Ceramic Tiles on Upstairs Floorboards

[The Client]

There are a number of threads that provide guidance on how to tile on to wooden flooring but I would like to ask for specific advise. This being. I want to lay ceramic tiles in my upstairs bathroom
, which is boarded out with 18mm chipboard, whilst minimising the height difference between old and new floor. Whilst cost is important it is of secondary importance to height difference and quality.
Is there a better product to replace the chipboard with than ply? What thickness of ply? One thread suggests 25mm yet I have other advise that suggests 18mm?

Ta

[gcol]

The Client wrote:

Is there a better product to replace the chipboard with than ply?

Nope - it provides good support, is stable and it's relatively cheap.

The Client wrote:

What thickness of ply? One thread suggests 25mm yet I have other advise that suggests 18mm?

You can generally get away with 18mm but it's still a bit too flexy for my liking so I recommend using 25mm.

By the way, well done for having a look before posting - most people are too lazy.

[The Client]

gcol wrote:

The Client wrote: Is there a better product to replace the chipboard with than ply? Nope - it provides good support, is stable and it's relatively cheap. The Client wrote: What thickness of ply? One thread suggests 25mm yet I have other advise that suggests 18mm? You can generally get away with 18mm but it's still a bit too flexy for my liking so I recommend using 25mm. By the way, well done for having a look before posting - most people are too lazy.

Ta

Does 18mm ply give any benefit over 18mm chipboard?
Does 25mm ply give any benefit over adding 6mm ply over 18mm chipboard?

[alogbe]

Like The Client, I've done some searches and made some enquiries on this and I'm confused by the number of different opinions I've found, e.g. -

"a hardboard subfloor is no good, it must be ply"
"ply is no good unless it's 15mm at least"
"15mm ply is no good, it must be 18mm" (or sometimes "25mm")
"it must be marine ply"
"it must be a hydrofuge treated OSB board such as Eurostrand"

- and today, from a 'specialist' in a tile shop:

"you don't need any of those, a flexible adhesive is OK"

Any guidance will be appreciated.

[gcol]

All the information you need is on this sticky. Look half way down the page at the "timber floors" bit.

[gcol]

The Client wrote:

Does 18mm ply give any benefit over 18mm chipboard?

Do you mean using ply instead of chipboard or laying 18mm ply over chipboard? You don't tile onto chipboard. If over boarding with ply, use 12mm.

The Client wrote:

Does 25mm ply give any benefit over adding 6mm ply over 18mm chipboard?

Do you mean 25mm ply on it's own again 6mm ply and 18mm chipboard? I'd go for the ply every time. If you want to overboard the chipboard use 12mm (6mm is way too flymsy). You might get away with 9mm if the floor is very good and solid but to be on the safe side I'd recommend using 12mm.

[The Client]

gcol wrote:

The Client wrote: Does 18mm ply give any benefit over 18mm chipboard? Do you mean using ply instead of chipboard or laying 18mm ply over chipboard? You don't tile onto chipboard. If over boarding with ply, use 12mm. The Client wrote: Does 25mm ply give any benefit over adding 6mm ply over 18mm chipboard? Do you mean 25mm ply on it's own again 6mm ply and 18mm chipboard? I'd go for the ply every time. If you want to overboard the chipboard use 12mm (6mm is way too flymsy). You might get away with 9mm if the floor is very good and solid but to be on the safe side I'd recommend using 12mm.

Thanks for all the advice. Given that no one has suggested an alternative to ply then It is clear (given that I want to reduce the height difference) that if I want a quality Job that I should use 25mm ply. Thanks again.

[gcol]

You mean you didn't believe me? How rude
You're doing the right thing, good luck with job.