Thanks Vinny We have all enjoyed your humour. It takes a lot to come up with a funny comment on nearly every video but you have done it. RUclips should honour your contribution.
I've watched dozens of videos to help decide what to do about my 90 year old basement. Most are advertisement of some commercial product. This is by far the most informative and complete discussion of water management in a basement. Thanks so much!
spot on with this description i have fitted 2 of these with the sump pumps and still working ok to this day the one it was raining hard and the cellar was flooding badly and we didn't have the correct fitting for the waste supplied by the company we were about an inch before it flooded totally thank god my neighbour plumber had it in his van and the builder drove to his house to pick it up problem solved and its been 10 years and no problems reported
I would like to add that understanding and directing drainage around the foundation is extremely helpful. Clay around your foundation will be forever soaked, so that is a problem, light turf soil not so much. Coarse sand allows more flow. Fine sand densely packed against the wall creates a barrier. Gravel at the bottom helps runoff. You can use gravel trenches as buffers. Relatively simple groundwork with basic materials used strategically can do a lot for moving water away from your structure.
When you think about the wall construction fundamentals, you have a lot of 'layers'. The outside wall for protection against bulk water and to protect the insulation from UV, mechanical damage and bugs. You have the cavity, for draining and drying. You have the four control layers (thermal, vapor, air, water). On the inside/warm side you have the structure, for sheer and keeping things upright. When building a basement, people throw these fundamentals out of the windows and have complete faith in a 'waterproof' concrete wall and floor. No wonder things go wrong so often... Like you said in the video, try to waterproof the outside and apply some kind of drainage plain (like the dimple drainage board), to have it more like a typical wall construction, as I explained earlier. Some general advise regarding basements: - Don't use traditional building materials, like wood studs and drywall, in a basement due to the higher moisture. These organic materials tend to rot and mold more easily. - Instead use metal studs, foam insulation, proper vapor barriers, paperless drywall, synthetic baseboards, and pvc flooring. - If you insulate from the inside, try to make a ventilated wall cavity, to reduce humidity and dry any damp. - Grading around the house must slope away from the house, to reduce hydrostatic pressure against the basement wall. - And monitor the humidity levels inside the basement.
We have Georgian (1805) house with a cellar. It is built on the edge of a flood plain with a hill on the other side. We get ground water flooding about 15cm deep in the cellar a couple of times each year and generally it drains within 3 hours after flooding. We assist that with a sump pump. Not a major problem. When the river floods above the banks it saturates the groundwater and the cellar floods about waist deep, we keep a 3 inch petrol pump handy to handle that infrequent event. When they built the house they knew about the floods hence no real damage is caused to the structure.
Our old friend used to build houses many years ago with his business partner. He is very good. This one day however they were digging foundations for it and were having a break when the neighbour came out. He asked "Will your work affect my basement office?" They said with surprise "What!?" No one had told them in planning that the house next door had a basement and that most of the houses in that street did. They had to adjust their digging and go down deeper and obviously support the wall where nexts doors basement was. That could of ended badly.
Best lecture it dicusses techniques people find agter many years of experience. The issues he is mentioning are so common and after watching this, he videos are wel researched, well edited and save time money and hassle after watching his videos
Interesting to hear him call sump pumps a remedial solution. They're both code requirements in most US basements, along with drainage systems. Then again, they have houses older than our country over there. ;)
I used to work for a preservation company and we do basement waterproofing and yes there’s a lot of things to know and main company we used was Delta and Newton
It's good to see you also having the same view as me about letting the moisture/water get in through an existing basement wall, collecting behind the Newtonite type layer and catching it in a recess around the base of wall with a french drain type pipe which takes it to a sump to be pumped out. I never like the idea of tanking the inside surface of a wall trying to hold the water pressure back as you only need one small imperfection, especially lower down where the hydrostatic pressure is greatest. If you are doing a new build with concrete walls then it does not matter how good the waterproofing concrete itself is, you will never get water entering through a concrete wall or slab. Like you said at beginning, it can over top the wall, or it comes through the junction of the base to the wall or the junction in the wall. Preventing water coming in at the base/wall junction (and you will always have to have a junction/joint here) is done by the use of a plastic water bar that you put either on the outer face or in the middle of the joint with half in the base part and the other half in the wall. The principle is that it makes the water path incredibly long and due to all the ribs, the concrete actually contracts and forms a seal. You talk about the walls being poured in one continuous pour, but I was always brought up to have movement/contraction joints at 6m otherwise you get drying out/contraction cracks in the wall. That is how underground reservoirs are constructed. I'm a structural engineer by the way!!
We must have watched different videos. He NEVER said let the water in and into a French drain. He said if you have to do the waterproofing from the inside use crystalline waterproofing. Which is the correct way to waterproof from the negative side.Then add the drain as a backup in case of failure. But the truth is ,if crystalline waterproofing is installed correctly it rarely fails. But I can’t argue with redundancy when waterproofing. And what do you mean that it doesn’t matter how well the concrete is waterproofed water will never go through the concrete. It absolutely does matter how well it is waterproofed. Water WILL go through concrete.If it is not properly waterproofed.I have been in the waterproofing industry for over 45 years and have waterproofed more foundations than I can count. On everything from single family homes to 50 story high rises with five stories of mechanical rooms and parking below grade and I have NEVER seen an expansion joint or control joint in a foundation wall.
Very accurate video, the number of house having water issues because of misplaced french drain must be staggering. While everything is dug up, putting the french drain a foot lower is very easy and makes all the difference but most people installing it really don't know.
I've just finished building our house, and we've put a basement in, which is part of the reason went for a Polar Wall ICF building. So far so good and zero moisture down there! Also helped having UFH and MVHR to keep the condensation at bay!
Hi Roger, great to see our work illustrated in your video, I feel privileged to have been part of your channel, looking forward to seeing you up north,
I don’t even have a basement, but I was still very interested to watch this. It definitely doesn’t seem like a DIY job, but as with all these projects it’s very important to build up your knowledge before embarking on it, so as to ensure you don’t end up getting some rogue traders in doing the work! Happy to volunteer my help digging if it’s in the south?
Very informative. I found one of the biggest problems was penetrations, especially drainage, even using puddle flanges. The most successful (and expensive) basements I had involvement with, was using two coat mastic asphalt internally, with a loading floor and loading walls. The big advantage being you could fix anything to the floor and walls.
Thanks for the video very interesting. I have been thinking about doing something with my basement but I think I'll just leave it and let it breath as it always have.
I recently came across your channel thanks to your noisy plumbing video. Now I'm addicted! I love your explanation of things, I find it all very interesting, even if I don't end up doing half the things you are talking about. Keep up the great work.
Great video. I have a 93 mq basement, which is amazing because it has 2 windows and the ceiling is 3.30 m high. Problem is I can't really dig outside (with the exception of one side) the house and it should be insulated from the inside, as you described. But that is a hell of a job, that costs a lot of money, therefore I never did it. I have also dump issues that I am trying to fix with dryrods. I hope they work because my walls are 70 cm and I had to buy a lot of these rods.
also may i add that water can float a basement and even shear it away from and engineering tie in (including rebar and brick concrete tie in methods) to counterbalance the pressure on the external wall and even on the basement floor, bore holes can be drilled in the bottom of the basement floor and sump pumps scattered so to balance the pressure of the water under the basement. For very large basements, floor sump pumps can even be positioned so to level off a structure and even-out the pressure from below a basement floor. So sump pumps not only get ride of the water but can also be used stabilize a building, this method was used on a hospital positioned along the Thames river, as the water table height can be quite low . even thou the basement was tied in with extensive rebars, the rebar snapped due to the the sheer force of the water table. solution - 8 sump pumps positioned so to keep the water out and each electronically controlled to float the basement on the water table/ground (ps the basement moved 2 feet so tte sump pumps were used to float/move the basement back into position) sounds impossible but true.
Not basement related but I put perf pipe round an outbuilding below raft foundation that got soggy sometimes, fed off to a soakaway and excavated down side of it and put 25L mixing bucket full of holes and wrapped in landscape fabric. Cut a hole in a patio tile so I could put sump pump down there for really bad rain.
My friend lives in a Victorian Terrace house with an original basement, 50 yards away is a deep railway cut. When it rains heavy, the cut floods but not the old basement! Water taking the easy route.
Wow, just the video I need. Most likely having a new basement under the new extension this year, will be watching this with interest. Already planned for the French drain system as I live on a slight slope and can drain away naturally. Is there much steel reinforcing involved and how thick are the walls?
You didnt mention some important details. where is the project loacted? Gradient of ground above and below walls that require tanking? (Slight is subjective) Depth of excavation? Do you have existing stormwater drains available for those proposed french drains?
Thank you for yet another interesting video! What is your opinion on the use of breathable systems for insulating/draining basements? We are primarily installing the isodran systems here in Northern Sweden. It is dependent on having the basement heated to dry out the basement wall. You insulate the outside and leave the basement wall naked. The idea is that water will run on the outside of the insulation and perhaps on the wall down to drainage pipes at the bottom of the basement foundation. The water is then transported to a pump well or some other water collecting system. The insulation consists of 100mm sheets of EPS beads covered in tar that allows for water transfer through it. I think it has worked well for the installations that we have done but I think with too much water on the outside the system could be oversaturated.
Roger, every time I watch one of your videos am learning something I even saved myself a lot of hassle cleaning the silicon with bleach as you suggested n the results where way better than I was expecting, year ago I think it was mid 80I was asked to do some plumbing n some electrical work in Hackney, when I got there they had couple of dehumidifiers in the basement n some heaters to dry the basement up, the bloke said to me we are not quite ready yet mate best you come back in couple of weeks, I asked them what they where doing n he said we nee to dry the basement well n then "tank it" basically he said once the place is totally dry we will paint the walls with tar n then render over it with waterproofing render then he said problem solved, so I asked what happens after everything it done will the tar n rendering not come away from the wall falling down in chunks he said No I give my customers a 20 year Guarantee, told him but u wont be around the first winter mate let alone 20 winters later guess what I never went back after that, but am "sure he would have honoured his guarantee" if they could find him LOL
Planting anything on the face of the internal wall to hold back water is a waste of time. The hydrostatic pressure will blow it off. The British Standards show another skin of masonry so the membrane is held in place. I bet that job failed. Bitumen paint is not a great idea
Love it you share this so important knowledge. Have researched this a little, but there is conflicting or not totally thought through designs out there. You give the information I need 😊
Love the bit at begging Rog. So true been in many old buildings in hove where they shake as busses go past because people have took stud walls out in hove not realising there load bearing just assume there not needed because their stud
Excellent vidéo Roger !! You perfectly covered that topic… maybe the only point you didn’t mention is water getting in through the concrete floor in the basement though capillarity effect …
You showed the French drain ideally being below the wall level rather at the bottom of the wall level. However you hopefully have foundations below the bottom of the wall!. Is it better to have the bottom of the French drain level with the bottom of the foundations - and not below it so that you minimise under-mining the foundations itself? I find adding a damp proof plastic sheet layer that covers the wall and down to the bottom of the foundation reduces any risk of any issues. Adding a rodding port to allow clearage of any sift after years of service also helps. I find putting the French drain itself within a filter membrane increases the risk of silt clogging the holes on the French drain itself and the risk of having to dig it up again in the future.
I wonder how many existing basements are actually done properly- I bet it’s not many, especially in older houses. I’d be extremely cautious of buying or even renting a basement property. So many possible issues. Generally people didn’t use basements for anything other than storage in the old days, so they weren’t made to be perfectly warm and dry. Looks like a hugely expensive nightmare to retrofit an old basement to come up to living-in standards, and a pretty hugely expensive one even if it’s a new build. Best avoided altogether I’d say. I looked at a flat with a basement when I was buying a house - they’d recently renovated it, and it looked clean and new, but I could tell it was basically just tanked and sealed, with standard plasterboard put over it and would probably last a year or so before you started seeing damp issues. Jogged on from that one.
Hi Roger, Excellent video very informative. Quick question in the last part of the video where you insulate from outside and use the French drain. In relation to the floor how do you prevent water coming from that direction, Thanks Mark
Dad had a basement built two lots of waterproofing, still had a small leak tiny , cement mixed with antifreeze, worked a treat maybe it worked like the crystal cement, anyway that was back in the nineties, haven't seen any leaks since it not a habitable space👍👍👍
Basements seem to be more common in France and Germany, often used as garages. They seem to me to be dry and damp free and I’ve mainly visited in the summer. How can this be? This video reminded me of the John Lewis store in Kingston, it has a Waitrose in the basement and then two levels of underground parking under Waitrose, three level basement and right next to the Thames. The building must have been built to very high standards as the car parks do not appear to be damp, the video made me aware of the complexity of that build. Under the new home office building in London that used to be Dept of Environment has huge i.e very deep underground structures beneath the office block.
@@disklamer London is built on clay with a high water table, challenging for engineers. They seem to be up to the challenge as there has been a huge amount of subterranean construction under London, some purposely not on any maps/drawings. There have been several serious problems where the construction of super basements in residential properties have collapsed, resulting in damage to neighbouring properties. Jimmy Page (Led Zeppelin) and Robbie Williams had a big falling out as neighbours regarding Williams’ super basement.
Humidity is not a problem in winter because the outside air is dry at low temperatures. It may be at a 100% relative humidity at -5°C, after it warms up in the house to 10-15°C, it's essentially dry (10-15% rH). So in winter the best way to dry your house is to ventilate it with outside air when it's cold outside (commercial objects usually have humidification systems installed in a central HVAC unit, but that's another topic). In summer, the outside air has a lot of moisture, even if it's relatively dry at 40-50% relative humidity, at 30°C. When this cools to 20-22°C in the night, the air is at 100% rh. So ventilating your cellar in summer is gonna be a bad idea. I'm having damp issues in my cellar, thanks for the video series concerning the topic.
I understand that paradox with dragging moist air in and I did hesitate to say it but a lot of people have a humidistat on a fan and it seems to help especially if it is on during the night
Correct. We have mvhr running in our victorian basement most of the year but turn it off in the summer and run our dehumidifier to keep the RH down working a treat!
Hi Roger, this is a great information. Thank you. I am not sure is when you insulate with polystyrene and DPC from outside, you are tucking in the membrane into wall. But at what height? Is this 150mm above Ground Level? In that case it will expose and can see it from outside? I have a small basement store under stair and I have got to do all 4 side walls and floor. So I am thinking just to go for surface coating 2 x coats plaster. I actually wanted to use this space for a attached en-suite. Is that treatment enough then tile from inside? Much appreciate it if you could advise me.
You material is really excellent - so detailed and so realistic. As for basements, you are dead right. They won't be waterproof and the only way is to provide a way to get rid of the water that gets in.
Insulating from the outside is not possible in my case, what type of insulation would you recommend from the inside? Foam board, fiberglass wool, spray foam, etc? Would I put another vapor barrier between the insulation and gypsum so that the condensation doesn't affect the insulation? Thank you
My trade is a plumber but I wrote articles for the building trade press for over 30 years and have been on countless training courses. Some of it sticks in my brain
Your neighbor should sue his architect. It is complete negligence to have the soil above the foundation wall. Keeping the join of cavity wall above any horizontally moving water. This has absolutely nothing to do with Sika. I have been in the waterproofing industry for over 45 years n the USA. I disagree about the “dimple board” being waterproofing ( I know technically it is but it relies on mastic sealing the sheets together. Not acceptable in my opinion. We only use it as protection and drainage over a proper waterproofing membrane as you showed.And thank you for only recommending crystalline waterproofing for blind side waterproofing. Finally someone that actually understands waterproofing . There is so much misinformation about waterproofing and sealants on RUclips.
Hey Roger, I dug out my own basement that included going 60cm wide under the existing founds of the back wall. It was boulder clay and I was 50 yrs old. It was the hardest work of my life, and I’m a very hard worker. I then concreted the walls shuttering ‘pockets as I went. The walls were all 60-80 cm deep. I used little rebar, and ended up having to get an engineer to design surface beams on the inside. I then put a 1m sump pump with French drain in to it that circled under the floor slab. With the sumo working to take the water table directly in to the land drainage via a pump I’ve had only a little water ingress. Here’s the shocker, I’m midd terrace!. I made a lot of mistakes. I should have used a structural eng. instead of listening to the architect. The wall should have gone in after the floor, but how do you keep the soil from caving in. I suppose I could have used corrugated sheet but I was in a limited budget. The walls should have been designed with rebar to reduce these being 60+ cm deep. Digging down is a killer. Get hell, get professional guidance re the design and ensure you get a structural engineer. I had a bit of a leak over the top of the concrete wall head where it meets the existing foundation. I decided to drill a hole right through to the source of that water and inserted a 25mm stainless tube and ran a 20mm flexi pipe to the sump and it dealt with the]at problem. It’s just a store for my amassed tool kit (I’m a cabinet maker but done it all as they say) if you want pictures or any thing you think may be of hell do get in touch. If there is any other way to add space to your house, do not dig a basement!!!
@@SkillBuilder you’re amazingly good at responding to the “little people”. Love that! I’ll take a video of my basement but I’m not altogether sure how to upload that to you. I’ll certainly have a go on Monday at some point. Every blessing Peter (arch angel)
ello Fella, I have to say what you conveyed to us all is right on with facts. I have a question for you about basement walls that are 8 inch wide cinder blocks. The inside of the blocks have 3 hollow oval radius on the ends with roughly six inches long length that face the outside and inside walls of the basement. Would filling them with aircrete or aircrete styrofoam mix for insulation and waterproofing ?? Also, was thinking coating the inside wall with hydraulic cement 1/2" to 3/4"thick two layers to totally waterproof the basement walls ??? I do not have time or the funds to take care of the outside of the home. Drop me a line with your opinion for me to consider. Thanks VF
The principles are the same, albeit pokering / vibrating the concrete within can be problematic, and of course, differing substrates naturally require differing systems, i.e., elasomeric products as the primary waterproofing are good, with fibre mesh reinforcement embedded in to it, followed by Rogers guidance regarding drainage protection sheets, linked to appropriately sited land drainage, with rodding eyes to prolong their service lives is a great way to reduce risk further as well.
There is a block wall in my basement,it continously is generating mould, would it be beneficial to drill holes to fill the inside of the blocks with expanding foam?
Great video Roger. I heard you also have the option of a suspended timber floor and have the sump pump under that. Sounds like a better option for drainage but not sure about how well the floor would cope with no air circulation. Or alternatively suspended concrete beams with blocks in between. Any thoughts
Ive got a cellar in a home built 1863. Ive got problems that have been over 40 plus years including court action against the local Water Authority. Section 24 sewer issues. Since leakage is in heavy rain and due to hydrostatic lift which doesnt occur every year.There is now know for there to be in the sewers, building debri from major demolition works from 27 years ago coupled with sink holes in the area. The Water Authorites defence was legal technicaly in an attempt to bankrupt me before the case could be heard.There solicitor admitted before the Judge they had no defence other than legal technicality. What people can afford a case thats estimate was over 1 million pounds sterling.Preceeded by solicitors argueing the case at £350 - £ 500 a letter. Even solicitors via Pro Bono wouldnt touch it since the defendants stratagy in defence would be to deliberatly escallate the case costs to make the case unaffordable. British justice at its best.
Hi Tim We did a video about Thames Water washing their hands of a problem. I think the cost of brining a case against them is outrageous. There is no justice if it is only for the rich
@@SkillBuilder Yes thats the defence make the case uneconomical to take to court.I am still waiting for the Water Authorithy to deal with an issue pre Christmas which included flooding of cellarage.Will see if i can find and view your video. At the time i was advised if i won the court case it would be a case pressident.
Traditional tanking grade mastic asphalt in three coats with a single brick wall and loading concrete to base ,I know not exactly modern but very affective .
Thanks Roger, really good stuff, so many ‘poo traps’ even for professional designers and specialist installers to fall in. It would seem that a sizeable sump/pump should be integral in every design as part of Plan A.
I had my basement/ceilar tanked a few years ago, it is this damp, not sure if it was do work not done properly(was not cheap) not too sure what to do now. Any help/advice would be greatly appreciated. I am based in Leicester if you want to visit. Thank you
Building now basement with 6 inch cavity wall. What do you think about this ? And bitumen paint outside 5 coats. And yes, 6 inch French pipe below the basement Slab.
Great, non exhaustive video Roger, which clearly sets out the main principles, and I think we should all have a whip round and get you some new young labourers to do the digging for you Sir ;-)
So the upshot is don't have a basement ha ha, "Where's James"? he could help lol. Thanks Roger, my sister is having issues with her basement with water coming in, in certain rainy situations. Her house is in Gillingham in Kent. No significance there. Maybe she could use some of these ideas. Reminds me of the time my brother built a concrete septic tank on the side of a hill outside his property with a footpath lower down the hill, it failed and I can just imagine the walkers looking up in horror as a wall of P*** and S*** hurtled towards them. The weight of water is much underestimated.
Scope of waterproofing is defined in types. A B C for internal and external applications. Do research viewers the British standards BS8102 of waterproofing in below ground structures .
Over the past couple of years I have genuinely learned more from Roger than anyone else! We appreciate all the content Thank you 🙏🏽
Thanks Vinny
We have all enjoyed your humour. It takes a lot to come up with a funny comment on nearly every video but you have done it. RUclips should honour your contribution.
I've watched dozens of videos to help decide what to do about my 90 year old basement. Most are advertisement of some commercial product. This is by far the most informative and complete discussion of water management in a basement. Thanks so much!
Man i wish this guy was my grandpa. This is the type of inteligence i respect the most, practical usefull knowledge.
spot on with this description i have fitted 2 of these with the sump pumps and still working ok to this day the one it was raining hard and the cellar was flooding badly and we didn't have the correct fitting for the waste supplied by the company we were about an inch before it flooded totally thank god my neighbour plumber had it in his van and the builder drove to his house to pick it up problem solved and its been 10 years and no problems reported
I'm not a builder but I really appreciate the time and effort you gift to make these fantastic videos. Thanks
I would like to add that understanding and directing drainage around the foundation is extremely helpful. Clay around your foundation will be forever soaked, so that is a problem, light turf soil not so much. Coarse sand allows more flow. Fine sand densely packed against the wall creates a barrier. Gravel at the bottom helps runoff. You can use gravel trenches as buffers. Relatively simple groundwork with basic materials used strategically can do a lot for moving water away from your structure.
Can you recommend anywhere to learn these basic methods?
When you think about the wall construction fundamentals, you have a lot of 'layers'. The outside wall for protection against bulk water and to protect the insulation from UV, mechanical damage and bugs. You have the cavity, for draining and drying. You have the four control layers (thermal, vapor, air, water). On the inside/warm side you have the structure, for sheer and keeping things upright. When building a basement, people throw these fundamentals out of the windows and have complete faith in a 'waterproof' concrete wall and floor. No wonder things go wrong so often...
Like you said in the video, try to waterproof the outside and apply some kind of drainage plain (like the dimple drainage board), to have it more like a typical wall construction, as I explained earlier.
Some general advise regarding basements:
- Don't use traditional building materials, like wood studs and drywall, in a basement due to the higher moisture. These organic materials tend to rot and mold more easily.
- Instead use metal studs, foam insulation, proper vapor barriers, paperless drywall, synthetic baseboards, and pvc flooring.
- If you insulate from the inside, try to make a ventilated wall cavity, to reduce humidity and dry any damp.
- Grading around the house must slope away from the house, to reduce hydrostatic pressure against the basement wall.
- And monitor the humidity levels inside the basement.
We have Georgian (1805) house with a cellar. It is built on the edge of a flood plain with a hill on the other side. We get ground water flooding about 15cm deep in the cellar a couple of times each year and generally it drains within 3 hours after flooding. We assist that with a sump pump. Not a major problem. When the river floods above the banks it saturates the groundwater and the cellar floods about waist deep, we keep a 3 inch petrol pump handy to handle that infrequent event. When they built the house they knew about the floods hence no real damage is caused to the structure.
Our old friend used to build houses many years ago with his business partner. He is very good. This one day however they were digging foundations for it and were having a break when the neighbour came out. He asked "Will your work affect my basement office?" They said with surprise "What!?" No one had told them in planning that the house next door had a basement and that most of the houses in that street did. They had to adjust their digging and go down deeper and obviously support the wall where nexts doors basement was. That could of ended badly.
most underrated video ever !, anyone else seeing this
Best lecture it dicusses techniques people find agter many years of experience. The issues he is mentioning are so common and after watching this, he videos are wel researched, well edited and save time money and hassle after watching his videos
Interesting to hear him call sump pumps a remedial solution. They're both code requirements in most US basements, along with drainage systems. Then again, they have houses older than our country over there. ;)
You have to take in account that it is a lot wetter here in the uk,we have lots of rain yearly
It’s great to listen to someone explain it like yourself better than the professionals could ever do cheers mate Diamond block
I used to work for a preservation company and we do basement waterproofing and yes there’s a lot of things to know and main company we used was Delta and Newton
It's good to see you also having the same view as me about letting the moisture/water get in through an existing basement wall, collecting behind the Newtonite type layer and catching it in a recess around the base of wall with a french drain type pipe which takes it to a sump to be pumped out. I never like the idea of tanking the inside surface of a wall trying to hold the water pressure back as you only need one small imperfection, especially lower down where the hydrostatic pressure is greatest. If you are doing a new build with concrete walls then it does not matter how good the waterproofing concrete itself is, you will never get water entering through a concrete wall or slab. Like you said at beginning, it can over top the wall, or it comes through the junction of the base to the wall or the junction in the wall. Preventing water coming in at the base/wall junction (and you will always have to have a junction/joint here) is done by the use of a plastic water bar that you put either on the outer face or in the middle of the joint with half in the base part and the other half in the wall. The principle is that it makes the water path incredibly long and due to all the ribs, the concrete actually contracts and forms a seal. You talk about the walls being poured in one continuous pour, but I was always brought up to have movement/contraction joints at 6m otherwise you get drying out/contraction cracks in the wall. That is how underground reservoirs are constructed. I'm a structural engineer by the way!!
We must have watched different videos. He NEVER said let the water in and into a French drain. He said if you have to do the waterproofing from the inside use crystalline waterproofing. Which is the correct way to waterproof from the negative side.Then add the drain as a backup in case of failure. But the truth is ,if crystalline waterproofing is installed correctly it rarely fails. But I can’t argue with redundancy when waterproofing. And what do you mean that it doesn’t matter how well the concrete is waterproofed water will never go through the concrete. It absolutely does matter how well it is waterproofed. Water WILL go through concrete.If it is not properly waterproofed.I have been in the waterproofing industry for over 45 years and have waterproofed more foundations than I can count. On everything from single family homes to 50 story high rises with five stories of mechanical rooms and parking below grade and I have NEVER seen an expansion joint or control joint in a foundation wall.
I'd help dig. Worth it for the education. Serious too!
Cheers Roger! I have a flooded WW2 bunker under my house I need to deal with. Thanks for the tips!
Very accurate video, the number of house having water issues because of misplaced french drain must be staggering. While everything is dug up, putting the french drain a foot lower is very easy and makes all the difference but most people installing it really don't know.
I am not even thinking of building a basement....and If I did I'd whatsapp Roger to do it...and yet... *_here I am_* 😂
Likewise 😂
You could always volunteer to dig his ...
Call me. I’ll do it.
Your videos helped with my bathroom refurb - thank you!!
I've just finished building our house, and we've put a basement in, which is part of the reason went for a Polar Wall ICF building. So far so good and zero moisture down there! Also helped having UFH and MVHR to keep the condensation at bay!
Izodom 2000 for me. No basement though.
Hi Roger, great to see our work illustrated in your video, I feel privileged to have been part of your channel, looking forward to seeing you up north,
Many thanks for your help Rubi, Rubi, Rubi. We will certainly come and see you in sunny Leeds. Not that you see a lot of sun in your underground lair.
@@SkillBuilder and you still managed to call me Rudi hahaha
I don’t even have a basement, but I was still very interested to watch this. It definitely doesn’t seem like a DIY job, but as with all these projects it’s very important to build up your knowledge before embarking on it, so as to ensure you don’t end up getting some rogue traders in doing the work! Happy to volunteer my help digging if it’s in the south?
Very informative. I found one of the biggest problems was penetrations, especially drainage, even using puddle flanges. The most successful (and expensive) basements I had involvement with, was using two coat mastic asphalt internally, with a loading floor and loading walls. The big advantage being you could fix anything to the floor and walls.
Hi Paul, Asphalt internally, loaded or not, is not a great idea, and the latest revisions to BS;8102,2022 will offer guidance on penetrations too.
Very kind of you to share this technical info...
Thanks for the video very interesting. I have been thinking about doing something with my basement but I think I'll just leave it and let it breath as it always have.
Any change?!
I recently came across your channel thanks to your noisy plumbing video. Now I'm addicted! I love your explanation of things, I find it all very interesting, even if I don't end up doing half the things you are talking about. Keep up the great work.
Glad you like them!
Hey thanks for the knowledge. I learned a French drain today and where to put it.
Great video. I have a 93 mq basement, which is amazing because it has 2 windows and the ceiling is 3.30 m high. Problem is I can't really dig outside (with the exception of one side) the house and it should be insulated from the inside, as you described. But that is a hell of a job, that costs a lot of money, therefore I never did it. I have also dump issues that I am trying to fix with dryrods. I hope they work because my walls are 70 cm and I had to buy a lot of these rods.
Very informative. We live in an area with a very high water table and moisture is a constant problem
Cheers Roger, brilliant explanation 👍
I was involved in Nudura ICF job in Kent last year, worked well, high up though so no probs. Good job explaining Roger 👍
Could it be the same job in Longfield?
@@SkillBuilder afraid not, 7oaks 👍
also may i add that water can float a basement and even shear it away from and engineering tie in (including rebar and brick concrete tie in methods) to counterbalance the pressure on the external wall and even on the basement floor, bore holes can be drilled in the bottom of the basement floor and sump pumps scattered so to balance the pressure of the water under the basement. For very large basements, floor sump pumps can even be positioned so to level off a structure and even-out the pressure from below a basement floor. So sump pumps not only get ride of the water but can also be used stabilize a building, this method was used on a hospital positioned along the Thames river, as the water table height can be quite low . even thou the basement was tied in with extensive rebars, the rebar snapped due to the the sheer force of the water table. solution - 8 sump pumps positioned so to keep the water out and each electronically controlled to float the basement on the water table/ground (ps the basement moved 2 feet so tte sump pumps were used to float/move the basement back into position) sounds impossible but true.
Very Comprehensive Roger .... Wish this was around when I was in the game (As a Plasterer) 👍😎
Thanks Roger, very informative as usual!
So straight forward and practical.
Not basement related but I put perf pipe round an outbuilding below raft foundation that got soggy sometimes, fed off to a soakaway and excavated down side of it and put 25L mixing bucket full of holes and wrapped in landscape fabric. Cut a hole in a patio tile so I could put sump pump down there for really bad rain.
My friend lives in a Victorian Terrace house with an original basement, 50 yards away is a deep railway cut. When it rains heavy, the cut floods but not the old basement! Water taking the easy route.
Wow, just the video I need. Most likely having a new basement under the new extension this year, will be watching this with interest.
Already planned for the French drain system as I live on a slight slope and can drain away naturally.
Is there much steel reinforcing involved and how thick are the walls?
You didnt mention some important details.
where is the project loacted?
Gradient of ground above and below walls that require tanking? (Slight is subjective)
Depth of excavation?
Do you have existing stormwater drains available for those proposed french drains?
Thank you for yet another interesting video! What is your opinion on the use of breathable systems for insulating/draining basements? We are primarily installing the isodran systems here in Northern Sweden. It is dependent on having the basement heated to dry out the basement wall. You insulate the outside and leave the basement wall naked. The idea is that water will run on the outside of the insulation and perhaps on the wall down to drainage pipes at the bottom of the basement foundation. The water is then transported to a pump well or some other water collecting system. The insulation consists of 100mm sheets of EPS beads covered in tar that allows for water transfer through it. I think it has worked well for the installations that we have done but I think with too much water on the outside the system could be oversaturated.
Looking forward to seeing the live project.
Great film, thanks Roger
thanks so much man always pleasure to learn something new
Yes, I would like more on waterproofing please
Great content, I hate basements water damp mold ( mould ) what’s to like about them
Roger, every time I watch one of your videos am learning something I even saved myself a lot of hassle cleaning the silicon with bleach as you suggested n the results where way better than I was expecting, year ago I think it was mid 80I was asked to do some plumbing n some electrical work in Hackney, when I got there they had couple of dehumidifiers in the basement n some heaters to dry the basement up, the bloke said to me we are not quite ready yet mate best you come back in couple of weeks, I asked them what they where doing n he said we nee to dry the basement well n then "tank it" basically he said once the place is totally dry we will paint the walls with tar n then render over it with waterproofing render then he said problem solved, so I asked what happens after everything it done will the tar n rendering not come away from the wall falling down in chunks he said No I give my customers a 20 year Guarantee, told him but u wont be around the first winter mate let alone 20 winters later guess what I never went back after that, but am "sure he would have honoured his guarantee" if they could find him LOL
Planting anything on the face of the internal wall to hold back water is a waste of time. The hydrostatic pressure will blow it off.
The British Standards show another skin of masonry so the membrane is held in place. I bet that job failed. Bitumen paint is not a great idea
Love it you share this so important knowledge. Have researched this a little, but there is conflicting or not totally thought through designs out there. You give the information I need 😊
Great knowledge and education thanks Roger
Love the bit at begging Rog. So true been in many old buildings in hove where they shake as busses go past because people have took stud walls out in hove not realising there load bearing just assume there not needed because their stud
I was in Hove today.
@@SkillBuilder work of pleasure mate? Not much pleasure in brighton and hove anymore time downhill
Excellent vidéo Roger !! You perfectly covered that topic… maybe the only point you didn’t mention is water getting in through the concrete floor in the basement though capillarity effect …
I am assuming that the floor is hacked up and a membrane laid
@@SkillBuilder good point.
Great video mate. Thanks 👍🏽
Thank you! I learned a lot !!
You showed the French drain ideally being below the wall level rather at the bottom of the wall level. However you hopefully have foundations below the bottom of the wall!. Is it better to have the bottom of the French drain level with the bottom of the foundations - and not below it so that you minimise under-mining the foundations itself?
I find adding a damp proof plastic sheet layer that covers the wall and down to the bottom of the foundation reduces any risk of any issues. Adding a rodding port to allow clearage of any sift after years of service also helps. I find putting the French drain itself within a filter membrane increases the risk of silt clogging the holes on the French drain itself and the risk of having to dig it up again in the future.
I’d help you dig Rog, but I’m in NI. Great videos btw and very informative. 👍🏻
Decent explanation Roger. Always prudent to follow BS 8102 👍
It's 2022 revision is out now too Ross.
Thank you for sharing. Really quality info.
Glad it was helpful!
I wonder how many existing basements are actually done properly- I bet it’s not many, especially in older houses. I’d be extremely cautious of buying or even renting a basement property. So many possible issues. Generally people didn’t use basements for anything other than storage in the old days, so they weren’t made to be perfectly warm and dry. Looks like a hugely expensive nightmare to retrofit an old basement to come up to living-in standards, and a pretty hugely expensive one even if it’s a new build. Best avoided altogether I’d say. I looked at a flat with a basement when I was buying a house - they’d recently renovated it, and it looked clean and new, but I could tell it was basically just tanked and sealed, with standard plasterboard put over it and would probably last a year or so before you started seeing damp issues. Jogged on from that one.
The ground temperature under a long established building will often be at about 10-12 degrees C. the deeper you go the warmer it gets.
where did that come from?
Hi Roger,
Excellent video very informative.
Quick question in the last part of the video where you insulate from outside and use the French drain. In relation to the floor how do you prevent water coming from that direction,
Thanks
Mark
Dad had a basement built two lots of waterproofing, still had a small leak tiny , cement mixed with antifreeze, worked a treat maybe it worked like the crystal cement, anyway that was back in the nineties, haven't seen any leaks since it not a habitable space👍👍👍
Hi Clive
Are we talking about cement accelerator antifreeze?
@@SkillBuilder yeah the stuff that goes in cars 🤯
I fabric walled a massive basement home cinema once. we had to be very very carful with the nail guns to not puncture the egg crate stuff.
Basements seem to be more common in France and Germany, often used as garages. They seem to me to be dry and damp free and I’ve mainly visited in the summer. How can this be?
This video reminded me of the John Lewis store in Kingston, it has a Waitrose in the basement and then two levels of underground parking under Waitrose, three level basement and right next to the Thames. The building must have been built to very high standards as the car parks do not appear to be damp, the video made me aware of the complexity of that build. Under the new home office building in London that used to be Dept of Environment has huge i.e very deep underground structures beneath the office block.
Location, climate, soil and water table all make a difference.
@@disklamer London is built on clay with a high water table, challenging for engineers. They seem to be up to the challenge as there has been a huge amount of subterranean construction under London, some purposely not on any maps/drawings. There have been several serious problems where the construction of super basements in residential properties have collapsed, resulting in damage to neighbouring properties. Jimmy Page (Led Zeppelin) and Robbie Williams had a big falling out as neighbours regarding Williams’ super basement.
Great video what area are you in.?
Humidity is not a problem in winter because the outside air is dry at low temperatures. It may be at a 100% relative humidity at -5°C, after it warms up in the house to 10-15°C, it's essentially dry (10-15% rH). So in winter the best way to dry your house is to ventilate it with outside air when it's cold outside (commercial objects usually have humidification systems installed in a central HVAC unit, but that's another topic).
In summer, the outside air has a lot of moisture, even if it's relatively dry at 40-50% relative humidity, at 30°C. When this cools to 20-22°C in the night, the air is at 100% rh. So ventilating your cellar in summer is gonna be a bad idea.
I'm having damp issues in my cellar, thanks for the video series concerning the topic.
I understand that paradox with dragging moist air in and I did hesitate to say it but a lot of people have a humidistat on a fan and it seems to help especially if it is on during the night
Correct. We have mvhr running in our victorian basement most of the year but turn it off in the summer and run our dehumidifier to keep the RH down working a treat!
Hi Roger, this is a great information. Thank you. I am not sure is when you insulate with polystyrene and DPC from outside, you are tucking in the membrane into wall. But at what height? Is this 150mm above Ground Level? In that case it will expose and can see it from outside? I have a small basement store under stair and I have got to do all 4 side walls and floor. So I am thinking just to go for surface coating 2 x coats plaster. I actually wanted to use this space for a attached en-suite. Is that treatment enough then tile from inside? Much appreciate it if you could advise me.
You material is really excellent - so detailed and so realistic. As for basements, you are dead right. They won't be waterproof and the only way is to provide a way to get rid of the water that gets in.
Great video - very informative.
Great video Rodg, we’ll explained and informative. Ta
Insulating from the outside is not possible in my case, what type of insulation would you recommend from the inside? Foam board, fiberglass wool, spray foam, etc? Would I put another vapor barrier between the insulation and gypsum so that the condensation doesn't affect the insulation? Thank you
Thank you
Great video. Just wondering how I should seal the dimple mat. Must be a radon issue. Probably a smell...... and I don't do centipedes lol
There is a special tape to seal it
The only video to watch for peace of mind.
Diamond geezer. I’d love to work with you. Your brilliant
Thank you : )
What is your actual trade ..you seem very knowledgeable on a lot of subjects ...from a retired brickie .....!
My trade is a plumber but I wrote articles for the building trade press for over 30 years and have been on countless training courses. Some of it sticks in my brain
Your neighbor should sue his architect. It is complete negligence to have the soil above the foundation wall. Keeping the join of cavity wall above any horizontally moving water. This has absolutely nothing to do with Sika. I have been in the waterproofing industry for over 45 years n the USA. I disagree about the “dimple board” being waterproofing ( I know technically it is but it relies on mastic sealing the sheets together. Not acceptable in my opinion. We only use it as protection and drainage over a proper waterproofing membrane as you showed.And thank you for only recommending crystalline waterproofing for blind side waterproofing. Finally someone that actually understands waterproofing . There is so much misinformation about waterproofing and sealants on RUclips.
Hey Roger, I dug out my own basement that included going 60cm wide under the existing founds of the back wall. It was boulder clay and I was 50 yrs old. It was the hardest work of my life, and I’m a very hard worker. I then concreted the walls shuttering ‘pockets as I went. The walls were all 60-80 cm deep. I used little rebar, and ended up having to get an engineer to design surface beams on the inside. I then put a 1m sump pump with French drain in to it that circled under the floor slab. With the sumo working to take the water table directly in to the land drainage via a pump I’ve had only a little water ingress. Here’s the shocker, I’m midd terrace!. I made a lot of mistakes. I should have used a structural eng. instead of listening to the architect. The wall should have gone in after the floor, but how do you keep the soil from caving in. I suppose I could have used corrugated sheet but I was in a limited budget. The walls should have been designed with rebar to reduce these being 60+ cm deep.
Digging down is a killer. Get hell, get professional guidance re the design and ensure you get a structural engineer. I had a bit of a leak over the top of the concrete wall head where it meets the existing foundation. I decided to drill a hole right through to the source of that water and inserted a 25mm stainless tube and ran a 20mm flexi pipe to the sump and it dealt with the]at problem. It’s just a store for my amassed tool kit (I’m a cabinet maker but done it all as they say) if you want pictures or any thing you think may be of hell do get in touch.
If there is any other way to add space to your house, do not dig a basement!!!
Hi Arch Angel
I don't think you did too badly and the house is still standing. Yes please send the pictures in.
@@SkillBuilder you’re amazingly good at responding to the “little people”. Love that!
I’ll take a video of my basement but I’m not altogether sure how to upload that to you. I’ll certainly have a go on Monday at some point.
Every blessing
Peter (arch angel)
french drain is what they call weeping tile on the other side of the pond
mike holmes taught me that😀
ello Fella,
I have to say what you conveyed to us all is right on with facts. I have a question for you about basement walls that are 8 inch wide cinder blocks. The inside of the blocks have 3 hollow oval radius on the ends with roughly six inches long length that face the outside and inside walls of the basement. Would filling them with aircrete or aircrete styrofoam mix for insulation and waterproofing ?? Also, was thinking coating the inside wall with hydraulic cement 1/2" to 3/4"thick two layers to totally waterproof the basement walls ??? I do not have time or the funds to take care of the outside of the home. Drop me a line with your opinion for me to consider. Thanks VF
Love the video I do waterproofing and always use wykamol and it is the easy product to use
Have you looked at ICF? It has polystyrene on either sides of the concrete form
We are working on a job right now that uses this system
The principles are the same, albeit pokering / vibrating the concrete within can be problematic, and of course, differing substrates naturally require differing systems, i.e., elasomeric products as the primary waterproofing are good, with fibre mesh reinforcement embedded in to it, followed by Rogers guidance regarding drainage protection sheets, linked to appropriately sited land drainage, with rodding eyes to prolong their service lives is a great way to reduce risk further as well.
Hopefully Aerogel will solve all these things someday in the future. Waterproofing, fireproofing and insulating all in one package...
When I win the lottery, I'm giving half to this guy to supervise building my house. Legend.
There is a block wall in my basement,it continously is generating mould, would it be beneficial to drill holes to fill the inside of the blocks with expanding foam?
good talk Rodger, sorry, I am in the same age bracket as yourself, digging is a young man's game!
Great video Roger. I heard you also have the option of a suspended timber floor and have the sump pump under that. Sounds like a better option for drainage but not sure about how well the floor would cope with no air circulation. Or alternatively suspended concrete beams with blocks in between. Any thoughts
Ive got a cellar in a home built 1863. Ive got problems that have been over 40 plus years including court action against the local Water Authority.
Section 24 sewer issues.
Since leakage is in heavy rain and due to hydrostatic lift which doesnt occur every year.There is now know for there to be in the sewers, building debri from major demolition works from 27 years ago coupled with sink holes in the area.
The Water Authorites defence was legal technicaly in an attempt to bankrupt me before the case could be heard.There solicitor admitted before the Judge they had no defence other than legal technicality.
What people can afford a case thats estimate was over 1 million pounds sterling.Preceeded by solicitors argueing the case at £350 - £ 500 a letter.
Even solicitors via Pro Bono wouldnt touch it since the defendants stratagy in defence would be to deliberatly escallate the case costs to make the case unaffordable.
British justice at its best.
Hi Tim
We did a video about Thames Water washing their hands of a problem. I think the cost of brining a case against them is outrageous. There is no justice if it is only for the rich
@@SkillBuilder Yes thats the defence make the case uneconomical to take to court.I am still waiting for the Water Authorithy to deal with an issue pre Christmas which included flooding of cellarage.Will see if i can find and view your video. At the time i was advised if i won the court case it would be a case pressident.
There are companies that install the "Gutter" system that sits on top of the footer, and I have seen 2 of them removed.
I’m surprised you didn’t mention the most traditional basement solution Roger ,still great video explanation 👍🏻
Tell me more
Traditional tanking grade mastic asphalt in three coats with a single brick wall and loading concrete to base ,I know not exactly modern but very affective .
Thanks Roger, really good stuff, so many ‘poo traps’ even for professional designers and specialist installers to fall in. It would seem that a sizeable sump/pump should be integral in every design as part of Plan A.
Loved the music in last. Bit sounds Indian. And I appreciate for this well explained videos.
I had my basement/ceilar tanked a few years ago, it is this damp, not sure if it was do work not done properly(was not cheap) not too sure what to do now. Any help/advice would be greatly appreciated. I am based in Leicester if you want to visit. Thank you
Building now basement with 6 inch cavity wall. What do you think about this ? And bitumen paint outside 5 coats.
And yes, 6 inch French pipe below the basement Slab.
Can you please let me know your views on cavity wall for basement?
Great vid. Remember the mantra: you don’t stop water, you mitigate it.
Great, non exhaustive video Roger, which clearly sets out the main principles, and I think we should all have a whip round and get you some new young labourers to do the digging for you Sir ;-)
great content bub!
Great advice.
So the upshot is don't have a basement ha ha, "Where's James"? he could help lol. Thanks Roger, my sister is having issues with her basement with water coming in, in certain rainy situations. Her house is in Gillingham in Kent. No significance there. Maybe she could use some of these ideas. Reminds me of the time my brother built a concrete septic tank on the side of a hill outside his property with a footpath lower down the hill, it failed and I can just imagine the walkers looking up in horror as a wall of P*** and S*** hurtled towards them. The weight of water is much underestimated.
Scope of waterproofing is defined in types. A B C for internal and external applications. Do research viewers the British standards BS8102 of waterproofing in below ground structures .
Yes if you want to read that document you have to pay
Rolled your sleeves up for that one,
What about ICF builds heard they were waterproof , infact would love to see you do a video on icf pro and cons builds
Dan Cox is working on a job with ICF basement. We don't have much in the way of video on that but we have the story and it was not without incident.