Mobile Home Foundations

Manufactured home foundations

This material is provided as an informative example of the considerations that go into the foundation for a mobile home. It probably will not apply to your locale, as codes and standards vary from place to place and get updated over time. This is intended to give you an idea of what is involved in proper setup of a home. Don’t use this information if you are putting in your own foundation. Rather, locate your state and local guidelines so that you are in compliance with the rules an inspector will be checking in your area.

Manufactured home to be installed on three concrete ribbon footings 6″ minimum depth. The ground in which the ribbon footings are set must be level and compacted to 1,000 pounds per square foot minimum bearing capacity prior to the concrete pour.

Two continuous pieces of #3 (3/8″) rebar must run the entire length of the footings. The rebar must be bent up above the concrete at the ends of the footings. Extra #3 rebar must be vertically tied to the horizontal rebar at 16″ On Center maximum intervals.

Footing shall be constructed of twenty-five hundred (2,500) pounds minimum concrete with 3/4″ aggregate (air entrained concrete recommended). Finished concrete surface must be smooth and level. The manufactured home may be set after a minimum seven (7) days curing time.

Final height between house height and cut grade will be determined on site 18″ minimum to 36″ maximum. If ground level set, maximum hole depth is 24″.

A slope of 6″ per 10′ away from the house is required for proper drainage.

A minimum 32″ x 32″ access panel must be installed 3″ above grade. Panel cover must prevent infiltration of vermin or water under the house.
Retaining and stem walls shall be treated or covered with a water resistant material.

There shall be a minimum 1″ gap between the top of the retaining wall and the lower edge of the home. The final gap distance to be determined on site. Gap is to be properly flashed to prevent infiltration of vermin and water under the house.

One (1) square foot of ventilation is required for every one hundred and fifty (150) square feet of enclosed floor space. Are vents are to be distributed in a uniform manner on all four walls; two vents minimum per side.

Perimeter stem wall is optional. Channel can be installed before the house is set.