[Closed] Laying Flooring Tiles Problem

Aren't you meant to use a screed?

[i]So what went wrong ?

[/i]

Most probably that you put unflexible on top of flexible... How big are the tiles?

Is the chipboard screwed or fixed to the existing floor / joists, at regular spacing securely, thus preventing any movement, then screed then tile.

Thats how i did mine

not sure what your brand of adhesive say on the instructions but I would usually screw a WBP plywood sheet 12-15mm down on top of your floorboards, screwing at 150mm centres into the floor joists. (screws need to be long enough to go through both plywood and floor boards). There might be proprietary baords you can use instead of ply- aquaboard, although I have no experience using that myself.

Don't know if what I said is common practice but that's what i've done in the past, and is what i've seen professional tilers do and have had no issues with cracking or loose tiles.

edit: make sure you evenly spread the adhesive without any voids

My guess is that the chipboard is flexing as you walk on it causing the tiles to crack.

Remember watching Holmes on Homes (Canadian Builder) they secured the floor boards with screws to the joists then glued and screwed ¾” plywood on top of that to make the floor rigid before bedding the tiles down with a flexible tile cement and grout.

http://www.ultimatehandyman.co.uk/tiling/tiling_wooden_floors.htm

Did you lay the tiles directly onto the 'chipboard'? Normally you would have the normal floor (be it chipboard or floorboard) and you would either screed or put at least 9mm plywood on top of the normal flooe before then laying tiles. That is done to try and reduce flex in the floor.

So, if you have laid tiles directly on the chipboard then the floor is going to be too flexible and the tiles will crack. That is even the case if you use 'flexible' tile adhesive.

Edit: Damn, Kona got there first!

Woops! The other reason for laying a subfloor (ply) before tiling is that when you lift the tiles you will destroy the chipboard. If you've got studwalls fixed ontop of the chipboard, you won't be able to replace the chipboard either..

Interesting

But the T& G chipboard floor is a sub floor screwed down
and the flexible adhesive is meant for wood & chipboard based floors

But i had checked for flex and did not feel if not any movement

I have never heard of using chipboard as a subfloor; ply or tilebacker board yes, chipboard or mdf definately no (both swell-up and loose their strength when they get damp. Tiling adhesive is damp and so is anything used to clean the floor that gets past the grout.

If you've got studwalls fixed ontop of the chipboard, you won't be able to replace the chipboard either..

You will but you'll need to fit noggins in to catch the non T&G edges

 

Never heard of chipboard being used as a sub-floor..
Seen it used as floorboards in modern flats but if any tiles were laid it's been a ply subfloor laid..

You should have the chipboard floor screwed to the joists and then ply on top of that screwed down at 10 cm intervals. Even if you didnt feel the flex, it will be there. As above, if there wasnt a layer on top of the base floor then you will have to take tiles and chipboard up and lay an entire new floor as tile adhesive is horrific to try and scrape off. Or you will have to put up with cracked tiles.

Carlos, the kind of chipboard used for floors is not bog-standard - it is higher density, tongue and grooved, and more resistant to water. In fact, you get different grades of water resistance.

I'm a pro tiler so hopefully qualified to talk on the subject!

Chipboard floor. Upstairs or downstairs? If downstairs it is likely that you have a floating floor, the chipboard is 'floated' over a beam and block floor with insulation between. I have never successfully tiled one of these! there is just too much movement in the floor.

Having said that, if you could detect no movement it leads me to thing it's just caberboard, large tongue and groove boards nailed to joists.

If this is the case, Unibond? what was that for?

My prefered method of tiling a caberboard floor is use a product made by Schluter called Ditramat, a decoupling barrier (basically seperates the wood from the tiles) which gets glued using Rapid flexible tile adhesive to the boards then Flexible tile adhesive to stick the tiles down to this then grout with flexible grout.

If by Unibond you mean PVA then this is likely your problem. PVA dissolves in water, tile adhesive has water in it.

Give me some more details and I'll try to help more.

Never stick anything to chipboard and never use pva for tiling.

Your only option from here is to take them all up and start again with a proper base

If you want to do it properly either myself or Blazing Saddles will help.

ScotlandTheScared - Member

Carlos, the kind of chipboard used for floors is not bog-standard - it is higher density, tongue and grooved, and more resistant to water. In fact, you get different grades of water resistance.

Yeah I know, as long as two edges sit on joists, that still leaves the other 2 edges which (as its been cut) will require between joist noggins under the cut/joint to support the ends

I have taken up the broken tiles and found that adhesive was firmly secure
to the floor.
So what went wrong ?

probably the adhesive was firmly secured to the floor and it expanded. fwiw we've just had tiles put onto chipboard and the tiler did as Blazin-saddles said and used a decoupling layer as well as limiting the max size of tiles to 33cm. The problem was expansion rather than flexing of the floor

doesn't help you now though :(. I had never even heard of decoupling layers before

Yes, that's a distinct possibility. Depending how big the floor is, expansion or contraction of the subfloor 'pops' the tiles as they can't move with. flexible adhesive and grout can only take so much hence the decoupling layer, this allows the subfloor to move a bit without affecting the tiles.

Thank you everyone for your input But a big thank you for Blazin-saddles

Regarding PVA (uni bond) this was on the installation info on the adhesive.

Blazin-saddles can you tell me how you secure the decoupling matting to the floor.

Unless Blazin-saddles comes back with something more specific you might want to take a look at the video on the site for the stuff he recommended
http://www.schluter.com/6_1_ditra.aspx

It won't be expansion, it'll be shrinkage. But that doesn't help you! Just be aware of different types of ply, if you do redo the flooring!

Thanks Letteboy

Believe this has a Decoupling fleece into it too
http://viewer.zmags.com/publication/6c4e12a2#/6c4e12a2/8

Thank you all once again

The decoupling layer is secured to the floor using flexible tile adhesive, I use Weber SPF personally.

I'm moving into a new house in Oxford in a month or so, which needs extensive renovation. So that'll include new kitchen and bathroom and hence quite a bit of tiling. Don't suppose any of the tiling experts here are professionals who work in that part of the country, or know of someone they could recommend? (Sorry for the thread hijack!)

Where about do you live Grantway? If it's near tunbridge wells, bung me an email and i can sort you out a good price for the ditra (i manage a tile shop).

Carlos: True what you say about re-flooring, but still a major faff geting the old boards up!
Incidently, Noggings don't make it this far north; we're in Dwang land here!

Thank you again Blazing-saddles I owe you a good few pints 😉

Thanks Tom83 I am in East London but all hopefully done now

No problem. Happy to help if I have.

Gray, I'm in Leicester so too far away for me to be able to offer an assistance.