proofing…a full basement should def have a French drain…probably a larger footer…additional excavation…plus you have to calc HVAC for a basement…
Costs vary so much by location. I couldn't begin to predict. But if you're thinking why not make a full height space so you can use it, I agree it's an interesting idea. Probably it would be cheaper to build a 3 foot deep "crawlspace" like this and then frame knee walls up another 5 feet, in effect a semi-basement. Then your first floor would be above that. This would avoid the expense of a lot of excavation and especially a lot of concrete. It would also make it easy to incorporate windows so that you could get the best use of the space.
If you're building on a site with a slope of 3-5' you could also plan it as a "walk-out" basement this way.
In most places the cheapest way to go, however, is a simple concrete slab on grade with no crawlspace or basement at all.
@@HistoricHomePlans exactamundo
Hello Matt
I have a 28x80 moble home would like to raise it and put a foundation basement under it do you know any that would interested pinnacle NC thanks
why not increase the height of the post and make the basement full height? Whats the reason to leave it as just crawlspace?
how thick is the concrete slab ?
what is ledge? also I dont see a radon vent.
Ok why not do rigid up to the floor joist? Tape seams or foam adhesive. Way less money and you could get the roofing foam with OSB and have it as storage.
OK I missed some of that explanation so went back. You really need to do a sandwich wall/floor as the next step. Look up thermomass, I'm loving it in my place. Trying to make it standard in my houses.
Wait…. I guess I don’t understand how the spray foam comes up the inside of the foundation walls. Are the walls not poured with the slab?
Last 3 minutes might as well been radio.
Curious if radon gas is an issue?
I have no idea if it is or isn't in this location. But it's easily handled in a situation like this. As the gravel goes down, before the insulation and slab, bury a network of perforated pipes in the gravel, with a riser at a convenient spot. As the house is framed this riser will carry up an interior wall all the way up to the roof and vent any radon out high up where it can do no harm.
@@HistoricHomePlans great response and easy to install as part of the subgrade preparation for the crawl space slab.
The worst foundation is a plenum slab . I prefer a slab with the soil graded Away. I’m 50 years in this home with no issues . Got a high water table, than yes, a conditioned crawlspaces or encapsulated PROPERLY. Don’t use a company unless they’ve been around 15 years. I’m a contractor. 1/5 of all our jobs starts by ripping out the failed system out.
I like to see better ways to build homes but to add an additional 20,000 to the cost of a home with a concrete slab for a crawlspace? I agree, looks great but a properly installed encapsulated crawlspace is much cheaper. Am I missing something? Cost of a build must be considered or it would be unaffordable to most folks. As an inspector I can really appreciate a clean crawlspace. Just some of my thoughts.
Do you have 36-in footers underneath those piers in the middle of the crawl space?
Com'on really? It's the build show ,not DIY, NATION.
The footers only need to be as large as required by the loads they carry. Certainly an engineer was involved in the design of this house. With insulation rated at 25psi you can carry 3600 pounds per square foot. It wouldn't take much footer area to accommodate any normal residential load. A 3'x3' footer would carry 32,400 pounds.
Pennsylvania wants three times the size of the post... So at 6x6 has to sit on an 18-in diameter footer that runs 36 in deep... And you were talking about laying the foundation and compacting the stone but you didn't mention anything about how you treated the areas underneath where the footers were going to go and since you were talking about building a bulletproof crawl space I kind of thought it might make sense for them to have included some details about how they did that whole monolithic spray foam thing while also digging down and putting footing Piers underneath the column supports... Which would kind of negate the monolithic spray foam thing.
If they're going to detail they bulletproof method of a better crawlspace, would be nice if they gave all the details
As nice as it is to see Wade and you. It would have been much better to show what you were talking about. Jayman...
One thing I dont get is: why not dig deeper and just make a basement you can walk in? Does cost go up exponentially when you go that much deeper?
The high water table, can't go lower in this location.
😅 👌 👍
A great crawl space needs to be raked out of all debris and be smooth with proper slopes for drainage. Nothing worse than laying on your back on top of concrete spillage from a sloppy pour of the pads.
Why couldn't you have extended the concrete walls higher and had a basement?
Watch the video.... can't
@@snapcrack55 Why not?
You should use GLAVEL in lieu of regular gravel!!
What is glavel and why should it be used?
Best crawlspace is a basement...
it's almost like you didn't listen to the first 60 seconds of the video where they explain why they didn't do a full depth basement...😂
More like why they absolutely can not do a basement
Beat me to it
I agree about having a full basement because of very little extra costs and would probably advise against building on what looks to me to be a flood plain.
You guys crack me up. Basements are NOT cheap (at least not in upstate New York), and please do try your best to convince people from moving to the gulf coast from wherever you build basements. We need a break from the deluge of humanity. Perhaps you can warn them that the people here are freaks who say “hello” and “good morning” to strangers and expect reciprocation. 😂🤣
The build show has grown to a point that most of these build methods are unattainable for the average person.
I wish Matt would feature some smaller high end projects.
I don’t see how I could ever afford to build a house to these standards.
I like these $200k crawlspaces
crawl spaces like that are dumb.4 foot up or down and you can have a full basement for very little extra money.
Water table is an exception
Four feet down wasn't an option in this case due to site conditions. But I agree 4 feet up should seriously be considered.
It would be nice if the cameraman took video of what they are speaking about instead of just showing Matt. We know what he looks like.
Then don't build there. This is a waste of a house.
If you want to build a better crawlspace. ...build a basement somewhere else.
Dumb-it-down a bit boys OR at the very least have the camera show what you're talking about!
oof. not the greatest camera work on this one. talking about details and never saw them in the video
Great crawlspace, but you guys have made houses so expensive that if you don't make 250k a year you just stay homeless.
Bad camerawork
Nope... Try harder.
Would love a drawing detailing the base mat and the sill with bill of materials. Hard to follow details across mat and stem walls.
Stone, closed cell sprayfoam covering stone and up the wall a bit to be continued later, then concrete. Its just disconnected slab from ground contact.
Would love to see what they are pointing out .camera guy doesn't have a clue.
Question on this type of crawlspace: If the plywood/OSB decking is flush with the top plate, then how are utilities (plumbing/electrical/etc.) getting up from the crawlspace into an exterior wall?
In traditional framing the floor joists are sitting on top of the sill plate, so there is space accessible to create a path.
I like the fact that a rim joist is eliminated in such a design (if I am mentally picturing this build detail correctly).
My best guess is dropping electric from above for exterior walls. I'm not an electrician but have been in the trades for 20 years
A couple of possibilities. Electrical can easily be brought up an inside wall and the routed from there to exterior walls. Plumbing is a bit more of an issue. But in the more energy conscious designs for cold climates it's best to avoid plumbing in exterior walls anyway. Sometimes what is done, especially in bathrooms that have fixtures against an exterior wall is to frame a double wall, furr out the inner face of the exterior wall. This way the plumbing doesn't disrupt the insulation and it also places the plumbing inside of the foundation plate.
Good planning from the start of design makes all the difference. I rarely need to put plumbing in an exterior wall in my designs.
I have done this three builds now and we use a 2x6 for what Matt calls a mud sill and then we nail down a 2x4 on top of that.
That 2x4 is the bottom of plywood subfloor, then when you frame a 2x6 wall on top you have an 1 1/2 gap for two inches that you can slip your wiring out into the crawlspace area.
It works really well.
As for the plumbing we just brought water up through the bottom of the cabinets if they were on an outside wall and the plumbers chipped out a spot to hug the DWV so that the PVC got up into the wall cavity before it was above the toe space in the cabinets
Jackhammer and it sucks to do plumbing in these.
As one who has inspected hundreds of crawl spaces I appreciate how you are building this crawl space. Curious as to whether access to the crawl space will be from inside or outside.
Mine is similar and I'd bet money on inside access only. Just due to the fact that an outside door has the possibility to leak and let in bugs mice etc. Mine is accessed from the utility room. Same with my attic access.
@@justinballard7242 I would want interior only access to avoid issues you identified. However. I know some people do not want to give up interior floor space required for interior access.
YOu know you have a problem when mice traps are on your Amazon auto reorder list. As someone who has trapped over 100 mice and a dozen snakes from a crawl space within 18 months, I reccomend if you are going to have a exterior access door to your crawl space make sure the door has secure lock that holds the door agaist the jams and that is reinforced by magnets (kinda like cabinet), fully sealed, and all four sides of the door need to close against a jam. Anything short of this, mice are going to do a congo line around your door. Additionally, insist on any utility entering your crawl space to be installed through access ports seperate from crawl space vents. Any hole made in crawl space vent will also act as access location for critters to get inside. Lastly, investigate your house to see if there are any direct open locations that lead directly into your crawl space. I found a 4" x 16" gap into my crawlspace in my garage. It was covered by some steps so it was actually missed by 3 different inspectors. I trapped more than 50 mice in this location. The gap is now closed by a metal angle and foam sealed.
@@justinballard7242 Our access to our crawl space is in the floor of my husbands closet. It works perfect!
Suggestion….put the access for the crawl space from the corner area of garage floor. Works well….no cold weather,snow or rain to worry about when you do have to be in the crawl space.
The real tip from this Pro is to stop putting all that time and money into a termite floor that is also less stable and pour a monolithic concrete slab with PEX tubing in it for perfectly even heating system at a very low cost.
Hey Matt. I'm tearing down my first brand new spec home in the fort worth area if you want to use it for some content. This is a 500k + home, 3500+ Sq ft under roof.
Why is it being torn down
@@danjimielson utility provider wants to run a new line
@suspicionofdeceit there was an old blanket easement from the 60s on a big parcel. A portion of that property was purchased and split up into a few one acre lots. Since the blanket easement was created a pipeline was installed. When it was replatted it was limited to 30ft. Well the pipeline owner has been planning a new line within that easement and needs it to be 100ft wide to allow enough space for an additional line, but they hadn't broken ground on these properties or adjacent properties, so the old blanket easement, still didn't prevent us from building. When they realized a house was built they had their attorneys reach out to everyone. Since it's just a spec home and not under contract with a future owner, I offered it to them unfinished at a discount. We got the exterior finished and had sheetrock done and were just about to start cabinets when this all started. So we paused it while we finished the negotiation. I got a good deal on the house and then they asked if I could demo the house. A lot of this I learned as I got into it. I knew there was a pipeline, I got title insurance, and everything on our end was by the book, it just happened to get a little bit messy, but at the end I'm selling it for a good price and I get to tear it down which sounds fun to be honest.
How thick is the closed cell under the slab?
I wish I could afford the $1000/sf these guys probably charge.
In cases of high water table or when basement are not an option for sound technical reasons, I agree crawl spaces are the proper foundations. THe crawl space shown here is a giant leap from the typical crawl space design. I would not trust this crawl space will stay dry on its own, I would add a dehumidifer to assure conditions would not support mold growth. Worst thing that can happen is the dehumifier will get really bored, so leave some cross word puzzles behind. I am assuming this house will be blower door worthy. It would be a shame to have a Radon mitigation system installed post build yanking out air after much time/effort was made to make this drum tight so I hope there is some subslab mitigation is already builti in. The typical crawl space designs are ones that involve bare ground facing the floor deck which is supposely protected by fiber glass batting, which has been proven time and time again to be worthless and ineffective. Dare I say the typical crawl space is as inferior as the cardboard siding. The typical crawlspace design should be banned.. codes should focus on either slab or basement, and implement enough incentives to make basements more financially sensable. Crawl spaces should be the exception, but if you have to... use this crawl space design as your starting point and adjust to fit your local codes, lot dimensions and housing footprint.
My thoughts went immediately to radon mitigation options. I would hope that you could install a passive system before pouring the foundation, then if needed just install a fan if required.
Do you have a insulation recommendation for traditional crawlspaces to replace the fiberglass?
@@codyhuber The traditional (open soil) crawl space is obsolete. Depending on your location and condition of your home it might be equivalent or close to the costs to encapsulate your crawl space rather than reinsulate because both should address water damage, mold, and rodent issues before installation. If your crawl space has mold, water damage, and evidence of rodents, replacing the insulation will not correct any of these issues and likely make the problems worse if insulation is applied over them. If your crawl space has these problems, work with a respectable crawl space company that specializes in encapsulation. These companies have standard practices including the proper insulation that also complies with local building codes. If you are encapsulating the crawlspace request your installed use rockwool comfortbatts to be used on knee walls in the crawlspace. This insulation installs easily, maintains its r-value, bugs hate it, mice hate it, its water proof, dampens sound, and is moisture permeable.
@@bricelangston8634 thanks for the thoughtful reply! Do you have any info or links on what people will see inside their homes before and after doing this work? We had serious water issues down there before installing correct sump pump pit and footer drains around foundation. Just basic vapor barrier and water damaged insulation remain currently.
@@codyhuber The best before and after videos would be supplied by Crawl Space Ninja.
A good crawl space is all the challenges of a basement and SoG smoooshed together but this looks like a good one!
How to prevent rain & flood water from getting inside? And in case any, do you have drainage?
If you're building in a flood plane the whole house strategy needs to be reconsidered. If you're only dealing with high ground water, like here, then a good "french drain" around the outside perimeter should be enough. One danger people overlook is simple plumbing leaks inside the house. If a pipe bursts or a washing machine breaks, you can have a considerable amount of water. One thing people do is creating a small sump in one spot of the crawlspace slab, where it drops perhaps 1 foot (30cm). This gives a place for the water to go. Then they put a small sump pump in there that goes on automatically and also sounds an alarm, so that the occupants can know there is a problem.
Lol good luck taking that closed cell foam off when there's a leak!
all the costs of a basement without the benefits
I would love to do this to my current crawlspace. It’s a nightmare the way it is now.
Is foaming under the floating slab necessary down here in the Deep South? I love the idea of a conditioned crawl space but it would be elevated above grade to provide extra protection against potential flooding.
The foam does 2 things here. It insulates of course. But it also blocks the passage of water vapor and moisture upwards from the ground into the house.
In the south you _may_ not need the insulation. But you still need to block the water vapor. So something like a polyethylene plastic sheet is typical. Ten mils thickness is considered the minimum.
If you don't insulate the crawlspace you need to insulate the floor above, in all climate zones. I'm concerned about the possibility that if the floor above is insulated and the unventilated crawlspace is not you may end up with large temperature differentials. This could cause humidity problems. I wouldn't do it.
Really, the best way to go is to insulate the perimeter of the crawlspace, which they did in this video but didn't show. Then make sure the air in the crawlspace is linked to the house above. You can simply do this with a few floor registers. This way the air in the crawlspace is heated or cooled just like in the house. The area of perimeter insulation is less than the floor area so you'll save money this way.
I have a question. When you say your crawlspace would be elevated above grade, do you mean that the floor of the crawlspace would be near ground level, or that the floor of the house above would be raised more? If it's the first, then you're basically creating a concrete slab on grade and making your ground floor a "crawlspace". That's certainly acceptable and a good solution in a lot of areas. Traditionally this was done in the south routinely until the mid-20th century. But often the space was left completely open on all sides, with the house elevated on piers. This was a great strategy for protecting the house from termites, as well as decoupling it from ground moisture.
If you meant that the crawlspace floor would be a few feet below grade but that the first floor above would be elevated a few feet, then what you have is a semi-basement. That's got advantages as well since you can even get full headroom and use it as living space. It's an ideal solution for sites that slope 3-5 feet. Then you can have a walk-out basement.
To learn a lot more of the techniques and options I suggest you go to the "Build America Center" at the Dept. of Energy website. It's a great resource for this stuff. I can't post links but you should be able to search "build america center department of energy" and it will be near the top of your search results.
@@HistoricHomePlans thanks for the in-depth reply and explanation. Yes I was referring to where the floating slab would be ground level (or maybe lower depending on the water table) and stem walls would extend 2-3 feet above ground level and then the first floor of the house would sit on top of that. A semi-basement would be nice, especially if I can dig 3-4 feet below grade without hitting water, but living in southern Louisiana, that’s gonna be difficult. Now granted, the property is on solid land well above sea level and not on the deposit plain of the Mississippi where New Orleans and the southern parishes now sit. All that land below Lake Pontchartrain was created by sediment from the river.
A lot of new construction that I see here in New Orleans are built on raised slabs. They drive down pilings, construct stem wall foundation, fill it in with dirt and gravel and then pour a slab on top. My current house here in the city is about 120 years old and was built in piers, my crawl space is wide open to the elements and the critters-had to drag out a dead opossum one time which was smelling pretty ripe, not fun!! Before I moved in, there was no insulation and no subfloor. I can literally see daylight through the floor boards. I had about 2 inches of closed cell spray foam applied to the under side of my floor and 5 inches of open cell under my roof deck. It helps but this house is still an old shotgun-style house. It doesn’t even have sheathing on the exterior wall, just horizontal lap boards!
@@HistoricHomePlans Is it just for water vapour or liquid water as well?
I want to build ever crawlspace like this. The trick is getting clients to pay for it!
A cheaper option would be to put down a poly membrane and a couple of layers of EPS foam sheets, and then pour a thin concrete slab over the foam. Carry the foam up the inside walls of the crawlspace. Some jurisdictions might require the foam be covered for fire protection. That varies by locality.
An even cheaper approach would be to insulate with EPS outside the foundation. And then just put down a 10mil poly membrane and slab right over it. If the foundations are insulated around their perimeter on the exterior side you don't need any insulation at all inside the crawlspace. This is the approach I detail out on the projects I design.
The spray applied closed cell foam is certainly practical. But it is expensive and it is among the worst foam insulations in terms of environmental damage. I avoid it.
I've got a 3ft conditioned crawlspace. Above ground due to water table. So my house is 4 ft taller than a standard house
There is a flood plain in our area that they got permits to build on. The garage and play room are on the first floor with concrete slab and a drain hole. It floods like every 5 years. So people only put lawn furniture down there. Or they take the time to move everything upstairs right before it floods.
The front door has a full staircase. I have no idea what people do with their car when it floods.
What’s the Radon mitigation in this instance?
Don't see why it needs to be any different than a basement, dig a 4' hole out of the slab and suck air to the outside. Gravel existing under the slab will be key.
@@raterus I agree. I just didn't see any stubs coming out of that slab. When building over ledge, there will be radon. and possibly a lot of it.
Probably because the whole floor is sealed off with the spray foam with no perforations compared to a traditional concrete floor with expansion crasks and volunteer cracks.
Best crawlspace has 6 foot ceiling.
Go 2 more feet and you have a comfortable full height ceiling.
@@HistoricHomePlans yeah but then its a basement. 6 foot is just enough to walk straight up and still call it a crawl/walkspace