I always imagined that at some point we would need to decide as a group exactly what we mean by ‘durability’ and ‘sustainability’, in order to convey that information to the architects and/or contractors. At which point they try to meet our criteria within the constraints of our budget. For instance, what’s our position on heat pumps, or how negotiable is a flat roof? Perhaps I’m over thinking it, or perhaps that moment has arrived. Having said that, @els I don’t think we need definitive answers to every question for your proposal to move forward. Perhaps just a shared understanding of what’s important in a broad sense at this point…