TABLE OF CONTENTS Most residential construction today is supported on either concrete slabs-on-grade or on concrete or masonry foundations. There are a number of different foundation types, each of which must provide both the strength and stability to support the weight of the structure, its contents and occupants, as well as wind and snow loads that are transferred to the foundation by the structure.
Most jurisdictions prescribe minimum building code requirements for the construction of residential foundations. The following basic requirements from the CABO One and Two Family Dwelling Code are fairly representative of those found in many municipalities.
Fill material which supports footings and foundations must be designed, installed, and tested in accordance with accepted engineering practice.
The grade away from foundation walls must fall a minimum of 6 in. within the first 10 ft. Where lot lines, walls, slopes, or other physical barriers prohibit the minimum slope, drains or swales must be provided to ensure drainage away from the structure.
In areas likely to have expansive, compressible, or shifting soils or other unknown soil characteristics, the building official may require a soil test by an approved agency to determine soil characteristics at a particular location.
When topsoils or subsoils are expansive, compressible, or shifting, they must be removed to a depth and width sufficient to assure stable moisture content in each bearing area or stabilized within each bearing area by chemical treatment, dewatering, or presaturation. Unstable soils that are removed may not...
