Sheeted the roof today! We are running true half-inch five ply CDX plywood transverse across the entire roof. The roof of our tiny house is 105 inches wide so we used oversized sheets to pick up the full width. 10 foot ply is nearly twice the square foot cost of 8 foot, but it just ties the structure together so much better that we decided it was worth it.
One nice thing about continuous wide sheets is that you can break sheet spacing a little bit as long as it doesn’t mess up your installation strategy. 16 1/2 inch spacing on the rafters evenly spaces all the rafters and still gives a reliable press fit for the insulation. In our case where we are using a combination of rigid foam and mineral wool, bumping things up just a little bit dramatically improves yield on the foam sheets.
We knew our roof was likely to be just a tiny bit out of square so rather than try to devise some ridiculous system to compensate for that we just laid the sheets on a little wide and then snapped lines along the edges after everything was nailed down and cut them off with a circular saw for a nice clean roof edge. It worked well.
Working up on the roof places us completely in the shade of the huge horse chestnut tree. It was like working on a treehouse and definitely had us both thinking about a roof deck.
– Brian
