Getting More Space for Roof Insulation Above the Top Plate
When using solid-sawn rafters for a roof, what’s the approved method for getting more vertical space for insulation above the top plate on which the rafter rests? A 2×12 with a site-built vent baffle might only have about 9-1/2″ for insulation, which only allows about R-35 for batts or blown-in insulation.
I’ve seen some examples on the Web of adding a rim joist to the joist ends and a new top plate above the joists, and resting the rafters on the new top plate, but I’ve also heard (not confirmed) that approach isn’t favored by inspectors in our area (New Hampshire).
Is going with raised-heel trusses instead of rafters the correct approach?
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