During the heart of storm season, many in our area find themselves battling moisture and rain seepage in basements. According to a study by the University of Minnesota Extension, improper drainage is the leading cause of wet foundations. Homeowners can employ several methods of mitigation, including dehumidifiers and corrected gutters and downspouts. Severe cases of water require professional solutions including sump pumps, exterior grading adjustments, and perforated drain tile. Neglecting to rectify these issues can result in the buildup of mold and other airborne pathogens.
A common inexpensive solution is a membrane or coating. This can work as a temporary solution; however, the coating deteriorates over time and the water is still present at the foundation.
The University of Minnesota recommends three approaches. The first is installing an interior drainage channel above the concrete slab. This is one of the less expensive approaches to water mitigation. Water is collected and drained into a sump using a channel placed on top of the slab. The system is best suited to use with a concrete wall with cracks. This solution does not rectify the problem in the masonry walls because water remains in the core of the block at the floor level. This system does not completely remove water from the space, and mold or mildew could still be an issue.
The second approach is to place the drainage channel at the base of the wall on top of the footing. The drainage channel is connected to a drain pipe leading to the sump. This method drains the water out of the core of the block. Holes are drilled at the base of every block core to allow the water to properly drain. This involves the removal of concrete in order to adequately drill.
The University of Minnesota Extension study provides the third approach: an interior drainage system that is located beneath the slab. According to the study, a perforated drain pipe installed inside the perimeter of the footing is the most effective means of water mitigation. This requires removing and replacing concrete at the edge of the slab and placing drain pipe beneath the slab. As with an exterior system, the drainage pipe connects to a sump. This method is less expensive than many specialized drainage channel systems.