Overboarding floor panels?

[Ingram]

Hi guys. Been to look at a job today. Upstairs bathroom & en suite. Looks like previous tiler has tiled straight onto those chip board floor panels and they're cracking all over. Blokes asked me to chop tiles up then get a joiner to overboard it. The question is what with? Any advice will be much appreciated. Cheers.

 

[Flintstone]

Hello, Are you a professional tiler?

 

[Ingram]

Yes. Just not prepared many floors like this one. Any ideas?

 

[White Room]

What tiles are you fixing ?

 

[Ingram]

They'll be ceramic or porcelain.Similar to what's down already 300x300

 

[Flintstone]

if there's cracks all over its probably got a lot of deflection, over boarding isn't going to solve that problem. Best to take the tiles up and see what your dealing with.

 

[Rookery]

Probably 6mm Hardie glued n screwed, once I'd had a butchers at the sub floor

 

[Ingram]

Worsed case scenario get sub floor taken up and overboardrd with same thickness ply??

 

[Rookery]

I prefer not to tile onto ply nor to a single layer. If the chipboard is in bad shape then I'd remove it, fix new 18mm ply or t & g chipboard then over-board with the Hardie as above.

 

[Ingram]

Are the cement boards absolutely necessary ? As BAL reckon you can fix straight onto primed T&G Floor boards? Surely the 18mm ply is more rigid.

 

[Rookery]

Yes, in my opinion. It's already failed once so why take a chance.

 

[Flintstone]

You can't tile on to chipboard flooring

 

[Rookery]

You can't tile on to chipboard flooring

You can with Mapei S2 Quick and Weber do a similar one. BAL probably do one too. I'd still over-board though.

 

[Dumbo]

You can't tile on to chipboard flooring

Adhesive manufacturers say you can but it fails most times . S2 adhesive is no substitute for a badly prepared floor.

 

[Flintstone]

I would never risk it

 

[Ingram]

So even taking up the chipboard. Re boarding with 18mm ply and tiling onto ply with BAL Silgle part fast flex is still not good enough? Needs 6mm Hardie??

 

[Time's Ran Out]

Take old tiles up, leave but clean the chipboard floor, prime and fix (adhesive under and mechanical fixings) 6mm Hardie backer boards across joints. Tape Hardie joints and your good to go.
The only issue would occur if chipboard underneath got wet!
Also you have to be sure that the chipboard is well fixed, and no deflection.

 

[Boxtiling]

The bal fast flex should do the job if you've not already done it

 

[Time's Ran Out]

The bal fast flex should do the job if you've not already done it

And what preparation to the chipboard substrate?

 

[Dumbo]

And what preparation to the chipboard substrate?

Unless it's changed tj bal used to say this was OK for chipboard although I must say I wouldn't do it .

 

[Time's Ran Out]

Unless it's changed tj bal used to say this was OK for chipboard although I must say I wouldn't do it .

I think that's what was established in the thread then @Boxtiling seems to be going the direct flexible adhesive route!
When I've read the technical info on manufacturers packaging they've always left the decision to the installer by providing the relevant Bs 5385 code of practice. Usually a get out of jail card when the floor cracks through deflection!

 

[JMC tiling]

First thing you need to do is suss out why its failed. If there is a deflection issue then tiling the floor regardless of what substrate you use may well be a big no no and suggest something like a kerndean. Otherwise there's no way i'm using anything other then a cement board over the top. I prefer NMP glued and screwed.

 

[Boxtiling]

With the 18mm ply but 12mm ply would be enough

 

[Flintstone]

I never understand boarding a floor with 18mm ply when a 6mm cement board is superior

 

[Boxtiling]

A can honestly say that in the 16 years a have been tiling the a have only had 2 floors that a have had to lift and relay due to much deflection on the sub floor which a told the client at the time but got told do it the now and we will see how long it last and the cements are a bit pricey in Scotland