Why Does My Basement Leak?

First we should know how the house was built. Here in New Jersey most of the homes built from the 20th Century on have a concrete foundation. Concrete is porous, it can absorb and retain water.

There are two main types of concrete foundations, Concrete Block or poured concrete.

1. Concrete block is also known as CMU or Concrete Masonry Unit. Some of us still call them Cinder Blocks, although they are not made from ash or cinders that often. These hollow blocks are typically 8” H x16”W x 8”D
2. Poured Concrete walls are usually 8” thick of solid concrete.

These walls are sealed with a tar like substance before the backfill occurs. That is your house’s waterproofing. Most technically it is called damp-proofing. The tar is not permanent. It does not last forever. It is very similar to your roofing shingles. The tar has a 30-40 year life, and that’s it.

Snow melts, rain falls. Much of this moisture is pulled deeper into the frost line by gravity. The frost line is the depth in the ground in which the water NEVER freezes. Because this seepage is constantly moving beneath the frost line, you should expect water related problems year round. Times of extreme seepage occur usually in early spring and late fall. Of course a catastrophic event like a Nor’easter or a Hurricane can happen at any time.

As gravity pulls the ground water deeper into the soil, it moves sideways following the slope of the surrounding areas. Top soil will absorb some of the water but as rain continues to fall the absorbent layers become even more saturated and the water begins to follow the underground 'paths of least resistance' called Capillary Veins.

Think of these Capillary Veins as underground streams of seeping water. As this water approaches your home it collects in the loosely packed soil that is pressing against your foundation. In the meantime, the undisturbed soil about 2 to 5 feet from your home is much more solid and is unable to percolate the ground water away fast enough causing it to rise around the foundation of your home.

As the water level continues to rise the weight of the water causes pressure to build (Hydrostatic Pressure). This pressure forces water into settlement cracks in your home's foundation and sooner or later, into your basement.

What are the stages of water penetration?

• Stage 1: Dampness and wet spots appear, mold and mildew begins to form, efflorescence (White crystal like powder) appears discoloration of foundation and blistering paint.
• Stage 2: Walls wet to the touch, small amounts of water and a combination of signs from stage 1.
• Stage 3: Water on your basement floor and a combination of signs from stages 1 and 2.
• Stage 4: Heavy water in your basement and a combination of stages 1, 2 and 3.

If water is penetrating the foundation and entering the basement, these are times when a waterproofing company is needed. Call a professional to examine your foundation