Heated “Crawl Space” Pier Addition
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Hello-
We have a sono tube pier addition in Zone 5 (Toronto Canada)
Room is about 20 by 8 and includes 6 10 inch diamater concrete posts 4 feet deep (the engineer approved this foundation for our medium dense sand soil and frost line).
The soil has been topped with 3 inches of gravel and the gravel been sprayed with about 4 inches of closed cell foam and the foam runs up to the rim and is also between the studs of the knee walls. The idea is that this is a conditioned “crawlspace” all above grade. The exterior walls are Maibec siding, house wrap, then plywood.
It appears to not have any air leaks below the floor.
Plan is to have vents to the living area (with a fan to assist in winter) in order to condition the space. (We fireproofed and primed the spf).
We have just realized that actual concrete piers were not spray foamed at all so we are concerned that will allow vapor in from that concrete and / or cause condensation due to the concrete posts being cold in winter (and perhaps even in the summer).
Do you think we need to get the foam guys back in to spray the concrete posts?
Thanks for your help!
SM
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Replies
sandra111,
The piers are especially vulnerable to cold outside temperatures as they are probably close to the perimeter, and your rather unique crawlspace does not keep the soil below warm due to the combination of the thick foam, and being at grade. I would have them insulated.
Thanks for your help. I can see the issue. The posts are about 3' in feet from the exterior. Agree that the foam will keep any heat from reaching the soil.