How to Check Residential Truss Integrity

Check the condition of the roof material covering the roof trusses. Look for missing shingles or tiles. This can be done from the ground for single-story homes, or in the case of a multistory home a ladder will be needed to get a closer look. If any of the exterior of the roof has failed, the integrity of one or more of the trusses has likely been compromised.

Access the attic or crawlspace of the house. A ladder and flashlight will likely be needed if the space is unfinished. Look for evidence of water damage or insect damage. Evidence of termites or other boring insects is the presence of small piles of sawdust from the excavating activity of the insects. If you see insect damage, contact a professional exterminator. If water damage is evident, determine the source of the leak and make the appropriate repairs.

Inspect the metal fastener plates and the hardware used to hold them to the trusses. Metal plates designed to connect trusses should be stamped with labels indicating 16- to 20-gauge steel. If you detect any markings to the contrary, the plates are not rated to bear the weight, and the integrity of the trusses is compromised. The metal plates that hold the joists together should be fastened with metal screws designed for their ability to withstand shearing force. If gold-colored or brass screws are evident, these are deck screws and not designed for this purpose.

Check to make sure that the trusses are attached to exterior walls only; they are not designed to bear the additional force of interior walls pulling down on them. They should not rest on interior walls; otherwise, they will be unduly stressed and their integrity will be compromised.