Advice on build up

[seanmci]

We are looking to replace our floorboards (very bendy and have lots of holes) for either 22mm WBP or even marine ply. We have bought some porcelain floor tiles and would like to install under floor heating. Some advice please from those with experience -

Which ply would you go for considering we want rigidity and have splashy kids?
If we wanted to use a membrane on top of the ply what would you use?
Assuming build up would be - 22mm ply, membrane, underfloor heating, tile adhesive, tile.
There seems to be mixed advice on using a layer of insulation under the under floor heating. On the ground floor I plan to use it as we have a concrete slab, but upstairs on the new ply I think I should leave it out.

Any advice appreciated.

 

[Stef]

Hi, when you are at the stage of ripping your floor up then add extra timber into the floor & get it as strong as possible.
I would still overboard your ply with a 6mm insulation board then fit a heat mat, self level over the wires then tile.

 

[seanmci]

Hi Stef, thanks for the reply. What concerns me is the 'growing' depth of the tiled bathroom vs the carpeted areas upstairs. Could make for interesting thresholds?

Have you ever used a membrane over the ply (like damp proof membrane) / is there something suitable for this purpose and where is the best place to get it?

 

[Ajax123]

If you are lifting the boards you could insulate between them before putting you ply down

 

[jollyroger]

When you rip up the flooring, put some English "noggins", or Scottish "dwangs" in between the joists. Do anything you can to strengthen the floor before over boarding. My preference is 22mm treated T & G chipboard and a generous amount of glue and screws. Then overboard with insulation board.

 

[TJ Smiler]

If you are lifting the boards you could insulate between them before putting you ply down

What a great idea mate, Never thought of that before