Robert
REGISTERED
I currently have a 1920's commercial space (kitchen in CA, mild climate) that has a wood floor over a crawlspace completely below grade. We excavated to achieve 18" min. clearance and added a floor hatch (this is a plumbing repair and complete floor replacement job). My questions are about venting. In an unvented scenario, Residential code allows vapor barrier over earth with a dehumidifier installed (section R408.3.2.2.4). However, when I get to CBC (commercial) they do not have a dehumidifier as an option, and seem to require either making the crawlspace conditioned and insulating the perimeter, or needing vapor barrier over the earth and adding venting (CBC 1202.4.).
Questions: if the crawlspace floor above does not have insulation, but does not directly communicate with the space above (ie. a floor vent), is that considered conditioned space? And they mention the walls of the crawlspace need to be insulated....but in this case there are no walls, just concrete stemwall up to above grade, so are we allowed to call this conditioned spacee without adding any insulation to the exterior stemwalls?
As another option the CBC does allow mechanical ventilation, but that might be different from a dehumidifier as mentioned in the CRC? Can the residential solution apply in this case using a dehumidifier? The issue is difficulty in adding exterior vents (it's below grade with concrete stemwalls and impossible to get cross ventilation on one end of the crawlspace). Thanks for any insights.
Questions: if the crawlspace floor above does not have insulation, but does not directly communicate with the space above (ie. a floor vent), is that considered conditioned space? And they mention the walls of the crawlspace need to be insulated....but in this case there are no walls, just concrete stemwall up to above grade, so are we allowed to call this conditioned spacee without adding any insulation to the exterior stemwalls?
As another option the CBC does allow mechanical ventilation, but that might be different from a dehumidifier as mentioned in the CRC? Can the residential solution apply in this case using a dehumidifier? The issue is difficulty in adding exterior vents (it's below grade with concrete stemwalls and impossible to get cross ventilation on one end of the crawlspace). Thanks for any insights.
