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Concrete footings 101
Bearing capacity of soil
Understanding soil type and bearing capacities
Footing size
How to determine the minimum size for soil conditions
Footing problems
Pouring in wet soil and more
Frost heave & foundation footings
Frost protected shallow footings
Related Information:
Concrete calculator for footing pours:
Figure out how many cubic yards you'll need
Foundation drains for concrete footings

Additional measures are required for an unheated building. Unheated garages and other outbuildings rely on heat from the earth, which is a fairly constant 50 degrees, instead of heat from the buildings interior.

While a drainage layer is only recommended under wing insulation for heated buildings, a 6-inch drainage layer is required under unheated FPSF designs. Additionally, the horizontal ground insulation extends not only as a wing beyond the perimeter of the building, but continues under the entire unheated portion of the building. This insulation layer can be installed either directly under the slab, or entirely at one level beneath the lowest portion of the footing. In either case, and it must bear on 6 to 12 inches of gravel, and the compressive load of the building on the insulation must be determined to compare to the compressive resistance of the foam. The horizontal insulation must have a minimum of 10 inches of soil cover.

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