I'm trying to maximise headheight and was wondering if i could get away with 12mm plywood or OSB/3 under 9.5mm laminate (+ underlay). The joists are the original 6x2s spaced at roughly 300mm centres.
Personally I wouldn't use any thinner than 18mm if it's to be used as the main weight bearing floor. I would check with your local building regulations also. Personally I'd recommend using 22mm tongue and groove chipboard laid opposite to the supporting beams...... Laid staggered to fit your 300 spaces joists with all joins glued with expanding pu foam adhesive to prevent squeaks and screwed into joists
Thanks; it was actually BC who suggested to my builder that i could have less than the specified 18mm OSB/3. Builders were even trying to tell me i could have 6mm ply LOL. I'm not a fan of chipboard, i have to say; i've read too many negative things about it, and, as you say, would have to go to 22mm.
