Originally Posted by

My chipboard flooring has the brand name of CaberFloor. It is 600mm.
wide and 22mm. thick and the surface has a water risistant green
coating on it.

I always screww this stuff down so that it is possible to lift in the
future.

As others have said, set you circular saw to 22mm. depth or the
thickness of your chipboard.

I had to cut an 8 inch chnnel to lay some C/H pipes. When I put the T&G
back it did bow downwards between the joists when I stood on it. To
cure that I screwed a 390mm.strip of 4x2 to the chipboard so that it
fitted between the joists. Alternatively you could make a frame betwwen
the joists for the T&G to sit on, similar to making a ceiling hatch.

Chris.