Why Basements Leak Water
Most builders would agree that water leaking into the basement is a common warranty issue. Homeowners and builders are continually looking for ways to utilize every square inch of potential living space. As a result, basements are frequently being converted into useable space. Thus, designing to keep basements dry is more important than ever.
Some basement water problems occasionally arise during the construction process and disappear when a home s drainage system is fully functional. Other potential problems continue to exist and should be addressed as a preventative measure, especially in cases where the basement will be finished within the first year.
Walk through any basement early on during construction and you will often find water for any number of reasons: sump pump needs greater capacity or just power to run, final grade has not yet been completed, gutters are not installed, pipe penetrations have yet to be sealed. The list goes on and on. The result is basement seepage which may never occur again once everything is operational, but should be carefully analyzed for future ongoing problems.
Lack of drainage around the foundation wall can result in significant amounts of water entering the basement through tie holes, wall and floor cracks, floor seams, and honeycombs. Tie holes occur at the point in the wall where the metal remains of the rods that were holding the concrete forms together during the wallpouring process. They are found along the vertical seams where the two concrete forms meet. This distance between the vertical rows of tie holes is typically two, three, or four feet. Tie rods are usually round in shape or flat.
Round ties can present problems when used in colder conditions. After the forms are removed, the ends of the tie rods are broken off by rotating the end of the rod in a clockwise direction with a hammer. Because the concrete walls cure significantly slower in the winter time, spinning the ties can break the bond between the concrete wall and steel rod. The result can be a whole wall of leaking ties. The good news is tie rod holes, unlike wall cracks, will not move or shrink any further. Repair is simple and can be done by coating the surface of the hole with a two part epoxy or urethane paste or even hydraulic cement. An alternative approach to reduce the chance of ties leaking is to wait to break the ties until the contractor returns to pour the basement floor. Protruding rods, however, can present a safety issue.
Cracks in the floor or the space left where the floor meets the wall (called the cove joint) rarely, if ever, leak as long as the sump system and draintile system are working properly. On occasion, the cove joint can show signs of moisture in areas a great distance from the pump or in alcoves or bays. This joint can be injected with urethane and, when cured, stall the water long enough to allow it to drain. This is assuming the draintile is not blocked. Cracks in the floor should never leak. If water is coming up through floor cracks, the pump may not be working or the draintile has a blockage.
Honeycombs are areas in the wall where the Portland has not been able to encapsulate the aggregate or stones. The most common cause is concrete remaining inside a concrete truck too long. If the concrete cure advances inside the truck too far, the Portland will not mix well with the stones creating voids in the walls once the concrete is poured in place. Honeycombs can often be repaired with simple patching, though some will require an epoxy or urethane injection if they continue to leak after patching.
Another area where water problems are commonly found is at the point where pipes penetrate the wall. To do this, a hole is left in the foundation so that the pipe can be placed through the wall. After the pipe has been fed through the wall, the contractor will often use a brittle and rigid hydraulic cement to close the opening from inside the basement. Hydraulic cement begins to cure in minutes so it is usually only pushed two to three inches into the wall. Vibration in the pipe, among other factors, will often compromise the seal of the cement and cracking it (resulting in the area to leak again).
A common ineffective approach is to reapply the cement or to coat the area with a sealant. Coating the surface of the basement interior wall, typically, will not stop leaks. The cost- effective and permanent repair involves drilling through the old patch into the void behind it and injecting non-shrinking urethane foam to completely fill the void. The void around the pipe is often greater than so it is important the urethane be non-shrinking in nature. Shrinking foams will eventually fail in large void situations.
The most common cause of basement water in homes is from leaking wall cracks. Concrete walls will crack due to the release of water during the curing process. Cracks will commonly be found near breaks in the wall (such as windows and beam pockets) or in the middle of long walls uninterrupted by turns in the wall. These cracks will not automatically leak but often do. Surface repairs with rigid products such as hydraulic cement or epoxy will often fail again within a couple of years. Proper crack repair requires that the cracks be fully filled with either epoxy resin or urethane foam.
Advances in waterproofing techniques now allow builders to permanently repair cracks without calling in outside help. Builders including Pulte Homes, Dell Web, etc. now see the value in doing repairs in-house. As previously mentioned, proper crack repair requires that the cracks be fully filled preventing reoccurrences. With today s technology this is now possible and practical.