I am in the process of doing a barn conversion and I am looking to install 20mm oak EW to a first floor with UFH. I am proposing a floating floor using a D3 adhesive to glue the t&g. The problem I have is that the exising floor joists are quite unlevel. Am I OK to 'pack' the low joists with ply wedges or plastic packers? Also, is it advisable to plank each room separately and retain a threshold strip at each door opening - ideally I would like to the floor to flow through to the landing etc - is this OK if I leave 12-15mm expansion at each perimeter wall. Any additional comments welcome. Cheers.