For many years, the influence of roofing within our national energy codes has been much less that its impact on annual construction revenues. That’s because energy codes tend to focus on new construction projects while roofing is involved predominantly with existing buildings. As a result, national energy codes like the International Energy Conservation Code (IECC) and the ASHRAE Energy Standard for Buildings (ASHRAE 90.1) have tended to look at roofing from a narrow, new-construction perspective that makes it difficult to apply the code effectively to the re-roofing of existing buildings.
Perhaps the worst example of this disconnect between the new-construction focus of the code and the reality of re-roofing is found in the uninformed language used in the code to describe roof recovers on existing buildings as opposed to roof replacements. For many years, the process of recovering an existing roof was described in the IECC as a process “…where neither the sheathing nor the insulation are exposed.” Sheathing? On a typical flat commercial roof, we have a roof deck on which the roof insulation and membrane are installed, but sheathing is a term usually applied in residential construction to refer to a roof substrate over an attic to which shingles and other steep-slope roof coverings are attached.