Question

During construction of a house with a crawl space foundation, which of the following precautions must be taken to avoid the shifting that can be caused when the ground freezes?

Answer 1

To prevent shifting in a house with a crawl space foundation due to ground freezing, one should ensure footings are placed below the frost line, provide proper drainage, insulate foundation walls, and consider using frost-protected shallow foundations.

Step-by-step explanation:

During the construction of a house with a crawl space foundation, certain precautions must be taken to prevent shifting due to ground freeze. One of the key measures is to ensure that the foundation footings are placed below the frost line, which is the depth to which the ground freezes. By placing the footings below this line, the risk of frost heave, where expanding ice lifts the soil and thus the foundation, is greatly reduced.

Additionally, proper drainage around the foundation is critical to prevent water from accumulating near the footings. Water expands upon freezing, so preventing its accumulation helps in minimizing the risk of soil expansion and the resultant foundation movement.

Furthermore, insulation of the foundation walls and the use of frost-protected shallow foundations (FPSF) are techniques that can reduce the risk of frost-related issues. FPSFs use insulation to raise the frost line closer to the surface, thereby reducing the depth needed for footings.