I have successfully cut out my stairwell and sistered my joists etc, now I am thinking about the subfloor in my gite loft conversion... I have a length of 4.6m by about 7.5m and the joists are at 500mm centres and are 210 x 80mm and 4.6m long. There is very limited head room and would welcome suggestions about the thinnest safe thickness of flooring to use in this soon to be eaves bedroom please. I was hoping that 12mm ply or chip would be sufficient but my nagging doubts are telling me 18mm... Thanks!
I've never thought about it, but I boarded the centre section of my loft with shuttering ply from packing crates from work. It's only for storage & probably was about 16mm.
Ply pretty much always comes as 6mm, 9mm, 15mm, 18mm, 22mm and 25mm. You can get it thicker and thinner and in intermediate sizes for specialist uses. Even 18mm shuttering ply isn't rated as structural.
I worked on a show once where an actor had to bang his stick, made from 2" dowel, onto a deck made of 18mm shuttering, four weeks in and he had punched a hole through the deck. He was a strong chap tho, he could do handstands off a vertical scaff bar.