3285.303—Piers.
(a) General.
The piers used must be capable of transmitting the vertical live and dead loads to the footings or foundation.
(b) Acceptable piers—materials specification.
(1)
Piers are permitted to be concrete blocks; pressure-treated wood with a water borne preservative, in accordance with AWPA Standard U1-04 (incorporated by reference, see § 3285.4) for Use Category 4B ground contact applications; or adjustable metal or concrete piers.
(2)
Manufactured piers must be listed or labeled for the required vertical load capacity, and, where required by design, for the appropriate horizontal load capacity.
(c) Design requirements.
(1) Load-bearing capacity.
The load bearing capacity for each pier must be designed to include consideration for the dimensions of the home, the design dead and live loads, the spacing of the piers, and the way the piers are used to support the home.
(2)
Center beam/mating wall support must be required for multi-section homes and designs must be consistent with Tables 2 and 3 to § 3285.303 and Figures A, B, and C to § 3285.310.
(d) Pier loads.
(1)
Design support configurations for the pier loads, pier spacing, and roof live loads must be in accordance with Tables 1, 2, and 3 to § 3285.303 and the MHCSS. Other pier designs are permitted in accordance with the provisions of this subpart.
(2)
Manufactured piers must be rated at least to the loads required to safely support the dead and live loads, as required by § 3285.301, and the installation instructions for those piers must be consistent with Tables 1, 2, and 3 to this section.
Pier spacing | Roof live load (psf) | Location | Load (lbs.) |
---|---|---|---|
20 | Frame | 2,900 | |
4 ft. 0 in. | 30 | Frame | 3,300 |
40 | Frame | 3,600 | |
20 | Frame | 4,200 | |
6 ft. 0 in. | 30 | Frame | 4,700 |
40 | Frame | 5,200 | |
20 | Frame | 5,500 | |
8 ft. 0 in. | 30 | Frame | 6,200 |
40 | Frame | 6,900 | |
20 | Frame | 6,800 | |
10 ft. 0 in. | 30 | Frame | 7,600 |
40 | Frame | 8,500 |
Code of Federal Regulations
Maximum pier spacing | Roof live load(psf) | Location | Load (lbs.) |
---|---|---|---|
Frame | 1,400 | ||
4 ft. 0 in. | 20 | Perimeter | 1,900 |
Mating | 3,200 | ||
Frame | 1,400 | ||
4 ft. 0 in. | 30 | Perimeter | 2,300 |
Mating | 3,800 | ||
Frame | 1,400 | ||
4 ft. 0 in. | 40 | Perimeter | 2,600 |
Mating | 4,400 | ||
Frame | 1,900 | ||
6 ft. 0 in. | 20 | Perimeter | 2,700 |
Mating | 4,700 | ||
Frame | 1,900 | ||
6 ft. 0 in. | 30 | Perimeter | 3,200 |
Mating | 5,600 | ||
Frame | 1,900 | ||
6 ft. 0 in. | 40 | Perimeter | 3,700 |
Mating | 6,500 | ||
Frame | 2,400 | ||
8 ft. 0 in. | 20 | Perimeter | 3,500 |
Mating | 6,100 | ||
Frame | 2,400 | ||
8 ft. 0 in. | 30 | Perimeter | 4,200 |
Mating | 7,300 | ||
Frame | 2,400 | ||
8 ft. 0 in. | 40 | Perimeter | 4,800 |
Mating | 8,500 | ||
Frame | 2,900 | ||
10 ft. 0 in. | 20 | Perimeter | 4,300 |
Mating | 7,600 | ||
Frame | 2,900 | ||
10 ft. 0 in. | 30 | Perimeter | 5,100 |
Mating | 9,100 | ||
Frame | 2,900 | ||
10 ft. 0 in. | 40 | Perimeter | 6,000 |
Mating | 10,600 |
Code of Federal Regulations
Code of Federal Regulations
270
Mating wall opening (ft) | Roof live load (psf) | Pier and footing load (lbs.) |
---|---|---|
20 | 1,200 | |
5 | 30 | 1,600 |
40 | 1,900 | |
20 | 2,300 | |
10 | 30 | 3,100 |
40 | 3,800 | |
20 | 3,500 | |
15 | 30 | 4,700 |
40 | 5,800 | |
20 | 4,700 | |
20 | 30 | 6,200 |
40 | 7,500 | |
20 | 5,800 | |
25 | 30 | 7,800 |
40 | 9,700 | |
20 | 7,000 | |
30 | 30 | 9,300 |
40 | 11,600 | |
20 | 8,100 | |
35 | 30 | 10,900 |
40 | 13,600 |