2019 U.S. Virgin Islands Code
Title 29 - Public Planning and Development
Chapter 5 - Building Code
Subchapter VII - Foundations
§ 303. Foundation standards
(a) General requirements. Foundation walls or other permanent supports shall rest on solid ground or on piles when solid earth or rock is not found. Such foundation walls shall not be required in one-story buildings if the floor area does not exceed 750 square feet and the buildings are of wood frame construction. In such cases piers may be used.
- Footings shall consist of masonry or reinforced concrete.
- Where metal is incorporated in or forms part of a foundation, except reinforcements in concrete, it shall be protected from rust by paint, asphalt, or concrete.
(b) Bearing capacity of soil. Whenever the Department of Planning and Natural Resources, upon inspection of the site deems it necessary to establish the assumed bearing capacity of the soil, applications for building permits for the construction of a permanent structure or for the alteration of a permanent structure involving an increase in load on the foundation shall be accompanied by a statement from the designer as to the type of soil on which the foundation will rest and the assumed bearing capacity of this soil.
(c) Soil bearing values. Footings shall be designed so that the maximum allowable pressure on the supporting soil shall not exceed the values as set forth in the following table:
- Soil Bearing Values
| Type of Soil | Tons per Square Foot |
|---|---|
| Clay, soft | 1.0 |
| Clay, medium soft | 2.0 |
| Sand, fine loose (if confined) | 1.0 |
| Sand, coarse, loose; compact fine sand; loose sand and gravel mixture | 2.0 |
| Gravel, loose; compact coarse sand | 3.0 |
| Sand-gravel mixture, compact | 6.0 |
| Hardpan and exceptionally compacted or partially cemented gravel | 10.0 |
| Sedimentary rocks such as shales, sandstone | 15.0 |
| Foliated rocks, bedded limestone schist or slate | 40.0 |
| Massive bedded rocks, granite | 100.0 |
(d) Variation in the types of soil. Where footings are supported by soils of widely different bearing capacity, the allowable bearing value of the more yielding soil shall be reduced or special provisions made in the design to prevent serious differential settlements.
(e) Footing design. Footings shall be so designed that the pressure on the soil per unit of area shall be so far as possible uniform under all parts of the building or structure.
- The area of footings shall be in proportion to the full dead loads, including the weight of the footings. In no case shall the dead loads plus the live loads cause a pressure under the footing exceeding the permissible soil bearing capacity.
(f) Foundation walls. Foundation walls shall be of adequate strength and thickness to resist lateral pressures from adjacent earth and to support their vertical loads, but the thickness shall not be less than the actual thickness of walls supported by them.
