Building Truss

Raising the last roof truss is like threading a 120-pound needle.

Raising the last roof truss is like threading a 120-pound needle.

Big push to get a dry roof over the whole house by week’s end. We didn’t quite make it, but we installed almost all the trusses and we paved plywood over as much of the roof as we could. Our downfall was a tricky detail at the center of the house’s T shape, where two gables intersect at a right angle. With only one exterior wall available along a 20-foot distance, we had to support the other end of these trusses somehow. Colin installed joist hangers along the last perpendicular truss for this purpose. As each roof truss went up, our working space on the second floor (namely our headroom) kept shrinking, and maneuvering successive trusses into position was definitely a job for three lifters, with a fourth person standing on the trusses already in place to hold each new one steady.

Colin hammers in the final nails to secure a joist hanger.

Colin hammers in the final nails to secure a joist hanger.

Terry installed lateral bracing continuously so our trusses wouldn’t fall over, and the extra pieces of bracing sometimes stuck out and added further obstacles to the truss-raising. Also, we had to repair a manufacturer’s defect: two of the trusses came without center diagonal members. Colin cut two 2x4s to size (including precise angles on both ends), Terry showed us how to peel back the gusset plates at the offending joints, and at last we inserted the new members and secured them.

We aligned and leveled every roof truss, just like the walls.

We aligned and leveled every roof truss, just like the walls.

Terry and Turner on the scaffold attach a nailer across the truss bottoms to support the sheathing.

Terry and Turner on the scaffold attach a nailer across the truss bottoms to support the sheathing.

On to sheathing! Since the LOWEST point on the house roof is about 20 feet above terra firma, ladders wouldn’t cut it for easy access to the outside. Instead, we built a scaffold. Terry rigged up a couple of triangle frames out each window, and then we passed him long lumber to lay across for a platform. The scaffold allowed two people to stand outside the roof trusses while a third person fed them 4×8-foot plywood sheets to pave over. It was still awkward handling the sheets, especially once the bottom row was nailed on and the distance between floor and roof increased. Sometimes we left a space open to pass plywood through, but we had limited space to stage plywood atop the roof, so a few very long moves were inevitable. At least once, Colin lifted a sheet to Carson balancing between two truss bottom chords, who then turned the sheet and lifted it on to Terry and me near the peak.

We faced one rainy afternoon this week, and we took a break from roofing (VERY dangerous when wet) to build stairs. Carson and I framed the landing, which had to squeeze in tight between two walls already built and actually intersected a third wall. It was a fun physical challenge to raise the frame from the first floor up 8 feet to where we nailed it in place. Then Terry installed the stringers and Colin screwed on some temporary treads. The stairs instantly improved access to the second floor… it’s almost like cheating.

The stair landing.

The stair landing.

Colin installs temporary treads.

Colin installs temporary treads.

As I mentioned before, framing the roof’s T junction is a real pain. A series of four successively smaller triangle trusses fills in the funny space at 2-foot intervals, but we found no obvious way to sit them in the right spot. Working past sunset, Terry finally figured out how to shim the first triangle so its peak matched all the others. We’ll have to build the remaining trusses up basically the same way, and then we can get on with the roofing.

The latest. West side of the roof is fully sheathed with plywood and Roofer's Choice.

The latest. West side of the roof is fully sheathed with plywood and Roofer’s Choice.

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