Slab on Grade for Modular/Mobile Home Installation

[Apexpredetor]

I regularly design cookie cutter foundations (frost protected, full basement, block, poured, etc...), but I have been asked to design a simple slab on grade pad for a Double Wide home installation.

I can't really convince myself that a simple 6" pad with Welded Wire Fabric (WWF) will suffice. I am also looking at some not-so-great soils. Initial investigation looks to be a bit clay'ey. Large raised bed septic also designed for the site (not by me).

I know that every home installer around here uses these 6" pads without issue, but when I think about it I am having a hard time dealing with the frost heave potential in the expansive soil.

I am in NY, so heave is a concern for me.

Thoughts?

 

[RHTPE]

It's all in the base preparation. ASCE has a publication that addresses this - Design and Construction of Frost-Protected Shallow Foundations (32-01).

In my humble opinion, if the entire slab can rise & fall uniformly because of whatever frost may occur underneath, what is the issues? The key word being "uniformly". Obviously utility lines connecting to the dwelling must anticipate and accommodate movement.


Ralph
Structures Consulting
Northeast USA