We’re in the final stages of insulation. Some sections of the roof use trusses, and the height of the truss at the top plates is around 6″. Our required insulation is R30 (our Title 24) for ceilings, but that would compress the batts down to about half their height. No big deal, this is San Diego where temps are mild anyway. But I’m concerned that the last 12″ or so of the roof sheathing and the blocking between the trusses at the plates will be in contact with the batts and really poorly ventilated (e.g, the only air to get to that last 12″ will have to pass through the fiberglass).
In other parts of the house where we had truly unventilated roof spaces (vaulted ceiling) we used rigid foam. That would be a very tough solution to implement at the last minute for the truss ends.
Am I overthinking and overworrying here with the truss ends? Perhaps drop it to R19 for the last 12″ so it’s not packed tight?
Thanks for your opinions, as always.
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