A basement subfloor is any material that is installed below the floor. Basement floors are usually concrete slabs and these should have a subfloor to provide a good foundation for expensive floor finishes and lengthen its life.
Modern developments in home construction is to install subfloors to raise the value of the home for future reselling, convert the basement into a living space and add extra insulation to provide warmth, dryness and soundproofing. It also provides protection to the basement flooring material against high humidity by allowing the passage of air beneath the floor. Traditional functions of a basement subfloor are to protect flooring materials from moisture damage and give an even surface to the floor.
A quality basement subfloor material, whether it is made of polyethylene film, mastic, cement-based compounds or lumber must have features such as drainage capability, anti-leak to prevent discharge of moisture onto the flooring material. It should also give warmth to the floor by up to 30% and increase foot fall absorption. Conventional basement subfloor materials are hardwood and plywood panels.
The most important thing to keep in mind when installing basement subfloor is to ensure a firm, flat surface. Prior to installation, it should be ascertained that there is no structural damage and that all angles are square and joists in good condition. The selected subfloor must be suitable for the chosen flooring. It should also be strong enough to hold the type of flooring material and the furniture that will occupy the room. If in doubt, it would be wise to bring in a contractor for his professional advice and supervision.
Some subfloor panels may contract or swell when exposed to changing temperatures and humidity. Therefore it is advisable to keep them in the basement for 24 hours or longer and out of their packaging to let them get acclimatized to the basement atmosphere. They will then shrink or swell to the size they will maintain.
A basement subfloor will be a good investment in the long run. It can turn a cold, damp room into a warm and cozy living area.