We’re looking at 10 yr old tract houses to remodel and live in. But we hate the cathedralized ceilings which show up even in houses of 1700 s.f. — a local builder fad at the time. First, I know cathedrals aren’t good for energy efficiency with 4-6” of glass batts and no air sealing. Second, they may look grand in a big house but in a small living room or 12×12 bedroom they feel like an elevator shaft. We don’t like them … but the houses are cheap enough to think about.

So my wife came up with an idea, and I’m asking if it would be reasonable (improve energy efficiency w/o major expense) to lower the ceiling. Instead of a ceiling that peaks at approx 18 feet, we could attach new ceiling rafters for a 10 ft. ceiling to the structural, pitched rafters, then insulate and seal the new gypsum for the finished ceiling. My thought would be to use blown cellulose to R40+ as we upgrade the sealing and insulation of the rest of the (flat ceilinged) house as well.

The walls are usually 8 ft, so the new ceiling would leave a pitched surface approx. 30” (wall to new ceiling) which could be sealed and finished with interior rigid foam board and gypsum.

Is this reasonable? Am I once again missing a whole raft of “unintended consequences”? Would the cathedralized gypsum and insulation need to be removed for some reason?

Thanks for your opinions in advance.