Problematic Anhyrdrite floor! - Tile Advice

[jonnyc]

I got a full house on Gyvlonn LL to start next week.... nee bother at all.. ... what is the issue with these floors... you tile to skimmed walls . ? just think of a large skimmed floor.. same to prime , just longer to dry..

if only this was so easy dave.
what precautions have you made for this particular job,
have you tested this yourself and if so with what test meter.Or has someone else and if so, have they submitted a report in writing that would cover you in eventuality of any failure .

 

[doddy41]

Woudnt touch one of these floors with a barge pole too many things to go wrong

 

[DHTiling]

if only this was so easy dave.
what precautions have you made for this particular job,
have you tested this yourself and if so with what test meter.Or has someone else and if so, have they submitted a report in writing that would cover you in eventuality of any failure .

It is for a builder i have done tiling for, for a lot of yrs.. he force dries the floors.. last 3 have been done this way... easiest way to get them dry.. you can force dry a floor in 10 days... we run them for 3 weeks.. to make sure they are dry...

Some the damp testing methods are flawed IMO as they give a true reading at optimal conditions etc and not often that happens... we are told you need to do this and that.. then a few months later they change the goal posts and change their advice..

An example of this is the screed reps.. they say to make sure dry and use acrylic or epoxy primer.... NOW!! they say it is best to use a gypsum adhesive that are not even covered under BS..

So IMO force drying when they are heated is the option we go for , if the floor is not heated , then i don't touch .. but not tiled a none heated one yet..

These screeds are here to stay IMO , as they are quicker to lay and stronger than S&C screeds and of course cheaper as the speed of laying out ways the labour of a traditional screed.

When they first started to get mentioned on here , i had not even seen the in my neck of the woods but the past 2 yrs i have come across quite a few and this is the 4th for this builder as he likes these screeds..

This house is Gyvlon LL on both floor levels of the house.. and 3 bathrooms and over 60 mtrs i am told down stairs... the last one was 160 mtrs down stairs and when i first did one i bricked it because of all the scare mongering over this type of screed.. but the more i do the more reliant i am over them..

The biggest issue is the screeder .. they are a nightmare if not controlled properly as they over wet them to speed up the levelling out and this is what can cause friable surfaces and BIG failures.. make sure who ever is there when the screed is poured watches the slump test fro each pour to make sure it is the right consistency to get a nice strong hard screed.

 

[Ajax123]

It is for a builder i have done tiling for, for a lot of yrs.. he force dries the floors.. last 3 have been done this way... easiest way to get them dry.. you can force dry a floor in 10 days... we run them for 3 weeks.. to make sure they are dry...

Some the damp testing methods are flawed IMO as they give a true reading at optimal conditions etc and not often that happens... we are told you need to do this and that.. then a few months later they change the goal posts and change their advice..

An example of this is the screed reps.. they say to make sure dry and use acrylic or epoxy primer.... NOW!! they say it is best to use a gypsum adhesive that are not even covered under BS..

So IMO force drying when they are heated is the option we go for , if the floor is not heated , then i don't touch .. but not tiled a none heated one yet..

These screeds are here to stay IMO , as they are quicker to lay and stronger than S&C screeds and of course cheaper as the speed of laying out ways the labour of a traditional screed.

When they first started to get mentioned on here , i had not even seen the in my neck of the woods but the past 2 yrs i have come across quite a few and this is the 4th for this builder as he likes these screeds..

This house is Gyvlon LL on both floor levels of the house.. and 3 bathrooms and over 60 mtrs i am told down stairs... the last one was 160 mtrs down stairs and when i first did one i bricked it because of all the scare mongering over this type of screed.. but the more i do the more reliant i am over them..

The biggest issue is the screeder .. they are a nightmare if not controlled properly as they over wet them to speed up the levelling out and this is what can cause friable surfaces and BIG failures.. make sure who ever is there when the screed is poured watches the slump test fro each pour to make sure it is the right consistency to get a nice strong hard screed.

David... When was this one laid mate...if you know?

 

[DHTiling]

Around 7 to 8 weeks ago... heating has been on for 4 to 5 weeks... summit like he said

 

[jonnyc]

dave i agree with much of what you are saying. most of the 18 jobs i have done on these screeds have been forced dried and heating on for three weeks and i have not had a failure yet.
but and it is a big but , you do not mention that there has been a proper test by either you or the contractor.of course everything is fine until it is not!!this is key
but i do know of a problem right now whereby the same force drying has been carried out and the floor has failed. the same careful priming etc had s been carried out .this is now a very serious situation and i am afraid that to simply state that by force drying with no tests is suffice because no problems before does not work in case of law.

 

[DHTiling]

The test Jonny is to only see if they are at the correct RH.. if you heat a screed at high temps for a long period then IMO there is no damp... the builder dries them and gives the go ahead to tile.. his choice .. but i always ask at the start if he is sure they are ready.. he nods i tile..

 

[DHTiling]

And not that it makes any difference but he always uncouples as well , no matter what tile goes down..

I have had many chats with him about making sure they are dry but he is the decision maker and follows what Gyvlon rep told him to do drying wise.

 

[jonnyc]

ajax . please enlighten us as to what the advantage is of this type of screed .
you have a raft of experience in this field and i and many others really appreciate your advice as to how to deal with it once it is down.but why should we have to deal with it at all.
one of the advantages i thought it had was that it would dry quicker than sand/cement screed but this is only the case if a boiler is ready to be commisioned and force drying can be carried out.
you and i know that in reality it is very rare scenario.
second advantage could be no expansion joints through doorways and in open area over 40 sq mts. reality i have seen splits in doorways but this could be down to inexperienced screed pourers.
what with the liquid screed accelerators available now, that do not add much cost . these are far more interesting to me

 

[jonnyc]

The test Jonny is to only see if they are at the correct RH.. if you heat a screed at high temps for a long period then IMO there is no damp... the builder dries them and gives the go ahead to tile.. his choice .. but i always ask at the start if he is sure they are ready.. he nods i tile..

dave i understand you are only acting on instruction but this is only verbal.
i dont want you to turn work down , but i am trying to warn you that if it does go wrong it will be down to a duty of care and the onus is on you!! this is why i and others are so worried about this system. i cannot stress enough about the danger of tiling on to this screed without someone taking responsibility before the work takes place.
i will not repeat this again but beware.your livelyhood could depend on it

 

[bugs183]

All very good points JonnyC.
I really do want to like these screeds and embrace them, i'm not a Ludite or set in my ways, if it's new and easier to work with then i'm on it 100%,
but, as you say the theory of these screeds is fantastic, yet the reality is far from that.
As you say the screeders are a bloomin nightmare as the are not putting expansion strips in, i can honestly say that EVERY floor of this method has cracks in it.
In my theory as the screeders are pumping more they are getting complacent, they keep messing with the mix to get the floor done.
I've had my one man battle for firm answers on these screeds, and i had given up, but it's good to see someone else trying to get to the bottom of all this!

Our Gyvlon rep has gone very quiet over all of this.

There are far too many things to go wrong here:
The Screeders, over wetting, not putting the expansion strips, not getting the floors flat, not sanding, not educating.
The Moisture testing. Too unreliable, too vague, no training anywhere to help.
The adhesives. I've tried cement based and suitable primers, stuck to the tile, not to the floor. Gypsum based, stuck to the floor, not the tile. GBTA seems to work, but is massively expensive. Uncoupling seems one way, yet Schluter are reluctant to recommend gypsum based adhesives with Ditra.
The builders, not knowing what they are actually dealing with. or just believing the floor is fast track.
The tilers, only a small percentage even know this is a different screed, let alone how they are supposed to be dealt with.
The customer. Thinks the floor will dry quick, it doesn't then as soon as the tiler closes the door behind him cranks up the underfloor heating.

 

[Ajax123]

Around 7 to 8 weeks ago... heating has been on for 4 to 5 weeks... summit like he said

Just a small point .... It is not a gyvlon ll screed then. It is actually a Francis flower screed....one of mine.

 

[Ajax123]

All very good points JonnyC.
I really do want to like these screeds and embrace them, i'm not a Ludite or set in my ways, if it's new and easier to work with then i'm on it 100%,
but, as you say the theory of these screeds is fantastic, yet the reality is far from that.
As you say the screeders are a bloomin nightmare as the are not putting expansion strips in, i can honestly say that EVERY floor of this method has cracks in it.
In my theory as the screeders are pumping more they are getting complacent, they keep messing with the mix to get the floor done.
I've had my one man battle for firm answers on these screeds, and i had given up, but it's good to see someone else trying to get to the bottom of all this!

Our Gyvlon rep has gone very quiet over all of this.

There are far too many things to go wrong here:
The Screeders, over wetting, not putting the expansion strips, not getting the floors flat, not sanding, not educating.
The Moisture testing. Too unreliable, too vague, no training anywhere to help.
The adhesives. I've tried cement based and suitable primers, stuck to the tile, not to the floor. Gypsum based, stuck to the floor, not the tile. GBTA seems to work, but is massively expensive. Uncoupling seems one way, yet Schluter are reluctant to recommend gypsum based adhesives with Ditra.
The builders, not knowing what they are actually dealing with. or just believing the floor is fast track.
The tilers, only a small percentage even know this is a different screed, let alone how they are supposed to be dealt with.
The customer. Thinks the floor will dry quick, it doesn't then as soon as the tiler closes the door behind him cranks up the underfloor heating.

Cant speak for the Gyvlon rep.... If however you want to give me a call (07966651006) I will be happy to talk you through chapter and verse. That said much of what I have told you will have been outlined in the forums at some point.

 

[Diamond Pool Finishers]

Francis Flower is this you now ajax ? what is your position there then mate ?

 

[DHTiling]

Just a small point .... It is not a gyvlon ll screed then. It is actually a Francis flower screed....one of mine.

How do you know that Alan , did you speak to Dave ?