Help and advice on tiling bathroom floor

[vvvvw]

Hi
I am ready to tile my bathroom floor its about 5m2 max and at the moment its stripped to the joists fo plumbing.What would be the correct way to go.I cannot feel any deflection if there is its minimum.There seem to be so many different oipinions of what one should dne independent tile retailer said always lay ditra matt wether installing UFH or not.Thought that only help lateral defection and not vertical.Some people say 18 - 20 mm ply others say moisture resistant chipboard flooring others say 18mm ply with 6mm backer board.
Please can anybody out there clarify.All i am after is a tiled floor possibly with UFH but a floor that has a reasonible chance of not failing in 6 months time.



Many thanks :yes:



Martyn

 

[darren pealing]

18mm ply screwed every 200 mm,then primed,then quality flexi adhesives and grouts,that's external grade ply.

 

[darren pealing]

If you want added security ditra matting too,I've been back to jobs I've done with ply over the years and they have been perfect

 

[Diggy]

18mm - 24mm Ply , 200mm centres ( noggin if needed ) , Fastflex , flexigrout.



Diggy

 

[Alan.P]

Hi Martyn, welcome to tilersforums.com.

18mm minimum thickness wbp ply, seal it on the underside and sides but not the top face, if your going to go ufh then an insulation board, if not a de-coupling membrane, as for a definative, there isn't one, a lot of different factors and a lot of tilers will do the job their own way.

 

[afright]

I do not like tiling to ply that has been screwed direct to the joists, I either go over the top with backer board or Ditra,piece of mind really.

 

[Bubblecraft]

Hi & welcome to TF. I'd fit min 18mm ply, primed underside & edges, screwed every 200mm with extra noggins if required for added strength and tile with an SPF. If height is not an issue, I would highly recommend laying a 6mm hardi on top for added piece of mind.

 

[StephenR]

I tiled over ply (either 18mm over joists or 12mm over floorboards) no problem for 10 years and then just last year, I had my first ever call back. The tiles had cracked along each joint after only 6 months. This was not due to flex. Thank goodness they were cheap. I've also never taken up one of my floors. What a pain that was.

Anyway, the cracks were caused by shinkage in the ply pulling the tiles apart. The ply must have been stored poorly at some point and got damp as the gaps I found were larger than those I would have laid the boards with.

The risk at being at the mercy of something like poor storage means now, only over tile backer board or ditra for floors from now on.

 

[Alan.P]

I tiled over ply (either 18mm over joists or 12mm over floorboards) no problem for 10 years and then just last year, I had my first ever call back. The tiles had cracked along each joint after only 6 months. This was not due to flex. Thank goodness they were cheap. I've also never taken up one of my floors. What a pain that was.

Anyway, the cracks were caused by shinkage in the ply pulling the tiles apart. The ply must have been stored poorly at some point and got damp as the gaps I found were larger than those I would have laid the boards with.

The risk at being at the mercy of something like poor storage means now, only over tile backer board or ditra for floors from now on.

And there it is, as you say, never had a problem, and a lot of us have been doing so for years as well, advances in the trade have shown / taught us that it is wrong to tile direct to ply, yes we might get away with it 99 / 100 but does it make it right ?

 

[widler]

18mm ply then 6mm hardi,great stuff is hardi

 

[Rookery]

If I'm reading this right, you're back to the joists having removed the original floor covering? If thats the case, then 18mm ply on its own with or without extra noggins does not meet BS guidelines and would not be guaranteed by most adhesive manufacturers. 18mm ply should be used as an overlay ie on top of the existing floorboards. In practice I prefer not to add timber to timber so I overboard a sound floor with 6mm Hardie glued and screwed. I believe that even this method is below what BAL for example would recommend, they would say 10mm. In your situation I would suggest either new t & g chipboard plus Hardie overlay or perhaps 25mm WBP ply. As you can see from the replies, different people do it different ways.

 

[Alan.P]

If I'm reading this right, you're back to the joists having removed the original floor covering? If thats the case, then 18mm ply on its own with or without extra noggins does not meet BS guidelines and would not be guaranteed by most adhesive manufacturers. 18mm ply should be used as an overlay ie on top of the existing floorboards. In practice I prefer not to add timber to timber so I overboard a sound floor with 6mm Hardie glued and screwed. I believe that even this method is below what BAL for example would recommend, they would say 10mm. In your situation I would suggest either new t & g chipboard plus Hardie overlay or perhaps 25mm WBP ply. As you can see from the replies, different people do it different ways.

I just had a quick skim through my copy of BS, couldn't see it, can you give me the numbers.