Plywood over floorboards before Karndean/Amtico

[Gooner239]

Hello All,

I am in the process of renovating the bathroom and there is currently a 12mm OSB board laid over the original floor boards. We intend to have a Karndean/Amtico floor laid so I will be removing said OSB and replacing with 12mm plywood, which I take is common to both floor types.

Questions please:

1. What centres to fix the plywood?
2. What direction relative to the floorboards to lay the plywood?
3. What screws (gauge, length) to use for fixing?

Thanks all

 

[dazlight]

With 12mm plywood every 6” on centres and 4” on edges.
Lay plywood opposite way to floorboards
Screws use 25mm if you are going over 18mm floorboards.