Slab on Grade 2

[sigma1]

I am concerned about frost problems on a a 15'x25'x 4"+ thick slab on grade (on well drained sand-gravel mixture soil)for a detached, unheated with open sides to the elements structure we would like to build. The frost line in this area is aboud 42".

Any recommendations would be appreciated.

 

[ACtrafficengr]

Well-drained sandy gravel shouldn't heave much. If it goes down below the frost line, it probably won't heave.

Most severe heaving probems occur in silty soils.

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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."

Wm. Phelps Eno, ca. 1928

 

[ACtrafficengr]

A caveat: Check with the building code enforcement office in your area. Around here, they like to see frost walls, no matter what the soil type.

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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."

Wm. Phelps Eno, ca. 1928

 

[RDK]

Where are you located?

That will have a great impact on frost penetration depth.

In Canada a slab on grace is typically insulated with rigid polystyrene insulation on the outer face to 2’ below grade with a a board on the flat for 4’ out from the insulation.

A lot depends on how the building is heated and an economic analysis on how to minimize total costs.


For an un-insinuated open building there is not much you can do about it. Well drained soils are usually not frost susceptible. Make the slab a little thicker to resist any localized soil movement.




Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com