Engineered Slab on Grade or Footings

An engineered slab on grade that has been designed for it's climate is as reliable at preventing frost heave as a foundation and footing.We are creatures of habit, and we have always *known* that you have to go below the frost line to build a foundation, which is true, but that deep-seeded knowledge comes from a time long before rigid foam insulation existed. A slab on grade just moves the frost line by using a skirt insulation, and even that isn't always needed depending on climate and heat loss through the slab.

"Going below the frost line" just means using dirt as insulation, where a slab uses "insulation" as insulation. 1 inch of EPS foam insulates about the same as 1 foot of dirt. So you can dig a trench 3 or 4 feet deep to get below the frost line, or you can lay down 3 or 4 inches of insulation, same thing.

Here is a page abouthow to build a frost protected slab on grade foundation in cold climates so they won't heave, and it will explain clearly how to do it. There are countless slab on grade foundations built in very cold climates, and those done correctly have no risk of heaving. if you cannot find a local designer to build on for you here is anengineering firm that designs and delivers slab on grade foundation kits all across north America. Where are you building by the way?

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