I’ve been following this conversation with interest and here’s my query…..our 1960’s bungalow has the ugliest facing brick known to man but does have nice wide soffits . The cavity walls were ‘bead’ filled many years previous to us moving in and, perhaps fortuitously, we have had no issue with damp/interstitial condensation (IC) etc.
I would like kill a few birds with as few stones as possible and so why don’t I add further EXTERNAL insulation and have it rendered to any colour certified suitable by she who knows better? Thus warming the house and vastly improving its looks at the same time.
Am I imagining this but did I not read somewhere that there is the potential to cause IC through the addition of external insulation? Surely I’m correct (thinking back to my old ONC study days and the dew point curve) that by increasing the EXTERNAL temperature the dew point is pushed outwards and, therefore, lessening the chance of causing IC? Something in me is saying that I may cause a problem but I can’t see how? Any thoughts?
This is very common in Germany. They put some sort of rigid foam on the outside of the building, typically 10cm or thicker, and then they render directly over that. They attach it with some sort of anchors that have large (8cm?) washers. I suppose you would need to do something around the windows as well, although most I time I saw it done, they were changing the windows at the same time. I spoke to an architect there and he said it was better to have the masonry inside the insulation, because then the wall stays warm.