Plywood subfloor fixing

[grifter]

I will be putting 9mm plywood down over the existing subfloor mainly because l want to raise the floor.
My question is can l screw it straight down or should l use a wood glue or other adhesive before screwing?
Thanks

 

[Wayners]

Few pea sized blobs of a cheap polymer mastic as you go with screws.
If you use loads of polymer you would struggle to get it up if required.
PVA will weld it down.

Up to you

 

[Deluks]

Screws every 200mm in all directions. Use the spax self countersinking ones, 25 or 30mm.

 

[dazlight]

22mm / 25mm ring nails or screws.