ASTM International’s Building Performance Committee is developing a proposed standard that will help evaluate potential impacts of changes to the thermal and moisture properties of roof assemblies and the conditioning of space below roof decks. Specifically, the standard could help evaluate steep-sloped roof assemblies after adding insulation; making alterations in drying potential, ventilation, thermal, or vapor resistance; and/or changing the interior environment beneath the assembly.
Energy conservation is a growing concern for existing buildings, whether constructed a few years ago or a historically significant structure. Many of these buildings were originally constructed with uninsulated and unconditioned attics and roofs, but changing the roof assembly without understanding how the existing assembly operates can have major consequences to the structure. Without a proper evaluation, changes could have serious negative impacts on the integrity of the existing roof assembly or the supporting structure as well as creating condensation and moisture-related issues. The proposed standard would give designers and builders guidance on how to properly evaluate proposed modifications in order to avoid negative repercussions of those modifications.