When reviewing the search terms that people visit here with (yes, I know, kind of like egosurfing), I saw a couple of people coming here looking for remote walls and thermal bridging. And I did recently do some searching and found relevant content.
To recap, remote wall construction is a technique where you leave your wall cavities empty, you sheath the outside of your timber framing, you run an air/moisture barrier over the sheathing, then you put polystyrene over the outside of that (continuous insulation), and finally cladding over all of it. The advantages are that:
- your air barrier is moved outside the walls – so you don’t break your air barrier when you install power points and the like, so your house is much more air tight and therefore warmer
- your insulation isn’t prone to thermal bridging from the studs
- your insulation is rigid foam instead of batts – not as susceptible to collapsing and giving a lower R-value than you thought
You can combine with a similar system over the roof, giving you a conditioned ceiling cavity to run services in (and avoiding having fibreglass in your ceiling, which is one of my pet hates).
So, one of the questions that goes with all this is how you install continuous insulation, and cladding on the outside, without creating thermal bridging. The document I found that seems most authoritative is this study. And I think the conclusion is that the thermal bridging isn’t as bad as you might think, and in turn that means (thankfully) that you can just make your cladding as well attached as you need, and not mess around with fasteners that might not be durable or might not stand up to the wind you might expect.