The attached foundation details are approved for use in La Plata County where a professional design is not required or provided. These details are a minimum standard and are not a substitute for a professionally designed foundation system.

These foundation details are intended to be used for residential buildings and their accessory structures only, and are not intended for commercial buildings.

The basement wall details, shown in Standard 101 & 102 are intended to be attached to a floor system at the top of the wall section. These basement wall designs are not intended to be used as free standing retaining walls. Where such conditions exist, a cantilevered retaining wall should be designed by a licensed design professional.

A foundation drain is required at the base of the basement wall. Section R405 of the International Residential Code reads as follows:

Foundation drains shall be provided around all concrete or masonry foundations that retain earth and enclose habitable or usable spaces located below grade. Drainage tiles, gravel or crushed stone drains, perforated pipe or other approved systems or materials shall be installed at or below the area to be protected and shall discharge by gravity or mechanical means into an approved drainage system. Gravel or crushed stone drains shall extend at least one foot beyond the outside edge of the footing and be covered with an approved filter membrane material. The top of open joints of drain tiles shall be protected with strips of building paper, and the drainage tiles or perforated pipe shall be placed on a minimum of 2 inches of washed gravel or crushed rock at least one sieve size larger than the tile joint opening or perforation and covered with not less than 6 inches of the same material.

Dampproofing of foundation walls is required where they enclose habitable or usable space. Section R406.1 of the IRC reads as follows:

Foundation dampproofing. Foundation walls that retain earth and enclose habitable or usable space located below grade shall be dampproofed from the top of the footing to the finished grade. Masonry walls shall have not less than 3/8 inch portland cement parging applied to the exterior of the wall. The parging shall be dampproofed with a bituminous coating, 3 pounds per square yard of acrylic modified cement, 1/8 inch coat of surface-bonded mortar complying with ASTM C 887 or any material permitted for waterproofing in Section R406.2. Concrete walls shall be dampproofed by applying any one of the above listed dampproofing materials or any one of the waterproofing materials listed in Section R406.2 to the exterior of the wall.

NOTE: HEATED BUILDINGS MAY REQUIRE FOUNDATION INSULATION. THESE DETAILS ARE TO BE ADJUSTED ACCORDINGLY.

Foundation Details

• 8'-0" Concrete Basement Wall
• 9'-0" Concrete Basement Wall
• Connection of Top of 9'-0" Basement Wall to FLR. System
• 8'-0" Conc. Block Basement Retaining Wall Detail
• Concrete Stemwall
• Concrete Block Stemwall
• Monolithic Conc. Stemwall