Ok, so I've tried doing some research and struggling to come across the exact answers, may be a really stupid question though. We are planning on installing our own floorboards- which i think we have the method covered (22m P5 T&G).

 

But prior to laying the floorboards is there anything I need to install first. For example, our posi-joists are at 400 centers, but do we need to install noggins between the joists for future stud walls where they don't sit on top of a joist, or run parallel not perpendicular to a joist?

 

Do we need to install anything to take account of stairs, showers, toilets?

 

And I was looking at a video of how to install a wet room tray and they cut the floorboard out and installed a new board between the joists not over the joists. Once the boards are glued down im assuming it will be a very messy job to come along and cut out later, therefore do i need to be leaving a cut out for the shower area now?

This might assist ref the shower tray:

 

 

@zoe61 who’s posi joists are you using ..?? You need to get their site guide as all of this should be included. 

 

In terms of stairs, the designer of the posi joists should have taken this into consideration as you may need trimmers specially designed or installed for the staircase.