I am planning an extension above my garage, gone through planning but now sorting BR approval. The garage wall is two skin (brick/block) but with no cavity. When I build above this what is the best option? I have been advised that I can achieve the required u value by installing a two skin wall with no cavity and 65mm of insulated board to the inner leaf. I would prefer to have a cavity wall but is it worth installing steel beams with piers to support the inner leaf. This would probably cost more to build but the improved thermal performance may be better in the long run.
Any advice would be appreciated.
Any advice would be appreciated.