I’m an architect, but new to the applied reflective coatings. I have a residential attic with wood trusses to insulate. I was considering fiberglass batts with foil face or blown in fiberglass with a reflective coated deck. What would you recommend (specific products & manufacturer) and what coating is the best and/or most cost effective? Someone recommended the Heatbloc-ultra .68/sf installed.
Answer:
If you live in the South, applying a radiant barrier to the underside of the roof trusses is the best approach to dealing with Summer’s heat. It is also important that you have enough mass insulation on the floor to meet your local code requirements. As to putting a foil faced fiberglass in the roof line, a radiant barrier by itself is more than sufficient.
Based on their claims, a radiant barrier made with low emissivity metallized film will perform much better — emissivity of 0.05 vs 0.19.