tiling over floor grade chipboard

[Alberta Stone]

I'm from Canada and so the terms are a bit different, for clarity is this waferboard or particleboard or what precisely?

Any of these materials is not recommended by the manufacturer as statistically the product swells and does break down when subjected to moisture of any kind.

There is no professional tile trade in the world which will say that you can install rigid tiles over a single layer of wood of any kind, even plywood.
This is due to movement which the second layer reduces to acceptable tolerances.

In small areas you are most likely to "get away with it".
I hope it stands up for you as it is an investment.
But if a job is worth doing at all, it is worth doing it right.

The reason why the adhesive manufacturers and board makers do not recommend doing these things is that statistically they fail more than they succeed and that turns into lawsuits against installers and manufacturers.
We are all in this industry to produce something of lasting value and to make a profit, not to feed the lawyers.

It is in no way a conspiracy to make people buy more or pay extra.

 

[Branty]

Great post Alberta.
It is a form of particle board.
In certain circumstances, we (BAL) say you can tile onto a floating floor. Our adhesive, BAL fastflex, can be used. The responsibility lies with the tile installer to make sure the floor is rigid enough for a tile application. You can't just stick tiles to any floating floor. It has to be the correct wood, fixed correctly, and more importantly, the insulation under it has to be able to take a tile application. Which all to often it does not.
The problem is, is that most of these floors were installed when the house was originally built, those bathroom floors were then carpeted (Ewwwww!). You can bet your bottom dollar, that insulation is not suitable for a tile.

As you said, you 'can' tile onto a floating floor. And our Fastflex is the adhesive to use. But there are so many variables with them, unless you're 100% sure what the floor is constructed of, don't touch them.

 

[Branty]

just to give an indication of "potential" problems, I have (hopefully) attached a picture of a floor, tiled earlier this year - not by me I may add, I have just redone the whole thing - that was straight on to chipboard with no other preparation. The floor was less than 6 months old!

Great pic Grumpy.
This is a case of wrong adhesive, but probably wrong insulation.
With unsuitable insulation, over a period of time, with very small deflection (1-2mm). The insulation depresses down, but doesn't revert to original shape. Then what you have is a void between chipboard, and insulation. Leading to cracks, and debonding.
Unfortunately no adhesive can cope with this.

 

[sharpfamily]

thanks to all for taking the time to share your views and experience.

in return here's my observations:

my chipboard floor is not floating - it is on timber battens (insulation between) onto concrete with damp proof membrane under. I added a lot of extra screws, as Grumpy suggested in an earlier response, to make sure the floor was fully secure and free from measurable deflection.

as it's over 2 months since the tiles were laid, the bal spf must now be totally dry(?) so the green (moisture resistant) flooring grade chipboard has not reacted to the water/moisture in the spf when it was laid.

the original floor construction is over 17 years old so it should have fully adjusted to ambient conditions - any original shrinkage/expansion having already occurred. I carefully inspected the chipboard and found there were no signs of any dampness or any deterioration in the chipboard. It remains to be seen if there are any seasonal variations in ambient conditions that may affect the chipboard - ie hopefully no cracks at christmas! I'll let you know.

finally my apologies to any who took offence at my comment on extra cost to customers. none was intended.

best,
graham

 

[grumpygrouter]

I'm replying in the interest of a learning debate on this intiguing topic:

thanks grumpy - your picture is interesting. the main tile in the photo shows cracks which don't extend beyond that tile's perimeter. there are also signs of cracking within another tile; which appear independent to the cracks in the main tile. looks like a localised failure mode on each tile. what do you think caused such localised cracking? was it all down to the chipboard? would usage of bal 2 part superflex (or Ardex?) have prevented this? what did you do to rectify the situation?

it would be useful if any other forum members could also share descriptions of tile failures on chip board.
as i've described earlier, my tiling on green floor grade chip board with bal spf has so far been very successful..... is this really just a lucky one off.... so far.... to be tested by time? and what mechanisms over time may cause cracking?

best,
graham

Hi Graham, this was only one of several cracks in the floor in various places. My instructions to the client were to overboard the existing chipboard with 18mm ply screwed at a min of 300mm centres. Further into the refurbishment, after the tiles had been lifted, it was clear that the chipboard had failed in a number of places. The floor was taken up completely ( some considerable plumbing was then done on an opportunity basis) and I saw the bathroom without any floor at all. I mentioned to the client that this is now ideal as he can have 22mm ply laid instead of chipboard to give an excellent surface to tile onto.

Sadly, my instructions were ignored. The "joiner" persuaded him that "it was fine to have chipboard laid as it is stronger than ply. He then proceeded to overboard with 6mm ply ring nailed every 4 inches!!

You can imagine my dismay when when I saw what I was being asked to tile. I initially refused to do the job, but relented as the customer needed his floor finished as he had many guests arriving at the weekend for a family wedding and need the bathroom. I agreed to tile his floor and I did so with BAL Fastflex as suggested to you in my original post. I am no longer able to get Ardex 7001. I charged considerably more for the job than I otherwise would have because of the high cost of the adhesive and extra work involved because it is more difficult to work with.

The ONLY saving grace I can think of from this job is that the new chipboard that was laid was 22mm not 18. I have told my customer I will not warrant the work and that in all probablity it WILL crack. he has accepted this. I have done my best for the customer following his instructions and I have used what is probably the best adhesive available for this type of installation, however I have little faith that the installation will not fail. If it does so I will not waste my time and money redoing it.

In relation to your own tiling work, please bear in mind also that this floor I have tiled is no where near as large as the area you have tiled. My was only 9m2.

 

[Alberta Stone]

No offense taken Graham.

I hope the floor stays put for you.
The thing is this is a tiling forum and tradesmen who make their living from tiles cannot be recommending methods or protocols which go against the manufacturers and current industry standards.
(unless they have a really good case, which seldom happens)

We are all glad things seem to be going good for you, but if they stay that way it is the exception.

The method you employed is dicey at best.
Sometimes you win, most times you don't.
Would you respect a surgeon who operated by such principles?

 

[andy-p]

The ONLY saving grace I can think of from this job is that the new chipboard that was laid was 22mm not 18. I have told my customer I will not warrant the work and that in all probablity it WILL crack. he has accepted this. I have done my best for the customer following his instructions and I have used what is probably the best adhesive available for this type of installation, however I have little faith that the installation will not fail. If it does so I will not waste my time and money redoing it.

In relation to your own tiling work, please bear in mind also that this floor I have tiled is no where near as large as the area you have tiled. My was only 9m2.

grumpy i doubt very much your job will fail, i recently lifted a kitchen floor that had been down for about 8 years , the tiles were rock solid and not a crack in the grout anywhere, i was very surprised to see that the tiler had overboarded the chipboard with hardboard nailed with ringshanks , ordinary adhesive had been used.. im not recommending this practice but im sure you will be safe enough...

 

[sharpfamily]

thanks for the christmas greetings em.
just to let you know my tiled floor is still solid & crack free.
The SPF seems to have been totally successful.

So from this experience I would conclude that using simple SPF straight onto green floor grade chipboard can be worth the risk. The recommended alternative BAL 2 part is much more expensive and messier to use; and also expensive ply board overlay is maybe not always needed.
Obviously other circumstances may be different therefore ......caution is needed.

merry christmas .

graham

 

[grumpygrouter]

Thanks for the update Graham. Your floor is still quite new but here's hoping it stays solid and crack free for you.

 

[225driver]

:beatdeadhorse5: