Waterproofing crawlspace: what do you recommend?


  #1  
Old 10-14-08, 01:40 PM
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Waterproofing crawlspace: what do you recommend?

it's about 3ft high, all cemented floor and has block walls. I have water issues from almost all angles. Front of the house and one side are dirt, rear of house is concrete patio (about 50ft + of it and plus 2 oil tanks are on top of it). Access is from 2 windows in the front of the house - very fun crawling in. No side or rear access at all (that part is all below ground level)

I'm assuming the best and most expensive is dig out the foundation and put some sort of membrane right on the wall. But access is limited to small bobcat type machinery because of topography plus I dont know how much that will cost anyhow. Any ideas? The house outside measurement is about 50x50 and i dont care about any shrubs etc there.

Other suggestions ive heard are get a few tons of dirt and start about 6 inches above the current grade and slope away from the house at least 6ft

Then someone suggested the above regrade but put a rubber mat of sorts under there so no water got back near the house. (will it find its way back or not?)

The rear where there is a concrete patio..I really dont know how to grade that away from the house. I know you cant pour concrete on concrete)

I definitely dont know what i'm talking about so tell me...are any of those good ideas/bad ideas/ what can i probably do myself (maybe tamping a few inches of soil against the house?)

totally open to ideas here

thanks
 
  #2  
Old 10-15-08, 12:23 AM
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When dealing with water issues in a foundation you can work from the outside or the inside. It sounds like either solution will need a jackhammer. it's a neater job to go from the outside, especially if you're dealing with a crawlspace (under 6'), it's a pain to haul out old concrete and bring in new stuff

if you chose to go from inside the rough order is:
1.bust out floor around exterior wall to base of footing
2. run drainage tile to sump pump
3. cover drainage tile with coarse aggregate
4. place concrete to cover excavation
5. pray that frost doesn't penetrate below your footing

Maybe more convenient in your case would be to
1. excavate around the exterior of the foundation (including your patio)
2. apply tar-like coating to foundation wall or other vertical drainage layer (preferably not poly)
3. install a drainage tile around the perimeter of your foundation, draining to a low point
4. fill with coarse aggregate over drainage layer

If your concrete patio is sloping towards your house, i would immediatley break up the 3-4 feet closest to your house and start digging and dampproofing. replace the finished concrete with some decorative stone and it won't look out of place

Neither solution is easy, but unless you get right down to your footing, you won't have a good guarantee of stopping leaks.

I don't know your local climate, and i'm not an expert on foundation drainage, so only take this as general advice.
 
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Old 10-16-08, 07:10 AM
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Thanks, i definitely want to do it from the outside. I want to prevent water from getting in and eroding the block etc. (as well as prevent further mold issues)

PA winters can be bad but i called a few excavators to see what they would do for me. Only one called back so far. Then ill move on to the dreaded waterproofing companies and maybe even call a few landscapers. Cant hurt to get a bunch of advice and maybe come spring ill be ready to act. I cannot afford to do this wrong the first time and a few more months of dampness wont kill me.

any guesstimates at all about digging out the entire house from the outside?
 
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Old 11-06-08, 08:30 PM
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outside drainage didn't help

Just wanted to share our experience:

We also have a crawl space with a concrete patio at the rear. We ripped out the patio where it was abutting the house, dug out the foundation to the footer, applied waterproofing spray (tar?) to the foundation, then installed a drainage system along the foundation around the whole perimeter of the foundation. All of this was professionally done. The next spring, the crawl space flooded again as if we hadn't just torn up the yard and spent tons of money. So we got a jack hammer (our crawl space floor is packed dirt) and dug the sump pump hole down to about 2.5 feet. The pump hole is only 3 feet in diameter - that's the best we could do operating a jack hammer while kneeling. Filled the dirt with gravel and hoped for the best. The next spring, it was much better. Still damp, but no flooding. The conclusion is that we have an underground spring that becomes active during the spring thaw (we have snow from Nov - May) or during very heavy thunderstorms.

So I'd see about putting in a sump pump. We were able to do it ourselves for about $300 after throwing away thousands to the professionals.
 
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Old 11-07-08, 05:20 AM
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sorry about your terrible experience. Can i ask if anyone suggested regrading? or did you do that and it just wasnt in the posting? I'm fortunate enough /unfortunate enough to be on a hill so no water table issues per se.

No one has suggested water proofing spray/tar nor drainage against the foundation in my case. They all told me regrading was paramount. I've watched Holmes on Homes and hvae seen the tarpaper and other things applied against the walls outside so that must work. But no one here has suggested that yet.

And if i had the money they even suggested breaking up the patio and repouring 4 inches higher and sloping away from the house.
The regrading makes sense to me but my thoughts always were...wouldnt the water just run down the grade then into the ground and back into the house? But they all assured me IF it was run away far enough from the house, no it wouldnt happen

also 2 guys told me they would put plastic under the new dirt so water couldnt 'immediately' go into the ground. I have clay all around me so maybe the water wouldnt wick back to the house? dunno
 
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Old 11-08-08, 12:14 AM
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If water is coming in from all angles at the same time, this is an indication of a rising water table. There are experts that can install basement and crawl space drainage systems that can accommodate rising water tables.

If gutters and downspouts are clear and deposit water into drains or dry wells and soil slopes away from foundation to direct water away from foundation, then the water issue is not from excessive rain runoff. Neighboring properties or slopes that direct runoff onto your property can be an issue. If this is a problem, then drains or drainage ditches need to be installed to redirect water are needed. (Note: It is illegal to direct runoff onto neighboring properties.)

Patios that slope toward the foundation can be an issue. If this were the problem, then the moisture would be occurring on the side of the foundation where the patio was located. But, you report the issue is at all angles.

Water entering from all angles can be an indication of rising water table. Consult with a professional that specializes in basement/crawl space drainage and sump pumps.
 
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Old 11-08-08, 08:20 AM
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sloping toward house

Originally Posted by luckydriver
sorry about your terrible experience. Can i ask if anyone suggested regrading? or did you do that and it just wasnt in the posting? I'm fortunate enough /unfortunate enough to be on a hill so no water table issues per se.
Our house is on a fairly steep hill - higher in the rear of the house where the patio and the crawl space are than in the front. Regrading really isn't much of an option because of expense and because it doesn't change the fact that everything beyond our property is still a hill - we live in the mountains. The drainage work did a lot of damage to the patio and there is a large crack. When the snow melts I can see the water disappearing into that crack. I'm going to try to seal that if the weather still permits - we already have snow on the ground.

We had someone tell us that a membrane on the foundation would be the way to go. However the company here that does that went out of business and we've already dug up the yard twice and don't want to do it again.

I even had a water engineer (forgot the proper word) come out and look at the crawl space. He said the problem was that water was seeping through where the foundation hit the footer. I don't believe this - it doesn't explain water on the surface 15 feet away from the foundation. I still think it's an underground spring. There are lots of underground springs in this area - we get over 300" of snow a year so there is lots of water when it all melts. Our neighbors have one that that is caught in a huge ditch and the upper edge of their property and drains out through a pipe to the street. It looks like a faucet running wide open all the way into June. Then it goes dry.

We may just put in another sump pump - still way cheaper than digging up the whole yard again.
 
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Old 11-10-08, 10:18 AM
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Originally Posted by schnuezel

We had someone tell us that a membrane on the foundation would be the way to go.

.
Thats the best remedy i saw on tv. Someday i want to find a company that does it and get the estimate for the fun of it.

but the 'landlocking' of my house is going to be problematic no matter what i do. Even if i could do it all myself, actually hauling anything in or out of my narrow workspace will be very difficult. Who would have imagined 1/2 acre could be so limiting lol

No excavators have gotten back to me yet. I guess the economy isnt that bad
 
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Old 12-15-08, 08:46 AM
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Had a recommended pro come out today.

Remove all the concrete patio at the rear of the house.

Dig below the foundation level and put in a stone base. Starting a at the farthest part (ie most difficult to access part of the house) he would gently slope 4 inch pvc pipe allll the way around the house until it empties out down the hill away from my house. (i estimate this to be a 125ft plus run but he said just needs a gentle slope maybe 1/16 or 1/4). This pvc pipe would have holes at 4 and 8 oclock so the water comes 'up' into the pipe, after it falls near the house, and doesnt clog from the top. He said some people put the holes at the top and thats wrong.

on top of that pipe would be the pipe that ties in all my downspouts (which are currently overflowing against my house because all the inground drains are clogged. Then this solid pipe would go to the front of the house

A final pipe would start at the farthest part of access to the house and there would be a 12x12 yard drain at that rear patio (where tons of water pools) and that drain would lead via solid pipe to the front of the house as above. Maybe 1 more yard drain in back of the house depending how things go.

so 3 pipes (or more) would drain out away from my house for each of the above purposes. Also he would tar up the block wall while it was all dug out. I also asked for an estimate to add a 'mat' and he said he knew of one that wicked the water to the bottom faster. But i doubt i can afford it. I just want this to guaranteed work and i made that quite clear. Do it right the 1st time.

I have to lose all the bushes etc near my house but only 2 were of any consequence so i guess ill just start from scratch. Access to the rear yard is difficult but he said he can build a ramp over my 2ft stone wall up onto the upper part of the yard and it wont mess up that stone wall.

Oil tanks have to be relocated since i use oil for hot water but he said he can temporarily bury the line so i have my supply.

Recommended march or april start. I was glad to see he didnt want to do it in winter.

So now i sit and wait for the estimate. He said unless a spring pops up under the house, this will definitely work. He thinks he pinned down where most of the water is coming in and it makes sense. someone filled in where there used to be a window to the crawl and that's probably leaking like crazy.

so what do you think?
 
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Old 12-23-08, 08:41 AM
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the guy that just installed my boiler talked to me about my drainage issues. When he had his own equipment, he did drainage stuff around his own house. he said doing what was proposed to my house without a membrane was foolish and that just tarring up the concrete block would be a waste of money.

i tend to believe this based on what ive seen on tv. Plus with a membrane there, water cannot get in..period! I dont know how much membrane costs but he joked that i could use 'shower tile' or something like that? Said was 1/3 the cost.
 
 

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