Re: Slab & Frost heaves?

Posted by Jim G.

In Reply to: Re: Slab & Frost heaves? posted by douglas Brown

Thanks for your comments Douglas. I saw a reference in "The Complete Guide to Home Masonry" to floating footings for a small slab but there was no info on how small is small. They were talking about a 4'x5' slab; the slab for an oven will be approx. 75% bigger. As Rado's follow-up post says, this is still fine for our ovens.

For any who may be interested, the purpose for putting insulation under the slab is to prevent the ground from freezing in the first place as I learned from the PDF file referenced below.

In order to accomplish this, you need to extend the insulation out from the slab. "The Bread Builders" says to use 2" of foam insulation and to extend it 24" out from the slab. If I use the design guide to calculate the insulation I need, it must extend 40" out from the slab!! If I were building a garage this would be fine but it seems a little excessive for a small oven slab!

Sorry to ramble on so. I hope this is helpful.

Thanks to all for your help!

Revised Design Guide for Frost Protected Shallow Foundations.