Basement Waterproofing Definitions
This term describes the juncture where a wall meets the floor, and is a prime location for basement leaks. When it rains, the weight of the rainwater presses down on existing groundwater, resulting in a phenomenon known as hydrostatic pressure, which can eat away at basement walls, causing leaky a leaky basement. We don’t recommend sealing a cove joint — it’ll just make the pressure build up elsewhere. To alleviate the problem, the hydrostatic pressure needs a way to release. We usually do this by way of a French drain or an exterior gravity system (see below for definitions of these).
A sump pump is an electric device installed a the bottom of a sump basin, which is a small pit in the basement floor (usually no more than a foot deep). Its purpose is to pump accumulated rainwater to a suitable discharge location — sometimes a sewage or storm drain. Sump pumps can also be used to pump greywater, or excess water from washing machines, showers, or laundry sinks.
A French drain — also called a dual pressure relief system — is designed to relieve water pressure by collecting water and directing it into a sump pump. To install this, Midstate’s basement waterproofing contractors will dig a trench around the perimeter of the basement floor, fill it with a bed of crushed, washed stones, then embed a perforated pipe in the stones. The pipe resurfaces near the pump, sending excess water away for good.
Exterior Gravity System
These are essentially outdoor versions of French drains. If water is pooling in an area outside your home but near your foundation, Midstate’s basement waterproofing contractors will excavate the problem area, then lay a perforated pipe at the bottom. The perforated pipe is connected to a solid pipe, which directs storm water to another part of your property, or to a storm drain.
When installing a French drain, contractors sometimes need to leave a half-inch gap between the basement floor or basement wall. This is called a weep zone, and it’s often needed in fieldstone or block foundations that don’t have wall coverings.
All masonry foundations — whether they’re block, brick or stone — are typically constructed using mortar to hold the individual masonry units in place. The spaces between those units are called mortar joints, and they’re a prime location for water seepage.
A window well is the space dug into the soil surrounding a home’s foundation that allows light to reach low-lying basement windows. Because of their placement, window wells tend to attract a lot of rainwater, which can seep through the window itself or cause cracks in the foundation. Ideally, window wells should drain water away rather than collecting it.
Top of Foundation
The top of a home’s foundation should extend at least a few inches above ground level, but over time, many homeowners tend to raise the surrounding landscape and add non-porous surfaces like concrete or asphalt. Doing this allows water to seep through brickwork or siding, and over the top of the foundation into the house. The top of your foundation is also at risk if your home is situated in a low-lying area, or if a neighboring property is sloped toward you.
Foundation Wall Cracks
These are caused mostly by stress, settling or shrinkage that occurs as the foundation’s concrete cures, and are the most common source of seepage in poured concrete foundations. In general, they run from the tope of the foundation wall to the bottom. In most instances, they go all the way through the wall, increasing the potential leak damage.
Tie rods are the lengths of steel used to hold both sides of the concrete floors together during the initial pouring of a foundation. Once the concrete has hardened and the forms are removed, the ends of the ties are broken off, leaving part of the steel rod embedded in the cured concrete. Over time, these can rust, leaving holes through which water can pass. Any of these holes can cause a basement leak.
A common cause of basement water leaks is pipe penetration — areas where gas, water, sewer or electrical lines bisect pipes. These are usually sealed with only a temporary patch from the interior during original construction. This usually falls over time, allowing water to seep around the penetration and into your basement.
Porous concrete can be found in both newer and older foundations. Honeycomb concrete, for instance, occurs as a result of foundation concrete being consolidated poorly, and can form as soon as the concrete is poured. As concrete ages, it can also become soft, causing the surface to erode or crumble. This condition is commonly referred to as spalled concrete.
These collect water from the floor so it does not accumulate in your basement, and are generally installed at the lowest point in the floor. If you find water is coming up from the drain, we recommend contacting a licensed plumber to investigate the problem further, as it is generally not a waterproofing-related problem.
Basement floors crack for a number or reasons. Shrinkage during original construction is the most common. Other causes include settling of soil beneath the floor or upward water pressure. Interior drainage systems are generally the best way to solve the problems presented by floor cracks, as sealing them only tends to increase hydrostatic pressure.