Concrete in and of itself, is virtually watertight. But once you build a wall, you are likely to get shrinkage cracks which may allow water to penetrate the wall. As with all other parts of your house, basement walls are not necessarily waterproof. It is with the interrelation of other systems and the foundation system that keeps the basement dry. Some basements have a waterproofing system that was installed on the underground portions of your foundation. This will prevent the entrance of water from the surrounding soil. However, whether your foundation was waterproofed or not should not dictate whether it leaks. Repairs of basement leaks depend on quite a few variables and conditions. Before making extensive or expensive structural repairs to correct wet wall conditions you need to check other systems on the house that your foundation depends on to work correctly. The first is your drainage system. It is setup in two distinct systems. One is the system that handles surface water and the second is the system that handles the subsurface water. First, start with the surface water system. In many instances repairing, adjusting gutters and downspouts to help carry the water away from the foundation walls is all that is needed. A very important surface water system that is critical to the complete drainage system is the correct landscaping. The finish grade should be 6” below the top of the foundation wall. There should be 6” of pitch in the first ten feet away from the foundation. If you cannot attain this, a French drain or other consideration may be needed. The grade and landscaping must be cared for continuously to assure the health of the drainage system. Almost all foundation leaks are from poor landscaping. The subsurface water system consists of a drain tile system which will get the water to the sump pump. The sump pump must be in working order and should be checked periodically. Water does not have to run into the sump pump for the system to be working. There are numerous other outlets under the footings or floors for the water to go. Therefore, if you feel that this system may be compromised in some way, call the builder to have an expert look into it. If all these systems are working and there is still a leak, if it is a poured concrete foundation the source of the leak can be injected with a urethane or epoxy from the inside of the foundation.
Yes. As concrete cures the mixing water used in concrete evaporates from the concrete as causes the concrete to shrink. This may result in some cracks in the foundation. These cracks are not a structural concern and will not cause a water leak if the foundation is waterproofed. Cracks in concrete walls and slabs are a common occurrence. They appear in floors, driveways, walks, structural beams and walls. Cracking cannot be prevented but it can be significantly reduced or controlled when the causes are taken into account and preventative steps are taken. Most cracks should not be a cause for alarm.
- Causes of Cracks:
- Cracking can be the result of one or a combination of factors such as drying shrinkage, which occurs as water used to place the concrete evaporates; thermal contraction due to temperature change; restraint to shortening; sub-grade settlement resulting from poor soil conditions; and, applied stress caused by forces such as building loads, earth, hydrostatic pressure, or heavy equipment operated too close to the foundation wall.
- Types of Cracks:
- Cracks in walls appear in several forms. Nearly vertical cracks are usually caused by shrinkage or temperature change. A newly poured concrete wall has the greatest volume it will ever have. Tremendous force can build up inside a wall as moisture evaporates or when the wall is exposed to temperature change. Temperature and shrinkage cracks may appear before the structure is occupied to several years after the structure is occupied. A vertical crack that is significantly wider at the top or bottom could signify heaving or settlement. Diagonal cracks which emanate from the corners of windows, openings, or other changes in the shape of a wall (or slab) are called reentrant cracks and are another form of shrinkage crack. Horizontal cracks in walls are usually caused by applied load against the wall.
- Concrete walls shrink slightly as they dry out and contract and expand with temperature changes. Due to the density of the walls and the fact that they are bound by the footing and at corners, cracks are not uncommon. The horizontal steel included in our walls works as temperature steel – not to eliminate cracks but to make them smaller so waterproofing will cover them. These cracks do not affect the strength of the structure. Cracks that need attention are: In the wall if it averages 3/8” or larger and leaks (water puddles). You can measure the cracks with a device called a crack comparator. Cracks of lesser size can be caulked if desired with a grey colored latex caulk.