So....

I have breathable internal finishes, a humidity responsive VCL airtightness layer (Intello perhaps) over say OSB or panel-line, breathable insulation and then go for a straight-on-to-frame external insulation board such as Diffutherm or maybe I have a rendered straw bale wall....(ie no ventilated rainscreen cavity), all with vapour permeable external finishes... good so far...

...but just before I go any further, can I say that if this terms into another 'Do breathable walls work? / 'You don't understand what breathable means' etc etc, I will get upset (this is generally to be avoided)... the specific question or indeed statement for discussion is...

...aren't these systems very vulnerable (and in the case of the external finish - possible disastrously so) to a later owner applying a lovely thick slap of thoroughly vapour tight masonry paint or even sand cement render....?

J

-typo edit -

Posted By: James Norton...aren't these systems very vulnerable (and in the case of the external finish - possible disastrously so) to a later owner applying a lovely thick slap of thoroughly vapour tight masonry paint or even sand cement render....?-

Indeed they are! As Jacky says, it brings home the need for some sort of logging of what's been done, and for broader education.