I'm back to working on this old farmhouse.
The upstairs area was probably originally an attic, and had been converted to living space a long time ago.
The rafters are 2x4, 12/12 pitch. House is square, so the roof is a pyramid.
It currently has some 2" foam board insulation (often poorly fit with large gaps) under the (badly installed) drywall on the rafters. (Note that all this work is being done due to a bunch of interior fire damage)
I'd like to make the roof decently insulated so the upstairs doesn't roast/freeze.
I may build it thicker using horizontal 2x4's. Fiberglass would probably be easiest to install - though leaving venting space is a problem.
The main problem is that there is NO venting of any kind.
It's hard to do a ridge vent on all 4 of the pyramid ridges, and doing one at the peak will only vent the 4 center rafter runs.
I was thinking that if I did put a peak vent in, and then set it up so the horizontal 2x4's leave a inch or two open at the top, this would leave an gap up the length of the ridge to the peak. (though the flow would be up the underside of the roof to the ridge, then have to flow sideways over the old rafter in the gap left by the horizontal 2x4's)
Would that work?
Other suggestions?
Note that I'm in WA state, just a bit north of Seattle.
The roofing is only a few years old, so I'd rather not do major changes to it.