Vapour-open
Assessing risks in insulation retrofits using hygrothermal software tools, Heat and moisture transport in internally insulated stone walls, by Joseph Little, Calina Ferraro and Beñat Arregi, published by Historic Environment Scotland in 2015, defines vapour-open and vapour-closed as a: ‘Qualitative description of how easily vapour can diffuse through a material. Vapour-open materials, such as mineral wool or wood fibre, have low μ-values (vapour diffusion resistance factors) and allow vapour diffusion to occur relatively easily. Vapour-closed materials, such as a PE-membrane or foil layer, have high a vapour diffusions resistance factor (μ-value), which greatly restricts vapour diffusion.’
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Government approach could undermine delivery and regeneration.
World's first mass timber data centre.
The overlooked environmental aspect of data centre development.
Introduction to radon awareness
New technical information sheet published by CIOB.
Updated supplier guide can help electrical contractors engage with NHP.
CIAT confirm the winners of the 2026 architectural technology awards.
Government launches a one stop shop for flood preparedness.
Sir Edwin Lutyens: Britain's greatest architect? Book review.
CIOB publishes free template to help assess and manage risks.
ECA's reflections on Party Conference season
Burnham wants to be confident of winning before asking for a fresh mandate.
New Chief Construction and Scientific Adviser
Sergio Cavalaro, Professor of Infrastructure Systems at Loughborough University.
Building safety levy for England
CIAT publish estimator tool for members.
Water sector faces a growing crisis that could slow the delivery of vital infrastructure.