Tiling on wooden floors

[Tim Smith]

Hi

As I posted a few weeks ago, I was about to embark on tiling a wooden floor. I have tiled floors before but not on a wooden one.

The floor was a floating chipboard floor which I covered in 12mm marine ply and screwed every 6" in every direction. I then painted with a coat of PVA and water.

Over the weekend (it now being wednesday morning) I tiled about half the floor (30 tiles) using Unibond ready mixed tile adhesive for wooden floors.

I then stayed off the floor until this morngin but noticed that about 5 or

6 of the tiles still move up and down by a few mm's. I assumed that I hadnt glued it properyl so I took one of the tiles up (which happened to be at an edge). I found that the glue underneath hadnt really set particularly hard - it was easy to scrape the glue off the floor with an old chisel.

Im assuming that the glue sets when the moisture evaporates. If this is correct, does hte fact that the ply is waterproof, thick and painted with glue make this understandable ? or is something else wrong ?

If it makes any differenece, the tiles are big (45cmx45cm) so there are less grouting gaps where the air can get in ? Im not sure about the logic of this but anyway !

Thanks

Tim

[Grunff]

I've used this adhesive for tiling part of a worktop. It takes a very, very long time to set - much longer than it says on the pot. You need to allow a week before you walk on them.

The large tiles will also slow things down. Don't worry, just wait.

[Timothy Smith]

Thanks Grunff,

Now Ill have to replace the tile I took up ! I guess my wife will have to wait before filling the kitchen cupboards again !

Tim

[Timothy Smith]

Just a thought,

since the tin said 48hrs and everyhting felt reasonably solid (after all most of the tiles are) I walked on this last night and the worktop fitters did for an hour or so yesterday.

Assuming that all the tiles are still level and havent sunk, there isnt likely to be any other problems been caused by walking on it before it is fully set are there ? I assume that its best to leave longer then before putting general traffic but the odd footstep or so shouldnt cause any long term problems.

Is this correct ?

Tim

[Grunff]

I think it'll depend on how firm it had set :-)

There's no point worrying about it at this stage - you're either going to have to redo it, or it'll be fine. You can choose to redo it now, or to wait and see what it's like in a few days. I'd pick the latter.

[Christian McArdle]

If you decide to do it again, try a different adhesive. I used Ardex Flex

7001 Timber System and it was excellent. It certainly didn't take 48 hours to set. The tiles were 600x400mm slates. It's been down for over a year and there hasn't been so much as a crack in the grout (Ardex Flex FL).

[Timothy Smith]

Would you recommend that it is better to take them up and start again ?

Obviously this would be better to do before the glue sets any harder and can be taken off hte tiles.

Tim

[Christian McArdle]

That I couldn't be sure of. I have no experience of the Unibond product and don't know if it will ultimately succeed, or if it has already failed.

Christian.

[Grunff]

It's actually a pretty decent product. It has good adhesion, and remains quite flexible when set. My only complaint was the setting time - it really did seem to take forever. Because this was just a section of a worktop, I didn't really mind. I'm not sure I'd use it on a floor that I needed to walk on any time soon.

[Christian McArdle]

Yes, that's one of the advantages of Ardex Flex 7001TS. It claims it can be trafficked and grouted after 2 hours.

Christian.

[Timothy Smith]

Just spoke to Unibond who claim that the problem is that I let the PVA/water mix dry. The say that their instructions specify tiling the floor whilst it is damp. Ill have to check at home.

He also says that the fact that they have been walked on may well mean that the adhesion between the tile and the glue is now broken.

Im tempted to take the tiles up whilst the glue is still damp and try to clean them off and get it done properly.

Christian - would the Ardex glue have problems with me having let the PVA dry do you know ?

Tim

[Timothy Smith]

OK - I think it is going to come up and start again. Hopefully I will be able to scrape the existing glue off the floor and the pressure hose it off the back of the tiles. Unless anyone can suggest another wya ?

Tim

[Grunff]

I think that's too hasty. Cleaning semi-dried adhesive is not going to be easy, and will take a very long time. This will be especially true if it has dried sufficiently to be walked on without noticeable movement.

You may not be able to get many of the tiles up without breaking them - they are big tiles.

If you're really worried, how about trying to lift say 3 sample tiles at

3 locations. Examine the adhesive. Has it set? Were the tiles easy to take up?

[Christian McArdle]

I did mine with it dry. I also used standard diluted PVA, rather than their specified Ardion 51 primer. Indeed, if you read the Ardex instructions, they specify that the primer should be allowed to dry for at least an hour, not specifying a maximum.

Christian.

[Jonathan Pearson]

Same stuff, same application, same results, 2 yrs down the line - very very happy - not cheap but then again I was putting down slates which weren't cheap either

Jon

[Timothy Smith]

Just spoke to Ardex. They recommended a light sanding to remove the PVA from the floor and then using their primer ?

Did you use their primer ?

Tim

[Christian McArdle]

Personally, I used PVA. I couldn't get hold of the correct primer in time and only had a 2 day window to lay the floor.

Christian.

[Timothy Smith]

That makes me feel better then. I used a PVA/water mix (half bucket of water and a few big dollops of PVA). I didnt fancy sanding the whole floor ...

Tim

[Jonathan Pearson]

Yes I did, it was PVA like (from recollection), I used their stuff on the assumption that if it went wrong they couldn't blame anyone else - the primer was very cheap, at around £10 for 5 litres (I did 20sqm, and only used 1/2) - the 7001 system was the expensive bit around £25/bag, and the admix stuff was around £10-15 (maybe more) - I used quite a lot as of adhesive (more than they said I would) ~ 10-12bags , as I had 'uneven' slates to level out - the mixture is grey, which was fine for me and I used their grey flexible grout - not sure what other colours they had - as this is a 'professional' product you wont find it in B&Q / Wickes etc you need to got to a specialist flooring supplier, so as always go in in old scruffy clothes and they may go on the assumption that you are in the trade, hence perhaps get a discount

Good luck Jon

[Rick Hughes]

Too late now but best to use a 2 part flexible adhesive ... and importantly a waterproof flexible grout, I used a 2 part grout as well.

Rick