I run a small building firm and that's just the sort of project we'd undertake. The reason it's not so widely available is that there's no mass market demand, the technology is awkward and requires a lot of detailing, and it would be very hard to make money from. The only way to make decent money in the building business is to specialise - decide on one operation, invest in the equipment and train people to be able to repeat that one set of tasks. The less skill and training required the better, obviously. There are a lot of companies around making money from cavity wall insulation because it fits those criteria. I'm sure if the concept of external insulation for single skinned buildings becomes more widespread and there are more people actively wanting it done, then there will be companies set up to specialise in it. It's a difficult business to standardise though, because of various potential problems - how to finish the border with adjoining properties, how to detail around window recesses without leaving weak points for water ingress, how to deal with roofs where there is minimal overhang. It would be a difficult business to guarantee for the same reasons, and also because the quality of the rendering work is crucial, and there are not many plasterers who have the patience to apply render in a way that can genuinely guarantee it won't crack after a few years.
It's difficult, as a builder, to simply read about new techniques and then start doing them. Building is something that traditionally has always been passed on from one individual to another, with all the little tricks and knacks that go with it. That's why most builders don't even want to hear about new techniques - they've spent a long time learning how to do things properly one way, and there's no motivation to have to go back to square one.
Personally, I get a lot of pleasure out of learning new techniques, but it's daunting, especially when trying something for the first time which is costing a customer a large amount of money and which I'm taking full responsibility for.
I think there is a real need for some form of national education program to teach people in the industry about eco-principles and detailed hands-on techniques. But that could only happen with regulation that made it mandatory, the problem then being that if people are forced into something, they're more likely to approach it with a negative attitude. Like everything else in our society, things will only change seriously when climate chaos keeps disrupting business as usual on a serious and regular basis, and the media machine starts working itself up into a self-righteous fury about 'why nothing has been done to prevent this outrage'....