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Outbacker 12-30-2008 03:41 PM

Crawl space concrete question
Kind of a weird title to this topic, but that is okay. I have a rancher house with a crawl space under it that is currently a dirt floor. There is plastic over the dirt, however, it is technically a dirt floor, but the foundation is concrete. I have recently had rats burrow under the concrete and taken up residence in the crawl space. I have found their access hole and filled it in with a bag of redi-mix concrete, and surveyed the remainder of the foundation and determined that this was their only access. BTW, I hate rats, or any rodents, with a passion, and to know the buggers were down their just grosses me out. So the only solution to ensure this never happens again is to have a concrete foundation poured, and this is happening next week. The company is bringing the truck, a line pumper and finishing guys as I am not going down there and spreading concrete for a day. Now, my questions. Should I dig a hole at one end into the ground, insert a PVP pipe and rocks and use this for a drain. Will this be sufficient? What other prep things should I be thinking about before they get here?

triple D 12-30-2008 11:37 PM

just a small sump....
Have them slope the entire slab to the entrance to crawl. Then put a small 12x12x12 box in pour. This way if you ever have a pipe break, you can drop a $75 sump pump in hole, and a few feet of garden hose, and walla, your crawl is all pumped out. I see no reason for a perminent drain, its been dry under there this long, right? Good luck....

inspectorD 12-31-2008 06:01 AM

I agree
Just make sure they install new plastic 6 mill at least under the new concrete.
And after they pour install a dehumidifier in that area, it is going to get really wet down there as the concrete cures and the underside of your joists could start to grow things. That is a whole separate subject.
Check out Building Science Corporation for great articles on crawlspaces.

Outbacker 12-31-2008 02:26 PM

Thank you very much for the answers. There is currently plastic sheeting over the soil, though I may go buy more and have them lay the new stuff over the old stuff to ensure that it is fully covered. I was also thinking that if I put a empty 20 liter pail at the low end, and they pour concrete around it, then I can remove it later, or just cut the pail off at the concrete level, and use that as my sump. And yes, it has been dry down there since we bought the house 4 years ago.


inspectorD 12-31-2008 03:38 PM

Sounds like you have it covered. Nice idea with the plastic bucket, that's the way to recycle it.:)
Hope you enjoy a happy new year.

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