Waterproofing basment walls

[Drew99GT]

Whelp, this spring's record rainfall in my area has left one of my basement walls seeping water. It's pretty bad. Part of it is the grade slopes right to the wall. I have downspout extensions but they weren't long enough; I redid those to get roof water out "over the hump" of the grade so that water can't get to the basement walls. The basement already has a french drain with sump pump along the uphill side wall (house is on a hill). I got an extension pipe for that as well. In order to regrade the yard, I'd have to rip the deck out...........it would be a mess and quite expensive, so I need the best possible concrete/masonry waterproofer. Drylok is the time tested name but Behr has better reviews on Home Depot. Does anyone have any experience with either? Also, what should I do about the joint between the slab and the wall? I was thinking use a premium silicone caulk? I've also read about people using rubber based coating on walls, something a local contractor would had to apply? Anyone know something like that?

Thanks!

 

[JTK]

If you can't keep it out from the outside, I've had great luck with hydraulic cement for patching seams and cracks, then top-coating with paint-on products like Drylok.

I've also used a dry mix product called Thoroseal on uncoated concrete block walls. That worked well too. It was a dry mix you mixed with water and a container of some special juice. Messy to apply.

 

[DoiInthanon]

If, at the end of the dry season you have a gap between the soil and the exterior wall, consider filling with sodium bentonite. In these parts it is used to seal leaking ponds. In oil country, it may be used as a constituent of drilling mud.

I used it with success on my leaking basement wall.

I originally put in a French drain on the exterior and interior of the footing with cross collection under the slab all drained to daylight. I was shocked 3 or 4 years ago to find a wet spot adjacent to the deeper upslope wall. In my case surface drainage was proper and still intact. At the end of the driest season, I bought a few bags of bentonite at the farm store and worked it into the void(exterior basement wall/soil) with a stiff piece of sheet metal. So far so good.

Sodium bentonite is basically montmorillonite, a clay. This is used frequently in environmental work, so is benign and will never harm the environment or your property.

 

[Warstud]

Can you take pictures?

 

[philipp10]

if it was me I wouldn't waste my time on the inside. Find a way to get that water diverted from outside.

 

[Al]

Trust me you need to get the water away from the house. No matter what you do you will not be able to seal perfectly. I learned the hard way after multiple drylock sealings on my house and daughter's house. Did I mention I had a wall fall in?

Anyone that knows anything will tell you what I just have.

Originally Posted By: philipp10
if it was me I wouldn't waste my time on the inside. Find a way to get that water diverted from outside.

This man speaks the truth

 

[demarpaint]

It is always best to deal with it on the outside. With regard to the waterproof basement paints, like Drylok, Tite and some of the others. For best results they should be applied to walls that have no paint, waterproofing products, etc. on them. That's usually buried in the small print on the label or in the spec sheets.

Drylok says this:

"DRYLOK Extreme may be applied over
previous coatings in sound condition. but the
warranty is void."

They want their product to penetrate the surface and seal it up, going over another coating doesn't allow that. I'd spend my time and money solving the problem from the outside.

 

[KD0AXS]

We just had to have a complete waterproofing system put in because it wasn't done properly when they built the house. You can seal the walls, but unless you give the water someplace to go, it's going to find another way in.

First, they tore up the concrete floor around the perimeter of the basement, and installed a new drain tile system. (Drain tile is under the rock)




Then they installed a product called InSoFast on the walls and laid plastic dimple board on top of the footings.



After the InSoFast was installed, then they poured new concrete.






The InSoFast does several things. It's insulation, vapor barrier, and framing all in one. It attaches to the concrete with adhesive and/or screws. (they used both) It has channels in the back, so now any water that might come through the walls will run down into the drain tile and to the sump pump.

You also need to get as much water away from the house as possible. Rather than downspout extensions, run them underground and far away from the house with 4" PVC pipe.

 

[Pop_Rivit]

Originally Posted By: Drew99GT
In order to regrade the yard, I'd have to rip the deck out...........it would be a mess and quite expensive


Do it right or don't do it at all.
Home ownership comes with costs. There's nothing hard about removing a deck, pulling it out of the way, correcting the grade, and then putting the deck back. Renting a bobcat isn't expensive, and for an unskilled operator it may take a couple hours to correct the grade. Of course, you could do what KD0AXS suggests, but I'd prefer not to let the water into the basement in the first place. Besides, doing it right and correcting the grade is far less expensive than having someone jackhammer the basement floor.

 

[Drew99GT]

What about digging a trench along the side of the house even with the evestrough? Under my deck is all rock. I was thinking remove enough rock, dig out a trench about 1 square foot along the area where the grade is bad, and end the trench where the grade slopes away, and extend it out into the yard??? It won't be perfect and some water will obviously drain through the soil, but during torrential rains, water draining towards the house will hit it and hopefully take it away from the house. Thoughts?

 

[howie2092]

Correct the grade around the foundation first. A good 4-6 feet of sloping soil from the foundation out. Compact the soil with a machine (backhoe or bobcat). Overlay the soil with something like rock or mulch over landscaping fabric - anything that sheds water away from the building - all around. Make sure all the downspouts are channeling water well away from the foundation. Standing water around the building must be eliminated.

R&R the deck is a very minor project compared to wrecked basement walls and heaved basement slabs.

Once the basement is completely dry, paint the floor and walls with Dryloc. That will keep the musty smell out. Use backer rod and sikaflex to fill the gap between the walls and slab.

PRO-TIP: if you have cracks in your foundation, fill them with hydraulic cement... then smooth the surface using styrofoam blocks. Using styrofoam to spread the cement makes the hydraulic cement blend in with the walls. Like finishing drywall. Dryloc over the cracked wall makes it look like nothing ever happened.

 

[doitmyself]

Originally Posted By: Drew99GT
What about digging a trench along the side of the house even with the evestrough? Under my deck is all rock. I was thinking remove enough rock, dig out a trench about 1 square foot along the area where the grade is bad, and end the trench where the grade slopes away, and extend it out into the yard??? It won't be perfect and some water will obviously drain through the soil, but during torrential rains, water draining towards the house will hit it and hopefully take it away from the house. Thoughts?


Drew,

sometimes people put a small swale or even surface type French drain next to the house and it makes the problem worse by diverting water towards the foundation even more. I installed "flashing" of sorts (like around a chinmey) around the house we live in.

Here's the idea, but mine is only 30" wide, then there is a good surface grade to move any water away. Make sure you use equipment (level)to maintain a slope so your drain actually works. USE POND LINER UNDER YOUR MAKESHIFT GROUND GUTTER. I eliminated our water problem for hundreds of dollars instead of thousands (plus a lot of sweat).

 

[Alfred_B]

Originally Posted By: Drew99GT
What about digging a trench along the side of the house even with the evestrough? Under my deck is all rock. I was thinking remove enough rock, dig out a trench about 1 square foot along the area where the grade is bad, and end the trench where the grade slopes away, and extend it out into the yard??? It won't be perfect and some water will obviously drain through the soil, but during torrential rains, water draining towards the house will hit it and hopefully take it away from the house. Thoughts?


I think that would be very beneficial. You can do a french drain but you need to have it low enough for the water to drain away from the house.

 

[MNgopher]

Fixing on the exterior is always the best approach. Doing whatever it takes to take water away from the foundation rather than towards it is the best approach. Perhaps more of a pain? yes. More reliable than waterproofing internally? Definitely!

Your trench idea is a good start, but as noted, I would move it even further out from the eaves if possible, and slope all the drainage from the house to it.

 

[Drew99GT]

OK, I've been thinking about this all night last night. Here's the plan; remove all rock to where it's even with the evestrough; get a load of dirt and build up the grade next to the wall; do the ditch where my new grade/material meets the existing ground where it slopes into the wall; put the rock back over it so it looks pretty. I'll use plastic matting under the rock and tape it to the wall. That new "berm" for lack of a better term, will really help surface runoff from reaching the wall.

 

[doitmyself]

Before using plastic, at least check out the 20+ mil rubber pond liner at one of the big box stores or a local landscape store. It lays flat, is not slippery,is nearly impossible to puncture, and lasts forever (EPDM like car seals). Roofing rubber (they put stone over it on flat roofs) is very similar, maybe cheaper, but is not fish safe

. I didn't attach my membrane to the foundation because the siding overhangs enough. I just folded it over and the stones compress it to the foundation.

Exaggerate you berm and your swale. In a few years there will be settling and filling (from experience). Try to make the berm directly adjacent to the house with as much slope as possible, maybe 1" per foot. Try to maintain at least 8 inches between your house sil plate and the ground/rocks to avoid rot. If possible, use a hand tamper to compact the berm to reduce settling.

Besides the grade away from the house, the water that collects in your swale needs to drain away to spot where it can run away from the house. I can't remember my numbers, but probably at least 1/4" per foot of run. In the winter, things will ice up with the possibility of backing "up" your grade.

Good luck.

 

[philipp10]

Originally Posted By: doitmyself
Originally Posted By: Drew99GT
What about digging a trench along the side of the house even with the evestrough? Under my deck is all rock. I was thinking remove enough rock, dig out a trench about 1 square foot along the area where the grade is bad, and end the trench where the grade slopes away, and extend it out into the yard??? It won't be perfect and some water will obviously drain through the soil, but during torrential rains, water draining towards the house will hit it and hopefully take it away from the house. Thoughts?


Drew,

sometimes people put a small swale or even surface type French drain next to the house and it makes the problem worse by diverting water towards the foundation even more. I installed "flashing" of sorts (like around a chinmey) around the house we live in.

Here's the idea, but mine is only 30" wide, then there is a good surface grade to move any water away. Make sure you use equipment (level)to maintain a slope so your drain actually works. USE POND LINER UNDER YOUR MAKESHIFT GROUND GUTTER. I eliminated our water problem for hundreds of dollars instead of thousands (plus a lot of sweat).

I had water coming in on an old house years ago, practically a spout at the base of the wall. I did exactly as you desctibed, plastic 4 feet out and a way to keep it in place. Never had a water problem again. You HAVE to do it from outside as there is no way you can seal every leak. Pull the deck, grade and replace it. And since this is a pretty low skill job, you could get it done fairly cheaply. I would grade it AND put a barrier in place to direct the water away to the street.

 

[sleddriver]

There's a couple of articles I recall reading in Fine Homebuilding. One is how to correctly install perimeter/curtain drains, to divert water that moves across your property towards your house. The second described how to properly remove water from a dripline when gutters are not feasible. Since you have gutters, this may not apply. However, the techniques they described were very useful on how to do a shallow/trench drain effectively.

I like the above idea of using pond liner attached to the foundation wall. Not sure how long silicone would last though. I like Sonneborn's NP1 urethane adhesive/sealant better. You'll have to check its adhesion to the pond liner. It sticks tenaciously to concrete, wood, steel, glass, asphalt shingles, stone, brick, etc. Takes 12+ hrs to cure, being a urethane. But once cured, it isn't going anywhere and it's waterproof.

+1 on hydraulic cement..apply quickly!

 

[Mr Nice]

If basements are known to be problematic...
Why build a house with a basement ???

 

[Clevy]

Originally Posted By: doitmyself
Originally Posted By: Drew99GT
What about digging a trench along the side of the house even with the evestrough? Under my deck is all rock. I was thinking remove enough rock, dig out a trench about 1 square foot along the area where the grade is bad, and end the trench where the grade slopes away, and extend it out into the yard??? It won't be perfect and some water will obviously drain through the soil, but during torrential rains, water draining towards the house will hit it and hopefully take it away from the house. Thoughts?


Drew,

sometimes people put a small swale or even surface type French drain next to the house and it makes the problem worse by diverting water towards the foundation even more. I installed "flashing" of sorts (like around a chinmey) around the house we live in.

Here's the idea, but mine is only 30" wide, then there is a good surface grade to move any water away. Make sure you use equipment (level)to maintain a slope so your drain actually works. USE POND LINER UNDER YOUR MAKESHIFT GROUND GUTTER. I eliminated our water problem for hundreds of dollars instead of thousands (plus a lot of sweat).

I was going to suggest something similar to this diagram. At my girls house instead of dighing in a weeping tile and attaching to sewer I laid super 6 poly out 9 ft and added 8 inches of topsoil and reseeded.
Now the water stops and funnels off the corners to my garden.