Replacing T&G with ply ready for tiling

[RKB]

Can somebody confirm I'm OK with this?
1. Rip up bathroom flooring to rework plumbing
2. Replace with 18mm wpb ply straight onto joists ( should they butt, or do I need expansion gaps?)
3. Secure with 2" screws every 300mm

Floor should be ready for ceramic tiling..... I was going to talk to Ardex to see what adhesives and grout they recommend.

Do I need to consider noggins between joists at the door threshold, or anywhere else, or will the 18mm ply be substantial enough??
Thanks

 

[masona]

That's fine, try and join the 2 board butted together on the centre of the joist, if not double the joist and extra noggins where heavy foot traffic is a good idea. Might be an idea to fit safe plate over pipe/cable as well.

 

[RKB]

Thanks Masona.