Bathroom Flooring - advice please

[r1flyguy1]

Hi All,

I'm currently in the midst of an extension on the house and have a brand new 2.4m x 2.4 bathroom space to utilise.

The joists are in and I have used posi-joist so that plumbing and wiring will be very easy for access not that it makes any difference to the questions below

Anyway as its brand new flooring to go down and want to best chance of waterproofing, etc, I would like your expertise with the following....

Q1. Would 12mm Marine ply with 6mm no more ply atop be a good idea for a tiled finish, or would the overall thickness with tiles be too much?

If so,

Q2. Should 6mm Marine ply with 6mm no more ply be more preferential to keep the floor thickness down.

And

Q.3 Should I decide to go the electric underfloor heating route what options do I have in regards to floor thickness.

Many thanks in anticipation.

[Gingerbread Man]

Typically most floors are chipboard at 22mm thick. So anything around this thickness would be pretty standard. I'd be tempted just to ply it as one board and then tile to it.

UHF is laid, self levelled/ blinded over with tile adhesive and then tiled onto. Helps to create a void free base. Electric UFH is typically cheap to buy, so it won't Be a dreadful expense. Make sure you have your floor stat in from your controller.

[r1flyguy1]

I've been reading up on horror stories of tiling onto the original boards & some people recommend using a second ply later to tile onto to prevent damage to the main boards should you ever feel the compulsion to change your tiles.

What's the general consensus

[Gingerbread Man]

Correct, people often overlay a 4mm sheet or ply or similar as a sacrificial layer for if you ever wanted the tiles back up. I thought I posted about that, but must have been in a different thread.

Number one rule is no flex. If the subfloors fine, work with it, but with a sacrificial layer to aid future works if required. Often people swap out chipboard for ply to correct any flex in the floor.

Edited by Gingerbread Man on Monday 20th April 08:35

[paulwirral]

Always overboard it regardless , especially with UHF , I've twice had cracked tiles through movement on different jobs , most annoyingly one was my own ! It doesn't take much for the joists to move a little and then the tiles break even with flexible adhesive and grout , it's not worth the risk .

[Gingerbread Man]

Laid a floor with an anti coupling membrane, I think that's the technical line. Ditramat. Aids any flex if you're worried.

[r1flyguy1]

Thanks all,

Just a matter of deciding what individual thickness of boards to use and UFH, tiles etc to create both a rigid structure and without going excessive on the overall depth.

It's a brand new floor so, walls, skirting, boarding, doors all to go up/on to suit

Happy for anyone to recommend the ideal floor makeup

Thanks again

Gary