Dampness or moisture in basements or crawl spaces of buildings can be a major factor causing or contributing to foundation problems.
The reasons for the dampness can vary, even though the problem in most cases is the same; excessive water in and around the foundation area, which in turn deteriorates the concrete causing cracks and other, related problems.
The first step in remedying or repairing any foundation problem is water management.
Here are some questions to ask yourself that may help isolate the problem:
- Is all the siding attached, are all the windows properly fitted? In many cases water enters through rotten windows.
- Are all the gutters secure, do they overflow? Gutters are needed along the bottom edge of all roofs, and downspouts are essential. Are all downspouts connected?
- Inspect all drains from downspouts and drains in basement window wells making sure that they are not blocked.
- Add clear plastic window well covers to all basement windows.
- Begin by diverting or piping away all the water coming from the downspouts. Three feet is a start, 10 feet would be good, but the further it can be piped or diverted away from the building the better.
- Re-grade the landscaping making sure that it all slopes away from the house, even if it is only a gentle slope.
- Flower beds should be higher than the lawn. Lawn is better than flower beds because it does not let as much water through.
- Patios (concrete slabs) often sink or settle and then channel water towards the house. These would need to be removed or replaced.
- The driveway needs to slope away from the building. Any area surrounding the house that tends flood or appears waterlogged after it rains should be drained.
- If your neighbors property drains on to your property, consider installing a drain that would break the flow of water before it reaches your house.
- Any brick or concrete block above the grade level should be sealed with a clear water sealant.
Repairing poured concrete foundations is usually easier than block foundations. Non structural cracks can be sealed with a polyurethane injection into the crack. Structural cracks can sometimes be repaired with an epoxy crack sealant which is also very successful at stopping water penetration which in turn reduces the possibility of the cracks getting worse.
Block is nearly impossible to repair if the block is shifting, straps and other systems attempt to hold the movement in check, but in the end the foundation may have to be rebuilt. This involves jacking the house up off the foundation and building a new foundation wall.
If the wall is damp and deteriorating it may need to be sealed and an external barrier and drain system installed.
First, a trench is dug around the building. This trench is dug down below the floor level of the basement. Plastic drainpipe is then installed to take the water away from the building. The pipe is then covered with pea gravel. The complete foundation is then sprayed with a tar type sealant (Polymer) and sheets of Styrofoam with special water channels are stuck to the wall.
The Styrofoam creates a solid water barrier and funnels the water into the drain at the base of the foundation which, in turn, carries it away from the building.
In the case of a serious foundation failure, Wall anchors may be needed to hold the wall in place or a retaining wall of poured concrete and rebar may be built to support and hold the original concrete block foundation in place.
NOTE: Poured concrete foundations in general tend to hold up better than concrete clock foundations. All poured concrete will develop hairline type cracks.