Insulation Entirely Above Roof Deck

Insulation entirely below the roof deck.

Insulation entirely above roof deck.

2007 levels are based on today s energy. Generally more insulation is needed for condensation control in colder climates. Placing all of the iecc code required insulation above the roof deck with a vapor retarder will provide acceptable hygrothermal performance in all climate zones figure 7. Insulation entirely above the roof deck.

Roofing with insulation entirely above deck a roof with all insulation 1 installed above outside of the roof structure and 2 continuous i e uninterrupted by framing members. Ashrae 90 1 defines a roof with insulation entirely above deck as a roof with all insulation 1 installed above outside of the roof structure and 2 continuous i e uninterrupted by framing members table 1 compares prescriptive requirements of the 2004 and 2007 editions of ashrae 90 1.