Without a spacious subfloor to work on or continuous sill plates to work up from framing the long rake walls is a bit of a brain bender. Here is how we tackled the task:
1) Use the 2×6 rafters that will ultimately be the roof to build up from the floor to above the wheel well height (worked out perfect).
2) Taking actual measurements off the trailer as we go, mark all stud locations onto two identical full length story sticks.
3) Square straight up off the trailer flange and mark locating points onto the repurposed rafters. This should in theory allow us to frame the wall already square.
4) Cut the sill plates and mark them out using the story sticks. Precut all the studs to the longest length needed and lay them transverse across the trailer.
5) Lay the story poles longitudinally across the studs, align with and clamp at the marks on the repurposed rafters, sandwiching the studs and holding everything square.
6) Line the studs up with the marks on the bottom and top story pole and nail on the sill plates. Use a string line to ensure the entire length of the sill is dead straight.
7) Screw the top story pole to the studs to hold them firmly in place and then use a tight string line to pull the line of the rake and mark out the tops of the studs.
8) Set the circular saw to the rake angle and cut off the stud tops in place. Nail on the top plate.
9) Double check square from bottom corners to a fixed point of equal height higher up on each side. Nail on shear panels or a diagonal board to hold the wall square.
10) Measure everything really carefully and draw up a plan to make the opposite wall much easier to frame in the morning!
– Brian
