Well, I’m somewhat ashamed to post this, but I never thought about it before, I just did it because they told me to. Why insulate the floor between living space and crawlspace? I was just crawling around under a house and there was no insulation anywhere in the original house, and I thought it was wierd. I was later talking to someone who said why bother? Hot air rises and cool air falls, so hot air shouldn’t “leak” into the crawlspace, and who cares if the cool air does. I’m guessing that due to the climate of the S.F. Bay Area, it doesn’t make a huge difference, but I shamefully pose the question anyway: Why insulate?
Thanks for your help.
Edited 10/24/2006 1:37 am by SBerruezo
Replies
this might help
http://forums.taunton.com/tp-breaktime/messages?msg=80469.1
most crawls are not conditioned space, so it is cool and damp. That can lead to excessive condensation on the underfloor system and eventual rot. insulation changes the dew point location and a VB helps control moisture
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
Just noticed your location. That dry clime makes it less important but up here in Maine, your feet can get mighty chilly too.
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
More important than "hot air rising" is the fact that warm will always lose heat to cold - that's why it is so comfortable laying on a tiled fireplace hearth in summer. New Age thinking, atleast in cold climates, is to insulate the sidewalls of crawl spaces,vapor barrier properly installed over soil, no venting, no joist insulation, and treat the crawl space as living space as regards heating and cooling. Anyone who has spent time in a crawl space in summer knows that the warm & moist air entering through the vents just condenses on the cool surfaces and drips water. Someday the building codes will catch up with good practice.
Randy
If the floor is uninsulated, it's a cold surface. Heat flows from hot to cold. Though you are fighting gravity a bit, free convection can still move air around to keep the heat flowing into that cold floor and out to the great outdoors. And think about it: if you have a forced air furnace, that alone produces an enormous amount of air mixing, putting fresh heated air in contact with that cold floor all the time.
If you care about energy loss, insulate your floor. If you can make your crawlspace a "conditioned space" per another poster's recommendation, that'd work too. Thank goodness you're not in a really cold climate, though, as you'd have a missing vapour barrier to deal with.