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.

 

[John Wingfield]

200SQM of various porcelain tiles plus adhesive came in at £4.5k

 

[Flintstone]

Strange how whitebeam and myself commented on here and they have vanished.
Some good advice here for you John. Large investment to risk

 

[WetSaw]

Here or on the other thread with the same question?

 

[peteablard]

Out of interest what adhesive have you got?

 

[John Wingfield]

Mapie Keraquik

 

[Flintstone]

Here or on the other thread with the same question?

On here.

 

[J Sid]

200SQM of various porcelain tiles plus adhesive came in at £4.5k

and same again for fixing, so supply and lay an Ditra uncoupling is about 15% of that. A small price to pay I would say.
so your against the use of a uncoupling membrane on cost grounds only ?

 

[John Wingfield]

Not against it. I had heard from both sides re using it and not using. Obviously cost is a factor, so I wanted to ascertain whether or not it is truly required.
If I need approx 180SQM of Ditra I cant seem to find anywhere selling it less that £1300. That is quite a bit higher than 15%, plus I would also need to add some more thinset on to that cost, so Im looking at about 25%

 

[J Sid]

you are claiming the vat back? being a new build.
should find it for just about 1k

 

[John Wingfield]

Didnt think I could, as we bulldozed the old place on the land and rebuilt? When I looked at the regs re VAT reclaim, that process didnt fit into any of there categories

 

[J Sid]

from what you say it sounds like you can.
I would double check if i was you.
did you use the same foundations?

 

[John Wingfield]

No, new foundations laid with new beam and block flooring

 

[J Sid]

you can claim vat back on materials, not labour or plant hire.
why did you think not?
call them
Telephone: 03000 569 145
Monday to Friday, 9am to 4pm
only claim once and not longer then 3 months after completion.

 

[J Sid]

a 5% advisory free would be nice John if it turns out you can claim

 

[Diggy]

If I was spending £4.5k on tiles the modus operandi would have to be:

1. Commission UFH
2. Decoupling mat
3. Tile ( with some appropriate expansion joints - taking into account the ditra.)

Also £1300 over the cost of the whole build ( guessing between £300kkish 2 storey , £180kish single storey? - very ball park ) is about 0.5% ish of total build cost? So in the grand scheme of things you might have a cancel one family holiday :0)
You see where I'm coming from.

Diggy :0)

 

[John Wingfield]

LOL....I will ring an find out. Will have to dig out all the invoices for materials.

I will put the matting in - you have all convince me. I will also ask that the UFH is commissioned first. I have looked around online and there are so many choices:

Bal rapid mat £1393
Ditra £1328
Tilemaster anti-fracture £1260
Durabase £1068

Plus Ardex AF200 x3 15L tubs =£230

What peoples thoughts on Durabase C++

 

[hmtiling]

I get on well with durabase and am confident in using it

 

[J Sid]

all good, ask your tiler his thoughts. I hope you are using a tiler and not letting your builder do it

 

[Old Mod]

Strange how whitebeam and myself commented on here and they have vanished.
Some good advice here for you John. Large investment to risk

It was the other thread Andy.
I just looked and it's been deleted mate.

 

[One Day]

Positives: Ditra is the original, without doubt the best and has zero history of failure. There is NOBODY with poor confidence in Ditra, whereas many of us remember the Durabase problems some years ago.

Negatives: It will increase your adhesive use by around 30% and raise height 4mm.

If you're not using Stone (which really benefits from Ditra) then I'd go with Rapid Mat - it's the easiest to use.