Slab on Grade at Doorway
Slab on Grade at Doorway
(OP)
I'm trying to come up with a good detail at the doorway of an industrial building. I'd planned on having the perimeter grade beam come up about 6" above the slab on grade and leave the slab on grade 'floating'. But at the doorway, throw a couple of dowels in and notch the gradebeam down 6", or would you notch it further and run the slab over top at the doorway. It's been a while since I've designed a concrete foundation and I can't remember what is (or if there is a) standard way to detail the door openings.






RE: Slab on Grade at Doorway
The dowels will prevent the stoop from heaving and blocking the door at the doorway and the frost wall will prevent frost heave and keep the stoop from becoming unlevel (preventing the door from swinging open)
RE: Slab on Grade at Doorway
This results in a single slab joint (between interior slab and exterior pavement) instead of two twin joints on either side of the grade beam, with the grade beam top exposed.
As far as heaving, if we drop the grade beam and extend the slab over the top, there is a concern (as MotorCity mentions) of the earth just inside the grade beam freezing and heaving.
However, you can and should have perimeter insulation placed on the inside face of the grade beam anyway (in non-door areas) and this insulation (usually 2" thick rigid in our region) would extend up the inside face of the grade beam and turn horizontally under the slab for 2 feet or so. This protects that dirt from heaving to some extent.
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