WAC 246-359-720
Installation requirements for manufactured
homes. The department will use the following criteria for
approving the installation of manufactured homes:
(1) New and relocated manufactured homes must be installed
according to the manufacturer's written installation
instructions;
(2) If the manufacturer's installation instructions are
unavailable for manufactured homes, the department will accept
the following:
(a) American National Standards Institute (ANSI) A225.1,
1994 edition, section 3; or
(b) The installation instructions of an engineer or
architect licensed in Washington.
(3) The department will inspect the installation to
determine if the manufactured home is placed on a properly
prepared site and anchored according to the:
(a) Manufacturer's installation instructions;
(b) ANSI A225.1, 1994 edition, section 3; or
(c) Design of an engineer or architect licensed in
Washington.
(4) The department will require, at a minimum, specific
instructions be obtained from a licensed engineer or architect
when a manufactured home is to be installed on a site where the
specific soil bearing capacity is not addressed in the
manufacturer's instructions.
(5) The department may review, at a minimum, the following
installation requirements:
(a) Heat duct crossovers, except that heat duct crossovers
supported above the ground by strapping or blocking to avoid
standing water and to prevent compression and sharp bends to
minimize stress at the connections are also accepted;
(b) Dryer vents exhausted to the exterior side of the wall
or skirting, when installed; and
(c) Hot water tank pressure relief lines. These lines must
be exhausted to the exterior side of the exterior wall or
skirting and downward.
(6) Water lines, waste lines, gas lines and electrical
systems must be installed according to the requirements of this
chapter.
(7) When skirting is used the skirting must:
(a) Be made of a material suitable for ground contact
including all metal fasteners which must be made of galvanized,
stainless steel or other corrosion resistant material;
(b) Be recessed behind the siding or trim and attached in
such a manner to prevent water from being trapped between the
skirting and siding or trim; and
(c) Have vent openings located close to corners which:
(i) Provide cross-ventilation on at least two opposite
sides;
(ii) Are designed to prevent the entrance of rodents by
covering the vent openings with corrosion-resistant wire mesh
with mesh opening of one-fourth inch in dimension; and
(iii) Have a net area of not less than one square foot for
each one hundred fifty square feet of under floor area.
(8) Provide access to the under floor area of the
manufactured home so that all areas under the home are available
for inspection. The opening must not be less than eighteen
inches by twenty-four inches. The cover must be of metal,
pressure treated wood or vinyl.
[Statutory Authority: RCW 70.114A.081. 99-03-065, §
246-359-720, filed 1/18/99, effective 2/18/99.]