Stem-wall Ground Insulation

The prevent frost heaving you can insulate on the ground instead of digging below frost level. This is called a frost protected shallow foundation or FPSF. Here we frost protect the greenhouse stem-wall using this method.

We used 4'x8' sheets of 2.5" thick expanded foam insulation covered with a layer of 6 mil plastic. The plastic layer prevents the styrofoam from absorbing moisture so that its insulation value is not reduced.

A 6" layer of dirt protects the plastic from mechanical and UV damage.

The dry-well is also insulated to help prevent ice from blocking the greywater from draining in winter.

Ever wondered if ground insulation actually works?

Here you can clearly see the boundary of the insulation where the heat from the ground hasn't reached through to melt snow.