A long storey but my project started out as an extension & refurbishment but has turned in to a new build due to old foundation constraints... I have planning permission for a certain height building and the room heights worked out OK (2.35m) but I had not accounted for Part E as it wouldn't have applied. I factored in a first floor thickness of 300mm originally but it now seems I need to make it 415mm if following robust details (RD). I want to maintain the ceiling height and cannot make the building any taller (neighbours and council objected to planning and pre-apps for taller buildings were all negative) so would like to know if there are any innovative ideas to meet Part E without going to the extent of RD?
I plan to use metal web joists @400cts and 256mm deep.