Section 125.1602. Installation.

(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-1 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”x18”x6 ”	16”x16”x6 ”	16”x16”x6 ”
Spaci ng:
Main Beams	6' (ii)(iii)	6' (ii)(iii)	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.

History: 1979 AC; 1982 AACS; 1983 AACS; 1985 AACS; 1998 AACS; 2003 AACS; 2008 AACS.