Home Inspection Tips—Dealing With Grading and Drainage Problems

By: David Haigh

Let’s face it. Your basement is a hole in the ground, and you don’t want water getting into that hole. Grading and drainage are issues every home owner faces. Home inspectors find grading and drainage problems to be quite common.

If grading collects and holds water near a foundation wall it can cause basement flooding. That can lead to mold growth as soon as 48 hours after flooding, something you definitely don’t want. Of course, any amount of flooding can damage those valuable items you’ve stored in your basement, and you don’t want that either.

If you’ve lived in an area for quite a while, you maybe familiar enough to detect certain weather patterns, such as a wet spring that could cause flooding. You may already know you have to be on guard concerning water getting into your basement. However, aside from immediate flooding, water leakage over a long period of time will rot and damage wood framing structures and also cause damage to the foundation. That’s something to be aware of, too.

The grade is like a roof on a house. A grade that pitches or angles towards a home can direct water right to your home. If the ground is frozen in winter, heavy rain can cause flooding next to your foundation wall. Of course, heavy rain any time of year can cause flooding. The problem is that the water will leak into any cracks it finds. Thus, you get water in your basement and damage to your foundation.

If you’re looking to buy a home, you’ll want to ask the owner about any flooding in the past. Was this a wet year? What about wet years within the past ten years? Such years are bound to happen. You don’t want to be surprised by unanticipated flooding in the basement. Any possible evidence of past flooding is important to learn about before you buy the home. You want to be able to wisely make an informed decision on purchase or negotiation with the seller.

If you’re selling a home yourself, here are some ideas to reduce water leakage into the basement.

First, angle or pitch all grades away from your home. The ground right next to the foundation should be sloped away from a building at a slope not less than 1 inch per 1 foot of grade over a distance of no less than 8 feet. Of course, if the house has a hill side directed to the house, following this recommendation may be cancelled out as water runs down the hill.

It may be necessary to install a grade or below grade drain. This will direct water away from the ground next to the foundation. An engineer may need to design such a drain. Though this could cost several thousand dollars, consider it an important investment to ward off problems that could cost much more in the long run.

You could also drain water from gutters into dry wells placed at least 20 feet from the building. This depends on several factors, such as the soil conditions and general pitch of the surrounding grade. Consider the elevation of the house, too, such as when living in coastal flood plains or wetland areas. High water tables may be as close as 3-4 inches underneath a home’s basement slab throughout the year. A word of caution--don’t drain sump pumps into city sewers, as it’s illegal in most places.

Another suggestion is to keep grass clippings from piling up around the perimeter of your home. Over time grass clippings can raise the grade a little and make something like a low moat that collects water. That water will likely seep into the ground and find small cracks in your foundation and end up in the basement.

Water where it doesn’t belong is a plague to most home owners and home inspectors. Taking preventive measures now will make life easier for you, your inspector and prospective buyer.