I have a floor area approx. 30m to tile. Half is on exterior ply the other half on screed. Will I need to put down a uncoupling membrane over the whole area before I tile. The tiles are ceramic .

Forgot to mention the floor will have underfloor heating

In principle, you do not require a decoupling membrane. You will just need to ensure that you have an expansion joint across the point where the two substrates meet.

However, things to consider are:
How stable is the ply floor? i.e. thickness, deflection etc..
Are you putting insulation boards under the UFH? (I presume it is electric UFH)
Do you intend to apply a floor smoothing compound over the UFH?

You will need a control joint between the screed and ply floor, what thickness of ply is fitted

Hi Jimbo, what thickness is the ply? decoupling also expansion joints to be considered Thickness of ply important, before we can advise

Triple response, same answer

Bet that is not a record though, knowing this forum

Same

Thanks for the quick response.It is 18mm ply and a wet piped system layed on insulation board. How can I disguise the expansion joint without it looking obvious

whilst it will do no harm I would not have thought uncoupling essential with ceramic but the joint is essential.

On domestic jobs, you can use what is called a Cold expansion joint.. this is basicly a joint of around 4mm to 6mm and silicone is used.. same colour as the grout to be used..

Mapei do silicones to match all the grouts in the ultra colour range..

Thanks for your help Dave . I will take your advice

Dural will make expansion joints to order, and match them to your grout colour
Based in Wakefield
01924 360110

Bet they cost

Originally Posted by Dave

On domestic jobs, you can use what is called a Cold expansion joint.. this is basicly a joint of around 4mm to 6mm and silicone is used.. same colour as the grout to be used..

Mapei do silicones to match all the grouts in the ultra colour range..

A viable alternative to metal expansion joints,but do not have as much longevity ! will inevitably need to be replaced !

Originally Posted by whitebeam

Bet they cost

No
main guy used to work for Schluter....
E.G...
Dural uncoupling membrane £5.00 a metre plus VAT
They will replicate ( near copy ) nearly any Schluter trim at a fraction of the cost.
Ring em and see !

not always the best look for a domestic setting though Tina

A nice expansion joint in my opinion looks better than a bead of silicone and lasts longer in any setting,either domestic or commercial.

Originally Posted by Yorkshire Tiling Services

A nice expansion joint in my opinion looks better than a bead of silicone and lasts longer in any setting,either domestic or commercial.

very true Tina, does your friend do them in all the colours ?

will PM you reps number
have a good chat, you will be pleased & surprised !
Love Tina xxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Originally Posted by Yorkshire Tiling Services

No
main guy used to work for Schluter....
E.G...
Dural uncoupling membrane £5.00 a metre plus VAT
They will replicate ( near copy ) nearly any Schluter trim at a fraction of the cost.
Ring em and see !

I guess you are refering to Gerard, top man imo. They do every colour under the sun. A good exp joint can make a job, true pro finish

Originally Posted by Phil Hobson

I guess you are refering to Gerard, top man imo. They do every colour under the sun. A good exp joint can make a job, true pro finish

Thanks Phil