A pier and beam foundation problem usually centers around soil moisture under the house. After a foundation inspection, Granite Foundation Repair, will determine the appropriate pier and beam foundation repair method.
Let’s look at the construction of a typical 1900 to 1960 pier and beam house in the Dallas, Ft. Worth area. Posts, which we call piers, were set one to two feet into the ground and extended 2 to 4 feet into the air. Atop the posts were layed beams. Atop the beams are the floor joists, and atop all of that is the hardwood or plywood flooring.
In some instances the posts were set into a concrete pad one foot deep and two feet on a side. More recently, atop the concrete pad or footing sits a poured concrete tube. And sometimes in place of the tube are one or more concrete blocks. Or even a more modern variation is when the pier and pad are one poured concrete assembly.
To see what we mean, take a look at the picture below of a modern pier and beam foundation construction using concrete block and pad.
Regardless of the pier type, piers are spaced 6 to 8 feet apart in a series of rows extending under the house.
Soil under a pier and beam foundation on clay soil must be as dry as dust. The least bit of additional moisture will cause the soil to expand. Soil expansion will drive one or more piers upward, raising the floor. Often times the moisture under a house is uneven, perhaps due to a leaky pipe, or poor drainage at the perimeter. Then, the pad and block assemblies will raise unevenly.
To stop a pier and beam foundation from moving, keep all moisture out, provide adequate ventilation, and assure that the soil remains dry and crumbly. Once the soil is absolutely, completely dry, the foundation can be shimmed to achieve uniform elevation across the house.