The installation of all manufactured homes shall comply with
the requirements of this section.
(1)
Installation of a new manufactured home.
(a)
The installation of a new manufactured home must be conducted according to the
manufacturer's instructions.
(b) If
the manufacturer's instructions do not address an aspect of the installation,
you may request:
(i) Specific instructions
from the manufacturer; or
(ii)
Specific instructions from a professional engineer or architect licensed in
Washington state. For example:
* A manufactured home is installed over a basement and the
manufacturer's instructions do not address this application;
* A manufactured home is installed on a site where the
specific soil bearing capacity is not addressed in the manufacturer's
instructions.
(c) All manufactured homes installed in
Washington state must be permanently anchored except for those installed on
dealer lots. On dealer lots, temporary sets are permitted without anchoring
being installed. A manufactured home must be anchored according to the
manufacturer's installation instructions or according to the design of a
professional engineer or architect licensed in Washington state. Local
jurisdictions may not prescribe anchoring methods.
(d) A manufactured home must have a skirting
around its entire perimeter. Skirting must be installed in accordance with the
manufacturer's installation instructions or if the manufacturer is not
specific, to the standards in this section. Do not enclose with skirting, areas
under recessed entries, porches or decks, (whether constructed as part of the
home or added on site) unless skirting is of the fully vented type and
installed so as to allow water to freely flow out from under the home. Porch
areas open to the crawl space area of the home must have the vapor retarder
removed and the ground directly below the porch must slope away from the home.
Skirting must be vented and allow access to the under floor area in accordance
with the manufacturer's installation instructions or as required below if the
manufacturer's instructions are not available.
If the manufacturer's skirting and access instructions are
not specific, skirting, ventilation and access shall be installed as
follows:
(i) Skirting:
* Must be made of materials suitable for ground
contact.
* Metal fasteners must be made of galvanized, stainless steel
or other corrosion-resistant material.
* Ferrous metal members in contact with the earth, except
those made of galvanized or stainless steel, must be coated with an asphaltic
emulsion.
* Must not trap water between the skirting and siding or
trim.
* Must be recessed behind the siding or trim.
(ii) Ventilation:
For homes sited in a flood plain, contact the local
jurisdiction regarding proper skirting ventilation. Except for those
manufactured homes sited in a flood plain, all skirting and vent openings
must:
* Be covered with corrosion-resistant wire mesh to prevent
the entrance of rodents. The size of the mesh opening cannot exceed 1/4
inch.
* Have a net area of not less than one square foot for each
one hundred fifty square feet of under floor area.
* Be located as close to corners and as high as practical and
provide cross ventilation on at least two opposite sides.
(iii) Access:
* The under floor area of a manufactured home must have a
finished opening at least eighteen inches by twenty-four inches in size.
* Opening must be located so that all areas under a
manufactured home are available for inspection.
* Opening must be covered. The cover must be made of material
suitable for skirting or venting as required in this chapter.
(e) A manufactured home site must
be prepared in accordance with the manufacturer's installation manual or to the
requirements of the Model Manufactured Home Installation Standards 24 C.F.R.
Part
3285 , Subpart C.
(f) If the
home is pit set, a drainage system must be installed to divert groundwater from
the underside of the home.
(g) Heat
duct crossovers must be installed in accordance with the manufacturer's
installation instruction manual or if the manufacturer's instructions are not
available, to the requirements in the Model Manufactured Home Installation
Standards 24 C.F.R. Part
3285.606 .
Heat duct crossovers must be installed to avoid standing
water and installed to prevent compression, sharp bends, and to minimize stress
at the connections. In all cases, the duct must be supported at least one inch
off the ground (exception to the Model Manufactured Home Installation Standards
24 C.F.R. Part 3285).
(h)
Dryer vents must exhaust to the exterior side of the wall or skirting. Dryer
ducts outside the manufactured home shall comply with the dryer manufacturer's
specifications or shall be made of metal with smooth interior
surfaces.
(i) Water heater pans are
only required where the installation instructions specifically require a pan
for warranty or the home was produced after May 31, 2006. The water heater pan
drain line must drain to the exterior of the home. The water heater pan drain
line and the PRV drain line must not be interconnected.
(j) Water heater expansion tanks are not
required by the department; however, you should check with your local
jurisdiction for their requirements prior to installation.
(k) Water piping must be protected against
freezing in accordance with the manufacturer's installation instructions or by
use of a heat tape listed for use with manufactured homes and installed as
required by the heat tape manufacturer's installation instructions.
(l) The testing of water lines, waste lines,
gas lines, and electrical systems must comply with the manufacturer's
installation instructions. If the manufacturer's installation instructions
require testing of any of these systems, the local jurisdiction is responsible
for verifying that the tests have been performed and passed. Electrical
connections and testing are the responsibility of the electrical section of
labor and industries except where a city has assumed the electrical inspection
responsibilities for their jurisdiction. In that case, the city's electrical
inspectors are responsible for the electrical connections and
testing.
(m) A vapor retarder must
be installed under all manufactured homes. Joints in vapor retarders must
overlap a minimum of twelve inches. Voids, cuts, and tears in the vapor
retarder must be patched or repaired with an approved method.
(n) Clearances underneath manufactured homes
must be maintained at a minimum of eighteen inches beneath at least
seventy-five percent of the lowest member of the main frame (I-beam or channel
beam) and the ground or footing. In no case shall clearance be less than twelve
inches anywhere under the home and eighteen inches at the heat duct cross over
locations.
(o) Heat pump and air
conditioning condensation lines must be extended to the exterior of the
manufactured home.
(p) Roof ridge
cap or ridge vent must be installed as required by the manufacturer's
installation instructions.
(2) Installation of a relocated manufactured
home.
(a) A relocated manufactured home must
be installed according to the manufacturer's installation
instructions.
(b) If the
manufacturer's instructions are not available, you may use either:
(i) The Model Manufactured Home Installation
Standards 24 C.F.R. Part
3285 ; or
(ii) The instructions of a professional
engineer or architect licensed in Washington state.
(c) For the installation of a relocated
manufactured home, all of the requirements of subsection (1)(c) through (p) of
this section must also be followed.
(d) Hot water tank pressure relief valve
(PRV) drain lines must be installed in accordance with Sec. 3280.609 of the
Manufactured Home Construction and Safety Standards Act (Title 24 C.F.R. Part
3280) .
(e) Carbon monoxide alarms
shall be installed in accordance with Sec. 3280.211 of the Manufactured Home
Construction and Safety Standards Act (Title 24 C.F.R. Part
3280). Carbon
monoxide detectors installed in relocated homes are permitted to be battery
operated.
