I haven't been able to find a diagram of a roof with the exact configuration ours has. I think the board on which our joists rest is called the wall plate but what is the name of the board that sits on the joists and on which the rafters rest?
This is in a garage and I think the plan was to make the roof space bigger for a future conversion because windows are already in place and wiring. The reason I'm asking stems from the fact that I want to sister a couple of joists so I can remove part of one for an opening.
Best Answer
I'm not sure there's an official standard name for this specific scenario, but I'd call it a purlin or an elevated wall plate, maybe. A diagram in this discussion has it as a raised top plate. This article discusses purlins as an intermediate rafter support member.
jwh20 is right in that this is a non-standard roof framing method, but there are a few reasons it may have been done (one of which you mentioned--attic space). Another is to create an "energy heel" or "raised heel", where there's more vertical space for insulation. Yet another would be to raise the fascia/soffit height to clear windows or improve appearance (in the case of a very steep pitch). In your case the ceiling joists may have been run through to create backing for the soffit, which is often added later at a lower level.