Basement Science

Tuesday, October 29th, 2013

Do you ever wonder why and how your basement leaks? The main reason that a basement leaks is because the home’s exterior waterproofing is failing. There are two types of exterior waterproofing that are supposed to keep a basement from leaking:

1) Coating on the foundation walls

2) A drain around the bottom of the foundation- called a “footing drain”

Wall coatings can be inexpensive black tar coatings called “dampproofing”. Dampproofing doesn’t bridge wall cracks, doesn’t stop water completely and doesn’t last forever. Even today, 85% of homes still only get their foundation walls dampproofed.

Footing drains, or french drains, are plastic pipes with holes or slots laid around the outside of the footing or at the bottom of the walls. A bed of crushed stone is installed around them and the soil around the outside of your home is pushed back over the drains. There are many things that can go wrong with these drains.

Common problems include-

– The drains don’t lead out anywhere

– The place they lead off to is blocked, clogged or crushed

– The drains clog as the water washing into them brings silt and sediments (mud) with it

– The drains have very little or no stone around them- stone is expensive

– The drains are not connected as a continuous loop or are installed too high

Footing drain failure is the most common cause of a wet basement. When this happens – the soil around the outside of the foundation can’t drain and it becomes saturated. The weight of the water in the soil creates hydrostatic pressure, and pushes water into the basement through:

* The joint between the footing and wall- most common

* Through wall cracks and pipe penetration- very common

* Through porous block walls – very common if you have block walls

* Under the footing- pretty rare

Exterior waterproofing is not the solution! Tar Heel Basement Systems offers a solution to keep your basement dry all year round.