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Ask Mr. Crawlspace

Before I install a vapor barrier, can I just cover up the debris in the crawl space?

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No, all debris should be removed from the crawl space before you put in a vapor barrier.

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Why do my wood floors buckle and cup in the summertime?

If you have a crawl space and the cupping is upward, then hot, moist air from the outside is entering the crawl space. The wood floors then absorb the moisture from their underlying side, making the bottom of the boards expand and the boards "cup" upwards. Installing a closed crawl space will prevent any outside [...]

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What is causing the musty smell in my house?

Many things can cause a musty smell. You might need a ventilating fan in the bathroom. You could have poor indoor air quality. If you have a crawl space, then that odor is probably coming from high moisture levels in your crawl space [...]

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If my crawl space isn't level does it matter?

Yes. You need to level your crawl space to create positive drainage.

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What if I have cracks in my foundation walls?

Small cracks in foundation walls may be sealed with caulking, cement or expandable foam. If you can, monitor cracks to see if there's any movement or change in size, and consult a structural engineer if you see any evidence of such. In most [...]

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What about any around holes in my foundation walls?

Holes in foundation walls need to be sealed to prevent outside air from moving into the crawl space.  Use materials such as caulking, cement and expandable foam to seal the holes.  If any holes are larger than a quarter of an inch, you [...]

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I live on the coast. Are foundation vents required for a closed crawl space here?

In your area, installing a vent designed to relieve water pressure in the event of a flood is important. There are vents available that meet flood vent requirements for closed crawl spaces.  Check with your state and local building codes for the placement [...]

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What do I do with my foundation vents when I close my crawl space?

It is best to leave existing foundation vents in place and seal them with a foam insulation board. The insulation board should be cut to the size of the vent and installed from the interior of your crawl space. Once the insulation board is fitted, the edges should be sealed with a caulking and/or foam adhesive.

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I am building a new house. Should I arrange to have vent holes put in my foundation?

No, unless they are required by code in your area.  For a closed crawl space in areas that are not required to have vent holes, just have your mason install the foundation without openings. [...]

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What about the gaps around electrical and plumbing penetrations between my crawl space and living space?

Sealing around electrical and plumbing penetrations prevents air from moving into the wall or living space from the crawl space.Use a caulking or expanding foam that is fire rated for sealing these voids to make sure you meet state and local building code requirements.

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