In traditional building construction if you built in a climate where the ground freezes you had to make sure the foundation of the building was below what is called the frost line to prevent frost damage to the foundation. In many climates, this meant building an entire basement under the building or digging a hole in the ground several meters deep to get the bottom of the foundation below the frost line. Modern technology however, using what is called FPSF (frost protected shallow foundations), has virtually eliminated the need for expensive little used basements. In many northern climates the footing of a building doesn't need to be any deeper into the ground than 12 inches (approximately 300 mm.) even though the frost line is 4 feet deep or more.
The idea behind FPSF is very simple. You use rigid foam insulation to protect the footing and foundation of a building from frost damage. In the fall of the year when the weather starts getting below freezing the ground will start slowly freezing from the top down. The insulating value of the earth and snow on the ground slows this process so that by the time spring and warm weather return the ground is frozen 3 or 4 feet deep. This depth is the frost line. The ground temperature almost always lags behind the air temperature in winter so that the depth of the frost line is deepest in early spring. If you place extruded polystyrene insulation in the ground below the surface but above the footing of the building, you significantly raise the frost line to as little as a foot or less. An inch of rigid foam polystyrene insulation has the same approximate insulation value as 4 feet of soil (R-value of 4 to 5) so it doesn't take a lot of insulation to significantly raise the frost line. Generally, the insulation is put in two locations, vertically on the outside of the foundation wall and on top of the top surface of the footing extending out horizontally from the wall. The horizontal insulation also helps by directing ground water away from the foundation.
There are several advantages to this type of building construction. The most obvious benefit is you don't have to dig a huge hole in the ground to start your building. You only need to dig a foot or two deep. This saves significantly on the cost, labor and time of building construction. The cost of building materials is also a benefit. The extra cost of the insulation is almost always less than what is saved in concrete or block. This benefits both the contractor and the owner of the building. In most cases, FPSF saves on heating costs as well. There is no basement to heat and the part of the building that is below ground is well insulated. It is also environmentally friendly. Because you are only digging a shallow foundation, you do not disturb tree root systems.
This building technology is not new. It has been used in northern Europe for almost half a century but only recently has it been applied in other cold weather countries. It is now common building practice in many parts of the world so if you are planning a building it is to your advantage to look into FPSF.