Michigan Administrative Code › Department - Licensing and Regulatory Affairs › Bureau of Construction Codes › Manufactured Housing › Part 6 - HOME INSTALLATION › Section R. 125.1602 - Installation

Current through Vol. 24-12, July 15, 2024
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.