Florida Administrative Code › 15 - DEPARTMENT OF HIGHWAY SAFETY AND MOTOR VEHICLES › 15C - Division of Motor Vehicles › Chapter 15C-1 - GENERAL › Section 15C-1.0103 - Foundations and Piers

Current through Reg. 50, No. 138; July 16, 2024
These guidelines shall be used when the installation of
				  foundations and piers is not specified in the manufacturer's instructions or
				  when the manufacturer's installation instructions are not available.
(1) Piers:
(a) Piers shall be centered under the I-beam
				and installed in accordance with Table A. The maximum spacing of piers shall be
				eight feet (8'). First pier shall be within two feet (2') of either end of the
				home. The pier foundation shall be a minimum of 4'' x 16'' x 16'' solid
				concrete pad precast or poured eight inch (8'') minimum in place or other
				material approved and listed by the department.
(b) Piers may be constructed of regular 8'' x
				8'' x 16'' concrete blocks, open cells (with open cells vertical), centered on
				the footing or foundation. A 2'' x 8'' x 16'' pressure treated or other
				material approved and listed by the department, pursuant to Rules 15C-1.0105
				and  15C-1.0106, F.A.C., shall
				completely cover the top of the pier with pressure treated shims (1/4'' minimum
				and 1 1/2'' maximum thickness x 3 1/2'' minimum width x 6'' minimum length)
				centered and driven tight from both sides of the I-beam between the wood plate
				or cap and the main frame. Single tiered block piers shall be installed
				perpendicular to the main I-beam. Exception: When a pier has been capped with
				at least a four inch (4'') solid concrete block or other material approved and
				listed by the department, pursuant to Rules
				 15C-1.0105 and
				 15C-1.0106, F.A.C., one-fourth
				inch (1/4'') of wood stock or wood shims or other material approved and listed
				by the department, pursuant to Rules
				 15C-1.0105 and
				 15C-1.0106, F.A.C., shall be
				installed between the pier and steel I-beam. (See Figures A, B and D)
(c) Center Line and Perimeter Piers: Center
				line piers shall be located at each end of center line and eight feet (8') on
				center, except where openings of four feet (4') or greater occur, piers shall
				be located on each end of the opening within six inches (6'') of jamb studs or
				ridge beam posts. (See Figures A, B, C and D) Any openings fifteen feet (15')
				or larger in the exterior sidewall and/or marriage wall shall require blocking
				at each end of the opening with three (3) 4'' x 16'' x 16'' pads (See Figure
				D). Piers shall also be installed on each side of any perimeter door or
				fireplace. Bay windows or any opening forty-eight inches (48'') or more shall
				require blocking at each end. Fourteen feet (14') or wider units with I-beam
				spread of less than eighty-two inches (82'') and twelve feet (12') wide units
				with an I-beam spread of less than seventy-five and one-half inches (75 1/2'')
				shall have perimeter blocking installed at a minimum of eight foot (8') on
				center. Piers shall not be required under the clear (open) spans between ridge
				beam posts.
(d) All piers over
				thirty-six inches (36'') and corner piers over twenty-four (24'') in height
				shall be double tiered with blocks interlocked and capped with two (2) 4'' x
				8'' x 16'' solid concrete blocks side by side and perpendicular to the I-beam
				or other material approved and listed by the department pursuant to Rules
				 15C-1.0105 and
				 15C-1.0106, F.A.C., and
				cushioned with wood shims or pressure treated plate. Pier height is measured
				from top of footer or foundation to top of cement block stack, including 4''
				cap block(s). (See Figures B and D)
(e) All piers over fifty-two inches (52'')
				shall comply with local requirements.
(f) Metal and/or precast support piers shall
				be installed on a base or footer of a minimum size of 4'' x 16'' x 16'' solid
				concrete or other material approved and listed by the department. (See Figure
				C)
(g) Metal and/or precast support
				piers shall be restricted to a maximum four inch (4'') locking mechanical
				height adjustment and shall be restricted to a maximum height of not more than
				twenty-four inches (24'') measured from the ground base or footer. This
				twenty-four inch (24'') maximum shall not include the four inch (4'')
				mechanical extension or adjustment. Exception: Center line or perimeter
				supports are permitted to exceed the twenty-four inch (24'') maximum. (See
				Figure C)
(h) The minimum distance
				between the finished grade under all new and used mobile/manufactured homes and
				the bottom of the I-beam shall be eighteen inches (18''). Where the grade is
				sloped, twenty-five (25%) of the lowest member of the main frame may be set
				below eighteen inches (18''); however, under no circumstances may the bottom of
				the I-beam be set below twelve inches (12'') from the finished
				grade.