New Build UFH Tiling

[John Wingfield]

Hi all

First post on here as need some advice. We are building a house and have got to the point where the floors need tiling.

The floor is a sand and cement screed that was NOT poured. It has been in the house since August.
The screed contains water based UFH which has not yet been turned on / commissioned.

I am going to be doing the tiling - done plenty before in previous houses, but never onto a screed with UFH. The chap in charge of the build has stated that we need to use a decoupling membrane on the screed to stop the tiles cracking.

I dont believe this is required, as the screed has had plenty of time to dry out (5 months) and I will have expansion joints between each room between the doorways.

Just after others experience / advice on this topic?

Thanks
John

 

[J Sid]

what tiles are you using? And has the ufh been commissioned?

 

[John Wingfield]

Porcelain throughout, UFH has not be turned on / commissioned

 

[J Sid]

the floor needs turning on and commissioning.
some will say you can get away without an uncoupling membrane but I am in the camp which would advise some sort of uncoupling. There are many out there and not to expensive.

 

[John Wingfield]

I looked at Ditra which seems seriously expensive. I need to cover about 180SQM

Any other your would recommend?

 

[hmtiling]

If it was my house I'd decouple it.
Tilemaster do a good one.

 

[One Day]

Your risk lies in the fact that the floor hasn't been commissioned.
Once commissioned, and cooled - the cracks, if any should happen.
If you are fixing a porcelain, or strong stone then you'll likely be ok - especially if you have bays and expansion joints in the screed already.
If you're fixing a weak stone - marble / travertine etc then definitely uncouple.

Look at the cost of a membrane - even Mapeitex (probably the cheapest option at the moment) and you weigh up - how much do I value my stone/tiles?
- am I prepared to risk it?
- is the extra outlay worth the piece of mind?

Many of us have fixed long-lasting floors without Ditra, but never onto uncommissioned screeds without Ditra.

 

[peteablard]

I would strongly recommend using one but if the customer declined I'd still be happy to lay porcelain without it providing the UFH had been commissioned

 

[WetSaw]

Get the heating commissioned before you do anything.

 

[J Sid]

as harry said tilemaster is an option.

I wouldn't say it was seriously expensive, I don't know what you've paid for your tiles and there quoted fixing costs are, but would estimate to supply and fix Ditra would be about 10% to 15% of that. Well worth the peace of mind.