R
Rob1980
Thanks, 300mm centres I can do, I've not put the joists in yet.
I can garantee there is no movement in the joists, they are c16 treated regulated.
The joists will all be fixed with angle brackets - solid.
Not sure what you mean
About spanning 2 meters, these will be sat directly with no spanning and laid in the normal fashion as if they were spanning gaps.
My concern in terms of the thickness of the boards is the fact that the room joining it will be floorboards with no carpet, and I want to avoid a big step if possible.
So if by reducing the gap in the joists to 300 will be ok, would I then need marine ply or normal ply?
Cheers
I can garantee there is no movement in the joists, they are c16 treated regulated.
The joists will all be fixed with angle brackets - solid.
Not sure what you mean
About spanning 2 meters, these will be sat directly with no spanning and laid in the normal fashion as if they were spanning gaps.
My concern in terms of the thickness of the boards is the fact that the room joining it will be floorboards with no carpet, and I want to avoid a big step if possible.
So if by reducing the gap in the joists to 300 will be ok, would I then need marine ply or normal ply?
Cheers
Ok. You want to save money by not screeding.
The joists should be treated c16. If tiling on, it would be more solid to put them in at 300mm centres, but 400mm is ok.
18mm ply is, as you say, compliant with building regs at 400mm joist centres. However, this is minimum requirement and really only for carpet.
We have always used 22mm minimum. 25mm is better. My builders merchants stocks 22mm tongue and groove flooring plywood, which is good for a sub layer for tiling. 6mm Hardibacker glued and screwed over the top. It sounds like you are going to put the joists in more like battens. They must be packed and fixed down at close centres. 47x100mm timber can only span around 2 metres. All edges of plywood need to have noggins. I always glue the ply to the joists as well as the tongue and groove. I prefer the Spax flooring screw to fix, at 200mm centres, 60mm long. (Screwfix)