Builders ruined a floor :( - Tile Advice

[Mathew2019]

Hi guys. I'm new to this forum and I'm in some need of advice. Halfway through a major refurb at home. I've got a timber floor downstairs and bought some 60x60 porcelain tiles. My builder took off all old floorboards, for the wiring and plumbing work etc, however he replaced it with 18mm marine ply. I told him many many times that I'm skeptical the ply will be strong enough and that tiles will crack.

He however managed to convince me with many assurances that plywood is fine for a floor and can be tiled direct onto them (with ditra). So we laid the ply, and the ditra matt and laid the tiles with flexible adhesive and grout. (i used professional tilers). Floors were primed too.

I was shocked by the results. The floor felt so cheap and horrible. Walking on it with shoes felt fine, however walking on it bare foot felt nasty. There was so much vibrations that the cutlery on the worktops could be heard rattling and you could feel the vibration on the feet.

I've now made him rip the floor up, and I've told him to lay floorboards.

Could anyone offer the best approach which is also somewhat cost effective.

My plan is to lay 18mm floorboards, with either ditra matt, dural matting, or 6mm cement boards, or 6mm ply. Could anyone advise the best option?

I should also add, the joists and timber work do feel solid.
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Also i should add, the final breaking point for me was there was around 6 sections on the floor i could hear a loud clicking noise when walking over, my guess is that it was loose ply. And i noticed some grout crumbling.

 

[hmtiling]

22mm cement board and a crack mat would be the best option. 18mm ply fixed at 300mm centres deflection(bounce) free overboarded with 6mm cement boards and a decent s1 adhesive should be fine.
Consult the tiler not the builder with regard to prep. If the builder could tile he'd be a tiler

 

[Bill]

Wrong approach by you and the builder I am afraid.

If you were getting vibrations from 18mm ply then floorboards would be no different.

Firstly you need to stop as much deflection in the floor as possible and this is done by adding extra/strengthening joists, supports etc.

Then add the 22mm ply on top along with 6mm cement boards - the crack mat (Ditra etc) is not a necessity as it only covers lateral movement but if you can afford it then it wouldn't do it any harm.

This is a concise version of what you need to do. Follow manufacturers' regs on the flooring and not a builder's poor advice. Any decent pro tiler would tell you the same.

 

[Mathew2019]

Wrong approach by you and the builder I am afraid.

If you were getting vibrations from 18mm ply then floorboards would be no different.

Firstly you need to stop as much deflection in the floor as possible and this is done by adding extra/strengthening joists, supports etc.

Then add the 22mm ply on top along with 6mm cement boards - the crack mat (Ditra etc) is not a necessity as it only covers lateral movement but if you can afford it then it wouldn't do it any harm.

This is a concise version of what you need to do. Follow manufacturers' regs on the flooring and not a builder's poor advice. Any decent pro tiler would tell you the same.

Hi thanks for your reply and input. That is exactly what I instructed him to do strengthen the joists etc.. I previously had floorboards down which was replaced for the ply. When we had floorboards there was never any vibration issues so i assumed the ply was a bad idea. In terms of 22mm ply, this may cause leveling issues with the rest of the house, what would you suggest?

 

[Dumbo]

To be fair 18mm ply is pretty strong , I'm not saying it's the right thing to do but as @Tom Astley says I think you need to look at your joists and strengthen them , and make sure all edges of the ply are supported would of been a good move .

 

[hmtiling]

To be fair 18mm ply is pretty strong , I'm not saying it's the right thing to do but as @Tom Astley says I think you need to look at your joists and strengthen them , and make sure all edges of the ply are supported would of been a good move .

If 18mm ply is fixed at 300 centres and the joists aren't shot that will more than adequate with a 6mm cement board on topimo Jerry

 

[Dumbo]

If 18mm ply is fixed at 300 centres and the joists aren't shot that will more than adequate with a 6mm cement board on topimo Jerry

Back in the older days I've tiled slate straight on to 18 mm ply .
Back when ply was decent

 

[hmtiling]

Back in the older days I've tiled slate straight on to 18 mm ply .
Back when ply was decent

Same here

 

[Dumbo]

Same here

And for that reason i think it's the joists

 

[CJ]

Rip lot up.
noggin joists to within an inch of their lives, 22mm ply, overboard that with 6mm Hardibacker or similar. Glued & screwe.

That should be solid..........then tile.

 

[Dumbo]

I would think about more than noggins if it's as bad as the op says I would think about some osb or ply flitch plates

 

[Sean Kelly]

Have you tried bouncing up and down in the middle of your room? That's what I do when I quote for work. How bouncy is the floor? Put a near full glass of water at one end of the room. Does it spill when you bounce? The amount of job I've had to turn down because of 'deflection' (amount of bounce). This can be caused by not enough joists or noggins or poor quality ply or a combination of them all. I even had to say no to tiling my best mates kitchen/diner because of the bounce.