Advice on yet another wooden floor project!

[Stuartpaul]

Afternoon all,

Intending to tile a new 18mm chipboard floor with 600 x 600 porcelaine tiles. Joists are 400 ish centres (old house!).

I am not going to overboard with 6mm ply despite many old and bold builders telling me this is the way to do it as I'm aware this is now a defunct way of approaching the job.

The options are either no more ply or crack interferance membrane (recommended by local tile shop) with flexible adhesive and grout.

I'm leaning towards no more ply as it would help beef up the floor a little (there is some deflection in it) despite it raising the height more than I would like.

Not a lot of price difference between the two options but wondering if the pro's out there can recommend the best approach (and no, I'm not going to rip it out and start agian with thicker ply!).

Thanks

Stuart

 

[Gazzer]

The backerboard approach will add very little extra strength to the floor and the Ditra is for lateral movement and not deflection..
Extra noggins in the floor would be the way forward IMO

 

[Stef]

No more ply isn't going to solve any deflection issues,
If you have any bounce in that floor it must be rectified now.

 

[Stuartpaul]

Thanks for the quick responses.

To use an old fashioned saying I appear to be screwed! Just like the floor but that's been glued as well so taking it up to reinforce isn't an option.

On that basis is there a less painful option? If I have to replace grout occasionally then that might be something I have to live with!

 

[Gazzer]

You could try screwing the boards to the joists at 200mm centres. It may pull the whole floor together and make it more rigid.....be careful that you dont go through a pipe or cable. Its worth a try and all it costs is a box of screws.

 

[beanz]

The only other option is to add height. 12mm ply (screwed at 150mm centres), and Ditra. Although, someone will be along shortly to correct me, as 15mm is the BS minimum recommendation. 😉

 

[Ajax123]

How much height have you got available. You could screw battens down at right angles to the existing joists. That would remove the bounce. Fill the gap between the battens with rigid insulation or with screed then over board the lot by screwing down hardibacker screwed down to the battens and all the way through into the chipboard between the battens. Will add floor height though...

 

[beanz]

If you don't want to come up that high, or it's just not possible.. You have the option of ripping up entire floor, fitting noggins, screwing Ply (I think it'd have to be 22mm, but not 100% sure about that!?! Maybe it's 18mm minimum?), then Ditra. 😉 The Ply would have to be screwed at 200mm centres, so bear that in mind when putting in the noggins..

 

[Martino]

if the floor is not able to be deflection free...or you cant be bothered to rectify the problem then dont tile it....go for karn dean....alot of bathrooms we do now that are floorboards we opt for karn dean.

 

[Stuartpaul]

Thanks again.

Floor is already screwed at greater than 200 centres (mostly 150 but many a lot less).

I can add extra height but reluctant to go more than 10mm plus the tiles (10mm as well). Could potentially go to 12mm (i.e. sheet of ply) but that 's about it.

Ripping up has been considered but the mess, inconvenience and cost have made it something of a non option really.

It isn't that I can't be bothered to remove deflection, - it's the factors mentioned above that make it very difficult to achieve within a sensible budget.

Looks like the tiles are going back then!

 

[beanz]

Why would you send the tiles back!?! What's restricting you from going higher with the floor? Is it purely that you don't want a step? A small step can be more of a trip hazard than a big step...

 

[Stuartpaul]

It's the relationship with the rest of the house and the general flow within a 1930's semi.

I am sorely tempted to go with backer boards and flexible adhesive/grout as we really like the tiles but the fear of problems later is offputting.

 

[jindru]

Ive just tiled a 30s kitchen with porcelain. The floor was level with the room next door and was concrete.deflection was not a problem and the step up was ok .the customer was happy with a timber hard wood edge.i never understand why anyone worries about a tiling step up. You have the same in reverse between lino and a decent carpet

 

[Stuartpaul]

It's not the threshold that's an issue. The planned installation will leave a threshold of approx 12 - 15mm. I think this is enough otherwise you're into real trip hazard territory.

We still want the tiled floor but in light of comments and advice on this thread can't see a way of achieving it.