Tiling on ply wood floors

[mattaylor21]

Hi all!
I have been reading a lot of posts about avoiding tiling directly onto plywood.
Most of my work is bathroom fitting and I usually rip out all the floorboards and strengthen the floor joists and run a line of 3x2 between the joist where a joint in the plywood will be. Then I glue and screw 18mm best ply down to the joists at 300mm centres. I feel this gives a very solid floor which I then seal with acrylic primer and tile. This method also ensures there is no step into the room at the doorway. I have done loads of floors in this way and never had a problem! ( touch wood )
Have I been doing it wrong all these years? I'm just interested on everyone's thoughts of this way of doing a floor.
Most of my customers have electric UFH as well so I install that to the ply (or insulated boards if they want them) and then pour a layer of self levelling to cover the UFH before I tile it.

 

[Andy Allen]

I wouldn't say you have been doing it wrong....just there's better ways of doing things.....as with most things in the building trade things progress ...you either stick with what you know or progress with it....choice is yours really. .

 

[Alan.P]

As above, as times and technology move on we learn better ways of doing things. The belt and braces is as your doing, board, insulation board and fix, BUT if you do do it with just the ply then it's the underside and edges of the boards that should be primed, sometimes the tiled surface as well, depending on adhesive being used and manufactures instructions.

 

[Stef]

I would still overboard 18mm ply with either Hardie backer board or insulation board if ufh is being installed.
I've had one problem floor in the past couple of years & it was tiled direct to ply in the exact same circumstance as above.
IMHO, ply isn't a good enough surface to tile to nowadays.

 

[mattaylor21]

Thanks for the replies guys.

 

[nybor62]

i agree with steff,

 

[mattaylor21]

I like to do a thorough job and every day is a school day!
So as for UFH over ply and and then self levelling over the UFH that would give a surface to tile on??
So you guys would prefer to just over board the original floor boards with a thin tile backer board and tile on that?

 

[Stef]

I like to do a thorough job and every day is a school day!
So as for UFH over ply and and then self levelling over the UFH that would give a surface to tile on??
So you guys would prefer to just over board the original floor boards with a thin tile backer board and tile on that?

Exactly, glue & screw a cement board onto the deck.
If I had the option I would fix 18/22mm ply then overboard, done my own downstairs shower & fitted ply then overboarded with 4mm Wedi board, hasn't budged since laid.

 

[mattaylor21]

Does that add much cost to the job? I can't imagine 4mm wedi is a great lot to buy?
Sorry if I'm being thick but what is the actual advantage of have the wedi board? Just so the adhesive sticks better?

 

[Stef]

It will slightly decouple as it's a separate layer.
I hate tiling to ply as I stated it's not a good surface to tile to.
Tiling has moved on massively in the past few years & so has the products that they can be fixed to.
I still hear 25+yrs Tilers claiming that PVA is ok to tile to as they've always done it that way without problem!!! [emoji35][emoji35]