All modular homes must be supported. This may be accomplished through the use of piles, piers, or cribbing (blocking). The spacing of 8 feet is recommended and in no case should spacing exceed 10 feet. The home should be supported under all exterior doors and large windows.
Piles used to support modular homes are required to be designed for existing soil conditions. See Table A below
Support Spacing
| Type of Soil |
[6'] |
[8'] |
[10'] |
| Soft Clay, loose sand, loose gravel |
22"2 |
25"2 |
30"2 |
| Firm clay, compact silt |
16"2 |
18"2 |
20"2 |
| Compact sand, compact gravel, stiff clay |
12"2 |
14"2 |
15"2 |
| Shale, rock |
10"2 |
10"2 |
12"2 |
When using a pier foundation, the footing of the pier should be built below the frost depth and in no case shall the top of the footing be closer than 4ft. to grade. To determine the size of footings to be used refer to Table A above. When footings are installed in soil not identified in Table A, the design must be in conformance with accepted engineering practices. The concrete piers supported by the footing shall be a minimum of 8' diameter if circular, or 8" X 8" if square. A minimum of four ½ inch-reinforcing bars must be used in the construction of the pier extending from the footing into the column.
Wood cribs shall be placed on a concrete or pressure treated wood footing as detailed on the wood crib detail. Materials used to build a wood crib must consist of good quality lumber arranged in such a manner that each layer rests at a right angle to the layer below. Each layer must be securely nailed. A wood crib must at reach a height of more than 1 and 1/2 times its width.
Modular homes are required to be anchored to the ground through the use of ground anchors or the foundation unless it can be demonstrated by calculation or local experience that ground anchorage is not required. Information for calculation purposes can be found In Part 4 of the National Building Code of Canada. The use of anchors greatly reduces the cost of the insurance and therefore should be considered even if you do not fall into the above mention parameters
