Dave writes from Crownsville, Maryland: "I want to insulate and drywall a ceiling in a sunroom enclosed below an unheated workshop and an open patio. The patio has no roof and a slate surface over a waterproof membrane system. The entire ceiling is framed with 2x12's and would be difficult to vent. What would be the best insulation to use?"

Answer: Faced R-38 Fiberglas™ insulation will fill the cavity. The facing should be toward the warm-in-winter side. Owens Corning does not manufacture that type of roofing system. I recommend contacting the manufacturer or a roofing contractor for ventilation requirements.