How do I protect my shallow footing from frost?

Frost-Protected Shallow Foundations

The footings of most foundations are placed below the frost depth.
Either extruded-polystyrene (XPS) or denser types of expanded-polystyrene (EPS) insulation may be used to insulate a frost-protected shallow foundation.

How deep are frost footings in MN?

The Minnesota State Building Code requires footings to be a minimum of 42” deep in the southern part of the state, and a minimum of 60” deep in the northern part of the state.

What is a shallow frost protected foundation and where might it be used?

A frost protected shallow foundation (FPSF) is a practical alternative to a deeper, more-costly foundation in cold regions with seasonal ground freezing and the potential for frost heave.

What happens if footing is not below frost line?

This will cause your footing to raise slightly. Then when it thaws it will sink back down. The problem is that water expands when it freezes. So if your footing was above the point where the grand freezes, the soil supporting your foundation will expand.

How deep do footings need to be for frost?

about 4-feet
Most building codes in cold-climates require foundation footings be placed below the frost line, which can be about 4-feet deep in the northern United States. The goal is to protect foundations from frost heaving.

How deep do deck footings need to be in Minnesota?

Footings must be sized to bear loads and suitable for allowable soil-bearing Page 2 2 pressure (MRC Table R401. 4.1). The minimum depths of footings must be either 5′-0” (Zone 1) or 3′-6” (Zone 2). Refer to Minnesota Rules 1303.1600 for the counties included in each zone.

How deep do fence posts need to be in Minnesota?

Dig holes Posts need to be set below the frost line to prevent heaving. For regular privacy fences, holes need to be at least 36 inches deep or half the fence height, whichever is greater, plus six inches for base gravel.

Can you build a deck without footings?

Putting a wooden deck surface over a concrete slab will allow the deck to stay stable without the usage of footings. Plastic piers require the digging, but unlike footings, there is no concrete involved. The pier is put into the hole and attached the post, giving you your deck without wasting hours installing footings.

Why do you need a frost protected shallow foundation?

A frost protected shallow foundation allows builders to construct a structurally sound foundation that is more resource efficient and less costly than a conventional foundation. The FPSF

When did they start using frost protected footings?

Frost protected insulated footings were used as early as the 1930s by Frank Lloyd Wright in the Chicago area. But since that time, the Europeans have taken the lead in applying this concept over the last 40 years.

How many homes have insulated shallow foundation footings?

There are now over 1 million homes in Norway, Sweden, and Finland with insulated shallow footings which are recognized in the building codes as a standard practice. In the United States, insulation has been used to prevent frost heave in many special engineering projects (i.e., highways, dams, pipelines, and engineered buildings).

How does frost protection work on an unheated building?

Frost protection of an insulated foundation also works for an unheated building by conserving ground geothermal heat beneath the building. Unheated areas of homes, such as garages, may be constructed in this manner.

A frost protected shallow foundation allows builders to construct a structurally sound foundation that is more resource efficient and less costly than a conventional foundation. The FPSF

How to calculate the R-value of a frost protected Foundation?

To calculate the necessary R-value of the foam needed for a frost-protected shallow foundation, most designers look up the air-freezing index for the area in which they are building. The higher the index, the colder the climate.

How does a FPSF affect the depth of a foundation?

An FPSF incorporates strategically placed insulation to raise soil temperature and the frost depth around a building, thereby allowing foundation depths as shallow as 16 inches for almost all areas of the continental U.S.