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crawlspace ventilation Post New Topic | Post Reply
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alex bondrea
Posted: Apr 18, 2014 11:13 AM
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crawlspace ventilation
Hi I’m new and I need some advice from experienced people I have to spray a crawlspace whit close cell is it concrete slab, looks dry The furnace is in crawlspace I was thinking to spray the celling and the walls (cement blocks) What do I have to do whit ventilation??? Spray over them or leave them open How about the slab??? Do I have to do anything about it??? Spray it??? Do I have to do something after spraying???? (Furnace is hanging in crawlspace) |
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mason
Posted: Apr 18, 2014 02:13 PM
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Most often the slab has a vapor barrier that it is poured over. But, if you don't have the information, conduct a moisture test on the concrete. Tape a plastic sheet 2'x2' and leave overnight. If there is condensation on the underside of the plastic then the concrete needs a vapor retarder on it. With the furnace, you need to provide combustion air to it that is not coming from the crawl space unless you build an enclosure for it. If not the foam requires a thermal barrier over it. You can either do a vented crawl space, and insulate the under side of the 1st floor with closed cell foam, then vent according to code. Or seal the walls with foam, and leave the space unvented. Check out articles on basements and crawlspaces for details and more information at building science.com Joe Lstiburek has some very good articles on doing the job right. |
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alex bondrea
Posted: Apr 18, 2014 02:24 PM
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thank's The furnace is new and has PVC flue pipe and fresh air intake directly outside |
