Underfloor bathroom heating

[Russinating]

Looking at sorting out the above, got the matt and boards spec'd, and already got porcelain tiles.

Boards (6x): http://www.diy.com/departments/aquadry-waterproof-board-l600mm-w12m/261366_BQ.prd
Mat: http://www.screwfix.com/p/klima-underfloor-heating-mat-1-5-sq-m/76438

Edit: Kind of answered my own question now, but just to check, is this adhesive definitely suitable/compatible with the above? http://www.diy.com/departments/mapei-grey-tile-adhesive-w20kg/38141_BQ.prd

 

[Nedved11]

Goes without saying but you will also need to add the flexible additive if going on a wooden floor along with suitable flexible grout...

 

[Russinating]

Thanks. What does the flexible additive do?

 

[Maccapacca]

After seeing how amazing Ditra matting is I would always use that under any tiles for the rest of my days.

Use flexible adhesive and grout

 

[Russinating]

Right...

Floor adhesive: http://www.tilehq.co.uk/fast-setting-grey-flexible-wall-or-floor-adhesive-20kg.html
Additive: http://www.tilehq.co.uk/latex-plus-6kg-additive-for-use-with-keraquick.html
Floor grout: http://www.tilehq.co.uk/ultracolour-plus-white-100-5kg-flexible-wall-floor-grout.html

Look ok? Thanks guys.

 

[Maccapacca]

I don't think you need the additive.

What's the sub floor?

 

[Russinating]

Great, that saves a few quid.

Unsure of sub floor yet as we get the keys tomorrow. What difference would that make?

 

[Maccapacca]

If it's new ply or chipboard or screed board then just use ditra matting over the top stuck down with adhesive then ufh then tile

 

[Russinating]

Don't know if you missed it from the OP but I'm going to be putting this down: http://www.diy.com/departments/aquadry-waterproof-board-l600mm-w12m/261366_BQ.prd

Unless I'm missing what you mean? Thanks for your help so far .

 

[Maccapacca]

Those boards aren't totally waterproof neither is the adhesive you should tank over the board with something.

Although I haven't and it's been fine.

 

[Russinating]

Any idea what? Only finding stuff about wetrooms at the moment which seems a bit excessive (and expensive!).

 

[Maccapacca]

http://www.diynot.com/forums/tiling/wetroom-tiling-sealing.316051/

All on there

 

[mattyg]

If it's new ply or chipboard or screed board then just use ditra matting over the top stuck down with adhesive then ufh then tile

UFH then screed then ditra mat then tiles. Surely.

 

[Maccapacca]

Wet yes he's using electric matt

 

[Maccapacca]

http://www.schluter.co.uk/ditra-heat.aspx

If he was using the ditra system

 

[mattyg]

Ok crossed wires I assumed when you said Ditra Mat you meant Ditra Mat which is what the decoupling membrane is mostly referred to, Not Ditra Heat which is a completely different system

I would use WEDI board over the subfloor. Water resistent and insulates. SO the heat form the mat goes up inot the room and NOT down into the ceiling of whatever is below. Obvioulsy making sure all joins are taped and sealed with the usual WEDI sealant and tape. Then UFH. Then screed then Ditra mat (decoup) then tile.

Or he could use the DItra-heat

 

[Russinating]

WEDI boards look good, thanks. Would you take them all the way under the bath to floor the whole room or just up to it?

I would need 3x 2500x625mm (12.5mm) for the whole floor, so not a huge amount but just wondered. The bathroom is a conveniently sized 2450x1820mm .

 

[Participant]

If it's new ply or chipboard or screed board then just use ditra matting over the top stuck down with adhesive then ufh then tile

I thought tiling onto chipboard was a no-no?

 

[mattyg]

I poss over engineered my bathroom but after having previous issues when some advice was it ok tile direct onto plywood. This time I researched. Most of which was on the tilers forum
http://www.tilersforums.co.uk/

I replaced my old floorboards with 22mm WBP. Primed with BAL SBR. And taping and sealing the joints
I then fitted the WEDI boards onto the ply and again taped and sealed the joints.
Then I lay the UFH matting. And covered with Screed. ultraplan renovation screed. (self levelling and really easy to use.)
Then laid DitraMat decoupling membrane. Its like a plastic, fabric backed matting that will keep the tiles still but allow a small amount of movement from underneath.
It also adds another level of possible water proofing.
Then Tile onto that.

Then wait 2 weeks before switching on the UFH.
I know the wait is murder but if you do it any earlier you risk thermal shock.

 

[Russinating]

Does sound like more hassle than it's worth