Maintenance of Roof Trusses

Annual Inspection

• A roof inspection will detect truss damage in the early stages. Warning signs include missing shingles, insect activity, evidence of water leaks, breaks or bows in truss components, shrinkage, cracks, fungus and loose or separated connections. Annual inspections are recommended for residential and commercial properties. Commercial buildings should be inspected once every 10 years by a structural engineer.

Moisture

• Leak prevention is vital to maintaining steel and wood trusses. Moisture is responsible for the majority of damage to wood trusses, according to the New York Landmarks Conservancy. Trusses are exposed to moisture by leaking roofs or gutters, separated mortar joints, or faulty engineering or construction. Moisture causes rust and corrosion damage to steel, as well as rot, warping, decay and fungal growth damage to wood.

Insects

• Insects, especially termites, can cause serious damage to wood trusses. Chemical treatment of the wood is the first line of defense. If insect damage is detected, a pest control specialist should be called in immediately. If the damage is extensive, the services of a building contractor may be needed as well.

Structural Problems

• Structural damage may be caused by problems at bolted connections or by shifting foundations and walls that put unreasonable stress on truss members. Signs of structural damage include cracks, splits or bowing of the wood. Visual clues of damage can be verified with diagnostic equipment, including physical probes, moisture meters and measuring tools. In historic buildings, x-ray radiography or a fiberscope may be used to detect damage to old wood.

Repair

• Some truss repairs fall into the DIY category while others need the expertise of professionals. The repair type depends on the location of the damage and whether the truss is exposed or hidden. For patch repairs, a new piece of wood can be used to replace the damaged wood. In hidden areas, a section of wood can be centered over both sides of the damaged site and bolted in place. For damage in compression members of exposed trusses, the area can be cut out and replaced with a new section. Usually, wood is used to replace wood; however, steel components may be used to repair and reinforce when warranted.