A floor is made of three layers: the supports (called joists), the subfloor and the finished layer (hardwood, tile or carpet). The joists support the subfloor. The subfloor is attached to the tile, hardwood or carpet.
Plywood is the most common subfloor material in recently built homes. Older homes typically have subfloors made of 3/4-inch thick x 4- to 8-inch pine. Oriented Strand Board (OSB) also can be used for subfloors.
All of the most common subfloor materials are wood-based and susceptible to termite damage. In fact, termites prefer these softer woods to hardwoods and may cause significant damage to the subfloor before feeding on hardwood floors.
Signs of Termite Damage to the Subfloor
Termite damage in the subfloor can affect the structural integrity of the home and cause movement in the floor. The floor may squeak as boards rub against each other or against nails. A damaged subfloor may sag, and the top layer of tile or hardwood flooring may pull away from a sagging subfloor. Termites are not the only reason hardwood flooring or tiles can pop loose, but it is a good idea to call a pest control expert to check for termites if you have floor problems.
When termites damage the subfloor, they frequently damage the adjacent floor joists. Before beginning repair work, confirm your termite technician and contractor have inspected all nearby structural timbers for damage.
To limit the risk of continued damage or reinfestation, do not begin repair work until the termite infestation has been treated, preventative control measures have been taken and a subsequent inspection has determined the active termite colony has been controlled.
How to Prevent Termite Damage to the Subfloor
The subfloor above a crawlspace is particularly susceptible to subterranean termite damage. Many older homes do not have adequate ventilation in the crawlspace, which can allow excess moisture to build up inside. Your termite inspector can recommend techniques to help ventilate the area, as well as provide preventative treatment for the area with termiticides or other materials.
Termite Tunnel on Joint in Sub Floor: