Texas Administrative Code
Title 10 - COMMUNITY DEVELOPMENT
Part 1 - TEXAS DEPARTMENT OF HOUSING AND COMMUNITY AFFAIRS
Chapter 80 - MANUFACTURED HOUSING
Subchapter B - INSTALLATION STANDARDS AND DEVICE APPROVALS
Section 80.25 - Generic Standards for Multi-Section Connections Standards
Universal Citation: 10 TX Admin Code ยง 80.25
Current through Reg. 49, No. 38; September 20, 2024
(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.
(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.
(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.
(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.
(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.
(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.
(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.
(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.
(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.
(3)
Electrical Crossover.
(4)
Shipped loose equipment:
(A) Electrical
equipment such as ceiling fans, chandeliers, exterior lights, etc., which may
have been shipped loose, must be installed in accordance with the adopted
(NEC). Connect all corresponding color coded or otherwise marked conductors per
the applicable sections of the NEC.
(B) Bonding strap removal: 240 volt
appliances (range, dryer, etc.) shall have the bonding strap removed between
the ground and the neutral conductors. Cords used to connect those appliances
shall be four conductor, four prong.
(5) Main panel box feeder connection: The
main panel box is wired with the grounding system separated from the neutral
system (4-wire feeder). The grounding bus in the panel must be connected
through a properly sized green colored insulated conductor to the service
entrance equipment (meter base) located on or adjacent to the home. A licensed
electrician is required to run the feeder from the pole to the main panel box
in the home.
(k) Fuel Gas Piping Systems:
(1) Crossover Connections: All underfloor
fuel gas pipe crossover connections shall be accessible and be made with the
connectors supplied by the home manufacturer, or, if not available, with
flexible connectors listed for exterior use and a listed quick disconnect
(Method A), or a shut-off valve (Method B). When shut-off valve is used, it
must be installed on the supply side of the gas piping system. The crossover
connector must have a capacity rating (BTUH) of at least the total BTUHs of all
appliances it serves.
(2) Testing:
The fuel gas piping system shall be subjected to an air pressure test of no
less than 6 ounces and no more than 8 ounces. While the gas piping system is
pressurized with air, the appliance and crossover connections shall be tested
for leakage with soapy water or bubble solution. This test is required of the
person connecting the gas supply to the home, but may also be performed by the
gas utility or supply company.
(3)
The gas system must be inspected and tested for leaks after completion at the
site.
Disclaimer: These regulations may not be the most recent version. Texas may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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