Water runoff from rains is beneficial for vegetation, lawns and gardens but can potentially be a large problem for homes if the site drainage does not function properly. Proper site drainage is probably one of the most important items we look at during a home inspection. It may not be an immediate safety issue but can end up making the structure unsound and cost tens of thousands of dollars to repair.
Proper grading is something that is usually standard on most newer homes. This usually calls for a 6 inch slope away from the foundation within the first 10 feet. This allows water that falls around the foundation or off the roof to run away from the home. If grading is not done properly, this can cause a concentrated amount of water runoff to soak into the soil near the home. If it remains a problem long enough, it can also cause settlement of the foundation footings.
A swale is essentially a drainage ditch to route water away and around that would have run toward the home. In neighborhoods, the homes may be build close together and may be built at different elevations. The neighbor behind you may be up on a hill. The drainage from their yard would run toward your home. You can’t really do anything about the drainage in their yard so if it is affecting your, a swale may be just the remedy. The water would run into the shallow ditch and run around your home to lower ground or the road.
Installing gutters can be very effective as long as they are properly maintained. If you are in an area with a lot of trees, you may have to clean them out in the spring and fall. The only thing that is worse than lack of a gutter system is gutters that are clogged or improperly sloped. The gutters can spill over, causing a concentrated area of moisture even worse than poor grading. Over time, this again can lead to saturation of the soil around the foundation. A small problem over time can lead to a very costly repair if not properly maintained.
A drain tile is a corrugated pipe that is buried underground. Typically pea gravel is placed on top of it. Sometimes sod is installed on top. When water runs toward the drain system, it soaks into the ground. The pipe is perforated so it will accept water that soaks into the ground. Once the water has entered the pipe, it is channeled (using gravity) to an area of lower elevation.
Some problem areas may have no other solution than to install a sump pump at a low elevation area. As the water level increases at the collection area, the pump kicks on, pumping the water away to a discharge area.
Newer have a drain tile system installed next to the footings. If a heavy amount of water got close to the footings, the drain system would carry the water away to the storm drain system. Not all homes are equipped, older homes do not have a system like this. It is essential that other means of drainage be used in older homes to help prevent settlement and footing failure.