Anhydrite Screed

[Spare Tool]

Have to go look at a 90m floor on Monday..just came across this and as Webber recommend set plus for the adhesive I would always choose a slowsetting adhesive over a rapid set where possible, I've read many threads on here where it is advised specialist anhydrite adhesive should be used but no manufacturer seem to make a slowset version...is it taking a gamble using a cement based adhesive or as long as its prepped and primed correctly as it states in the Webber advice slowset cement based can be used without worry..or does anyone know of a manufacturer making a slowset specialist anhydrite adhesive?
I should mention the screed is over wet ufh, tiles 600x600 porcelain..
Tiling onto anhydrite screeds - Weber

 

[stone tiler]

I would always go with the Anhyfix if possible. Just a bit more peace of mind for me.
Speak to Tilemaster, they might be able to knock you up a batch that'll go off a bit slower.

 

[Dave]

Its not a gamble imho as long as you prime properly but imwould go rapid adhesive , so it hydrates quicker on the primed screed.. Just the way ive always done it.. And my weber choice would be rapid spf..

 

[Ian]

Yeah set plus isn't the right adhesive to be using, unless you're mixing it with an additive. Anhyfix would always be my choice for and anhydrite screed.

 

[AD Ceramics]

Kerakoll Eco H40 is slow set and suitable for anhydrite screeds, mineral based.

 

[bcd-87]

Its not a gamble imho as long as you prime properly but imwould go rapid adhesive , so it hydrates quicker on the primed screed.. Just the way ive always done it.. And my weber choice would be rapid spf..

@Dave your the stephen hawkins of tiling

 

[Qwerty]

@Dave your the stephen hawkins of tiling

What?.....he's in a wheelchair and talks like metal mickey!!?? 😀😉

 

[AliGage]

I've just done 5 Ensuite floors on a wet heated Anhydrate screed.

Once dry.....

Sanded off the latency.
Primed 3:1 with Weber PR360. It took two coats.
Fixed ditra using weber SPF slow set.

All floors have been down around 4-5 weeks depending on which room it is.

 

[Dave]

I've just done 5 Ensuite floors on a wet heated Anhydrate screed.

Once dry.....

Sanded off the latency.
Primed 3:1 with Weber PR360. It took two coats.
Fixed ditra using weber SPF slow set.

All floors have been down around 4-5 weeks depending on which room it is.

I prefer 4 to 5 coats

 

[AliGage]

After two coats Dave it wasn't absorbing anymore. I had to mop a third off the surface before it skinned over.

 

[peteablard]

I dilute it 4:1 and it normally takes 4-5 coats

 

[Dave]

After two coats Dave it wasn't absorbing anymore. I had to mop a third off the surface before it skinned over.

4:1 ratio for me , prevents possible skinning as you say ...

 

[Dave]

Weber say 3:1 to 5:1 but 3:1 for me is strong ... So i use 4:1 but like anything else , use what works for you .. 🙂

 

[Ajax123]

Kerakoll and benfer both do slow set compatible materials. H 40 ideal from kerakoll but can't remember what the benfer one is called off the top of my head.

 

[Tile Shop]

What about BAL APD? They say that only needs 2 coats.... 1st 1:1, 2nd neat. Wouldn't most acryllic primers be the same principle? Mapei said the same thing when i spoke to them about Primer G.

Due to a couple of issues we've been advised of, it seems to me that primer and cement addy is still the safest way to go.

 

[Spare Tool]

Thanks for all replies..had thought about uncoupling but this will add around £1500 onto the tiling bill and will probably quote me out of the job and as porcelain tiles I think its a bit unnecessary..
Few conflicting replies here, I would in all honesty prefer a slowest flexible so keracol might be worth looking into not that there's anywhere around here I know that stocks it.
I can easily get hold of Webber and tilemaster. If I do have to use a rapid ady then might as well go with anhyfix, although Paul advises against it and recommends cement, could you tell us the issues you've been advised of Paul?
I shall ring both Webber and tilemaster tomorrow and get them to email a spec for me..

 

[widler]

Ive used anylfix on a 100m2 floor, no matting , porcelain tiles, been down a couple of years i think now, no issues.
Its like glue to spread , but its what i would use 😉
Im sure if u asked tilemaster they would make a batch slower setting for a 90m2 floor

 

[AliGage]

What about BAL APD? They say that only needs 2 coats.... 1st 1:1, 2nd neat. Wouldn't most acryllic primers be the same principle?

I was originally advised to do neat with Weber (not by weber).
Tried it, it skinned and I had to peel it all off and start again.

 

[widler]

If you use any primer neat it will form a skin, without a doubt

 

[Just Rizzle]

andy don't be a fool it a gamble using cement on anhydrate.
just laid 50 sqmts to day on an anhydrita floor using anhyfix. it is a rapid set but as the winters coming the setting time is slower.

dave you've used anhyfix. you've said so one this site. is the reason your not recommending it as the two local suppliers WONT supply you with it and tilemaster turned your account down.
your not giving best advice to andy dave

 

[J Sid]

andy don't be a fool it a gamble using cement on anhydrate.
just laid 50 sqmts to day on an anhydrita floor using anhyfix. it is a rapid set but as the winters coming the setting time is slower.

dave you've used anhyfix. you've said so one this site. is the reason your not recommending it as the two local suppliers WONT supply you with it and tilemaster turned your account down.
your not giving best advice to andy dave

Ray, so what your saying is Tilemaster is the best adhesive for anhydride screed, why is it the best?
So do we now take it as read, that the only opinion that matters on the subject of adhesives is yours? 🙂

 

[bcd-87]

What?.....he's in a wheelchair and talks like metal mickey!!?? 😀😉

lol oh yeah... not the wheel chair and ultron voice

 

[Dave]

andy don't be a fool it a gamble using cement on anhydrate.
just laid 50 sqmts to day on an anhydrita floor using anhyfix. it is a rapid set but as the winters coming the setting time is slower.

dave you've used anhyfix. you've said so one this site. is the reason your not recommending it as the two local suppliers WONT supply you with it and tilemaster turned your account down.
your not giving best advice to andy dave

No i havnt used anhyfix , i was going to but job fell through and as for your comment on me getting an account , your wrong again , i never applied for an account , it was my bro ... so get your facts straight before shooting your mouth off.

You come on here and say anhyfix is the best but wont admit how you tiled to anhydrite before gypsum adhesives came out ... Your so full of it its unreal..

 

[bcd-87]

No i havnt used anhyfix , i was going to but job fell through and as for your comment on me getting an account , your wrong again , i never applied for an account , it was my bro ... so get your facts straight before shooting your mouth off.

You come on here and say anhyfix is the best but wont admit how you tiled to anhydrite before gypsum adhesives came out ... Your so full of it its unreal..

There's only one way to settle this

 

[peteablard]

I still use a cement based adhesive and will continue to do so as the builder insists on it. It's not a gamble if you do it properly.

 

[Just Rizzle]

since 1982 I've been doing tiling as profession. I first learnt to tile using sand and cement. ive worked on some large projects in my time .shopping centers. prisons . listed buildings such as the. natural history museum allot of these projects had some of the meanest quantity surveyors in the game. if it wasn't right you didn't get paid.
all the time I've been tiling I've been learning so my knowledge of my profession isn't just family bathrooms.

anhydrites unfortunately are here to stay and if your going to tile them you need to get it right. if you don't you are the one the customer is going to come after .
I've done a fair bit of research on these screeds and been on a course to explain the pros and cons of using them.
the course was about 8 yrs ago. my conclusion from talking to reps technicians with adhesive manufacturers is this

under no circumstances should cement based adhesives be used on anhydrite floors there's simply to much risk of failure no matter how many coats of primer you wish to put on prior to tiling. I recommend tilemaster because they give me confidence in there products. and there easy to get hold of and talk to. there are other anhydrite addy manufacturers but were I live there hard to get hold of.
weber do a anhydrite addy but its not available as yet in the uk, for some reason, so that's why they recommend there spf.

what I try to do is give best advice to people who are less experienced as me.
p s theres only one on this site that's full of it🙂

 

[bcd-87]

@Dave stephen hawking him

 

[widler]

Ray, so what your saying is Tilemaster is the best adhesive for anhydride screed, why is it the best?
So do we now take it as read, that the only opinion that matters on the subject of adhesives is yours? 🙂

I would of thought that its best to use the right adhesive with the right substrate, i know u can use cement addy on anhydrite, it says so on the bag, it also says on a lot of stuff to PVA 1st
I would of thought all us pro tilers on here 😉, who go on about the belt and braces approach whould welcome Anhydrite addy as its the correct addy for the right substrate
if one fails with cement addy the addy manufacturer will no doubt say you have used the wrong addy

 

[CJ]

All very well using the stuff, but I've never even seen it in my area.

 

[StevieBoy]

Ive recently laid 2 of these floors. I scraped off all the laitence, but most of it had come loose it anyway by the time the plasterers / chippys and everyone else had finished walking all over it, then hoovered it clean, then gave it two coats of diluted BAL SBR rollered on in opposite directions.

Then tiled it with slowset flexible from Topps, which is made by Palace.
Grouted with BAL flexible wide joint grey grout, and after 3 months all is still ok.

 

[widler]

This is all well and fine , is this not the old
'ive done it for years and never had a problem' senario ??
again, remember pva , it was fine to tile onto for years, but now 😉

You watch, in a year or two they will tell you that you can't use cement addy on gypsum screeds 🙂