04/11/2025
Just and observation, 84% humidity externally and 86% and rising internally. Observed and written in 1856, Darceys' law of physics in regards to moisture movement in porous materials states that once humidity levels go above 85%, water vapour has liquid water droplets in it. So if you have an insulating LIME BASED plaster that is vapour open but capillary shut, it will cease to function. Vapour may pass through, albeit very little, but the liquid water will be left behind. Most if not all imported lime based insulating plasters are vapour open/Capillary shut. Even if the bag states it is capillary active, it is to the bare minimum, under 10%.
And, you can take that to the bank!
Irish Quicklime mortars a 100% vapour and capillary open. Remember, a dry house can be a warm house, and Irish lime is the best at doing this.
Irish lime is better lime!