A good foundation is like a really good pair of shoes: The right foundation completes a style and can stand cool, dry and comfortable no matter the weather. Like shoes, choosing the ideal foundation depends on where you live. In cold climates like the northeast, a full basement foundation is clearly the best way to go-providing a nice warm floor in winter, a place to put mechanicals such as boilers and water heaters as well as water pipes, the circuit breaker box and anything else you want to reach without trudging through the snow.

People living in climates where frost is not a problem have two major foundation choices, principally slab-on-grade and raised-wood floors.

Cutaway of a raised wood floor.

Slab-on-grade
As its name implies, a slab-on-grade foundation consists of a perimeter footing that aligns with the outer walls of the house. A smooth slab of concrete is poured in between. A welded metal grid reinforces the concrete slab and a plastic vapor barrier and rigid insulation prevent moisture and the cold from transferring from the ground into the concrete.

If a slab-on-grade foundation sounds a lot like the garage floor in most homes, that's because it is. The major differences are that the smooth hard slab serves as the sub-floor for carpeting, linoleum or other finished flooring and the perimeter foundation is not open at one end to accommodate the garage door and driveway.

Not-So-Fab Slab
While slab-on-grade foundations can be constructed quickly and easily, they have several drawbacks. First, a concrete slab is cold and hard. Putting a finished floor on top does little to add warmth and cushioning. Another detractor is that many houses lose their architectural style when the floor is at the same level as the ground outside. Of course, in flood-prone areas, the disadvantages of having the floor at grade level are obvious. Another concern is that electrical lines and water pipes are often placed directly under the slab. Most will last the life of the house. The problem comes when homeowners want to make additions and encounter major difficulty rerouting wires, sewer and fresh water line.

Taking the High Road
Slab-on-grade is the least expensive foundation, but also the least desirable foundation. A full basement is much more expensive while offering the most comfort, room and other attributes that make for a good foundation.

A raised wood floor foundation is the ideal compromise. It offers the lower expense that comes with using an on-grade perimeter footing and no basement hole (and therefore much less concrete). It also offers isolation from moisture and pests.

At the same time, it offers many of the advantages of a basement foundation: The raised wood floor is constructed in the same manner and at the same height as a home having a full foundation. It also offers the comfort of a softer wood sub floor and allows pipes and wiring to be run above grade under the floor.

Raised Floors are Green Floors
The simple truth is that softwood lumber is a sustainable, renewable building product. And when you consider that laminated purlins, engineered I joists and oriented strand board sub flooring utilize smaller trees more completely, it's clear that choosing wood over concrete with metal reinforcement is a much greener choice when it comes to green building and the environment.

Raised wood floor foundations have been used off and on for decades and their durability is well proven. That's why you might want to give raised wood floors a careful look. After all, if the shoe fits…

More information about raised floor foundations:

Southern Pine Council

Hometips