Water in a crawl space

[Redvette]

What is an acceptable amout of water under a 6 mil vapor barrier, during the 9 month rain season in Washington State? There were no signs it ever got above the vapor barrier.

[Jim Katen]

Originally posted by Redvette

What is an acceptable amout of water under a 6 mil vapor barrier, during the 9 month rain season in Washington State? There were no signs it ever got above the vapor barrier.

None. If you can splash it with your hand, it's too much.

Damp soil is fine.

- Jim Katen, Oregon

[randynavarro]

I concur.

[Mark P]

The vapor barrier will float. Last week I was in a crawl space that had 4" of water over 100% of the crawl and the 6mil plastic just floating on top. If you just stuck your head in you might not even know there was water under the plactic.

[Erby]

Had a floater just a couple of weeks ago. Got about five feet in and realized it wasn't just wet and muddy by the entrance.

Tossed a couple of rocks. Just like they were landing on the water bed, with the ripples and all.

Declined to go any further until the water was gone.

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[hausdok]

Hi,

I didn't say anything earlier because I agree with Jim and Randy; however, it is possible to build a house with water underneath it and not have that water harm the house.

I once did a 27-year old house in Everett that was built on a flood plain. The builder knew that there'd be water under it, so the piers projected well above the crawlspace floor and the barrier had been very carefully applied so that it covered all of the foundation walls as well as the floor. There was a layer of washed-rounded pea gravel over the soil floor; I could feel it through the plastic. The top of the barrier was sealed to the walls with mastic and stopped just below the top of the wall. The rest of the barrier was sealed at every joint with waterproof tape and it was also sealed to the top of the piers with mastic. The whole thing was like a swimming pool liner with a series of raised piers and posts coming up through it and the water on the wrong side of the liner. It was obvious that the builder had designed it specifically to float on top of the water when the water level in the adjacent wet land rose. There was about 4-inches of water under the barrier and it was like hands and kneeing across a water bed. The underside of the house was pristine; kraft paper backed insulation under the floor that was in great shape and properly installed, no mold, no rot, just clean joists, insulation and plywood sub-floor. I came out of there dry as a bone - even after lying down and rolling over about a dozen times while I looked up at the underside of the floors. That same year Jeff Tooley began writing his articles about sealed crawlspaces in JLC and I became a fan of the process. I'm planning to open up a separate company here cleaning out and permanently lining crawlspaces. You can learn more about that process at advancedenergy.org.

So, no, there shouldn't be water, but, if there is, they better have done a perfect barrier install, not like the one you see in Erby's photo.

ONE TEAM - ONE FIGHT!!!

Mike

[Jim Katen]

Originally posted by hausdok

Hi,

I didn't say anything earlier because I agree with Jim and Randy; however, it is possible to build a house with water underneath it and not have that water harm the house.

I once did a 27-year old house in Everett that was built on a flood plain. The builder knew that there'd be water under it, so the piers projected well above the crawlspace floor and the barrier had been very carefully applied so that it covered all of the foundation walls as well as the floor. There was a layer of washed-rounded pea gravel over the soil floor; I could feel it through the plastic. The top of the barrier was sealed to the walls with mastic and stopped just below the top of the wall. The rest of the barrier was sealed at every joint with waterproof tape and it was also sealed to the top of the piers with mastic. The whole thing was like a swimming pool liner with a series of raised piers and posts coming up through it and the water on the wrong side of the liner. It was obvious that the builder had designed it specifically to float on top of the water when the water level in the adjacent wet land rose. There was about 4-inches of water under the barrier and it was like hands and kneeing across a water bed. The underside of the house was pristine; kraft paper backed insulation under the floor that was in great shape and properly installed, no mold, no rot, just clean joists, insulation and plywood sub-floor. I came out of there dry as a bone - even after lying down and rolling over about a dozen times while I looked up at the underside of the floors. That same year Jeff Tooley began writing his articles about sealed crawlspaces in JLC and I became a fan of the process. I'm planning to open up a separate company here cleaning out and permanently lining crawlspaces. You can learn more about that process at advancedenergy.org.

So, no, there shouldn't be water, but, if there is, they better have done a perfect barrier install, not like the one you see in Erby's photo.

ONE TEAM - ONE FIGHT!!!

Mike

If I saw a house like that, I'd want to see foundation engineering documents that took the water into account.

- Jim Katen, Oregon

[hausdok]

Hi Jim,

Well, not necessarily that you'd want to see them, but that you'd advise the client to do some more investigating, no?

I shook my head at how perfect the barrier install was and then explained to the client that there's not supposed to be water under a house. I then recommended that the buyer contact the municipality and ensure that the city had appropriate engineering documents on file showing that the footing depth and size were specifically designed taking into account the type of bearing capacity of the soil, the fact that the house was on a flood plain, and showing that they (the city) had known about the flooding, and had engineering documentation on file specifying that the barrier be installed that way and that it was OK to build it like that. Lastly, I told him that if the city had all of that, I'm a belt and suspenders kind of guy and I would personally have liked to have seen a pump in there, though I knew that said pump would probably run 24/7 during the rainy season.

From that point on, it was none of my business.

ONE TEAM - ONE FIGHT!!!

Mike

[Jim Katen]

Originally posted by hausdok

Hi Jim,

Well, not necessarily that you'd want to see them, but that you'd advise the client to do some more investigating, no?

Well, actually, I'd want to see them with my own eyes just to satisfy my curiousity. I'd expect to see either some very deeply placed piers or a hull.

- Jim Katen, Oregon

[Brandon Whitmore]

Hey Erby,

I can see your hands, but where the heck is the rest of you body[:-magnify

[hausdok]

He's not allowed to show it. We've got a prohibition against posting obscene photos here. []

OT - OF!!!

M.

[Erby]

That timed photo thing on the Sony Cybershot is a great tool. But alas, as Mike said!

[Sodapop]

Originally posted by Erby

Had a floater just a couple of weeks ago. Got about five feet in and realized it wasn't just wet and muddy by the entrance.

Tossed a couple of rocks. Just like they were landing on the water bed, with the ripples and all.

Declined to go any further until the water was gone.

Image Insert:

37.23 KB

Have a sump pump installed.

No amount of water is acceptable in my opinion.