• Unsolicited questions instead of answering your question. But. Isn't dot and dab insulation going to cause condensation/damp issues? Unless your vapour barrier line is 100%. Wouldn't a build-up with no cavity/void be better?

  • ideally you'd want hygroscopic material to avoid interstitial condensation and to upgrade the buildings moisture management at the same time - some kind of mechanical ventilation

  • Do you though? there are air bricks in the corner of each room and while the crittall windows are obviously not air tight, the addition of secondary glazing (decent hardcote LowE) will mean a lower amount of condensation in the bigger air gap as it acts to lower the dew point on the inner surface of the outer pane and move it to the inner pane which being warmer means you do not get the same 0º-22º plus moisture interface on 4mm of glass.
    it’s on the 6th floor and cavity wall so as long as the joins between slab and walls are good then damp is only ever going to come from people/cooking/washing so an extractor in the bathroom would be a good idea but lowering the dew point of the internal surfaces is always going help, just don’t see how allowing that to move through the walls is a good idea?
    A friend is building a hempcreate house and that’s totally breathable all the way through which is fine when starting from the ground up not trying to improve something 60 years old

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