Where can I find written code concerning “sistering” damaged rafters. The spans, allowable length, etc. I know we don’t quote code, but I want to learn more when talking to my clients about this particular situation.
I’m sure it would depend on how badly the rafters that you are considering “sistering” were damaged. I may start by using the exact same rafter tables that are called out in the code…or call an engineer.
While not a rafter, I called out some damage by the builder to two trusses. Seems they had misplaced the skylight and had to move it. An engineer came out and had a very specific repair. It stated the size and length of the new sistered boards as well as the nail size and specific nailing pattern. When I did the re-inspect of the repairs with the engineers specifications in hand, they were not even close to the corrections the builder had made. Don’t even try to discuss the whys and wherefores. Just tell them an engineer should be making the repair calls.
The engineers license is one of, if not the oldest in the United States. They are VERY protective of their licenses and have no qualms about turning someone in for crossing the line into their purview.