Alabama Administrative Code › Title 535 - ALABAMA MANUFACTURED HOUSING COMMISSION › Chapter 535-X-13 - REGULATIONS FOR THE INSTALLATION OF MANUFACTURED HOMES AND MANUFACTURED BUILDINGS AND THE MANUFACTURE OF GROUND ANCHORS AND TIEDOWN DEVICES › Section 535-X-13-.06 - Minimum Blocking Standards

Current through Register Vol. 42, No. 9, June 28, 2024
(1) Pier foundations shall be installed
					directly under the main frame of the home or building. The piers shall not be
					further apart than six (6) feet on center when using a minimum pier foundation
					of a 16" x 16" x 4" concrete pad or equivalent in the minimum soil bearing
					capacity of 2000 lbs. PSF. Piers shall be no more than two feet from each end
					of the frame.
(2) The minimum pier
					foundation shall be a 16" X 16" X 4" concrete pad, precast or poured in place
					concrete slab. All grass and organic material must be removed and the pier
					foundation placed on stable soil. The minimum soil bearing capacity for the
					minimum pier foundation is 2000 lbs. If the actual soil's bearing capacity is
					greater than 2000 lbs., an assumed value of 2,000 lbs. must be used to
					determine pier spacing. In a soil bearing capacity below these values, the pier
					foundations must be increased in size according to the bearing load and the
					soil bearing capacity of the soil. Two (2) 8" X 16" X 4" concrete pads are
					considered minimum. All debris, grass, grass sod and other foreign material
					that would be under the footers must be removed before footings or pier
					foundations are installed. Pier footing must not be placed on a mound. If the
					space under the home is to be enclosed with skirting or other material, the
					skirting shall be vented, and a ground vapor retarder of 6 mil rated
					polyethylene sheeting or equivalent should be installed. Venting shall be
					provided for the crawl space at the minimum required by the latest publication
					of NCSBCS/ANSI A225.1. The vapor barrier should cover the entire area under the
					home and overlap at least 12 inches at all joints. All decayable material, such
					as grass, roots, twigs, and wood scraps shall be removed from beneath the
					home.
(3) Piers may be manufactured
					load-bearing supports or devices and must be approved for the loads and use
					intended, or piers shall be constructed of regular 8" X 8" X 16" concrete
					blocks, with open cells in a vertical position when placed upon the pier
					foundation. A 2" x 8" X 16" treated wood or hardwood plate or a concrete cap
					shall be placed on top of the pier to serve as a pier cap. A true 1" thick
					hardwood plate is optional. All piers must have a full size cap covering the
					pier.
Additional full size plates not less than (1" X 8" X 16") may
						be used; but, the additional plates shall not exceed 4" in total height. The
						frame may be cushioned with treated wood, hardwood, or other Commission
						approved shims (wedges) and the shims shall not occupy more than 1" of vertical
						space between the top plate and main frame. One shim at least 4" x 6" nominal
						is to be placed on each side of the main frame on single tiered piers. Two
						shims are to be placed on each side of the main frame on double tiered piers.
						Shims must be used in pairs and driven tight. Concrete block piers are to be
						placed perpendicular to the main I beam or frame.
(4) All piers over 32" (over four 8" x 8" x
					16" concrete blocks) in height shall be double tiered with the blocks
					interlocked.
(5) A minimum of 12"
					clearance shall be maintained from beneath the main frame or I beam to the top
					of the soil's surface.
(6) The
					maximum pier height shall be no more than 60 inches unless designed and
					approved by a registered engineer or a higher height/different design is
					required by the National Flood Insurance Program (NFIP) floodplain management
					criteria.
(7) Exterior
					sidewall/marriage wall blocking - In addition to providing piers for supporting
					the frame, piers are also required to support the special roof loads. The
					support piers are required at all marriage wall and sidewall openings 48" and
					greater in width. These piers are to be placed at each side of each opening.
					The most commonly occurring openings are sliding glass doors and full bay
					windows. Typical marriage wall openings are cathedral openings and passageway
					openings which are 48" and larger. Recessed walls are considered sidewall
					openings. Each ridge beam column shall be supported by piers under the marriage
					wall. Piers shall be placed under heavy loads such as masonry-faced fireplaces,
					etc. Marriage walls shall have piers at each end of the home. Exterior door
					openings shall have piers or an approved support device on each side.
(8) Marriage wall piers shall be constructed
					to the same requirements as all other pier requirements.
(9) Perimeter pier foundations are required
					to be 8" X 16" X 4" concrete pads. Perimeter piers shall be single tiered and
					placed parallel to the sidewall.
(10) To assure that the manufacturer's
					warranty remains valid, all new homes and buildings must be blocked according
					to the manufacturer's installation manual.
(11) All new manufactured homes or
					manufactured buildings shall be installed in accordance with the manufacturer's
					installation instructions. Effective October 20, 2008, the Manufacturer's
					Installation Instructions must meet or exceed the minimum requirements of the
					HUD Model Manufactured Home Installation Standards. Manufacturers may provide
					training to the installers of their homes to include lagging, sealing, and
					complete trim out. Paragraphs 1-9 shall apply to all used homes and buildings
					when the manufacturer's installation instructions are not available. It is the
					installer's responsibility to ascertain for himself which homes may be
					installed according to the State's minimum blocking standards.
Author:
Jim Sloan
Statutory Authority:
Code of Ala.
							1975
, §§
										24-4A-3,
							24-5-31,
							24-5-32,
							24-6-4.