Mich. Admin. Code R. 125.1602 - Installation
Rule 602.
(1) For
all new homes brought into or sold in Michigan, the manufacturer shall provide
express written instructions for the installation of each home specifying the
location and required design load capacity of the piers and the location and
the required design load capacity of any other recommended stabilizing systems,
if required. All homes shall be installed according to the manufacturer's
installation instructions. The person installing a home has the option of
installing a plastic vapor barrier on the ground under the home, unless the
manufacturer's installation instructions specifically mandate the placement of
the vapor barrier. Crossbeaming shall not be allowed under a home installed
after July 16, 1998, unless approved by the manufacturer of the home. In the
case of a pre-owned home, the approval also may be given by a licensed design
professional registered in compliance with the requirements of 1980 PA 299, MCL
339.101 to 339.2721.
(2) In the
absence of the manufacturer's installation instructions, the installation of
homes shall be in compliance with specifications prepared by a licensed design
professional registered in compliance with the requirements of 1980 PA 299, MCL
339.101 to 339.2721 or, if a licensed design professional is not available, in
compliance with all of the following specifications:
(a) All grass shall be removed and the
foundation footing shall be installed on or in stable soil.
(b) Piers shall be installed directly under
each main frame beam, unless crossbeamed after approval from the manufacturer
of the home or a licensed design professional registered in compliance with
1980 PA 299, MCL 339.101 to 339.2721.
(c) Footing and pier spacing shall not exceed
the minimum span identified in table A-l and a positive grade shall be
established.
| Table A-1 | ||||||
| Soil Capacity | 1500 PSF | 2000 PSF | 2500 PSF | 3000 PSF | 3500 PSF | 4000 PSF |
| Footi ng Size (a)(f) | 24"x24"x6 " | 22"x22"x6 " | 20"x20"x6 " | 18"xl8"x6 " | 16"xl6"x6 " | 16"xl6"x6 " |
| Spaci ng: | ||||||
| Main Beams | 6' (iiXiii) | & (ii)Ciii) | 6' (ii)(iii) | 8' (ii)(iii) | 8' (ii)(iii) | 8' (ii)(iii) |
| Peri meter | (v) | (v) | (v) | (v) | (v) | (v) |
| Marri age Beam | 8' (ii)(iv) | 8' (ii)(iv) | 8' (ii)(iv) | 10' (ii)(iv) | 10' (ii)(iv) | 10' (ii)(iv) |
(i) All
footings shall extend 42 inches below actual grade. The footing may be less
than the 42-inch depth if supported by a soil analysis. A footing shall be
installed in compliance with R 408.30401et seq. of the Michigan building
code.
(ii) Piers shall be located
under each main beam and marriage line beam starting within 2 feet from the end
of each beam then spaced according to this table.
(iii) Piers may be offset up to 1 foot to
allow for such obstruction as axles (if permanently attached to
frame).
(iv) Additional piers shall
be added on each end of every opening in the marriage wall which is 4 foot or
larger and shall be considered columns.
(v) Perimeter piers shall be installed on
sidewall openings greater that 4 foot and exterior doors.
(vi) Footing shape may be other than square.
Maintain equal amount of footing area.
(d) Piers shall be installed under the center
beam/marriage line of multisectional homes at all interior openings of more
than 4 feet on the marriage wall and at each end of the marriage
line.
(e) The piers nearest each
end of the home shall be within 2 feet of either end of the home
frame.
(f) Concrete block piers
shall be constructed of at least 8-inch by 8-inch by 16-inch blocks and placed
on the foundation footing. The blocks shall be placed with the open cells
vertical. A cap shall be placed on top of the pier. A wood plate that has the
same dimensions as the pier and cap may be placed on top of the cap for
additional leveling. Shims may be fitted and driven tight between the wood
plate or cap and the main frame I-beam and shall not take up more than 1 inch
of vertical height.
(g) Pier
tiering shall comply with all of the following requirements:
(i) Piers 30 inches in height or less above a
footing may be single-tier construction composed of 8-inch by 8-inch by 16-inch
open cell concrete blocks that conform to ASTM standard C 90-99. The standard
is adopted by reference in
R
125.1102 of these rules. Blocks shall be capped with
2-inch by 8-inch by 16-inch hardwood or treated wood, with a solid concrete
block cap, or with a 1/4-inch solid steel plate. Blocks shall be set with the
openings vertical.
(ii) Piers that
are more than 30 inches in height above a footing shall be double-tier
construction with blocks interlocked and capped with a 4-inch by 16-inch by
16-inch solid concrete cap.
(iii)
The concrete blocks of double-tier piers that are more than 80 inches in height
above a footing shall be filled with concrete and steel reinforcing
rods.
(h) Piers shall be
installed perpendicular to the main frame of the home and shall not be offset
from the foundation footing.
(3) Crossover heat ducts shall not lie on the
ground. Heat duct strapping shall not restrict the opening.
(4) A home shall not be placed in a
designated floodway, as determined by the Michigan department of environmental
quality.
(5) An anchoring system
shall be installed on a home.
(6)
Permits shall be obtained for the construction of footings and accessories and
the installation of homes from the enforcing agency charged with the
administration and enforcement of the codes pursuant to the
Stille-DeRossett-Hale Single State Construction Code Act, 1972 PA 230, MCL
125.1501 to 125.1531.
Notes
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