Update on the garage truss reinforcement — got it level finally

I did the same thing on my 1970s detached garage last summer. That sag was driving me crazy every time I pulled the truck in. I used a 20-ton bottle jack and some 4x4 posts to get the ridge line back up. It’s nerve-wracking hearing those old boards creak while you're cranking the jack, but seeing that 3-inch dip level out is such a win. One thing I did differently was using PL Premium construction adhesive along with the plywood gussets. I also swapped out the standard nails for some Simpson Strong-Drive SDWS screws. They pull the wood together much tighter than I coud ever get with a hammer or my Bostitch framing nailer. I also went with 3/4-inch CDX for the gussets since I had some scraps laying around from a subfloor job. Having that platform up there makes a huge difference. I used some old OSB sheets for my catwalk, and it saved my knees from crawling across the bottom chords all day. It’s a lot of grunt work, but knowing those trusses aren't going to shift again when the heavy snow loads hit this winter makes it all feel worth it.

I went through a similar process on my pole barn, but I ran into an issue where the lumber had developed a "set" after sagging for so many years. Even after jacking it level and sistering with new 2x6s, I noticed some slight creep a few months later becuase I only used nails and construction adhesive.

On the second round of repairs for the remaining trusses, I switched to using Simpson Strong-Tie SDS screws and 1/2-inch carriage bolts instead of just oversized plywood gussets. The bolts really helped sandwich the old and new wood together in a way that nails couldn't quite manage, especially since the original chords were slightly twisted. I also made sure to check the top plates of the walls; sometimes that sag isn't just the truss failing, but the walls spreading outward. I had to pull the walls back in with a heavy-duty ratcheting cable puller before the ridge would stay put permanently. It’s a lot of extra hardware, but it gave me more peace of mind than just relying on the glue-and-nail approach.

I used GRK RSS Structural Screws when I did my shop's trusses becasue the drawing power is insane compared to standard nails. They realy suck the new lumber into the old stuff so there's zero gap. For those plywood gussets, I always slap on some Titebond III Ultimate Wood Glue before nailing. It’s easier to spread than the thick tubes of construction adhesive and basicly welds the wood together once it cures. Did you end up using a Milwaukee M12 Palm Nailer for the tight corners, or just a standard hammer?

Glad to hear you got it level. When I did my shop, I found that pre-drilling the pilot holes for my fasteners was the only way to keep that old, dried-out lumber from splitting. Those 40-year-old chords are like glass. I also made sure to stagger my gusset nails in a zig-zag pattern instead of straight lines to avoid creating a new stress crack along the grain. It felt like overkill at the time, but three winters of heavy ice later and that roof hasn't budged an inch. Getting that first flat line across the ceiling is a great feeling.

I always grab my Bosch GLL3-330CG laser for truss work. String lines are fine, but that green beam shows exactly where the crown is as I'm pumping the jack. If you've got that much sag, watch the heel joints where the rafters hit the ceiling joists. I ussually reinforce those with Simpson SDWC screws to prevent outward thrust. Also, make sure your top plates are tied into the gable ends with some 2x4 blocking. If the trusses are too stiff now, they might start pushing your walls out if the lateral bracing isn't solid. Better to check it now than see your siding buckle next season.

Quick update — I appreciate the tips. I actualy grabbed a box of those GRK screws for the last few gussets after reading about the drawing power. You guys weren't kidding, they realy pull everythign tight. I did notice some of that splitting on the older chords like mentioned, so I started pre-drilling everything. Hopefully that stops any of that creep from coming back later on.