gyvlon floor and I am the bad boy!

[Gazzer]

So i am starting a gyvlon floor today but the hygrometer says 85%.
I tell the client that it is too high and he goes ballistic at me. I explained all about the issues and what needs to be done when tiling onto these floors and he seemed to understand. Now i am getting blamed for any delay..... The facts are that he didnt decide he wanted tiles until last week. Today is the first chance i have had to check the floor. My thoughts were to sand the floor and check moisture
So he either sees that i am working to spec or i reckon he will have to get someone else.
50m2 of failed porcelain sounds expensive to me.

 

[DHTiling]

Use gypfix , you can tile at 85% RH then.

 

[Gazzer]

The info i had for gypfix said 75% ??? If 85% is ok then everyone will be happy. I was using gypfix anyway.

 

[Gazzer]

As usual Dave. You are right......dunno where i got 75% from ?
Happy days again.

 

[DHTiling]

75% with cement based addy

 

[Skyline]

Hi, don't know if this link helps but it looks like they do mention 85% RH...?

ncdirect.co.uk.co.uk/pdf/gypfix.pdf

 

[Gazzer]

When i left the job last night the hygrometer had gone down to 83%. Happy days i thought and now i can crack on with the job. well this morning i arrive and check the hygrometer which has been in place overnight.......94% !!. Now to explain to mr angry !

 

[jonnyc]

ive had this problem as well where reading showed 76 one day and got ready to start and went back up to 85 overnight. used the ball box and still in same place.
drives me nuts these screeds but i wont take the risk.
ive seen two failures very recently ( not my own )and can be very expensive to put right if kitchen on top and needs removing to relay floor.

 

[Gazzer]

Exactly my thoughts Jonnyc. Too much of a risk for me.

 

[Ajax123]

Three things spring to mind

How long was the floor box left on the floor before reading the moisture? The usual reason for this happening is tha the. Is has been left too long on the floor and it has built up a micro climate inside the measuring chamber underneath. They should usually be left for no more than 72hours. Any longer than this and you get interstitial condensation problems such as those you are seeing.

The other other thing that can cause itis if the box is read to soon. They should really be left on the floor for indium 24 hours to reach equilibrium. Unfortunately the ball ones say read after 4 hours. This is not lon enough. The reason for this is that we are dealing with such low moisture contents. It takes a while for the chamber to equilibrate. So you ge a reading of say 85% at four ours which tells you there is moisture there but not how much (typically it wold be aout 1% which is next to other) then it is left overnight and the system equilibrates to 92% (whichis about 1.5%) moisture. Throw n a few temperature and atmospheric variables and the whole thing is upskittled. If it is below 75% itis much drier at aout 0.3 to 0.5% and responds more slowly to atmospheric changes.

So with floor boxes it needs to be minimum 24 hours maximum 72 hours. If you have not read it within this time it will not be accurate.

If itis below 85% ( not 85% or below!!) then it could be tiled with one of the gypsum adhesives althoughi would always take two readings personally to corroborate each other one at 2 hours and a second at 48 hours.

Of course as I said three things spring to mind... The third is that it might simply not yet be dry...

Clear as mud I know... Ay wpquestions see me after the lesson..

 

[jonnyc]

thanks

that may explain some readings i have had as well.
do you think that there is a better meter than the ball one that is not too expensive or is the ball one fine.

QUOTE=Ajax123;633632]Three things spring to mind

How long was the floor box left on the floor before reading the moisture? The usual reason for this happening is tha the. Is has been left too long on the floor and it has built up a micro climate inside the measuring chamber underneath. They should usually be left for no more than 72hours. Any longer than this and you get interstitial condensation problems such as those you are seeing.

The other other thing that can cause itis if the box is read to soon. They should really be left on the floor for indium 24 hours to reach equilibrium. Unfortunately the ball ones say read after 4 hours. This is not lon enough. The reason for this is that we are dealing with such low moisture contents. It takes a while for the chamber to equilibrate. So you ge a reading of say 85% at four ours which tells you there is moisture there but not how much (typically it wold be aout 1% which is next to other) then it is left overnight and the system equilibrates to 92% (whichis about 1.5%) moisture. Throw n a few temperature and atmospheric variables and the whole thing is upskittled. If it is below 75% itis much drier at aout 0.3 to 0.5% and responds more slowly to atmospheric changes.

So with floor boxes it needs to be minimum 24 hours maximum 72 hours. If you have not read it within this time it will not be accurate.

If itis below 85% ( not 85% or below!!) then it could be tiled with one of the gypsum adhesives althoughi would always take two readings personally to corroborate each other one at 2 hours and a second at 48 hours.

Of course as I said three things spring to mind... The third is that it might simply not yet be dry...

Clear as mud I know... Ay wpquestions see me after the lesson.. [/QUOTE]

 

[Ajax123]

Unfortunately jonnyc the ball type is the most widely available and so most cost effective. They are temperature sensitive as they work using a ceramic plate conductor. Nt perfect by any means. In Europe the accepted method is the carbde bomb but one of these would sting in excess of 300 quid. They are more accurate though. With practice electronic meters can be interpreted but these ar even more expensive.

I am happy to say though that if used correctly the hygrometers are usually no trouble.

 

[Gazzer]

Well that makes a total mockery of the instructions given and no wonder there are failures !
The client is getting more and more upset and I am losing money by having to travel to the job to do this test.

 

[Pebbs]

Ajax,

I need a lesson to, I get so confused with this Gyvlon screeds, that I am ending up making a quick exit of site when questioned about them..

Pebbs

 

[The D]

I hereby declare this type of sub floor to be unfit to receive tiling. I am also declaring war on the manufacturers and the installation company’s for this product. :smilewinkgrin:

 

[Ajax123]

I hereby declare this type of sub floor to be unfit to receive tiling. I am also declaring war on the manufacturers and the installation company’s for this product. :smilewinkgrin:

That of corse is despite the hundreds of thousandsf square meters that have been tiled without issue.

Good luck with that mate. One of the strangest things I see is that in France alone there are around 6million square meters of gyvlon type screeds laid and around 85% of these are tiled in smaller domestic situations similar to most of the guys on here. They have almost zero failures. No one will claim there are no failures at all but there are so few that they are pretty insignificant. Germany is similar although n a smaller scale and holland have actually introduced legislation which favours these types of screeds. What is different about the UK. I think it is dinosaurs (or is that Deanosaurs) no offence intended ... Who refuse to move with the times. These screeds are not going away and will oly increase in the domestic market with the same veracity that they have done in the contract market. The companies who supply them oh supply a demand in the market. If you would like to try and stifle the demand you will be looking to taken not only some f the largest construction companies in the world but also the tens of thousands of small builders, screeders,plasterers, floor layers, self builders, plumbers, heating engineers, environmental lobbyists, health and safety lobbyists who are all moving slowly but inexorably towards a flowing screed preference. I also hear people say builders ony use it cosits cheaper or quicker. These are not always true and in the vast majority of cases cost and speed do not even enter the equation becoming incidental behind all the other considerations builders and contractors have to take account of.

Adhesives have become available much more widely in the last few years. You often say you are being treated as a guinea pig doing all the testing but actually mostof the testing has been done already. I hear often from tilers phrases like "i always use this manufacturer and have never had a prolem" or "This is the best adhesive and primer". Phrases which are bandied about without apparent regard for the nature of thesubstrate and the application in question. What we seem to be incapable of grasping in the uk is that the adhesive that you have always used may not always the best adhesive for these screeds. The best adhesives tend to be Portland cement free...yet we still maintain our adherence t the British Standards because these say cement is best...Just cos the British standards say it does not make it fact.

 

[Ajax123]

Ajax,

I need a lesson to, I get so confused with this Gyvlon screeds, that I am ending up making a quick exit of site when questioned about them..

Pebbs

What do you need to know Pebbs. When I get back to work I will be happy to meet up with you somewhere, buy you a coffee and a bacon butty and go through these screeds in detail. There is not really that much to it. There are four basic steps from the tilers point of view.

1. Is it dry
2. Is it clean and free from excessive dust and contamination
3.Is it heated (if yes it must be comissioned first in ALL cases)
4. Is it sound i.e. cracked, soft or broken. If so does it need any special treatment eg. Ditra, levelling compound, crack repairs etc.

Select your adhesive based on impartial and sensible advice (my suggestions wold be go with gypsm adhesive or, cement free adhesive before going for one based n cement. If cement it must be go for an epoxy primer in reference to usng an acrylic primer.

Also always bear in mind that Gyvlon is only one manufacturer amongst numerous who supply in the uk. I will be starting work for Francis flower limited in the very near future which is a direct competitor to Gyvlon.

 

[Ajax123]

Well that makes a total mockery of the instructions given and no wonder there are failures !
The client is getting more and more upset and I am losing money by having to travel to the job to do this test.

They are not my instructions mate. I can oly say it how it is based on experience and testing in the lab. There is really no reason why the client should not do the test themselves itis hardly rocket science. I often Recomend to clients tha they buy themselves a hygrometer for 80quid which in the overall cost of a build is peanuts. The canteen test the screed and tell you when it's dry. Really that is how it should be in my opinion anyway.

 

[The D]

I will be happy to tell all the poor sods that have had a problem that it is ok as they are insignificant

 

[macten]

Most customers I've met haven't got a clue if it's a Gyvlon screed or not.

 

[Ajax123]

I will be happy to tell all the poor sods that have had a problem that it is ok as they are insignificant

Insignificant in the context of statistical analysis... It would be great if no failures occurred but there are plenty on traditional screeds and other substrates. Why pick on anhydrite alone...That seems a bit substratist

 

[Ajax123]

Most customers I've met haven't got a clue if it's a Gyvlon screed or not.

My usual answer is treat it as anhydrite anyway because what you do with anhydrite will work with other screeds a well.

 

[Gazzer]

They are not my instructions mate. I can oly say it how it is based on experience and testing in the lab. There is really no reason why the client should not do the test themselves itis hardly rocket science. I often Recomend to clients tha they buy themselves a hygrometer for 80quid which in the overall cost of a build is peanuts. The canteen test the screed and tell you when it's dry. Really that is how it should be in my opinion anyway.

I never said you did Alan , I am feeling little disillusioned with it all. I have a Hygrometer from a reputable company yet the instruction given are now wrong so it seems ??? Wait a bit while I get my crystal ball !

I am thinking of drafting a letter to give to clients with these floors that it is up to them or a third party to ascertain when the floor is dry and ready for tiling.

 

[jonnyc]

i dont want to get in to an argument here really but what i do know is that i have not found a single builder to date that has reused this type of screed if they have had to wait for the screed to dry properly.
they dont see the point of it.
many will have had tiles laid on damp screeds and will continue to do so till they have a problem.
when i ask why builders why they used anhydrite they all say because it is done quick and assured by their screed companies that it will save time.
with tiling only in mind what benefits does an anhydrite screed have apart from speed of screed installation.
i suppose two of those benefits are supposed to be that you get a dead level screed. not in most of the instances i have encountered. I have only laid on 15 or so of these screeds but most are no better than sand/cement with fibres.
the benefit is not having toi have as many expansion joints but i find this fallacy as well as have had cracks in screeds many occasions.
When a comparison is made to the uk and france and germany . i actually think they have had more time to get used to the product. this is quite new to us.
Just as much at fault are the screed layers not so much the suppliers of product.
they just dont have the experience

 

[macten]

My usual answer is treat it as anhydrite anyway because what you do with anhydrite will work with other screeds a well.

So straight away I'm adding on for hire of floor scarifyer, hygrometer that may or may not give me a reliable result, and the added cost of calcium based adhesive all on the off chance.
That's just great for my business that is.

I'm not having a pop at you Alan, you've always tried your best to educate us tilers with very informative posts and I accept that gyvlon is here to stay.
It's just that our job is hard enough as it is and in my own perfect world I just wish these screeds would disappear.