Minimum crawlspace clearance over slab
user-6688073
| Posted in General Discussion on
Hi,
I’m thinking about a small addition to my house that would intersect with an existing laundry room. The laundry room is slab on grade though the rest of the house and the addition are/would be raised foundation. In order to get the floor at the same height, the part of the addition that overlaps the old laundry room would create a crawlspace roughly 12″ high over the slab. I’m wondering if this is okay or is something I can work around in some way. I would prefer not to have to remove the slab but I definitely want the floor of the addition to be at the same height as the rest of the house. Any thoughts, or advice?
I live in Sacramento, California and I do plan to get permits – but I will be attempting to build this myself.
Thanks,
John
Replies
I don't see why you shouldn't be able to do that, with some planning. Proper moisture sealing, floor insulation, rodent access blocks, etc. should guarantee a good result. I assume, of course, that the floating slab will not be attached to the new foundation in any way. In my old 1840 house, the circa 1850s addition, timber frame with log joists on non-mortared stone foundation, and dirt floor, with exposed ledge at one end and only 18" of soil before ledge on the other, has only 14-15" from ledge to subfloor on one side. There's access into the crawlspace, but no way to "crawl" around under about 1/3 of the space, so no way to insulate. I've talked to spray foam companies, who say there's not enough room for them, I've thought about rigid foam, but no room. All that's to say, make sure the underside of the addition that sits over the slab is bombproof before closing it in. let us know how it goes!