After locking the roll-up door’s steel panels in place on saw horses, the author laid out the stiles and rails for the four identical carriage doors.
The dotted lines indicate where the author will cut through the assembled doors after they have been fastened to the steel panels.
The author glued up the panels from shiplap siding, ripping the edge profile off glue joints and reinforcing them with Festool Domino tenons.
The author used 5/4-inch stock for the frames, and assembled the stiles and rails with Domino tenons.
While fastening the panels to the frames, the author used his story pole to avoid placing screws where the doors would be cut.
Once the carriage doors were assembled, the author spread construction adhesive on the steel door panels.
Then the carriage doors are clamped in place. Dozens of 3-inch self-tapping coated screws driven through the backs of the roll-up panels into the stiles and rails of the carriage doors join the wood and steel door sections together.