Slab foundations can be built on a poured or block foundation. Some of the most frequently asked questions or concerns of a homeowner is water getting in to the duct work under the concrete slab which is part of the heating system and the concern of mold being present in the home.
The major reason is in this area of the country when the house is built there is no code requiring the builders to install drain tile along the footer in the original construction. What happens is over the years during the rain the ground becomes saturated and water seeps underneath the slab foundation. The water comes in contact with the duct work which is normally constructed in metal. Over time the metal duct work will rust and deteriorate in which will allow the water to infiltrate the heating system. The reasoning why this leads to mold and unhealthy conditions in the winter the water will be cold and the heating system will be producing heat. This causes condensation which allows the mold to thrive. Another sign of water in the heating system could be high humidity throughout the house and windows sweating. This can also occur in the summer months, resulting in your air conditioner pushing cold air through the heating system while there is water present.
The key to resolve this:
- Control the water by excavating around the property
- Cleaning the foundation and inspect for structural damage
- Repair any structural damage that is found
- Waterproof the foundation
- Hand trial tar on the wall
- Install a drain board
- Soil separator
- 4 inch perforated tile packed in 1 inch river washed gravel
- Tie perforated pipe into solid schedule 35 PVC
- Run all down spouts and footing tile in solid schedule 35 PVC a minimum 35 – 40 feet away from home
- Some applications require a sump pump due to the grade of the lot
- All work is completed with a finish grade, seed and straw where required