The building is really taking shape as the last of the roof is nearing completion. This has been built in reverse to most roofs. So starting on the inside of the building with an air tight barrier, then the insulation batts, next is a wind tight barrier, then metal battens and an eight millimetre foam cell thermal break and finally the corrugated iron.
There are several reasons it was built this way, the small roof cavity meant limited access for workers, but the key reason is to ensure that the batts would be installed correctly, without any gaps, and allowed better access to install the final airtight barrier correctly. This method also ensures that there will be no tradesmen in the roof space ensuring that that insulation layer is not disturbed, compressed or damaged. It also means that in the planning process, extra consideration was be taken for installation of the lighting, power and plumbing.