Assessing condensation in mineral wool in walls

[David Lam]

Dear all
We've been following this guidance on assessing moisture risk in a stone and brick wall insulated with mineral wool internally.
https://wufi.de/de/wp-content/uploads/s ... n_Risk.pdf

The useful guide is for a roof.
The example contains no substrate, eg timber structure.
Why?

For our assessment of the wall I assume we need to model the actual materials in the wall, i.e. 100mm stone, 230mm brick, 40mm mineral wool, plasterboard, plaster.
Am I correct? Or do we not model the stone and brick.
We are getting incredibly low levels of water content in the 1mm thick slice of mineral wool and I expect we are not performing the assessment as you intended. We are using a 'measured' mineral wool (dark green).

Any advice would be most welcome.

Thank you
David.

[Christian Bludau]

Dear David,
this guide is intended for situations in which the insulation is next to a non-absorbent surface. In the case of masonry, dew water may occur on the cold side of the insulation or in the pores of the bricks, but depending on the absorbent capacity of the brick, this water is directly absorbed and sucked into the brick. This is probably the reason why in your case there is only a very small amount of water on the outer slice of the insulation.
Christian

[David Lam]

Thank you Christian