sydthebeat, I dont plan on heavy storage but as you say about supporting walls , i have two supporting walls along most of the floored area so should give extra support with any storage laid over or nearest to these supporting walls.
kingspan/xtratherm polyisocyanurate foam under the flooring -is this the foilbacked stuff or other product? and if counter battening for additional 50mm height
1. will there be issues with condensation when no gap with chipboard put back on top?
2. What U value would this give when you say meeting current reg.?
3. What are your comments on my dormer room situation with only firbreglass insulation stuffed in walls/ceiling?