We had two distinct grids of underside trim to contend with, one located in the living room area and one in an adjacent dining room (a drop beam separated the two). We built the larger, living room assembly into two sections on worktables and lifted them onto plywood hangers; we later joined them together from their suspended perch atop the hangers. The grid in the dining room was lifted as one piece.
Here, Cregg and Tom set the living room’s underside trim on the plywood hangers. The clear space between the framing and trim assembly allowed access to the trim’s reverse side to install the pocket screws, which joined the two living room grid sections together (along with the tenons and glue).
Pulling these joints tightly together overhead resulted in a less seamless appearance than we were able to achieve on the table. In hindsight, it might have been easier to lift the living room grid as one piece; given the difficulty we had pulling these joints tightly together overhead. That said the hangers proved to be a good place to “park” the underside trim as we prepped for the next step.
To adjust the grid once it was raised to its final position against the framing shims, we held it in place with plastic shipping straps and staples. This allowed us to fine-tune the trim’s alignment side-to-side. We used a laser line to shoot through the living room to the dining room to line the grids up. Because each bay had to be precisely aligned visually with each adjacent bay, and because we planned to assemble the finished sides as boxes with only 1/8-inch clearance between them and the grid, we needed absolutely parallel alignment and perfectly square openings. We stretched a string the full length of each beam axis before permanently attaching the grid.
Thomas Moses of Artisan Builders touches up the joints connecting the two sections of the living room grid together with a Festool random-orbital finishing sander.