Foundation/Slab Design Un-Heated Building
Foundation/Slab Design Un-Heated Building
(OP)
How do others address designing foundations/slabs in unheated PEMB. Here is my problem - 4' frost, PEMB, unheated, large horizontal thrust reaction.
My concerns:
1. Slab moves due to frost heave - do you pour foundation wall with curb and attach panel to curb, let slab float - do you try to tie slab to foundation wall with rebar -
2. Hairpin bars from columns restrict slab movement - pour tie-beams that extend to frost in lieu of hairpins
3. Try to remove frost action by remove one of three componetnts of frost action, large amount of structural fill or graded gravel.
4. Will the subgrade freeze under the slab with-in a un-heated building - depends on moisture content.
What do others do.
At the highest cost - pour curb, float slab and provide tie-beams extending to frost depth. I feel this is the best option...
Jeff
My concerns:
1. Slab moves due to frost heave - do you pour foundation wall with curb and attach panel to curb, let slab float - do you try to tie slab to foundation wall with rebar -
2. Hairpin bars from columns restrict slab movement - pour tie-beams that extend to frost in lieu of hairpins
3. Try to remove frost action by remove one of three componetnts of frost action, large amount of structural fill or graded gravel.
4. Will the subgrade freeze under the slab with-in a un-heated building - depends on moisture content.
What do others do.
At the highest cost - pour curb, float slab and provide tie-beams extending to frost depth. I feel this is the best option...
Jeff






RE: Foundation/Slab Design Un-Heated Building
RE: Foundation/Slab Design Un-Heated Building
RE: Foundation/Slab Design Un-Heated Building
RE: Foundation/Slab Design Un-Heated Building
Without insulation in the roof, it's going to awfully warm in the summer. Automatic louvres may be adequate, to keep the heat in, in the winter.
You can remove the frost heave susceptable soil; drainage of any moisture will be an issue, in particular if not insulated.
Perimeter foundations should be taken down to below frost level.
You can provide rigid insulation under the slab to permit geothermal heat to rise and keep the frost from going down. This is OK if not a cold storage building with continuous frost conditions. This may mitigate the excavation and compaction.
You can similarly insulate the foundations and run ties in the slab for lateral thrusts from the PEMB. You may be able to do a stiffened slab foundation.
Dik
RE: Foundation/Slab Design Un-Heated Building
Now - They want to pour this 12,000sqft building foundation and slab in northern Montana this October and November and wait to erect the building in spring. Therefore the the slab will be exposed the first year.
Do I use air in the entire slab? - tough to trowel finish.
Pour a curb and float the slab.
Bury tie-beams to frost depth.
Insulation under entire slab is an option, but high $$$ and still may see frost.
Jeff
RE: Foundation/Slab Design Un-Heated Building
Dik
RE: Foundation/Slab Design Un-Heated Building
What do most use 1" rigid insulation = 1' depth, thus 4'=4" of rigid insulation.
Jeff
RE: Foundation/Slab Design Un-Heated Building
Dik
RE: Foundation/Slab Design Un-Heated Building