Listed below are specific installation instructions for previously owned manufactured homes. These installation guidelines are provided by Washington State Regulations and are intended to protect the purchaser. New manufactured homes are delivered with detailed installation instructions that must be followed. Adams County Building Inspector Tim Unruh, whose office is located at the above address, has the responsibility to inspect all trailers when they are set, and can respond to any questions you might have.
1) Ground cover to be 6mil black polyethylene (or equal) is required and must have 12" minimum lap at joints, WAC 296-150M-0610, 2015 IRC– Section 408.3. Unless placed on a slab foundation, it is not required.
2) The site where the mobile home is to be set must be cleared of all vegetation and debris.
3) The manufactured home must be set upon a permanent foundation, as specified by the manufacturer, and space from the bottom of the home to the ground be enclosed by concrete or an approved concrete product which can be either load bearing or decorative (c). The manufactured home must comply with all local design standards applicable to other homes within the neighborhood in which the manufactured home is to be located (RCW 36.01.225).
4) Blocking is to be set horizontal to the frame, with 8" x 8" x 16" hollow cell blocks placed on top, vertical to frame, and a 2" x 8" x 16" piece of wood as cap, with wood wedges to fill remainder of the gap. Maximum pier spacing is eight feet, with piers not more than two feet from ends of mainframe. Minimum distance from mainframe to ground (for 75% of area) is 18" with no part of mainframe closer than 12" to ground. WAC 296-150B-230, 235, 240.
5) Tie-downs now required in all of Washington State (spacing 8' O.C. to be spaced evenly).
6) Waterline from source to mobile home must be PB, CPVC, PVC, PE or copper for flexibility. 2015 UPC, section 604. Table 604.1.
7) At this point, an inspection by the building inspector is needed.
8) Inspector must check plumbing and sewer after installation.
9 Block skirting must be vented at a ratio of one square foot of venting for every 300 square feet of floor space in the mobile home.
10) Mobile home must have access panel in skirting, minimum of 18" x 24" with cover.
11) Piping from pressure relief valve on water heater must be run to exterior of fascia. Piping can be CPVC, copper or metal, but no PVC inside of building. 2015 UPC 608.5.
12) Duct for dryer exhaust must be run to exterior of skirting, 2015 UMC 504.3.
13) All stairways leading to and from the mobile home, over 30" in height, must have guardrails and landings at least the width of the stairs, 36" in direction of travel. Guard rails to be between 34" and 38" with no more than 3-1/2 inches between rails or ornamental closures, 2015 IRC 311.5 and312.1.
14) Final inspection!!!!! (Prior To Occupancy)
Any new installation of manufactured homes in Adams County must comply with above listed requirements, as well as pay a fee for installation and inspection.