Roger440

Get yourself on the traditional and listed building advice facebook group. You will find the people you need on there.

That incorrect. If the internal wall is effectively the same construction and has no DPC, then any issues with the outerwalls may well be present, indeed, likely to be on the internal walls. My internal wall was worse than the external as both sides were plastered with gypsum so nowhere for the moisture to go. At least the outsede walls had one exposed face.

Option 3) use a system/build up that is breathable from the base to the surface. That includes the paint. Your option 1 is pointless for the reasons i outlined earlier. Yes, you can check afterwards and see whats happening. Then rework accordingly. Why not do it properly first time? The key decision is, does it need to be breathable in the first place.? Thats going to depend on wall construction, ground conditions and a bunch of other variable unique to your house. If it does, option 3, if it doesnt option 2.

Gypsum plaster is vapour permeable. Almost everything is. The question is by how much I can assure you, compared to the rest of yourbuild up, not even close. Im my house it acted as an amazing barrier to vapour. the wall behind was sopping wet. If you put gypsum plaster on it, it will be even worse. As i said, if you are using plasterboard, no point spending big on woolboard and lime.

There will never be a proper inspection regime. 1, Not enough people who understand. 2, Bugger all would actually get built. The regs will change, and new more inventive solutions found to sign off. Building control is totally unfit for purpose and is just "gamed". I may have mentioned it before (!) but Ive a whole suite of certificates. Not one job is fully compliant to the regs in force at the time. Some not all.

If you want to do it right, seal it up, insulate as much as you can and get a dessicant based hehumidifier.

Why are you using lime and wool board? To ensure breathability of the solid wall i presume? If so, wacking a sheet of plasterboard on is going to undo you good work. Either, ensure the whole buildup is properly breathable, or dont bother, and use normal plaster and PIR, which would be significantly cheaper.

Or you could do this, especially as you are doing an old house, one presumes without DPC? https://www.lime.org.uk/products/sylfaenr-foundation-system.html This is what i did. Total build up depth, 225mm, so minmal excavation. Which is good as it had minimal foundations. Admitedly, insulation level not comparable to PIR, but i was more concerned with solving damp issues in the walls. You proposed route may make it worse. On my previous garage, i did as suggested above, Stone (MOT1) sand blinding, then 4 inch insulation (XPS), then concrete, 6 inch with thicker sides. So a raft That was plenty enough to drive cars over. Like you, i still dont understand why people lay a slab, then insulation, then a slab. Makes absolutely no sense at all. The XPS manufacturer wanted +/- 5mm over the length of the board (2400mm) which is tight, but doable with care and a laser..

Been discussed on 2 seperate threads in the last couple of weeks.

I believe it. Not that surprising TBH. One of the things with this forum is that its so far removed from real life for many. People on here are, by the very fact they are here, interested in these things. Want to understand, ask questions and educate themselves. The average man on the street just isnt interested and doesnt understand even a lot of the most basic stuff about buildings.

Having had the dubious privilege of being a landlord, id say 90% of people wouldnt know if there house was damp or high humidity from feel. Only answer is a humidity meter. Nothing else will ever work. Even that woint woirk for a good number. Or as a landlord, fit a PIV, and hide the switch.

Indeed. As i observed on another thread, outside burning your own wood, the cheapest heating option. Its a crazy world. Traditionally it was an expensive option, for those with little choice. Just need to go find another oil boiler for my barn/workshop.

Why a cavity behind the plasterboard I'll put my money on air circulating behind the plasterboard.

This. 100% guaranteed. Not so sure of a U turn, but the builders will get the blame.

They wont build them properly. They will just be more inventive about getting them signed off. The majority of the trades, nor the BCO's will ever understand. Which is why they will have to work round it. The few that do will make an awful lot of money. Its simply not realistic to replace most of the existing workforce with different people who want are smart enough to understand AND want to work outside in all weathers.

Excellent. Your link shows pics of a double size one. Looking like a job for next week

Thanks for the info. I was hoping not to have to mofify my freshly completed wall. Looks like i will be. The Hetta one fits in a single socket back box.

No reply to mine either.

Well, if it does, it not in any of the instructions.

Yes! Crap isnt it.

Cant believe that will be allowed

How will you do that is its password protected and you dont know what it is?

All rather predicatable. Indeed, was predicted by many.

They will have to use public transport.

All the more reason some of us will stick with petrol and diesel to the bitter end. Aside from the fact, that from an affordability point of view, an EV hasnt, and still isnt remotely viable.