Gyvlon floor....

[AGC71]

About to tile onto a gyvlon floor for the first time... would anyone have any recommendations? will be putting down 20mm limestone slabs.

[doug boardley]

remove all the laitence, sanding it off should do the trick, use an acylic primer or better still an epoxy primer.

[nybor62]

im about two start some floors next week gyvlon. low laitence,and have been assured there is no need to sand them down, just prime with suitable primer

[nybor62]

let me explain my last post ,when i was told the floors were gyvlon , i suggested to them that they would need sanding to remove the latency, there response was its a low latency screed so wont need sanding, just priming.

maybe i need to look into this further,as it will be my fault if it fails

[Yorkshire Tiling Services]

im about two start some floors next week gyvlon. low laitence,and have been assured there is no need to sand them down, just prime with suitable primer

At the best even a low laitance floor will need sanding. Sometimes more thorough depending if it has been laid right ! Sometimes gets mixed with too much water and makes more laitance
Prime with suitable primer.
Best use uncoupling membrane for limestone.
If under floor heated make sure it has been run then allowed to cool down before tiling.

[Dave]

Most of the newly laid Gyvlonn floors are all the LL version.

These screeds are low laitence and no film on top.. but by the time a tiler gets to it there is some surface contamination, hence the need to give it a quick light sanding to reveal the original surface and a nice clean substrate to bond to.


You main priority here is make sure the screed is dry, how long has it been down and has a residual moisture reading been done with a hairgrometer..?

[Ajax123]

The process is fairly simple but you cannot short cut it.

First of all it is essential that any underfloor heating has been comissioned prior to tiling. This is the same as sand cement.

Second - is the screed clean - it is likley as Dave says that if the screed has been laid for a while it will be contaminated with dirt and other debris. The easiest way to clean it is to run a sander over it. As it is LL you are not aiming to "remove" material - just clean it up. The client is correct in saying it does not need to be sanded to remove laitance but this doe not mean it is suitable to receive a primer straight away.

Third make sure it is sound and that any cracks are repaired (there are usually not cracks in it although this depends on the installation)

Foruth - check the moisture content. If you use acrylic primer with cement based adhesive this bit is also essential. If the screed has heating and this is not yet commisioned moisture testing is a waste of time. If you have no moistrue testing equipment speak to your addy supplier who may be willing to do it for you. Alternatively (and the test I have used many times in the past) do a simple polythene bag test. i.e. put a small sheet of polythene down about 1mx1m and put something on it to hold it down. Leave it there a couple of days and then lift it and look at the undersie and the surface of the screed. If it is still damp there will be a darkened patch and possibly condensation under the polythene. If it is dry there will be no change under the polythene and if it is nearly dry there will be a shadow around the edge of the polythene. This last case is the risk point and it is worth either waiting a week or so or getting a proper moisture test done. If the moisture testing is done for you the correct test is the hair hygrometer and takes between 48 and 72 hours to complete.

Do not let anyone bulls**t you that any other test will give you an accurate moisture test. It won't.
If you use a cement based adhesive the most robust primer type will be a water dispersible epoxy. You will normally need to dilute this 1:1 with water and one coat is normally sufficient although the manufacturers might say do 2 coats. COst wise they are not much more expensive than acrylics. This prevents ettringite formation by preventing migration of water borne sulphates in the screed.

If you are using a gypsum based adhesive you can be much more relaxed about the moisture side as they can be used when the screed is still around 85% rh. An acrylic primer is ok as the addy is fully compatible with the screed. This would be my preferred option and if you want to look at it p.m. me and I can sort you out some contacts. Bear in mind it is more expensive. It is much much much more robust though if tiling to dry areas such as lounge, kitchen etc. I would not put it into a bathroom but that would be tanked anyway so you can use cement addy without issue as it is fully divorced from the screed by the tanking membrane.

I have seen no failures where gypsum based adhesive has been used on Gyvlon screed.
I have seen few failures where epoxy and cement are used (provided the screed is dry)
I have seen loads of failures where acrylic and cement addy are used - usually due to application of primer, poor preparation or moisture or a combination thereof.

Any questions - feel free to ask.

[Ajax123]

Sorry about me spelling by the way

[Dave]

And my mentor comes to the rescue..

[Ajax123]

[Ajax123]

Dave - Creative Impressions have just taken on a new guy to flog the gypsum addys and levellers. He was national technical manager for Tarmac mortars and screeds and is one of the UK's leading experts in this type of technology. He probably knows more about Gyvlon screeds than I do so another very useful contact should you need one.

sorry all - end of sales pitch

[Dave]

Text me his number plz.. that floor i mentioned is coming off in october.. in fact it isn't a floor it is a whole house. ..


Oh!! nearly forgot and this will be of interest to thread opener.. can acrylic adhesives like Mapei VS90 be used on Gyvlon screeds to fix the likes of Ditra.. hence no sulphate reactions..?

[whitebeam]

Dave - Creative Impressions have just taken on a new guy to flog the gypsum addys and levellers. He was national technical manager for Tarmac mortars and screeds and is one of the UK's leading experts in this type of technology. He probably knows more about Gyvlon screeds than I do so another very useful contact should you need one.

sorry all - end of sales pitch

There the concrete impression people

[Ajax123]

There the concrete impression people

that's them. they also have gypsum addy and levelling compounds

[Ajax123]

Text me his number plz.. that floor i mentioned is coming off in october.. in fact it isn't a floor it is a whole house. ..


Oh!! nearly forgot and this will be of interest to thread opener.. can acrylic adhesives like Mapei VS90 be used on Gyvlon screeds to fix the likes of Ditra.. hence no sulphate reactions..?

will do.

can't see any reason why not. dura have one as well.....come to think of it so do b&q. only possible issue i can see is do they need to dry in the same way as tubbed dispersion addys. Not sure cos I not too familiar with them.

[Dave]

Can you check out this plz mate.. this is an option i see as a great adhesive for adhering membranes with no de-bonding issues.

These adhesives just need a porous substrate and do not have a mass water content

[Yorkshire Tiling Services]

Warning
just like adhesive manufacturers supply good products,they cannot control how they are used.
Same with Lafarge,they only SUPPLY gyvlon screeds,they do not lay them all.
If ,laid wrong wiv 2 much water then exces laitance might happen.
Test with key or something likefirst.

[Dave]

Nick.. have you seen the newer LL screeds.?

[Ajax123]

Warning
just like adhesive manufacturers supply good products,they cannot control how they are used.
Same with Lafarge,they only SUPPLY gyvlon screeds,they do not lay them all.
If ,laid wrong wiv 2 much water then exces laitance might happen.
Test with key or something likefirst.

The new generation LL screeds are more robust to this but you are correct that if significantly over watered they can cause issues. Testing with a key is not really an appropriate test as it will be quite misleading. When you put a medium pressure onto the point of a key you generate a huge point loading. Press hard enough and you will be able to scratch up even a top quality Gyvlon screed.

It it usually failry obvious when the screed is overwatered e.g the attached pic. This was poured at around 90mm over the specified flow tolerance. This equates to around 300litres of water more than was required in the batch. OUCH!

The water has the effect of segregating the consituent materials - same as overwatering levelling compound.

[Gazzatile]

You live and learn Thanks

[TT Tiling]

ajax123 your the man ,i know through laying on them my self its got to be right ,sanding sealer and dry , and with the right makes of everything ,good luck with the floor

[Yorkshire Tiling Services]

[quote=Dave;382971Nick.. have you seen the newer LL screeds.?[/quote]

Had a good meeting with Alan Jackson from Lafarge a while ago. The problem is,that altough they supply LL screeds,the sad fact is that many are not being installed according to spec.. causing excess laitance.
Also to add, there are also other Lafarge screeds out there,which are not directly supplied by the Gyvlon arm of the company. One such is Lafarge screed 10. This can be confused as Gyvlon... do not want to go into too much detail publicly.But the screed in question even got Lafarge confused as to what it was !
The fact is that even if a screed is supposed to be LL, then it should still be looked at closely to ensure that is so. I had a Gyvlon LL screed to tile last year,that still needed 3mm laitance removing before it could be tiled.
i got a specialist company in that I know... they diamond abraded a 60metre floor for me in 30 mins... totally dust free and flat.
In an ideal world we could trust LL, BUT I do not think we are there yet.
The way forward is for tilers to do their own screeding. Lafarge are interested in training tilers to do just that !
I,myself am going on a Lafarge Gyvlon screeding course in a couple of weeks.Another string to my bow. Have already got a few contacts lined up for work.

[Dave]

3mm is too much to remove from any screed,, that can take it below recommended thickness.. at most laitence should be around 1mm to 1.5mm.. excessive watering can effect as we know but a slump test should be done to determine the flow rate before the pour.

So many normal screeders think they can do flow screeds and the cannot.. some really bad pours being done at present..

[Colour Republic]

Had a good meeting with Alan Jackson from Lafarge a while ago........

I thought Alan Jackson and Ajax123 were one and the same

[Ajax123]

I thought Alan Jackson and Ajax123 were one and the same

damn - that's me cover blown.........

[simonb43]

HiYrkshire Tiling, how do you get on a screeding course for the Gyvlon mate ?? Any links to a website available ?

[phillacey]

Hi Ajax, do you have any contacts for gypsum adhesive please as have not been able to track any suppliers down.

regards

[nybor62]

try this company phil
http://www.creative-impressions.com/...20Adhesive.pdf

[Dave]

Hi Ajax, do you have any contacts for gypsum adhesive please as have not been able to track any suppliers down.

regards

Weber also do one..

[Ajax123]

Get hold of Sab at Creative Impressions for GBTA
Get hold of Mark Birch at Weber for Anhydrite.col (no point speaking to anyone else at this stage at Weber
Get hold of Darren Silver at Forbo Flooring about Alphycol.725

Contact numbers should be available at the websites for each company but if you struggle I can let you have some of them. I don't want to post mobile numbers on the forum without permission.