In recent years unvented roof constructions are favoured over ventilated pitched roofs because they are more cost effective and more ecological in cases where chemical wood protection becomes unnecessary. The basis of new German regulations in DIN 68800-2 concerning the application of chemical protectives in building assemblies, are vapour diffusion evaluations by the Glaser-method in DIN 4108.3 and requirements concerning the drying potential for construction moisture originating from field and laboratory tests. Because of their relevance to the vapour permeability specifications in DIN 68800-2 the results of the Glaser-method are compared to numerical simulations in the case of cathedral ceilings and the resulting implications are discussed. Furthermore the benefits and practical importance of modern simulation tools are demonstrated and an outlook concerning the development of user recommendations is given.

• HAM: computer models : glassy
• HAM: simplified models - analytical methods : compared to simulatin methods
• risk analysis : moisture
• roof : simulation of moisture balance

1. A new model for mould prediction and its application on a test roof
2. Ecological insulation materials - does sorption moisture affect their insulation performance?
3. Effect of interior and exterior insulation on the hygrothermal behaviour of exposed walls
4. More moisture load tolerance of construction assemblies through the application of a smart vapor retarder
5. Smart vapor retarder: an innovation inspired by computer simulations
6. The smart vapor retarder: an innovation inspired by computer simulations