- 9 December 2020
- Posted by: Eddy Cruysberghs
- Category: Building physics, Condensation problems
If you still use a vapour diffusion calculation and you get a linear cooling as a result, you can ignore it completely. These are programs from the 70’s, where you hit the dew point in the centre of 4 cm insulation. Today houses have to be energy neutral or even passive with 20 – 30cm insulation. Then the centre of the construction really doesn’t get over the dew point anymore.
NEN-EN-ISO 13788 is a European norm in which the Glaser method is explained. There are no requirements set for internal condensation by the Bouwbesluit; the determination method is therefore not controlled in the Bouwbesluit.
Do the necessary measurements in a construction yourself and calculate where the dew point is reached. This way you can determine yourself you don’t get a linear cooling, but always a parabolic cooling with a dew point in the final 2cm of the outer insulation layer. This then gives a lot of execution options.