American Basement Waterproofing

The cause of basement leaks vary and may depend on the type of basement you have. There are two primary types of basement walls constructed in the building industry. They consist of the poured basement wall and basement walls constructed with cinder blocks. Poor grading or drainage around the basement can cause a high water table. A sump pump malfunction can also allow the water table to rise and cause basement leakage. Cracks in basement walls, rod holes, mortar joints around beams and windows, and clogged or obstructed exterior drain systems are the most common causes of basement leaks in poured basement walls. Common causes for basement leaks in cinder block walls include the breakdown of mortar between the blocks, cracks, and obstructed exterior drain systems.

The majority of cracks in basement walls are caused by the settlement and shrinkage of concrete and mortar joints. This normally occurs during the first few years of construction. Settlement and shrinkage cracks are usually vertical in poured walls, and may be both vertical and horizontal in block basements. Frost and heavy equipment can also cause basement walls and footings to crack and move. Cracks caused by frost and heavy equipment are usually very large and diagonal. They are more likely to occur during the construction phase.

Repairs on poured basement walls are routinely performed from the inside of the basement. In many instances, a porch, patio, garage, or deck prevent an outside repair.

Crack injection repairs are the highest quality cost-effective solution when performed properly. There are many products on the market. High expansion polyurethane hydrofoam is the best injection product. The reason is that high expansion fills the entire crack so water can no longer enter the basement wall. While rigid enough to prevent water intrusion, high expansion polyurethane hydrofoam is flexible enough to withstand the expansion and contraction of basement walls during the summer and winter.

Other repair methods are basically surface repairs. Professional grade non-shrinking slow curing polyurethane epoxy surface sealants are recommended for proactive repairs on cracks that do not leak or rarely leak. Hydraulic cement and fast curing epoxy repairs may provide temporary relief, but generally fail due to the shrinkage of those products. Panel repairs actually make the crack bigger to allow water to flow down the basement wall behind the panel to a floor drain or sump pump rather than stopping the water at the source. While panel repairs generally work, they are far more expensive than crack injection repairs. There is also a risk of a mold and mildew problem developing behind the panel. Panel repairs can also become clogged with dirt that washes in with water through the crack and leak.

Rod leaks get their name from steel rods that were used to hold the forms together during the construction of poured concrete basement walls. The two primary types of rods are the slip out and snap off. Slip out rods leave a hole in the basement wall that is usually covered with a thin coating of mortar. Snap off rods leave the steel in the basement wall. Although back work crews are supposed to repair each rod on the exterior of the basement wall during the construction phase, many of the repairs fail due to settlement or poor craftsmanship.

Sump pumps act to lower the water level on the exterior of the basement wall to help reduce basement leaks. There are many types of sump pumps and drainage systems. Generally, water is pumped from a sump basin to a storm drain system.

When a sump pump fails water begins to rise on the exterior of the basement wall. In that event water can leak around the floor line where the basement wall and floor meet. In many instances cracks and rods leak that may have never leaked prior to the sump pump malfunction.

There are several conditions that can cause basement walls constructed with cinder blocks to exhibit the problem you have described. It may be as simple as replacing a defective sump pump or correcting poor grading and drainage outside of the basement wall. Making sure gutters are clear and diverting water from the foundation with down spout extensions can sometimes solve the problem. Cracks, mortar joint breakdowns between blocks, and an obstructed exterior drainage system can also cause this type of problem. In those events the installation of a sub-floor drain system may be necessary to solve the problem.

Beam leaks normally occur when water penetrates the mortar joint around the beam. This is usually due to shrinkage and cracks in the mortar.

The cracking and shrinkage of basement window mortar joints are the most common cause of a basement window leaks. Although less common, leaks can also develop around window frames.

The most common causes of egress window leaks are a clogged drain in the window well or water penetrating the window frame. Common causes for a clogged window well drain are leaves and dirt blocking water from entering the drain.