Foundations

Besides holding up the house, a foundation is also a connection between the soil and living space. How this connection is made is important for the health of the occupants and the durability of the house. The foundation should prevent problems due to moisture, radon , and termites, and also be energy-efficient. In short, a foundation should protect the house and its occupants from the negative effects of the ground.

Moisture Control

Moisture control is important because moisture’s effects upon foundations can mean mold growth or rot. Mold is a common allergen and a health problem for millions of people. Wood rot that results from excessive moisture can lead to costly repairs.

One of the most significant moisture sources to control is rainwater. For all foundation types, rain pouring off a roof needs to be channeled away from the building—usually via gutters, down spouts, and splash blocks. In addition, the ground around all houses should slope away to keep the water exiting from the downspouts from soaking into the soil around the structure.

There are a variety of strategies for controlling moisture in foundations. The specific techniques will vary from house to house with differing foundation types, climates, and soil conditions. Generally, moisture control involves using a piping and drainage system to divert water away from the building, as well as coatings or barriers to prevent dampness from passing into the structure.

If a building is in an area where the ground water extends above the footings of a foundation, then a system of drainage pipes or tiles should be installed to divert that water away from the building. A perforated drain pipe is usually located near the bottom of the footing, and the area above it is backfilled with gravel. Water in the vicinity will easily travel down through the gravel into the tile and away from the structure. Synthetic drainage mats now on the market can be substituted for the gravel.

Soil dampness can migrate horizontally through concrete or masonry foundation walls, or up through a concrete slab. Dampness can also rise up through a concrete footing into the foundation wall and then evaporate into a crawl space or basement. As remedial measures, cement-based foundation dampproof coatings are less odorous than asphalt or synthetic coatings, but since they are generally quite well separated from the living space , foundation coatings rarely cause problems for chemically-sensitive occupants of a house. Plastic sheeting is also often used as a barrier in foundation construction.

Radon Control

Radon is a radioactive gas found in small quantities in the soil virtually everywhere. Radon is invisible, you can’t smell it, and you can’t taste it, but it should be avoided because it is a known cause of lung cancer. If a great deal of radon is present in the soil, the gas can contaminate the air in your house by passing from...