Carpet over concrete in crawl space...venting in crawl space?

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Hoss

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Second quick question....(I have been saving them up while I searched for a good forum).

I want to use the generous dry warm crawlspace of the house for my hobby (model trains) and hobby storage.

1. I will be putting down used carpet all over the concrete without an underlay...just for comfort. Should I put any plastic barrier on the concrete first? The area is nice and dry in all seasons and if necessary I will put a small dehumidifier in later.

2. To help with air quality would it be a good idea to put some venting to the outside from the crawlspace. I had this in past homes. This house seems not to have any. It would be easy.
I was thinking even of some vent with closeable louvres....perhaps electrically operated. Or should I wait to see if humidity increases as much as I think it might when used as a living area with me down there breathing heavily? Maybe it won't be so bad.

Any ideas and tips on products would be very appreciated. Thanks.
 

Nestor_Kelebay

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I'd be concerned that even though the crawl space concrete floor seems dry, it's because the moisture is simply evaporating from the concrete so that it doesn't show. That happens often.

I would put the carpet down without any vapour barrier under it. That would allow any moisture that did come up to evaporate.

Also, I would try to use 100% Olefin carpet with a 100% Polypropylene backing. Polypropylene is one of the most water resistant plastics and certainly the most water resistant carpet backing you'd be able to find. Olefin is the most water resistant plastic from which carpets are made.

That way, if any water is coming up through the concrete and the backing of the carpet remains damp for long periods, the carpet wouldn't start to rot.
 
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joecaption

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Any form of carpet will hold moisture and mold up at some point. And the humity level will rust up anything stored down there.
If it's that warm down there it may be because of HVAC ducts leaking air, uninsulated pipes if your using forced hot water or no insulation under the floors causing a lot of heat lost.
 

BrianKiernan

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I think the carpet would be fine on the concrete, if the house or addition is newer there is probably a vapor barrier under the concrete slab.
 

Bevix

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To check for moisture, get some 6 mil plastic and carefully tape a 6 by 6 square on to the concrete floor. After a couple of days, if you see condensation on the plastic, then you have moisture coming through the slab. In that case, I would use some sort of barrier on the floor before I stored things near and dear to me in this space.

Regarding crawlspace vents, most current research shows that vented crawlspaces are not the best way to go. Go here:

RR-0401: Conditioned Crawl Space Construction, Performance and Codes — Building Science Information

for a pretty thorough discussion of this issue. This is a deceptively complicated issue, so if your current situation is working (no vents), I would not recommend venting your crawlspace. Depending upon where you live, you could make things worse, not better.

Good Luck!
 

isola96

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Hoss said:
Second quick question....(I have been saving them up while I searched for a good forum).

I want to use the generous dry warm crawlspace of the house for my hobby (model trains) and hobby storage.

1. I will be putting down used carpet all over the concrete without an underlay...just for comfort. Should I put any plastic barrier on the concrete first? The area is nice and dry in all seasons and if necessary I will put a small dehumidifier in later.

2. To help with air quality would it be a good idea to put some venting to the outside from the crawlspace. I had this in past homes. This house seems not to have any. It would be easy.
I was thinking even of some vent with closeable louvres....perhaps electrically operated. Or should I wait to see if humidity increases as much as I think it might when used as a living area with me down there breathing heavily? Maybe it won't be so bad.

Any ideas and tips on products would be very appreciated. Thanks.
Put the carpet it and get a dehumidifier if it seems like you have moisture and let us know if it helps down the road.
 

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