Water Seepage

Finished House Grade and Drainage
Proper drainage is a crucial consideration in selecting the site for a new house. This includes not only the drainage of surface water but also drainage of any subsurface or ground water that may already be present or that may accumulate over a period of time. If the subsurface or ground water level is close to the underside of the basement floor slab, water rises through the slab by capillary action, producing dampness. If the subsurface or ground water level is higher than the basement floor, water leaks in through the walls and floor or enters by capillary action, causing standing water in the basement and, at times, dampness in the rooms above.

Under ideal conditions, a house should be situated so that even during rainy seasons the subsurface or ground water level is at least ten feet below the finished grade--well below the average basement floor. In some cases it is impossible to eliminate dampness completely from a basement whose construction did not take into consideration the basic principles of good drainage. Only after soil borings have been done can anyone predict which, if any, course of action has a chance for success.