Ditra or not

[kaharrison9]

Good Afternoon

Have just been to see an 86m2 floor which the buider has overboarded the newly chipboard floor with no more ply.

Would anybody suggest Ditra which I often use on screeds or in theory the plywood shouldn't expand so no point in doing so.

The floor is fine with no deflection though that is not an issue with Ditra and there porcelain tiles.

Any thoughts.

Kevin

 

[Time's Ran Out]

Is it a floating floor?

 

[kaharrison9]

No all joists well strengthened.

One third is a new part of an extension but new 22mm chipboard running all way through the floor

 

[kaharrison9]

Correction- I mentioned the plywood should not expand I meant no more ply

 

[Time's Ran Out]

Ceramic/porcelain/stone tiles?

 

[Rosco100]

Correction- I mentioned the plywood should not expand I meant no more ply

hi if it's 6mm no more ply it's the equivalent too 18mm ply so just seal it with sbr and tile straight onto it

 

[kaharrison9]

Hi John
As above porcelain.
Usually all big floors I seem to do are heated screeds which I do with ditra.
Don't think I have done a unheated timber this size.
Cheers

 

[One Day]

hi if it's 6mm no more ply it's the equivalent too 18mm ply so just seal it with sbr and tile straight onto it

6mm nmp is equivalent to 18mm ply?!
What type of confounded wizardry is this?!!
Evidence please?

 

[kaharrison9]

Impish would you use Ditra or not regarding my question?

Regards

 

[One Day]

Impish would you use Ditra or not regarding my question?

Regards

Sorry - larking around there!
I wouldn't unless it was heated. If deflection (which Ditra wouldn't help with anyway) isn't an issue, then I see no need.
I've tiled plenty of large ply floors without Ditra and had no issues.
Cement board is more stable than timber too.

Only time I would insist on Ditra is if I was fixing a weak stone in which case a timber floor would probably be out of the question anyway...

 

[kaharrison9]

Cheers for that.

It is more on the lines I'm thinking.

One thing that I have often thought about is I believe that cement boards do not expand or contract like wood so if the case what use would Ditra ever be on top

 

[One Day]

If the newly laid chipboard has had time to acclimatise to the house and it's not a brand new - never been heated house with new joists - then I see very little risk of timber movement affecting the floor.

 

[kaharrison9]

The joists will be half old of the house and half new of the extension but the new chipboard was put down 3 months ago onto the old and new joists. It is an empty house.
I wonder what happens to cement board when timber moves as the cement board will not move at the same rate?

 

[Time's Ran Out]

I would have expected 86 sq mts of tiles to have a considerable affect on a chipboard floor!

 

[kaharrison9]

In what way John.

Overboarded with cement boards as well.

Cheers