Step 1. Once you decide on
the size of your wall frames, make an assembly jig by screwing together
two pieces of plywood. The top piece defines the interior dimensions of
the frame and the bottom piece supports the boards while they are being
nailed together using a nail gun (inset).
Step 2. Snap level chalk
lines around the room, and nail the chair rail boards to the walls. Then
cut a scrap block to match the measurement between the bottom of the
chair rail and the top of the frames. Slide this block along the chair
rail while holding a pencil to the wall to draw a layout line.
Step 3. Using your graph
paper layout, mark the location of all the frames on the surface of the
wall. Once you have marked all these locations, go back and check the
spacing between frames to make sure all of them are consistent.