Roof Framing and Sheathing

I really don't like being on a ladder. Having a loft provides really helps in this regard. Although I wasn't ready to put the loft floor down, I was able to put a few sheets of plywood sheathing across the loft joists. That provided a handy work platform that prevented a lot of work from the ladder.

The joists were temporarily supported by blocks underneath screwed to the studs, the joists screwed to the studs, and ultimately, two 3/8" galvanized bolts. In this picture you can see some of the metal bracing I used to provide rigidity. I don't know if it helps the finished product much, but it certainly helps stabilize the building before the sheathing and spray foam insulation are complete.

The ridge is too long for one board. At 22 feet, it is hard to find a single board to serve that purpose, and it really isn't necessary. I used two boards, and fastened them together with a couple of plates. The main purpose of the beam is to provide a good place to connect the rafters, and keep them in position. Ridge beams haven't always been used in house construction, but seem like the right thing to do and are required today.

My roof has two pitches. The front is 10/12. But over the loft, it is a flatter 4/12. Because there are two pitches, there is a center gable area.

The rafters aren't very long. Tiny houses on wheels are limited to 8'6" in width generally, so the building is narrow to begin with, and there can't be much overhang. As I recall the rafters were about four and five feet each - the longer ones on the steeper section. Figuring the angles on rafters can be a bit of an art. I doubt many modern carpenters often use the tables on the side of a framing square to determine these cuts, since most construction now uses trusses that are built at  factory instead of rafters. Since  my tiny house was designed on the computer using Sketchup, it was fairly straightforward to get accurate lengths and angles.

Normally joists would provide strength for holding the sides in at the roof. They prevent a heavy load on the roof from pushing the walls out. In this house, the only ceiling joists are those supporting the loft. And they are two feet below the roof line. The front has a cathedral ceiling, so no joists. To provide the needed strength, metal straps were installed where rafters joined the beam. Collar ties were bolted to the rafters of the 10/12 section. And in the loft section, metal straps were also used underneath to tie the rafters and beam together.

Sheathing above the loft was fairly easy. Panels were glued and screwed to the rafters. Being able to stand on the loft helped a lot, and the low pitch wasn't too bad to work on when that wasn't sufficient. But still, this is thirteen feet in the air, so need to be careful.

I needed some help on the steeper section. My son-in-law sat on the ridge, screwing down the top of the panels, and I worked from underneath, pushing the panels up to him, and screwing down the lower parts. I also built some temporary supports that I attached to the studs to keep the panels in place. The panels didn't slide off easily on the 4/12 section above, the could not stay in place by themselves on the 10/12 section without the supports.