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drewdin 09-23-2012 08:44 PM

Crawl Space Suggestions
Hi All,

I have a crawl space that is roughly 10' x 10' square. Its got a dirt floor and is only about 3.5' tall without any ventilation. The walls are cinder-blocks and it gets real humid in there, I wanted to cement the floor but I wasn't sure if that was correct.

I have read that I should put 6mil of plastic down and then some gravel over it, Ill post some pics of it tomorrow but I was wondering if it was better practice to just put a 2-3" layer of cement and call it a day.

Any help would be greatly appreciated.

nealtw 09-23-2012 10:04 PM

We do the poly, 3" concrete and ventulation.

drewdin 09-24-2012 08:26 AM

Hi nealtw,

I didn't think I could add ventilation as its under the extended part of my kitchen. It was a porch that the previous owner closed in and the only way to get in is the window from my basement. There is electrical and heating pipes there and that's it.

SO i should put poly onto the dirt floor, seal it to the concrete and then put 3" of concrete on top? Is that correct? What do I use to seal the vapor barrier to the concrete, liquid nails?

I'll have some pics of the entry and space on here later. Thanks

woodchuck 09-24-2012 11:43 AM

Put the polly down and leave it at that. Moisture will stay in the ground under the polly.

jmc0319 09-24-2012 01:29 PM

I just did the same to my crawl space. Put down the poly, it goes up 6" on the block foundation and is glued. Then we sprayed 2" of closed cell foam on the block. It has made a huge difference already.

drewdin 09-24-2012 02:23 PM

ALl i can find for closed cell foam is window weatherstripping at lowes/HD. What did you use for glue? Thanks again for the suggestions

jmc0319 09-24-2012 02:36 PM


Originally Posted by drewdin
ALl i can find for closed cell foam is window weatherstripping at lowes/HD. What did you use for glue? Thanks again for the suggestions

Let me be clear, I did nothing for this job except pay the pros with a check.

Wuzzat? 09-24-2012 04:12 PM

Black mold is worse than white mold.:eek:

nealtw 09-24-2012 05:11 PM

Our code calls for concrete but that is kinda new. What we is level the dirt os usually sand and glue 3 1/2 sill gasket to the foundation with acoustic sealer and poly on the sand and pore concrete. I'm sure you could get away with out concrete but if you insulate tha concrete walls and don't have venting, you are making this room part of the basement and should remove the window and leave the hole open.
If you are leaving it as part of the basement I would want concrete but getting it in there should be a job and a half.

drewdin 09-25-2012 06:53 AM

4 Attachment(s)
Thanks for the suggestions, here are some pics of the crawl space. It is located under my kitchen, the floor is the same grade as the outside dirt. I plan on pouring 3" of concrete over a 6mil tarp that will be sealed to the concrete surrounding. Then I will use something similar to Extruded Polystyrene Insulated Sheathing on the walls but I just want to make sure that is the bets way to do it.

The top picture is the entry to the crawl space, the next three are the left, center and right walls looking through the old window. I have already removed the older insulation and drywall that was placed on the dirt floor, it was so wet it was literally dripping water.

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