Hydrostatic pressure on basement walls is being exerted by saturated oil, causing water to seep or leak through the foundation walls into the basement. This condition occurs as a result of water accumulation around the foundation.
Common Causes of Water Accumulation Around the Foundation
The best way to control water seeping or leaking through the foundation walls into the basement is to minimize the amount of water that accumulates around the foundation. This accumulation can be cause by a number of factors which can be easily detected and corrected, as follows:
- Defective or missing gutters and downspouts to handle the rain runoff from the roof – the downspouts should discharge water away from the structure. Very frequently, however, an elbow or splash plate at the base of the downspout is missing, so the water is discharged directly around the foundation.
Improper grading – the ground area immediately adjacent to the structure should be pitched in order to slope away from the building. Around many homes, however, this area is improperly graded, resulting in surface water collecting around the foundation.- Unshielded basement-window wells. If not properly protected from rain or serviced with a drain, the area around basement windows can easily accumulate water that can leak through window joints or seem down around the foundation.
- Uneven settlement of walkways or patio – as with improper grading, if walkways or patios have settled and are sloping toward the house they can cause surface water to collect around the foundation.
- Leaky garden spigots – if the valve is faulty or is not tightened properly, water will drip or leak around the foundation. This water will enter the basement through cracks or open joints in the foundation wall.
If the house is located on an inclined lot, surface and subsurface water flows toward the house. Depending on the incline and the amount of water involved, water-flow control measures will include grading the lot on the high side so as to create a swale to collect and redirect surface water around the house. Another measure is installing a French drain – curtain drain – below the ground to intercept subsurface water and direct it away from the house.
Sealing cracks and open joints on the inside walls with a hydraulic cement-base or epoxy sealant can prevent water from penetrating the interior if the amount of water that accumulates around the foundation walls is not excessive. In addition, coating the wall will be particularly helpful when the wall is porous, such as a cinder-block wall.
On the other hand, if the amount of water accumulating around the foundation wall is excessive, as with poorly drained soil such as clay, waterproofing the exterior surface of the basement walls will likely be more effective than coating the interior surface. Also, a perforated drain pipe should be installed near and parallel with the foundation footing. This footing drain is designed to carry away the water accumulating around the foundation, thus reducing the hydrostatic pressure.
If you are considering to waterproof the exterior surface of the foundation wall using a pressure-pumping process that requires no digging or relocation of plantings, be very careful. In this process, a sealant pumped through tubes inserted in the ground is supposed to coat the wall and make it waterproof. Keep in mind, however, that the effectiveness of this treatment depends on the condition and porosity of the ground around the foundation. Many contractors performing this work don’t always take test borings and analyze the soil, so the process is usually not effective and requires additional measures.