Should you vent a Crawl-Space? Here’s our Solution + Things to consider

[@mechantics]

I appreciate the time you have taken to provide this resource; it's not easy finding reliable, first-hand knowledge on this matter. We purchased our first home here in Vero Beach, Florida, in June of '23. The house is a 1933 block structure, with a crawlspace beneath joists that support a diagonally oriented t&g subfloor beneath oak t&g flooring. My theory regarding the potential for long-term troubles is that, with the advent of central air, the equilibrium of moisture content of wood above vs below the air-conditioned living quarters is disrupted. The occasional crowning of the t&g flooring in isolated spots wouldn't bother me if not for the potential for unseen consequences. The idea of sprayed foam being applied to the underside of my flooring system sends shivers down my spine.......what if it's applied with just a few breaches? I mention that because there are a lot of companies that promote it as part of a full encapsulation. If I'm understanding correctly, you're suggesting integration of the crawlspaces air into the home cooling system. Am I at least thinking in the right direction? Thanks again! Nick

[@ClearCreekCabinMiniFarm]

@@mechantics I am not an Engineer and can only share my experiences. It’s obvious that moisture is the problem in your crawl space causing the wood floors to swell. I would seal the foundation wall blocks with a specialized concrete paint/sealer and + a ballasted vapor barrier on the dirt floor (6 mil polyethylene held down at overlapped seams with crushed stone & affixed vertically to the block walls) Instead of introducing conditioned air I would install a dehumidifier & a small fan to circulate the air to the dehumidifier & close any out side vents. I introduced a/c air primarily for heat in the crawl space for winter + my space has a poured concrete floor with poly underneath (much more forgiving) Good Luck - reach out to our email if you would like to discuss more - email address is in the “about” section here on YT

[@cbskip546]

That is the way to do it, vent to the inside of the hvac controlled house and not the outside.

[@ClearCreekCabinMiniFarm]

Thanks - Yes, reversing the fan so it blows the conditioned air from the full basement into the crawl space has kept it perfect under there - Never gets higher than 60% RH even on rainy days 👍

[@cbskip546]

@@ClearCreekCabinMiniFarm 👍

[@PolcoDiablo]

So you’re telling me we don’t need crawl space vents now? After 200 years of people building homes with crawl space vents? I’m confused

[@ClearCreekCabinMiniFarm]

@@PolcoDiablo Do your own research on the internet - studies have shown that ventilation to the outside can allow more moisture into the crawl space in southern areas of the country + in my case, I have a fully finished crawl space with block walls & a poured concrete floor. So, I do not want to introduce humidity or cold temperatures.