I've been using a succession of pedestal NG heaters for years (they wear out). I'd like to mount a Sunstar ceramic radiant heater (twin burner - 65,000 btu) beneath the roof (12 pitch, 20' floor to peak).
The manufacturer specifies a minimum distance to combustibles of 49" from top and sides of the fixture.
Question, would I meet fire code by affixing 1/4" cement board to the rafters? If so, what would the minimum distance become?