In situations where a foundation wall is significantly deteriorated and requires either replacement or stabilization, it may be more cost effective to construct a new concrete foundation wall in front of the existing deteriorated or bowed foundation wall instead of removing and replacing it. The cost of installing the new concrete foundation wall in front of the existing foundation wall is usually less, unless there are a lot of utility interferences which require relocation. There is also savings in not having to excavate along the exterior of the foundation wall and replace landscaping, decks, driveways, stoops, etc.
There are some disadvantages of constructing a new wall in front of the old deteriorated foundation wall which must be taken into consideration:
- There may be interference with utilities and the cost of relocating those utilities may have to be considered. For example, if there is a main sewer line running along the top of the wall with several drains connected to it the cost of relocating the sewer line must be taken into consideration. The reason for this is that the new concrete foundation wall must be continuous from the basement floor slab to the floor framing where a connection can be made to provide lateral bracing.
- If the stairs leading into the basement run right along the deteriorated foundation wall there may not be enough room to construct a new foundation wall and replacement may be the only choice.
- There will be loss of basement space taken up by the new interior concrete foundation wall, typically 8″ to 10″ for the entire length of the wall.
- If there was a problem with water penetration, the new concrete foundation wall may stop some of the water penetration but it is not a guaranteed water tight seal. When replacing a foundation wall new drain tile is installed along the exterior, and the wall can be damp proofed or water proofed from the exterior. Any problems with water penetration are typically solved.
- The exterior walls of the home carry the building loads to the foundation walls. Adding a new foundation wall to the interior will change the load path and the floor joists will be carrying the building loads back to the new foundation wall as the original wall continues to deteriorate. In some cases this may not be possible.