Drainage

The grade around the foundation of a home and the perimeter is frequently overlooked. The grade should not slope back towards the house. A slight or significant slope away from the house is recommended. Look for signs of erosion or holes in the ground, particularly close to the foundation. This could indicates a pocket which could trap water next to the foundation. If there is a grading problems it should be corrected. Water problems can deteriorate the footing, foundation, siding and even affect the framing. Improper grading and water control can lead to settlement cracks in the foundation and even structural failure. Many times a damp basement or crawlspace may be corrected by the use of proper drainage and grading.

The grade should be maintained so a minimum distance of 8" should be kept from the siding and wall sheathing. The building up of mulch should be discouraged. Existing mulch should be removed and replaced, or in time the mulch will become in contact with the siding. This contact can promote damp conditions and lead to termite or water infiltration and damage. If the siding is in contact the conditions should be altered. If the conditions are kept termite treatment is recommended.

As the soil around the house becomes saturated with water, a condition known as equilibrium will occur within the soil. This means once the soil surrounding the house cannot hold any more water through capillary action water will seek a drier area. This area can be under a crawlspace, into a foundation wall, or pond on the surface creating runoff. This run-off can cause erosion if not properly controlled. Excessive moisture may be diverted away from the house with a swale, or an underground drainage tile and gravel system (curtain drain).

Excessive water that is not properly controlled may also cause structural failure by a force known as hydrostatic pressure. If this ground water freezes the force can create a frost line crack in a foundation. (see foundation) The hydrostatic pressure force against the foundation may vary, depending on the soils, and adjacent structures.

For Example: The foundation is surrounded be a loose sandy soil. Ten feet away a hard pan clay vein runs parallel with the sandy vein. The water that is absorbed along the house will not absorb into the hardpan clay as easily as the sandy soil. The clay may become a barrier for the water to push against back towards the foundation. The foundation is more likely to move than the clay. This same principle may apply to a structure as well.

Any water should be free to move, and evaporate. Mulch, landscaping timbers, and retaining walls may sometimes trap water against the building creating a damp basement or crawlspace. Often a plastic ground cover is used rather than a drainage or filter cloth under the mulch. This will cause the water to stand and not allow natural drainage to occur, as well not allow water to evaporate. The trapped water under the cover may lead to damp conditions in a basement or crawl space and should be removed.

If gutters are installed, check to see if they are leaking or overflowing. Evidence of failing gutters may be determined by an erosion line on the ground beneath the gutters. The main purpose for gutters is to collect and properly control the water shed away from the structure. The downspout should have splash guards to help break the water force to the ground. It is recommended to install downspout extensions or drain tile to get the water away from the house. The drain tile may be terminated in a french drain (gravel filled pit lined with filter cloth) 10 or more feet from the foundation. Sump pumps and condensation drains should be diverted away as well. These drain pits may need to be quite large enough to hold 100 gallon or more.

Roots from trees and bushes can cause problems with the footing and foundation, and should be cut back if they are in contact with the house. Tree roots can can push in on the foundation and lead to structural failure or water infiltration. It is recommended to keep tree roots back from the house This will help air to circulate and help the ground around the house to dry out. Branches rubbing the house may damage siding, windows and roofing materials. Encroaching branches should be cut back from power lines, cable or telephone wires. Check to see if your local utility company will take care of this for you at no charge. Do not attempt to cut branches back from power lines yourself, this can cause electrocution. Ivy can be extremely damaging, by getting under trim and siding and thereby causing water problems to the house.

Whenever a steep hillside is present, a thorough inspection of runoff as well as any signs of erosion is necessary. Erosion of a hillside may lead to shifting or undermining of the foundation. If the hillside is covered with leaves, erosion may be apparent below. Leaves may break impact of the rain, however surface runoff flowing below may be leaving an erosion trail. Be sure to establish a proper ground cover such as grass, ivy, retaining system, etc.

Inspect any retaining walls for failing, rotting or leaning problems. Retaining walls need support that are referred to as dead men, back into the ground they are designed to hold back, front bracing, or supports that are driven or buried deep in the ground. Without this the wall may fail. Retaining walls need a place for water pressure, known as hydrostatic pressure to escape. Water pressure that builds behind a wall can cause premature failure. Even low walls need a space from which the water can drain. The pressure will cause mortar joints in block and brick to erode. Block and wooden walls can lean from the force and eventually fail. Filter cloth is recommended behind the wall to prevent dirt from washing through, the drains known as "weep holes".

Look for any signs of settling at sidewalks, driveways or patios. This could indicate a drainage problem or undermining of the slab occurring. This can be verified by using a dead blow hammer and listening for sounding and change in density sounds. There could be pockets under the slab trapping water against the foundation. A slab or sidewalk should slope away from structure. Any gap along the house should be filled with a polyurethane caulk. For example:

• Driveway to apron connection
• Foundation slab connection
• Basement stairs and sidewalk connection

Check your fences for loose post. If the post are wood, check with a sharp probe, to see if they are rotted at or below grade. Sight down the length to make sure no post are severely warped or out of alignment. This is more for aesthetics than anything.

You will also want to check your driveway. Concrete can settle and crack, if it is you may want to monitor it's rate of deterioration. Asphalt driveways should sealed as needed, this will help prevent premature deterioration. Gravel and dirt should be checked for ruts that could become impassable.

If you have severe grading problems you may have to consult with a civil engineer or a landscape architect. In some areas a grading permit might be required so check with your local codes. An experienced landscaper can come up with some functional designs to take care of grading problems.