I was wanting to create some storage space in my attic. I see that the bottom truss chords have joints fastened with metal nail gussets. I'm thinking of sistering (reinforcing) some boards to the bottom chords for more strength.
If I use construction adhesive and some screws, will the glue hold with the expansion and contraction of the framing members??
The glue and screws will hold here but that's not the issues you need to look into.
Realize that your attic space is designed to have engineered trusses that are only there to do two things - Provide framing support for the roof and ceiling. Standard trusses are not designed to carry additional weight. You can convert many attic spaces to storage but you must have a full span of larger dimension joists that can carry the expected storage weight load. For typical two car garage dimensions, this means 2x10's or 2x12's sistered alongside each bottom cord of each truss. Note that this is a general observation, your garage may require more.
Another factor is if there is any insulation in the garage space. Adding storage plywood can compress insulation and reduce it's effectiveness. Usually garage ceilings are not insulated but some are - worth checking.
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