Floor Joist Fire Safety

The advent of platform wood frame houses has helped reduce the incidence of home fires. Even with this new style of framing, a house fire can still occur. One area of concern in fire safety are the vast network of wooden floor joists supporting each level of the house.

Floor Trusses

• Floor trusses are commonly used in many housing projects because they are cheaper, straighter, use less wood and don't squeak after the installation is completed. However, these modified wood beams pose an immediate fire threat because of their honeycomb structure. The resulting extra airspace can help fuel a fire that will burn quicker than if the floor was supported by a traditional floor joist system.

During the Fire

• Floor trusses also pose a problem for firefighters entering a burning building. A burning truss system will give way much quicker than if the floor was constructed on top of floor joists. The problem is compounded by the fact that fireman cannot see through the floor and tell what type of framing structure supports the floor.

Fire Retardants

• The use of wood made fire retardant through a pressure-treated process is increasing. Typically, the wood is treated before purchase and then used to build portions of the building, where flammability is a concern. Some localities have even written the use of fire retardant wood into the building code, especially when the building is subject to public use.