| (a) Air infiltration and water vapor migration at mating
surfaces: Before positioning additional sections, the mating line
surfaces along the floor, endwall and ceiling, require material or
procedures to limit air infiltration and water vapor migration.
(1) Expanding Foam: Foam may be used along surfaces
that are accessible after the units have been joined. Where mating
line walls line up between sections, non-porous materials must be
installed prior to joining the units.
(2) Caulking: Caulking may be used along surfaces that
are accessible after the units have been joined. Where mating line
walls line up between sections, non-porous materials must be installed
prior to joining the units.
(3) Non-porous gasket installed along the perimeter
of all mating lines.
(4) Insulation, carpet, carpet pad or other porous
materials are not acceptable.
Attached Graphic
(b) Floor Connections:
(1) Gaps between floors up to 1-1/2 inches maximum
which do not extend the full length of the floor may be filled with
lumber, plywood or other suitable shimming materials. Fastener lengths
in shimmed areas may need to be increased to provide minimum 1-1/4
inches penetration into opposite floor rim joist.
(2) Gaps less than 1/2 inch width need not be shimmed.
(3) The floor assemblies of multi-section units must
be fastened together. Fastener options and maximum spacings are listed
in the floor connections figure in paragraph (4) of this subsection.
(4) Any tears or damages to the bottom board due to
fastener installation must be repaired.
Attached Graphic
(c) Endwall Connections:
(1) Endwalls must be fastened together at the mating
line with minimum #8x4 inch wood screws or 16d nails at maximum 8
inches on-center or 12 inches on-center maximum for 5/16 lags; toed
or driven straight; and
(2) Fastener length may need to be adjusted for gaps
and/or toeing, to provide minimum 1-1/2 inch penetration into opposite
endwall stud.
Attached Graphic
(d) Roof Connection: (Note: Fasteners must not be used
to pull the sections together.)
(1) Roof shall be connected with the fasteners and
spacings specified in the figure in paragraph (2) of this subsection.
(2) Gaps between the roof sections (at ridge beam and/or
open beam ledgers) of up to 1-1/2 inches wide maximum which do not
extend the full length of the roof must be filled with lumber and/or
plywood shims. Gaps up to 1/2 inch need not be shimmed. The fastener
length used in the shimmed area may need to be increased to provide
a minimum 1-1/4 inch penetration into the adjacent roof structural
member.
Attached Graphic
(e) Exterior Roof Close Up:
(1) Ensure that shingles are installed to edge of roof
decking at peak. Follow nailing instructions on the shingle wrapper.
Note: Wind Zone II (high wind) installations require additional fasteners.
(2) Before installing ridge cap shingles, a minimum
6 inch wide piece of 30 gauge galvanized flashing must be installed
the length of the roof.
(3) When flashing is not continuous, lap individual
pieces a minimum of 6 inches.
(4) Fasten flashing into roof sheathing with minimum
16 gauge staples with 1 inch crown or roofing nails of sufficient
length to penetrate roof decking. Maximum fastener spacing is 6 inches
on-center each roof section. Place fasteners a minimum of 3/4 inches
along edge of flashing.
(5) Install ridge shingles directly on top of flashing.
(6) Check and repair as necessary the remainder of
roof for any damaged or loose shingles, remove any shipping plastic
or netting, wind deflectors, etc. Make sure to seal any fastener holes
with roofing cement.
Attached Graphic
(f) Exterior Endwall Close Up: Cut closure material
to the shape and size required and secure in place, starting from
the bottom up, i.e.: bottom starter, vertical or horizontal siding,
then roof overhang, soffit and fascia. All closure material should
be fitted and sealed as required to protect the structure or interior
from the elements.
(g) HVAC (heat/cooling) Duct Crossover:
(1) Crossover duct must be listed for EXTERIOR use.
(2) Duct R-value shall be a minimum of R-4.
(3) The duct must be supported 48 inches on-center
(maximum) and must not be allowed to touch the ground. Either strapping
(minimum 1 inch wide), to hang the duct from the floor, or non-continuous
pads to support it off the ground are acceptable.
(4) The duct to the collar or plenum connections must
be secured with bands or straps designed for such use. Keep duct as
straight as possible to avoid kinks or bends that may restrict the
airflow. Extra length must be cut off.
(5) The installer should refer to the manufacturer's
instruction for assembling the overhead duct.
Attached Graphic
(h) Multi-Section Water Crossover:
(1) If there is water service to other sections, connect
the water supply crossover lines as shown in the applicable detail.
(2) If the water crossover connection is not within
the insulated floor envelopes, wrap the exposed water lines in insulation
and secure with a good pressure sensitive tape or nonabrasive strap,
or enclose the exposed portion with an insulated box.
(3) If water piping at the inlet is exposed, a heat
tape should be installed to prevent freezing. A heat tape receptacle
has been provided near the water inlet. When purchasing a heat tape,
it must be listed for manufactured home use, and it must be installed
per manufacturer's instructions.
Attached Graphic
(i) Drain, Waste and Vent System (DWV):
(1) Portions of the DWV system which are below the
floor may not have been installed, to prevent damage to the piping
during transport. Typically, the DWV layout is designed to terminate
at a single connection point to connect to the on-site sewer system.
For a used home where on-site DWV connections are not assembled per
the manufacturer's instructions, the DWV system must be assembled
in accordance with Part 3280 of the FMHCSS.
Attached Graphic
(2) The following guidelines apply:
(A) All portions of the DWV system shall be installed
to provide a minimum of 1/8 inch slope per foot for a 3 inch diameter
pipe or larger, in the direction of the flow. For all other pipe,
a minimum of 1/4 inch is required.
(B) Changes in direction from vertical to horizontal,
and horizontal to horizontal, shall be made using long sweep elbows
and/or tees.
(C) All drain piping shall be supported at intervals
not to exceed 4 feet on-center. The support may be either blocking
or strapping. When strapping is used, it should be nonabrasive.
(D) Piping must be assembled with the appropriate cleaners,
primers and solvents (note: both ABS and PVC systems are common, but
will require adhesives). Be sure to follow the instructions of the
product used.
(E) A cleanout must be installed at the upper (most
remote) end of the floor piping system.
(3) Water testing: At the time of installation the
water system must be inspected and tested for leaks after completion
at the site (the water heater must be disconnected when using an air-only
test).
(4) Drainage system testing: At the time of installation
the drainage system must be inspected and tested for leaks after completion
at the site.
(j) Electrical Connections: Depending on the model
and/or manufacturer of the home, electrical crossovers may be located
in either the front end and/or rear end of the home. Check along mating
line for other labeled access panels.
(1) Crossover connections may be one of the following:
(A) snap or plug-in type;
(B) junction boxes inside floor cavity (note: crossover
wiring routed outside the floor cavity must be enclosed in conduit).
If the boxes and/or covers are metal, they must be grounded by the
use of the ground wire; or
(C) pigtail between receptacles/switches between sections
(one circuit only and enclosed in a j-box according to the National
Electrical Code (NEC).
(2) Chassis Bonding: Each chassis shall be bonded to
the adjacent chassis with a solid or stranded, green insulated or
bare, number 8 copper conductor. The conductor is connected to the
steel chassis with a solderless lug. Alternate bonding: A 4 inch wide
by 30 gauge continuous metal strap may be used as an alternate, when
attached to the chassis members with two #8x3/4 inch self tapping
metal screws each end of the strap.
Attached Graphic
Cont'd... |
