If I paint the underside of a concrete roof deck, will the IRCC reduce the heat transfer to the interior of the building? The concrete roof deck is exposed to the interior of the building and has a single-ply roofing material on the outside. I’m not sure how to get the 1″ air gap – unless the air gap can be part of the interior conditioned space.
The concrete should be sealed before applying the IRCC. Concrete is very absorbent so this will increase the coverage of the IRCC. Use a recommended concrete sealer, or many times, a good interior acrylic paint will work. The IRCC will then become part of the roof assembly, and as long as no other material is directly sandwiched to the underside of the concrete, the IRCC will work fine. It will increase interior lighting levels, and it will also slightly lessen winter heat losses since concrete is very absorbent to infrared trying to escape through the roof during the heating season.