Width (V.E): Is measured in the direction of flow.
Frost-Protected Shallow Footings
In lieu of frost walls, the code recognizes frost-protected shallow foundations designed per ASCE 32, "Design and Construction of Frost-Protected Shallow Foundations". The department also recognizes the similar design standards of U.S.HUD "Design Guide for Frost-Protected Shallow Foundations", available for free download from
www.huduser.org/publications/destech/desguide.html and summarized below. Consult it or the ASCE standard for full design and installation information, including a more flexible, detailed design method that should be used for heated buldings with attached, unheated garages.
Note that both standards offer design methods for both heated and unheated buildings. For heated buildings, the designs rely upon containing the building's heat under the footings to avoid frost heaving. In the case of unheated buildings, the designs rely upon containing the earth's natural warmth under the footings and slab by the use of more extensive insulation. (For both design approaches, compliance with their frost-protection requirements is not necessarily the same as compliance with the ch.
SPS 322 Energy Conservation standards for slab-on-grade designs.)
Because the simplified heated building design methods rely upon buildings, including attached garages, with at least a 63 degree internal temperature, it is important the building designer consult with the owner regarding their intended use. Even if the initial owner plans to keep the building heated throughout the winter, future owners may use it otherwise. Therefore, the designer should be sure to communicate the operational needs of the building through means such as building placarding, notating the Rescheck Energy Report, and/or recording relevant information on the property deed. Failure to do so may cause severe structural damage to the building if future owners do not keep the building heated.
Unheated Building Design
1 Also see s.
SPS 322.33 for additional slab-edge insulation requirements.
2 Units are degrees Fahrenheit. See estimate provided on Mean Annual Temperature Contour Map.
3 Air freezing index shall be based on maximum year expected for a 100-year return period. See estimate provided on AFI Contour Map.
4 Ground insulation to the building interior can be extended beneath the entire slab where it is desired to protect the entire slab from frost heave action.
5 Ground insulation to the building interior can be in one horizontal plane (as shown in the detail) and covered with non frost-susceptible fill or the insulation maybe placed directly beneath the slab.
6 Insulation thickness recommendations are for extruded polystyrene (XPS) insulation.
7 The minimum depth of concrete footing and horizontal insulation is 10‶. A 6‶ drainage layer is required under the insulation.
8 Insulation placed directly beneath the footing shall be Type IV or Type VI XPS in accordance with ASTM C578. Maximum deadload placed on the Type IV insulation shall be 1200 pounds/square foot. Maximum deadload placed on Type VI shall be 1900 psf.
Heated Building Design
Minimum Insulation Requirements for Frost-Protected Footings in Heated Buildings1
(Simplified Method)
-
See PDF for table 
1 Insulation requirements are for protection against frost damage in heated buildings. Greater values may be required to meet energy conservation standards. Interpolation between values is permissible.
2 See AFI Contour Map for Air Freezing Index values.
3 Insulation materials shall provide the stated minimum R-values under long-term exposure to moist, below-ground conditions in freezing climates. The following R-values shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene - 2.4R per inch; Types IV, V, VI, VII extruded polystyrene - 4.5R per inch; Type IX expanded polystyrene - 3.2R per inch. NR indicates that insulation is not required.
4 Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.
5 Horizontal insulation shall be extruded polystyrene insulation.
