There are various reasons for a complete foundation replacement of a house.
Some of these reasons are:
1. The house has no foundation.
2. The foundation is made of unreinforced masonry, such as brick,
3. The concrete foundation is badly deteriorated.
4. Faulty or poor quality materials were used in the original foundation.
A complete foundation replacement is typically done in two or more segments. For example, first the north and west foundations are replaced. Subsequently, the south and east foundations are replaced.
A. Beutiful Home with Foundation Problems
The outside of this home shows no apparent signs that its foundation has badly deteriorated. (Photo A)
Underneath, however, the foundation is crumbling. (Photos B, C)
CLICK ON PHOTOS FOR LARGER IMAGES.
B. Deteriorated Concrete Foundation
C. Badly-Deteriorated Foundation
FOUNDATION RETROFIT STEPS:
1. The house is shored up securely. This will allow the removal of the foundation without damaging the house. There is no need to actually elevate the house off its foundation. (Photo D)
2. The old foundation is removed. This is a relatively simple procedure since most older foundations do not include any steel reinforcement. (No Photo)
3. A trench is then dug to accommodate the new footing. A modern footing is typically a minimum of 24" deep, as compared to some older foundations which are only 6" to 8" deep. (Photo E)
4. The old mudsill is typically replaced with new larger treated lumber to allow installation of proper foundation bolts. (Photo F)
5. Steel reinforcements (rebars) are then installed in the trench elevated above the soil with concrete spacers. Foundation bolts with large square washers are installed as well. (Photo F)
6. Wooden forms are built to contain the concrete. (No Photo)
D. House Shored, Foundation Removed
E. Trench for New Foundation
F. Foundation Rebars and Forms
7. Ready-mix concrete, delivered to the job site by a concrete truck, is pumped into the forms with a concrete pump. (Photo G)
8. After a day or two the wooden forms are removed. (Photo H)
9. Sometimes solid wood blocking is added in between the floor joists above the new foundation. (No Photo)
10. Framing anchors are installed to attach the new blocking to the new mudsill. (No Photo)
11. The stucco or siding at the foundation area may need to be patched and painted to match the rest of the exterior. (Photos I, J)