Author Topic: Waterproof exterior wall of basement  (Read 824 times)

pnw_guy

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Waterproof exterior wall of basement
« on: December 18, 2023, 09:41:36 PM »
I bought a SFH in the Midwest that has a cinderblock basement. This is a rental. The inspection report indicated that one basement wall had bowing of about 3/4 inch.

A basement repair company came out and suggested steel I beams to prevent further movement. 8 beams costs about $7K. This sounds like the minimum I should do. Comes with lifetime warranty.

They also noticed that thereís some discolor in the paint on part of the wall showing that it was wet at some point. Itís yellow and has some water patterns. Thereís a sump pump installed, but itís unclear whether the water got in before the system was there. Based on this info they suggested excavating the exterior walls and waterproofing. The cost is an additional $8K. Also comes with lifetime warranty.

Iím wondering how much evidence for water in the basement should I have before waterproofing the exterior walls? It doesnít look like a persistent problem. But from what Iíve read it can lead to mold issues etc. Or is the potential damage minimized due to the I beams?

Also, any idea on whether this is a good price? Does $8K to dig up and waterproof the basement sounds like a good price? Itís a 1000 sqft home.

GilesMM

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Re: Waterproof exterior wall of basement
« Reply #1 on: December 19, 2023, 06:30:18 AM »
The wall is bowing due to water pressure on the other side. If the water has entered before it will almost certain enter again and the situation will only get worse.  Waterproofing the outside is the only way to fix it.  If you want to verify the local price, get 3-5 competing quotes. 


Same goes for addressing the bowing. 3/4" is not much but you want to arrest it. Carbon fiber straps may be cheaper and easier for a small bow such as that to keep it from continuing.  Anchors are another option.  Get several quotes.

Paper Chaser

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Re: Waterproof exterior wall of basement
« Reply #2 on: December 19, 2023, 08:38:51 AM »
Water is likely causing the wall to bow. There may be easier options than jumping directly to the big hammer of exterior excavation/waterproofing.
First, make sure any gutters are clean and properly sloped toward downspouts. You don't want water coming down from the roof and landing directly at the base of the walls. Then make sure those downspouts are sending water away from the foundation ~10ft or more.
Then, consider the grade of the soil around the foundation. Obviously, you don't want any low spots along your walls that could allow water to pool or run back toward the house. A few bags or wheelbarrows of dirt could fix your problem or at the very least minimize it.
If you have a sump pump, you could also dig an interior perimeter drain along the wet wall. That wouldn't prevent water from passing through the wall, but it would direct any water that makes it through to the sump where it could be pumped out. If you live in an area prone to soil gas like radon, this option may not be appealing.

clarkfan1979

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Re: Waterproof exterior wall of basement
« Reply #3 on: January 02, 2024, 12:20:55 PM »
Water is likely causing the wall to bow. There may be easier options than jumping directly to the big hammer of exterior excavation/waterproofing.
First, make sure any gutters are clean and properly sloped toward downspouts. You don't want water coming down from the roof and landing directly at the base of the walls. Then make sure those downspouts are sending water away from the foundation ~10ft or more.
Then, consider the grade of the soil around the foundation. Obviously, you don't want any low spots along your walls that could allow water to pool or run back toward the house. A few bags or wheelbarrows of dirt could fix your problem or at the very least minimize it.
If you have a sump pump, you could also dig an interior perimeter drain along the wet wall. That wouldn't prevent water from passing through the wall, but it would direct any water that makes it through to the sump where it could be pumped out. If you live in an area prone to soil gas like radon, this option may not be appealing.

The steal beams seems like a great idea to stop the movement. I would hold off on waterproofing the exterior basement wall until I had more information.

I got water in my basement at two different houses due to a failed gutter situation combined with historic rainfall. I was out of town and paid high school kids to mow my lawn. They removed the piece of the downspout that lays on the ground and gets the water at least 6 ft. away from the house to mow the lawn and didn't put it back. We had historic rains and all the water dumped right next to the foundation.

Similar situation at a rental. It was a one-time event at both houses. 

Jon Bon

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Re: Waterproof exterior wall of basement
« Reply #4 on: January 02, 2024, 01:41:59 PM »
Foundation problems are almost always drainage problems. Treat the disease, not the symptoms.

Are you gutters clear and operating property? Is the grading done property and shedding the water away from the structure? Downspouts running clean and to daylight? Go walk around the house when its raining hard. Find where the water is going/pooling. If you have negative grading anywhere it will make itself apparent really quick.

I'd get a bunch more information before I spent any money on beams or paying a contractor.

I bought a house like yours about 15 years ago. I made a big stink about it, put in beams myself. Mine was way out more than 3/4 inch But really it was new gutters that made all the difference. I lived there about 5 years and I don't think anything ever moved. I sold it about 10 years ago, I don't think they ever dug anything out. This house did not have a sump pump. For the potential repairs what did you expect? Yeah you brought in a basement water proofing company, so they want you to spend $20k to make it better? If you are really concerned you have to bring in someone with no skin in the game.

How old is this house? I would imagine some bowing is going to be normal. Is the wall cracked, or simply bowed? 3/4 inch of a bow might just be a case of a hungover bricky!

Is the basement finished space? I would only water proof if that was the intent. Basements below grade are never gonna be as good as above grade space.

I would definitely do the grading and gutters then watch for a year before I did anything more. Its a new house (to you) been there for a while, I doubt its gonna have a structural failure anytime soon based on the information at hand.