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Wet crawlspace fix

4K views 31 replies 9 participants last post by  EdTDuck 
#1 ·
Hi all,
So I'm trying to stop water welling up into a crawl space (raised foundation) after heavy rain (fortunately not too often in my climate). This looks to be beyond my ability, so I'm hiring contractors. The solution they proposed involves digging a trench around the house and ~1-2 feet below the foundation wall, then filling with concrete, to basically provide an additional barrier to stop subsurface water intrusion. See attached photos for an idea.

Does anyone have experience with that type of fix? Does it work? Any concern about damage to the foundation?

Thanks in advance!
 

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#2 ·
WHOA !!!!!!!!! :no: you don't want anyone digging below your foundation at all ! BOTH fric & frac are contractors & proposed this ? ? ? are they really ' waterproofing ' contractors OR jack-leg wanna-be's from craig's list ?

generally speaking, you're never going to stop the water HOWEVER you can manage it,,, trench alongside the footer slightly above it ay a couple ",,, put in a sloped drainage pipe & lead that to a sump into which a zoeller m-53 pump has been installed,,, if that doesn't work, you may need a system inside the crawl space attached to the exterior sump

prior to backfilling & compacting, waterproof the exposed foundation w/( we use sika/sonneborn hlm5000 [no financial interest] ) protect that membrane w/waffleboard ( also sika/sonneborn )

we'll let some other chime in then i'll be back :laughing:

pri
 
#5 · (Edited)
You have adequate gutters and downspouts clean and flowing? Sometimes simple solutions work out pretty well.

I have found them the culprit in so many properties I was asked to renovate. Or bid on.

Sometimes the lay of the land is not your friend. See if you can change it if basic drainage is the issue.

Don't start digging around the foundation and essentially further lowering the path and the speed water can seek low ground without talking with someone coherent.

You would be surprised at how few of us have any patience with the likes of Angie's List. I am glad she is making money with the postings and the service. None of my clients ever would have subscribed to Angie's List though. Actually asking around your local area is going to get your further. Most on AL seem to be handymen, that have few licensing, bonding and insurance requirements. Nothing wrong with chopping them down a notch I guess. I guess AL rates nannies at the same time too?

Angie's List is for those that do not want to do their own homework and want to trust the whining types that thought they could play general or even responsible sub-contractors and then complain labor they got from the box stores they had no idea about how to even ask for a comprehensible bid.
 
#6 ·
Something just plan looks wrong in that pictures guys.
Turn it sidewise and look again.
It looks like there a multi ft. high grade just outside the foundation.
Which would make the house like it was sitting in a pond.
Need a picture further back to see the whole picture.
From those pictures there's no even a way to back fill the hole without it covering up the non water proofed parging or Stucco.
Just blows me away every time I see exposed wires and pipes run line that just waiting to be damaged or frozen.
What's up with the bug hole in the wall?
 
#7 ·
For some reason this website rotated the photos by 90 degrees, as JoeCaption noticed. These photos are not of my property, but they were given to me be the contractor to show similar jobs.

Anyway, yes we tried downspouts first and that didn't help. It's sub-surface water intrusion. The crawl space floor is maybe 18 inches below grade.

Unlike Virginia, it doesn't freeze here and rain is infrequent, but winter storms will put an inch of rain down, and that's enough to have standing water in the crawl space.

As for Angieslist- well I just use it as a starting point. Most people are reluctant to disclose they have crawlspace/basement issues, so it's hard to get references.
 
#8 ·
I had much the same problem as you. My lot is very flat ... With minimal slant. I first dug a French drain on the high side of the house, which drained into a sump 4-5' deep.

A sump pump there pumps the collected water to the front lawn approx 100' in front if the house ... Which us only about 4-5 inches lower than at the house. But at least it's not coming back.

That helped immensely, but did not completely solve the problem.

I then found the low point in thd crawlspace, cut out a section of flooring, and dug another 4-5 deep hole for another sump pump.

Having less than 2' headroom made the next part a lot of fun: dug trenches leading to the sump in the crawlspace.

The trenches and the sump were lined with gravel. In the trenches I used two inch pipe, with random holes drilled in it.

The sump connects to the line going way out to the front.

A lot of work...but problem solved.
 
#9 ·
it shirley would be a great help if you listed your location as this site asks :yes: no one knows where your ' here ' is

being a licensed contractor is no substitute of knowing how to ' waterproof ' structures,,, we work for licensed contractors ( genl & specialty ) &, rarely, h/o's,,, not knowing wtr runs downhill is a common gene amongst them all
:laughing:
 
#10 ·
East of Downtown Los Angeles.

The contractors bill themselves as a waterproofing/restoration company.

Interior French Drain+Sump pump is an option. I would prefer a more permanent solution. Thunderstorm=potential power failure=no sump=wet crawlspace. Battery backups only last 30 minutes or so.
 
#13 ·
this may be tangental to this thread but a moderator/bot/humorless poster w/juice has threatened me w/expulsion,,, seems his/it's perception of my referral to joe caption & jomama's popular waterproofing choice can/may/could/was construed as a personal insult to both/either of these men ( sorry if you're gender-sensitive ),,, my opinion of them is they are both respected posters w/varied & extensive experience,,, if either is offended by that recent post ? get over it - it weren't personal, guys ! ! ! :no:

just wish they'd get a job :whistling2: so i apologize to them,,, to anyone else who was offended, how could you be upset - nothing's personal !
 
#15 ·
I've never once suggested using concrete as a back fill to fix a foundation or crawl space leak.
Anyone taking the time to insult other posters that they know nothing about and not just spending there time sharing your expertise with the O/P does nothing to help out the O/P which is what were suppose to be doing here.
 
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#16 · (Edited)
Thanks for everyone's input. I'm speaking to another contractor about putting in perimeter french drains just above the foundation footing. My original concern with french drains is that I thought you shouldn't put concrete on top, but it seems this is ok providing you have a clean out.
 
#17 ·
we've never put conc on top of an ext sub-surface perimeter ( partial OR full ) drainage system,,, we surround the piping system w/clean #57 stone & that's cove';d by soil filter cloth,,, on top of that is the backfill'd soil originally removed being certain final grade is the correct slope AWAY from the bsmt wall :yes:

we also install cleanouts as appropriate but NO conc :no:

have to begin a job tomorrow ( we were originally the higher of 2 prices ),,, 13' excavation to the brm of a sump w/pump,,, wtrproof over his new conc wall's wtrproofing, 57 stone, soil filter cloth, 12' standpipe, etc,,, we WILL replace ALL soil taken out of the hole AND backfill in compact'd lifts,,, that's 6K worth of work & they pd him $5k,,, for our original price of 10K, it would've been done correctly & resulted in a happy client :thumbsup:
as a result of the 1st sub, now the gc has a wary client,,, do it right the 1st time is still good advice, yes ?
 
#21 ·
See earlier in the discussion- already tried gutters. It's not a surface drainage issue, but subsurface. The rear of the lot (terraced garden) is very sloped and there's a row of houses at the top of the slope. Some of their run off is inevitably soaking through (nowhere else for it to go) and being directed towards the house.
I'm leaning toward the perimeter french drain solution now, but between this forum and others there seems to be some conflicting ideas of whether it's ok to put concrete over french drains.

Let me try and summarize the main concerns of concrete over french drains and see if we can pick it apart (please chime in)...

1) If drain gets blocked or damaged, ya gotta dig through concrete.
- Clean outs should remove the blockage concern, and using good quality straight PVC should make damage unlikely.

2) Soil erosion as it washes down the french drain. Concrete slab will then subside/crack.
- Won't gravel wrapped in Mirascape soil separator take care of this issue?

Any other concerns?
 
#22 ·
think we should rename the op ' paul harvey ' rather than the quacker logon he pick'd :laughing: now for ' the rest of the story ', huh ?

no, it doesn't rule out a ' perimeter french drain ' ( interpreted as landscaper's ' swale ' ),,, based on my ever-expanding limited knowledge of your problem, we'd suggest the aforementioned excavation & wtrproofing however we'd then fill w/#57 stone,,, might not look as pretty as grass next to your very fine saltillo tile patio but, in the words of raymond loewy, sometimes form must follow function :yes:
 
#24 · (Edited)
Some tips that may not have been mentioned;
If you know there was excessive water in crawl, the mudsill may be wet as well, check it out to be safe. Fig.6: http://www.buildingscience.com/docu...nvestigating-and-diagnosing-moisture-problems

Check for a dry rim joist or bottom edge of floor joists on the sill; http://www.greenbuildingadvisor.com...ressure-treated-sill-plates-and-building-code

For others in cold locations; 3 ways to stop water and prevent freezing wall heave; pp.26, Fig. 13; http://www.buildingscience.com/docu...ybrid-foundations-retrofits-measure-guideline

As said already; http://www.easydigging.com/Drainage/installation_french_drain.html

Gary
 
#27 ·
Based on that and your description of the water welling up, i would say that any drain pipe that is not below the level of the foundation won't do any good. But I would keep it several feet away, if I opted for it. But, you probably are already experiencing some movement of your concrete every wet and dry season, so digging close could make that worse.

I would start with a sump pump pit under the house. Use some type of perforated sump. A 5 gal bucket with a lot of holes drilled in the side will do. With enough clay in the soil, you don't even have to trench to the sump, the water will just flow subsurface to the hole.

Use a pump with a float switch. I would run hose/piping to get it to drain off property.

Try it for a season and see if it controls the water under the house to your satisfaction.

I wouldn't worry about backing up the pump. A few hours without the pump won't kill you. When the power comes back on it will clear the sump.
 
#28 ·
what good would conc do on top ?,,, other than IF you were to place a sloped 6' wide slab about the wet side - THEN it might do some good,,, that conc's not going to redirect any appreciable amount of wtr impo :no:

oso, here's why we don't excavate BELOW a foundation,,, doing so removes any lateral support the soil under the footer presently enjoys,,, might not be much but its still better'n a sharp stick in the eye :yes:

have seen too many float switches hang up,,, that's why we ONLY use zoeller m-53's w/MECHANICAL floats sliding up & down on 2 stainless steel slides,,, in 18yrs, have never 1 go ****-up on us :thumbsup: using a 5gal bkt for a sump makes the pump cycle too often & subjects the pump to unnecessary wear & tear,,, our sumps are 30" high & 18" in diam,,, depending on soil, we will sometimes install a pump stand so any wash'd-out fines don't wear out the impeller blades & volute prematurely :thumbsup:

then again, we only do this for a living,,, considering all the rain atlanta's had this yr, living is pretty good :thumbup:
 
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