Last week I asked why roof gutters with no or short downspout extensions was so bad. The answer is, when dumping massive amounts of water on small isolated points of a foundation, even the best of soils and grading cannot handle the volume. Notice on this picture the mold and water damage going up the corner of the basement. This is where a downspout had been missing on the outside of the house. Gutters are good, but if not kept intact, they can also funnel water into a basement or crawl space.
Control of surface water is accomplished with positive landscaping, hardscaping, and sometimes gutters. But control of sub surface water can be a little more difficult…to recognize and to correct. Less than 10% of the time homes are built on land with a high water table. In these situations landscaping, hardscaping, and gutters will do nothing to keep water out of the basement. When a home is built in a water table or so close to a high water table that fluctuates with heavy rains and snow thaws, you will need to have a sump pump and drain tiles.
In this situation, basements and crawl spaces will flood. What I mean is the entire basement floor will get wet… not just damp walls and maybe some seepage stains along the edges of the floor. Flooded floors disclose themselves almost like leaving a dirt ring around your bathtub when you get out. There will be uniform water marks on all four walls at the same elevation off the floor.
There are other indicators of a high water table problem and we will cover those as we continue our journey with basement and crawl space moisture next week.