01 of 07
Introduction to Wet Basement Problems Caused Outside the Home
Wet or damp basements are a common problem in homes new or old, although the problem is more prevalent in older homes for a variety of reasons.
Wet basements create mold and mildew, and ruin flooring and wall materials. They can prevent a valuable space like a basement from being used effectively as living space. Even worse, a wet basement and wet basement wall can become a structural liability if not resolved, and will often prevent a home from being sold.
Basement waterproofing is inexpensive... and easy to install as the home is being built. However for an existing home adding basement waterproofing is very expensive because it requires extensive excavation and landscape repairs.
The good news is that not all wet or leaky basements require adding waterproofing or new foundation drainage systems as a solution. Very often the source of wet basement walls or a leaky basement is on the outside of the home, above the ground and easily repaired. You may find that very simple things like improper roof drainage, improper ground slope or even your neighbor's drainage may be causing your problem.Continue to 2 of 7 below.
02 of 07
Why Wet Basements Are Not Always Solved with Basement Waterproofing
Water flows downhill and that means down your driveway, patio or lawn, and into your home and down the basement wall until it stops. Your basement wall is now functioning as a mini Hoover dam, causing a reservoir of wet earth and pressure to build up against your basement wall. The pressure pushes the water into your wall and through the smallest crack. Or worse yet, the pressure creates its own cracks in the wall.
The more water produced by a rainstorm and the more sources of water being thrown... into your basement wall, the worse your problem. This problem can become so severe that structural failures occur from the pressure against the wall or from the erosion of the subgrade upon which the foundation of your home rests. At that point, whole corners of your basement wall may crack and fall away, requiring expensive foundation underpinning.
Waterproofing only reduces water penetration but does not address the root cause of the water problem. Furthermore, expensive interior or exterior foundation drainage systems do not address the root cause of the problem, either.
In this tutorial, we'll take a look at some of the easy things you can look for outside of your home that may be causing your wet basement and show you how to repair them.Continue to 3 of 7 below.
03 of 07
Check for Grade Sloping Into The House
As mentioned earlier, wet basements were more common in older homes. One of the reasons is that the soil that was back-filled against the basement foundation when the home was built tends to settle more than the surrounding undisturbed soils. As the back-filled soil settles, it may create low spots, allowing water to drain into the house.
Walk around the entire house with a critical eye, making sure the grade (dirt or lawn) slopes away from your foundation and basement walls. At about out 24"... away from the house, the ground should fall or slope away by at least 8". Regrading the soil around a foundation remedies the problem in many situations.
If the ground is near level at the house foundation and basement wall—or worse, sloping into the house—then you have a problem that requires regrading or re-landscaping so the soil is higher against the house and not draining into the foundation.Continue to 4 of 7 below.
04 of 07
Check for a Patio Sloping Into House
Patios may also contribute to the wet basement problem, as they may sometimes improperly slope toward the house. You may have a situation where the outside patio door threshold height is fixed and the lawn is higher than the door threshold. The patio (concrete or pavers) just follows the slope of the higher lawn, down toward lower height of the door threshold.
In cases like this, an option is to redo the patio. A small patio can be sloped gradually away from the house toward the lawn. With large... patios, they are sometimes constructed so they slope toward the center of the patio, where a drain funnels water through an underground perforated plastic drain pipe leads to the lawn area, possibly with a pop-up relief outlet.Continue to 5 of 7 below.
05 of 07
Check for Driveway Sloping Into House
Another culprit may be a driveway that is improperly sloping into your house. Or maybe you have a sunken piece of driveway near a downspout. The large, flat surface of a driveway can carry a lot of water, so checking its drainage is important.
This problem is especially prevalent in home lots having a small width, where the driveway may touch both your foundation wall and that of your neighbors.
If your driveway is draining into your house, then a solution may be to have a concrete contractor... pour a small curb up against your house where the driveway abuts it. This way, the water is directed against the curb and flows down the driveway into the street, rather than against your foundation or basement wall.Continue to 6 of 7 below.
06 of 07
Check Roof Downspout Discharge
The problem of improper drainage outside the home can be made much worse by an improper discharge of the roof downspouts. Roof downspouts can add a literal flood of water to areas prone to drainage problems.
To give you an example of how much water can be flooding out of your downspouts, a 1500 square foot roof will shed about 940 gallons of water in a 1-inch rainstorm. Assume that water flows out of an average of four downspouts, you may have as much as 235 gallons of water pouring out of one... downspout!
In many cases, you will find downspouts dumping water right near the foundations of a house or connected directly to an outside drain pipe leading the water down into the basement wall or footing drain system. This condition needs to be corrected. Downspouts coming from your roof gutter must have extensions leading several feet away from the house. Also, check to make sure the gutters are clean and flowing properly.Continue to 7 of 7 below.
07 of 07
Check for Your Neighbor's Runoff Draining Into Your Site or House
Another common source of problems, especially with small lots where the houses are close together, is that of water being discharged onto your property from a neighbor's house.
Make sure your neighbor does not have a downspout extension dumping water onto your property, finding its way across your driveway and draining into your house.
A solution for the problem of water runoff from your neighbor draining onto your property can sometimes be handled with what is called a French drain system.... This is a landscape project in which a gravel-filled trench helps direct water in the direction you want.