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Q. Roof Truss Repair

The previous owner of a house I’m working on cut out several internal webs from three consecutive roof trusses to create storage space in the attic. There’s no sign that this has caused any structural problems so far, but I’d like to replace the missing members and fasten them with plywood gusset plates and construction adhesive. Is this feasible, and does this sort of seat-of-the-pants field repair expose me to any legal liability?

A. JLC staff responds: A “seat-of-the-pants field repair” will expose you to liability, should the repair ever fail. That said, field repairs can be made, and they probably would resemble something like what you have suggested. Ideally, an engineer affiliated with the truss manufacturer that produced the trusses would design a suitable repair. But if the truss manufacturer is unknown or no longer in business, you should engage an engineer who would both sign off on the design, and inspect and approve your work afterward.

The best place to start is with the manufacturer of the connector plates used on the original trusses, says Bob Allen, a product manager for U.S. Construction Hardware. “I would advise you to take pictures of the condition, along with close-up pictures of the connector plates on the trusses [for identification], and send them to any truss manufacturer,” he says. “They should be able to point you in the right direction.”

A typical repair might call for a combination of dimensional lumber and plywood gussets “scabbed” beside the remaining web members to make up for the lost members. The repair design should include material dimensions for added members, plus a detailed fastener schedule showing the size, number, and placement of fasteners.

Gary Weaver, president of Timber Tech Texas, a manufacturer of roof and floor trusses based in Cibolo, Texas, has been crawling around attics doing truss repairs for 38 years. He says plywood gussets can be more time-consuming and not much more effective than double scabs. He also advises that, to ensure that any sag or deflection in the bottom chord of the truss does not get “locked in” by the repair, the ceiling first be “kicked up” with posts slightly longer than the floor-to-ceiling distance. Two-by plates or 2-foot-square pieces of plywood can be used to distribute the pressure and protect the ceiling and floor.

Regardless of the specific design details, under no circumstances should you take responsibility for the repair. The fact that there have been no structural problems yet doesn’t mean there won’t be some down the road. Chances are good, Weaver says, that interior walls are supporting the load in the situation described. However, this may not be enough in the event of high winds, a record snowfall, or a decision by the homeowners to move all their old college textbooks into the attic.

Richard Feeley of Feeley Mediation & Business Law, a Marietta, Ga., law firm that provides legal counsel to remodeling companies, confirms that a contractor should not attempt a truss repair without engineering support. “If you touch it, you own it,” he warns. A contractor who has not partnered with an engineer to make sure that the repair meets code and complies with structural requirements is indeed liable, and the risk could be great. Liability could include not just property damage but personal injury if the truss system fails and someone gets hurt. There can also be licensing implications, Feeley notes — if, for example, the job is permitted and a building inspector finds after the fact that you made an adjustment that required an engineered design.

Feeley points out another legal dimension contractors need to address as well: Be sure you cover the issue in your contract. “You need a change-order policy that covers unforeseen circumstances,” Feeley says. “If you find something that no one expected, you want to be sure you get paid for the work it’ll take to repair it.”