Basement and Foundation inspections by the Angus Home Inspector
Most basements, by the sheer nature of the fact that they are built into the ground, present the possibility that water can intrude, turning what was once a dry basement into a wet basement. This is because water in the soil can put constant pressure on basement walls. Plus, water follows the path of least resistance inside a home and over time can find its way into a basement.
Signs of a Damp or Wet Basement
Water stains along walls or floor. This could be caused by something simple such as an overflowing laundry tub or it could be a result of water seeping in through basement windows, the walls or the floor. Musty odor or damp smell. Excess moisture in a basement can cause an unmistakable smell.
Mold. It could be colored black, brown, yellow or green, and you won’t know for certain if it’s mold without testing it. Often the northwest corner of a house is known as a “cold corner” and susceptible to developing mold.
Efflorescence. This condition produces a white or sometimes grayish ash on the walls. Sometimes it sparkles. Efflorescence is caused by salt deposits left behind by evaporating water.
Spalling. When water gets inside the surface of concrete, brick or stone, salt deposits from the water cause the surface to flake away, peel or pop off.
The terms foundation and basement are not synonymous however we group them as they are most commonly found together in our climate. The foundation wall rests on a footing and acts as the support the home carrying its weight below the frost line. It prevents the house from moving as a result soil movement acting as a retaining wall resisting lateral pressure from the soil. The basement on the other hand is merely the space created by the foundation walls. Other types of foundations include crawl space and slab on grade (monolithic, or, supported on a foundation for example).
The material used for foundation walls include stone, brick, block, concrete, and, wood. Piers, made from similar materials, rest on a footing below the frost line. Pile foundations on the other hand can be made from similar materials, or steel, and are driven into the ground. They are often used when the soil is poor at the upper layers.
Another sign of needed foundation repair work are vertical or diagonal cracks in a foundation wall. This is a sign of settlement. Unstable soil conditions can cause your home to sink down into the ground causing stress on many areas, including your basement walls. The type of foundation repair needed will be determined by the specific cause of the foundation problems.
Most vertical cracks in a foundation wall do not seriously damage the structure of your home. Vertical cracks are most often caused by the shrinkage of the concrete as it cures, but they also tend to occur from damage as the foundation settles. The more significant problem in this case is that you are now vulnerable to water from the earth seeping into your basement.
Over 95 percent of basement concrete cracks are not a structural threat to the foundation, basement walls, or floor. Most wall cracks only pose a water seepage problem. Leaks are not only inconvenient, but the continued moisture can decrease the indoor air quality due to hidden mold, mildew, and fungus concerns. This normally is a small concrete repair job to do.
If your basement is damp and wet there is hope to cure this common headache. Water infiltration in lower levels or basements usually comes from two main sources. The major culprit is ground water which is the water from outside the home getting into the basement or lower level. The second cause is high humidity levels in the lower level that form condensation and precipitate. Ground water that saturates the ground on the exterior of the house can easily find a way into the basement or lower level. Water can enter the basement though breaches and cracks in foundation walls or small voids in the lower level floor slab. Water can also infiltrate through porous foundation walls. Many foundation walls are made of concrete block or brick which have natural pours that can let water to weep though. Poured concrete foundation wall structures do a better job in keeping water out.
The fundamental principle is to keep the water away from the exterior foundation walls of the home. All downspouts should be discharging a minimum of five feet away from the foundation walls. Gutters on the home should be free flowing and should not be allowed to overflow. Overflowing gutters will pour water close to the home, and exceedingly contribute to basement and lower level water issues. Replace leaking gutters and downspouts to help keep water away from the exterior walls of the home.
The grade around the entire perimeter of the home should be sloped away from the foundation walls so that water will be directed away from the foundation walls. Regarding the exterior is vital in keeping the basement dry. Remove objects and structures that are located close to the foundation walls that can hold water such as planting boxes, and wood walls, these types of structures can be a source of trapped water and lead to water infiltration.
Repair holes in the foundation walls. Holes and cracks will allow water in. Plugging holes and sealing cracks most likely will not solve all your basement water infiltration problems but doing so in conjunction with the other corrective actions should aid in helping to keep water out of the basement and lower level. Seal the interior foundation walls with hydraulic cement. The cement has to be applied to bare masonry walls in order to be effective. These types of cement sealers should be applied using a thick coating. The active principle is the cement sealer will cover and seal the small holes and cracks in the walls and help to keep water from seeping into the lower level and basement.
If water infiltration problems persists consider installing a basement drainage system. There are two basic types of effective drainage systems. The first type is installed on the exterior of the home against the exterior walls and the other type is installed inside the basement along the interior perimeter walls. If the home is already built the only practical solution is to install the interior type drainage system. This system consists of perforated piping that is installed under the basement floor slab. The perforated pipes are then tied into a sump pump. As water weeps through the foundation walls and as the natural water table rises the precipitate will be directed to the pump and be discharged out rather then enter the basement or lower areas. The sump pump must be discharging at least five feet from the exterior foundation walls to avoid redirecting the water back where it will find its way into the basement again.
Alleviate excess humidity. When humid hot air contacts cold surfaces water vapor forms. The condensation will drip down pipes and interior walls leaving the lower level damp and wet. The basement may begin to smell of mold and mildew. Consider installing a dehumidifier, and seal your dryer vent pipe so that it does not leak hot moisture into the basement. Install bathroom exhaust vents that discharge to the exterior and keep windows closed during very humid weather. Operate the central air conditioner during hot humid days. The air conditioner will pull condensation from the air. Consider installing central air-conditioning in the basement and lower levels if there is no air conditioning currently installed.
Please exercise caution when consulting with professional water proofing companies. Some of these companies may provide very expensive fixes to the problem when the majority of basement water problems can be corrected without having to spend a small fortune. If you choose to hire a basement water proofing company, make sure you do your due diligence and check their record with the better business bureau.