New Bathroom Floor - Plywood?

[zacnelson]

Hi there, I am making a new bathroom and ensuite from what used to be a bedroom in my house. I have removed the floorboards, and I plan to lay 16mm plywood first, and then put 6mm ceramic tile underlay on top of the plywood. I just have a few questions:
1) Is it also possible to use particle board, not plywood? Which is better?
2) Should I screw or nail the plywood? And should I use galvanised nails/screws?
3) Should I glue the plywood as well as screwing/nailing, and also should I glue the tile underlay sheet to the plywood?
4) With the tile underlay sheet, am I correct to use galvanised nails to fasten that (as well as glue of course)?
5) I believe that I am required to have an expansion joint in my underlay sheeting where there is a structural joint below it. Is a `structural joint' the location of the bearer that runs through the middle of the room?
6) Do I put silicone between the sheets when I make the expansion joint, or do I just leave a gap and wait until I have put the tiles in, and then put silicone between the tiles?

Many thanks,

Zac

[SilentButDeadly]

1) Is it also possible to use particle board, not plywood? YES Which is better? Hmmm........neither. I'd used compressed cement flooring like James Hardie Scyon
2) Should I screw or nail the plywood? Nails are fine And should I use galvanised nails/screws? Not necessarily
3) Should I glue the plywood as well as screwing/nailing, NO and also should I glue the tile underlay sheet to the plywood? YES
4) With the tile underlay sheet, am I correct to use galvanised nails to fasten that (as well as glue of course)? YES
5) I believe that I am required to have an expansion joint in my underlay sheeting where there is a structural joint below it. Is a `structural joint' the location of the bearer that runs through the middle of the room? You'll need an expansion joint where the flooring sheets under the underlay join
6) Do I put silicone between the sheets when I make the expansion joint, YES or do I just leave a gap and wait until I have put the tiles in, and then put silicone between the tiles?


But I'd still use compressed cement wet area flooring.....that way you have the floor and the tile surface in one sheet, not two. And the Scyon product comes with an installation guide.....

[silentC]

What are the regs in Vic? In NSW you need to waterproof the entire floor in a wet area, for that reason it's pointless putting tile underlay down over particleboard or ply flooring. Most people these days seem to use particleboard flooring in wet areas. I suppose if it's going to be waterproofed anyway, it doesn't matter much.

If you want to do a top notch job, use compressed cement flooring. The membrane will stick well to it and it will never rot out if any mositure gets under there. Make sure you use flanges around any floor penetrations and seal them well.

[zacnelson]

Thanks so much, both of you, for your kind advice.

If I was to just use cement sheet flooring, or Scyon, it would I imagine be quite thick. How would I even cut cement sheet that thick? Especially the problem of cutting holes for the plumbing, like the shower waste?

Regards,

Zac

[journeyman Mick]

Zac,
the sheeting is best cut with a dustless cutter but can be cut easily with a diamond blade in an angle grinder (very dusty process). Penetrations can be made with TCT holesaws or by drilling a series of holes with a masonry drill bit (hammer action off)

Mick

[Carpenter]

Use the Scion, its got a tongue & groove feature thats a big improvement over the old compressed sheet. It allows the two sheets to connect & eliminates the potential for movement at this point. Do not scrimp on waterproofing, go for a pro or you will be sorry. Not a good area to make a budget cut.