Spray foam for Florida crawlspace?
Good evening to all! I purchased a wood frame Spanish style house with a crawlspace in sunny (humid) South Florida. The house has a rat slab underneath and is vented throughout.
The batt insulation completely failed (still code here) and was removed. Hydrogen peroxide was sprayed on all wood members to clean. There are currently some ventilation fans removing air from underneath the home, not sure if this is a good idea, but the air that come out of the exhaust fans smells musty, I can imagine why it’s from a dark dark place lol.
The beams are from 1920 and have some type of black coating, looks like tar. I would not want to encapsulate because I do not want that air coming into the house without anywhere to go or the ability for fresh air exchange.
In South Florida it seems that every house with a crawlspace just has a musty smell, I would attribute it to the stack effect and the humidity level inside the house, because of the humidity level inside the crawl?
We currently have two dehumidifiers running 24/7 inside of the home to maintain 45% humidity. I’m seriously considering filling the hoist cavities with open cell foam, then spraying a 2″ top coat of closed cell. The only reason I’m considering that is because it would allow a full coating of closed cell on a near flat surface, rather than coating all the floor decking and the 2×8 floor joists.
The primary objective here is to provide a seal and to block humidity. I own several other units with concrete foundations and none of them have humidity issues and/or odor problems.
The reason I’m posting on this site is, after reading a lot of blogs and Q/A, there’s a lot of very professionals that understand building science on this site. The contractors down here have zero clue on crawlspaces. My concern is wood rot over the long term.
Any knowledge is greatly appreciated and respected. Thank you for your time.
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