Foundation Waterproofing
ฝัง
- เผยแพร่เมื่อ 9 ก.พ. 2025
- It will be buried beneath soil, concrete, landscaping, driveways, pool, patios, and so much more. All of that combines to mean we have to get it correct the first time. Drain and dry, down and out. Water away from the foundation and not held in tension is key.
.
.
#aarowbuilding #comobuilds #kcmobuilds #foundations #foundationwaterproofing #watermanagementsystem #dimplemat #coatings #builditbetter #construction #longliveourbuildings
This is the gold standard for foundation waterproofing. Anyone building a house today anywhere there's moderate rainfall, this is the only strategy worth considering. Like Jake said, there's never going to be a better more cost effective opportunity to do it properly than during initial construction. I live in Ohio where it seems like it's raining half the year and this will by my strategy when I eventually build my retirement home. Low maint will the name of the game. No one wants to have to worry about major home repairs in retirement.
You should extend the polywall material over the footing drains. Water will run to the lowest point regardless and get underneath the polywall, but this will be at the base of the footing where the drain sits. Silting from the top will be prevented. The area you excavated is basically an unfinished swimming pool …water will flow to the lowest point, and the drain will be there to move that water.
"Do 2" = belt and suspenders. Love it. Careful on the amount of clay that is backfilled because clay expands when wet and contracts as it dries.
Thank you
Excellent presentation. I am in the process of doing this now. Inground wall bitumen coated 30 years ago, spec for the day, failed at the cold joint, footing, first layer of blocks. Very detailed information especially about wrapping drainage pipe , water tables and a comment regarding putting in a flushing riser pipe.
It’s great to hear you are getting this done right and addressing the cold joint issue!
Excellent system breakdown. Other than the “burrito” and ridged pipe this detail is very common in my market. One of key details you mentioned that I don’t think people realize is the use of clay as a cap between stone and topsoil. With positive drainage away from the building, the clay will act as a backup for rainwater that is absorbed through the topsoil and help direct it away from the wall and ideally past the over dig.
Really like this style of water/damp proofing. I also like that the dimples are facing inward on the foundation wall with your dimple mat. Other products have dimples facing outward with fabric over the dimples that face outward.....the flat gets glued to the foundation wall, which when you think about it, ruins the idea of lowering hydrostatic pressure. Glad you mention that Polywall is EXTREMELY EXPENSIVE. I'd be happy with this installation.
Probably the only thing I would add is a vertical pipe or two for cleanout purposes.
We actually did a poor job of addressing this, we require a clean out about every 75’. This is a great point.
Very well explained, thanks
First comment! Hey Jake. Thanks for sharing! Keep the basement content coming!!!
You got it!
Outstanding! A few esoteric points, and I learned something new after doing this for 40 years.
Someone wins comment of the video!
5:25 ... you should key your footing so the stem wall / foundation wall locks into the footing, eliminating the cold joint.
Take a 2×, laying flat, positioned at the top of the footing so the top of the 2x is flush with the top of the footing, centered where the wall will sit, and then pour the footing.
Once you strip away the 2x, you are left with a keyway in the footing for the stem wall / foundation wall to lock into the footing.
There are a dozen ways to get there.
To accomplish what I wrote above, you would drill holes in the 2x for your rebar / footing reinforcements, and that would hold your rebar in place. And the 2x you used as a spreader bar, nailed on top of your footing form boards to hold the width of your footing, would be nailed into the 2x you are using as the key way to hold it flush with the top of the footings.
Using a keyway to tie the footing and the wall doesn’t eliminate the cold joint, it only helps to create a sturctural connection. They two pieces are still cast seperately creating a cold joint. There may be some benefit to reducing water pathway doing it that way but I doubt it is much considering the pathways water can take under pressure. The bar placed between the footing and wall in our assembly does the same thing as a keyway structurally without the effort of a keyway. Mind you I am not arguing against a keyway, we simply do not use that method.
@@jake.bruton.aarow.building, eliminating was probably not the correct way to word that.
I am writing from South Florida, where we would do a typical footing with reinforcements coming up out of it. A CMU block stem wall will be built on top of the footing, using mortar as the attachment / bonding agent to the footing. Reinforcements are placed in the CMU cells, tied to the reinforcements coming up out of the footing, and the stem wall will be solid grouted up to grade.
During our rainy season, we get torrential monsoon down pours daily around 3:00 pm. They will flood out the job site. When we get those heavy rains, depending upon the site conditions, I’ve seen water held back inside and outside of the stem wall.
I’m not saying water cannot get through the key way once the stem wall is solid grouted, but water will spend its time looking for another pathway.
Not all contractors / shell contractors do the key way here. But it is something that I think makes a difference.
Thanks for circling back on this and clarifying. Yes, that does make better sense now. In your case, a full filled or grouted assembly would make a world of difference and a keyway would change everything probably.
This was an excellent presentation and I am grateful. Well done Sir.
Great presentation for sure and nicely summarized… one upgrade would be to use either 3/4” round or even 1 1/2” round inside the burrito wrap to provide more void as well as prevent small rock chips from that 3/4” limestone from blocking or even entering that pvc inside the wrap.
Also, Baughman tile makes some excellent single wall 8-slot that’s incredibly strong and slotted 360 degrees around so no extra drilling and between the ribs of the corrugation so less likely to ever clog in combination with round stone
Here in Sweden dimple mats were widely used 20 to 30 years ago. For the last 15 years permeable systems such as Isodran have been more common, at least for heated spaces and not extremely high watertables. These permeable systems have no waterproofing but a 4 inch very permeable sheet of insulation on the outside of a "naked" basement wall (the sheets are made of small eps balls dipped in tar) and covered by geotextile and then dirt. The wall and some of the dirt outside is then dried out from the wall into the basement which causes more humidity in the basement from the beginning but considerably less later. Obviously a good drainage system with gravel, geotextile and drainage pipes below the foundation is also required to take care of water from the surface or the ground, but this water will not go into the wall. The problem with the waterproof system is the generation of condensation on the basement walls, which these permeable systems do not have.
I am careful not to wrap the drainage pipes in geotextile. Usually we only put geotextile on top and on the sides of the pipe, and at least 4 inches of gravel between. If you are unlucky clay can make the geotextile almost waterproof with a resulting disfunctional drainage system.
This is so so helpful thank you
Jake learned the hard way, it seems.
Flex drain pipe should never be used around a foundation - it crushes too easily. Jake is using the best product - rigid SDR perforated drain pipe. Only thing I'd add is a few cleanouts - if there's ever a problem, you can scope the drain and run a snake down it.
Top notch install, as usual.
For any potential clients reading this - hire this man - he's a helluva good builder - pay him well and it will be the best money you'll ever spend. I'd hire him over Matt Risenger any day.
I hadn't used that dimple mat before and for some reason I put the dimples out. I did install self adhesive membrane behind it. And I added silt fabric in front of it. And drain is below top of footer. So far very dry basement after very hard rains. Like you say one chance to do it while it's easy to get to.
Thank you for the great info.
Our pleasure!
I'm glad there are builders that care. I've got a basic at-grade slab in Florida (built in 80s) and it's so damp that if you set anything on the bare slab it will grow mold. Is there anything that can be done for that?
I've heard you can paint moisture barriers onto the slab, but post-construction application means you aren't reaching under the wall sill plates... I grew up in this house and I'm terribly ill, many doctors failed to help me, and now I can't help but think I'm one of the people who is sensitive to mold... Too ill and poor to help myself out of here.
Please steer me to a source/solution for a similar treatment for a daylight basement scenario....?
When all of that fails, instead of digging it up, the next step is running a dehumidifier on the air between the concrete and the plaster inside your basement. Just one more layer in keeping damp out of your house.
It is important that we always recognize that all of these conversations about the construction of the exterior wall don’t mean a whole lot without properly functioning HVAC equipment and responsible home ownership that is for sure.
The Form-A-Drain system has a distinct flaw, you need to set it level for your footings, but a level drain doesn’t put water anywhere, it just stands still.
The only saving grace is that the system is there as a pressure relief. If it is functioning properly it would provide pressure relief. I have a larger problem with the fact that I cannot wrap the Form-A-Drain system in filter fabric. It just has to be surrounded by gravel.
@@jake.bruton.aarow.building Correct, furthermore the whole point of the exercise is to remove the challenge of the water *away* from the wall and foundation. Having the French drain positioned away (and slightly sub level to the base of the footer) keeps the rising water from becoming a challenge.
Hey mate what did you used to attach the sheet to the wall please?
Great explanation, but it would be super helpful to include more video clips of the work in progress rather than just standing on the drain rock and explaining it verbally. You did include some additional video (e.g. making the burrito), but there’s nothing like that extra video footage in kind of a step-by-step sequence to really help people understand the entire process. I know it takes more planning, time, and effort, but it will result in more subscribers and more income from your TH-cam channel (if that’s your goal). Thanks for your efforts to showcase best practices in construction-much appreciated.
The tuff n dry system with fiber board is better to me. i don't like the idea of nailing holes in the walls. To hold up the dimple board. The French drain is the way to go though
Interesting point regarding water table. Is it overkill that I want to do this in Utah? Everyone tells me this is a dry state but all the basements I go into smell like mold/ mildew so I am not convinced this is a “dry” state.
I would still make the argument that water tables, seasonal rainfall, changing weather patterns, snowmelt, and even unkept sprinklers all add up to water and make the risk worth the effort. I wouldn’t skip it. You would really have to be high desert.
From watching numerous vids of the Build show I believe in many instances there are two drainage systems. External (yours) and internal, which is essentially mimicking the exterior system and then sumps to catch and then discharge any water. I would hazard a guess that this might be need in very high water table areas but I do not know that for sure.
You got it. Risk vs effort. If we suspect high water table or difficult to manage site water an interior partner drain is added often.
Jake, love the videos so keep ‘em coming. Two questions about this detail. First, why not use a true water proofing instead of a damp proofing? I realize hydrostatic pressure relief from the gravel and dimple mat should make it unnecessary but seems like an ounce of prevention from some redundancy down the road. Second, it seems that attaching the dimple mat with nails is introducing a further path for water, especially since the backfill will hold it (i think) once in place? Just curious. Thanks.
The damp proofing / waterproofing argument is pretty much a nomenclature thing in reality. The difference is kind of silly and none of it will matter once the concrete cracks a little. Right? Guess what, all concrete cracks. We know this and plan for it. That is why we put steel in the concrete. So even if we were to spend a little bit more money on a heavier layer and get a manufacturer to call it waterproofing the cracks that will probably form over the next ten years will create a discontinuous nature to our layer. So, the dimple mat lowers the pressure and hopefully drains the space keeping water from forcing itself through those small cracks. As to the attachment points, they aren’t deep and we keep them to a minimum.
@@jake.bruton.aarow.building Thanks Jake. Appreciate the explanation.
If you use a 5000 psi or higher concrete to begin with the amount of permeability drops significantly. Superior Walls use this method and their foundations don't even require water proofing.
Correct on the Superior Wall claims. The issue here is that bumping to 7500 PSI or so like they do is costly. Even if we use 5000 PSI the chances of cracking are still very high and a system like this on an 800 SQFT basement only cost something like $2k. For piece of mind I wouldn’t skip it.
@@jake.bruton.aarow.buildingAs they say, there are two kinds of concrete: concrete that has cracked and concrete that is going to crack. I would never skip the damp proofing and dimple mat on my own house regardless of the concrete mix used.
Question please.. Does a piping need to be placed so that has a downward fall?? Or is it fine to just lay it directly horizontal?
We install the drain tile piping level around the foundation because that section of pipe is there to release pressure and then as soon as we are away from the foundation it has slope to move the water away. The drain tile is about equalizing pressures and not allowing pressure build up, having an empty pipe for that water to enter is enough, the slope only needs to happen to drain once it is away from the foundation in otherwords.
Do you suggest washing the gravel that goes into burrito wrap?
I don’t think it is worth the effort. The arguement for doing so is probably sound however it doesn’t have that much gravel dust on it.
@@jake.bruton.aarow.buildingYou do want to use screened rock at a minimum to screen out the fines, although I would personally buy washed rock from the quarry for my own house to remove the rock dust thereby minimizing any chance of clogging the drainage holes and to keep the drainage system as free flowing as possible. But I’m a belt and suspenders kind of guy.
Does the liner used for the footer form end up catching moisture, though? I like the idea of it as a way to implement the form, but if it is impermeable, I'm not sure I like the idea of it acting as a cup underneath the footer.
If you put the poly wall barrier on the concrete, how does the moisture in the curing concrete exit to the outside of the basement? Would the dimple mat being made of such thick plastic be enough on its own to prevent outside moisture getting into the basement? - this is suggested by form-a-drain to be the case.
Remeber the interior side doesn’t get covered for sometime, drying can happen inward. I realize that some manufactures say a roll on or dimple mat is plenty, for my money, both is the right course. I don’t want to have to dig this back up.
I noticed a plastic strip on the top edge of the dimple mat with more fasteners, is this to protect/support the top of the dimple mat at finished grade?
This is a termination bar. It keeps things from getting in the topside.
Where are you draining the water to?
These go to daylight. Daylight whenever possible. A drywell can work if it is large enough too, or a sump pit.
Our HOA just signed a contract to have this done to a condo building that was built in 2002, concrete footing with a cinder block foundation. The technique used by the builder just didn’t last. So we’re having to dig up all the shrubs and redo it.
holes always down
Great details Jake. I think you've settled the holes up/down argument.
If you were placing external insulation on the foundation walls, would that go on before the dimple mat? Thanks!
I believe I would still place a dimple mat. However if you check out the UnBuild It Podcast on the topic we make a pretty strong arguement to not place insulation outside below grade because it is difficult to protect.
You could do that, but use a waterproof material like XPS and seal off all the seams, that way it becomes another waterproofing layer for the basement.
The dimble mat will protect the XPS against mechanical damage and prevent the build up of any water pressure..
Insects like to burrow in rigid foam insulation such as XPS. I’m a fan of using rigid mineral wool for exterior basement insulation. I know there are challenges with this approach as well, so proper detailing and installation are probably more important than the exact system components that used as there multiple ways to accomplish the same objective.