In a previous post says...
David,
If I gave a truss manufacturer a careful drawing of an existing truss,
a manufacturer could tell me what loads it could support?
TB


Tom:

Most likely they won't take the time to deal with it. This is a common
problem, but the truss manufacturers don't really want to deal with a
homeowner on a single project where they are not going to sell anything.
The possible profit to them is too small, so they won't consider it.
This is especially true if the existing trusses are not ones that they
built in the first place.

Most structural engineers (including me) don't really want to be
bothered with this type of problem either. The liability is high for a
very small return. I'd do it for a regular client, but only then. The
cost of engineering services to analyze the truss and its connections,
then design a fix is simply not worth the money in my view. You could
rent a lot of storage space or buy and build a small storage shed for
the same amount of money.

--
Bob Morrison, PE, SE
R L Morrison Engineering Co
Structural & Civil Engineering
Poulsbo WA