Hello all, some of you will know that I managed to get my hands on some of the Weber gypsum based adhesive last week (many thanks to Ajax123). Thought I would put up some info given to me by Weber as Im starting to see more and more anhydrite screeds and VERY few people seem to know how to work with it or the materials on the market suitable for the job and as the bags are in french thought it might be a help. I hope this post will go with the many others on here regarding anhydrite screeds and help people avoid disasters.

Weber.Col Anhydrite 2

A rapid-setting, flexible, lightweight tile adhesive for anhydrite screeds.
It is used to fix creamic, porcelain and natural stone tiles to anhydrite screeds.

Technical data

• Bed thickness 3mm-6mm
• Coverage (approx.) 2.7kg/m2 (solid bed 3mm thick)
• Open time 20 minutes
• Working time (pot life) 1 hour
• Set time 4 hours-light foot traffic
• Temprerature resistance -30 degrees to 70 degrees
• Water addition 6 - 6.5 litres per 15kg bag

Note: Setting times quoted at 20 degrees and are temerature and humidity dependant

Uses

• Interior
• Floors
• Heated floors

Constraints

• Not recommended for tiling onto substrates other than anhydrite screeds.
• Not recommended for tiles with resin backs.
• Not recommended for areas that may become wet.

Features and benefits

• Can be used as a pourable adhesive
• Lightweight for easy transportation and application
• 15kg of Weber.col anhydrite 2 covers the same area as 25kg of traditional adhesive
• Flexible for heated screeds
• Suitable for tiles up to 600mm x 600mm
• Ready for light foot traffic after 4 hours

Preparation

• Ensure that all surfaces are clean, dry, sound and free from dust, grease or any contaminating barrier.
• Remove any laitance by sanding and make good any unsound areas.
• Prime with Weber PR360 and allow to dry
• Check before use that the adhesive does not cause staining or discolouration of light coloured or translucent tiles.

Mixing

• Gradually add the bag of adhesive to 6 - 6.5 litres of clean water until a smooth workable paste is achieved.
• Allow to rest for 10 minutes
• Use within 1 hour of mixing
• Do not attempt to extend pot life by adding more water to the mix

Application

• Pour the adhesive onto the substrate and spread with a solid bed trowel.
• Use a suitable notched trowel to achieve a solid bed of 3-6mm.
• Tiles with studded backs may need to have adhesive buttered onto the back as well.
• Do not apply more adhesive than can be tiled within 20 minutes.
• Bed tiles down firmly into the adhesive with a slight sliding and/or twisting action to ensure a good contact.
• It is good practice to lift an occasional tile after fixing to verify that the required contact is being achieved.
• Leave appropriate clearance joints for grouting
• Make any adjustments within 10 minutes
• Carefully clean off any excess adhesive with a damp cloth or sponge from the tiles and joints before it sets.
• Leave for at least 4 hours before grouting (longer at lower temp).

Allowance for movement
Flexible joints should be incorporated to allow for slight movement due to changes in temprature, humidity etc. as inicated by BS 5385:

• Where the tiling meets other materials (e.g. floor perimeters)
• Along all internal corners - vertically and horizontally
• Over existing movement joints or changes in backround material
• Dividing large tiles areas into bays (every 3-04.5m on walls, 8-10m on floors)

Packaging

• Packed in plastic lined paper sacks. Grey:15KG

Coverage

• Coverage is approx. 0.9kg of powder per m2 for every 1mm of bed thickness

Storage and shelf life

• When stored unopened in a cool dry place at tempratures above 5 degrees, shelf life is 6 months from date of manufacture

Health and safety

• Harmful by inhalation. Irritating to eyes and skin
• Keep out of reach of children
• In case of contact with eyes, rinse immediately with plenty of water and seek medical help
• After contact with skin, wash immediatly with plenty of soap and water. Wear suitable protrective clothing, gloves and eye/face protection.

Thanks for the useful thread ,have you actually worked with this adhesive ?

Might be useful to know what it was like to work with - pot life, working time, setting time, ease of mixing and spreading etc......

And always heed this..

Not recommended for areas that may become wet.

I'll sticky this. Nice one.

Thank you gents. I am using it in the morning so rest assured will add to the post then, although I will only be using it to lay Ditra so I might not be able to give a very detailed review. I have think Captain Slow is using the same stuff soon so Im hoping he will be able to fill in the blanks I leave

That made my ears prick up as well Dave.

Just to add, both me and the supplier that I used to get this adhesive in were told by one of the reps that there is no need to prime the anhydrite screed before tiling, then when I got hold of the info above it clearly states to "Prime with Weber PR360 primer and allow to dry". Not to blame the rep but there is very little info on this stuff and I want to stress the importance of making sure that the prep is right.

I would be very careful on the drying time of the primer, have you already primed the floor ?

Yes I primed today.

a lot longer pot life than , creative impressions gypsum based addy,
how long as the webber one been on the market

Originally Posted by nybor62

a lot longer pot life than , creative impressions gypsum based addy,
how long as the webber one been on the market

I couldnt say how long it has been in production, it is only available from france and in french bags. Iv been told that there are no british standards regarding gypsum based adhesive, thats why its not made or sold over here.

What adhesive is the creative impressions?

Originally Posted by nybor62

a lot longer pot life than , creative impressions gypsum based addy,
how long as the webber one been on the market

It has been in the uk market around 5 months now if i recall right..

i did a job last year , gyvlon floors about 300 m2 in total using creative impressions gypsum addy as recommended by ajax , who did come out to see me on the job, have never had a call back the addy worked great
but the pot life was about 20 mins , you could only mix about enough for 2-3 m2 at a time
ajax was most helpfull top man

Originally Posted by nybor62

a lot longer pot life than , creative impressions gypsum based addy,
how long as the webber one been on the market

in France for several years. In the UK since about mid last year. I have been pestering various suppliers to get their gypsum gear into the UK and Weber listened. There are a few others on the way as well. The creative impressions stuff I think has had a slight change to formulation to give it a longer pot life as well. As for wet areas bear in mind the adhesive should not be used in areas where IT (the adhesive) might become constantly or persistently wetted. I would not use it in a walk in shower for example but I would be happy to use it in a domestic kitchen or bathroom.

Originally Posted by Dylante

That made my ears prick up as well Dave.

Just to add, both me and the supplier that I used to get this adhesive in were told by one of the reps that there is no need to prime the anhydrite screed before tiling, then when I got hold of the info above it clearly states to "Prime with Weber PR360 primer and allow to dry". Not to blame the rep but there is very little info on this stuff and I want to stress the importance of making sure that the prep is right.

It will depend largely on the moisture content of the screed at the time of tiling. the primer is essentially just to prevent the dry screed from sucking the moisture out of the adhesive. If the moisture content is high in the screed say up to 2% then the screed will not suck the life out of the adhesive and the screed may not need to be primed. I think though for the time being untill someone can offer a warrant that not priming will be ok I would prime.

I have been using the Weber adhesive today, no problem at all to work with. The bags are suprisingly easy to lug around (didnt realise how used I had got to lifting 20/25kg) being only 15kg. Mixed up well, hard to describe but felt very fine but with gritty bits in it. I was using it wet as I was pouring with it, pours out nicely and hold the notches of the trowel very well as well as being nice and creamy to spread around. I was expecting to have limited time to work with it but if anything I would say that it wasnt going off quick enough but this may have been down to the fact that it was a cold and damp day.

I have left a little bit of mixed gypsum adhesive on the screed in a room that is not being tiled and I am going to leave a little bit of cement adhesive next to it so that I can see how much better the gypsum bond to the anhydrite screed than the cement.

So all in all a big thumbs up to the Weber gypsum based addy, I hope it is easier to get hold of soon as it is nice stuff to work with

Could I ask which suppliers stock it and how much does it cost?
I have just looked a job (60 x 60 porcelain floor, appx 30m2, Under floor heating, anhydrite screed)
The client has had the floor laid twice by the same company and the tiles have blown completely. The company has now also gone bust!!
I was planning to strip everything off, cut out around the perimeter and install an expansion strip through the screed, scrabble the top of the screed,
prime as required and re-tile using Weber.set flexi. But, I would use the gypsum based addy if it is available.
Does anyone have anything to add to what I have planned?

Originally Posted by Rich

I have left a little bit of mixed gypsum adhesive on the screed in a room that is not being tiled and I am going to leave a little bit of cement adhesive next to it so that I can see how much better the gypsum bond to the anhydrite screed than the cement.

So all in all a big thumbs up to the Weber gypsum based addy, I hope it is easier to get hold of soon as it is nice stuff to work with

Rich, how did they compare in the end?...... a long time ago I know, but interested to see as got an anhydrite screed job soon. Ta mate

N&C Nicobond are just about to launch their gypsum based adhesive to market. It is called Gypfix and will undoubtedly be in their distributors in the next few weeks. Site trials are being carried out as we speak. Also Creative Impressions are now looking at increasing their own distribution network so at last the industry looks like it is listening to the need for gypsum on gypsum.

I think the weber stuff has been temporarily withdrawn due to the French packaging

Doh! Cheers for that!

Originally Posted by Ajax123

N&C Nicobond are just about to launch their gypsum based adhesive to market. It is called Gypfix and will undoubtedly be in their distributors in the next few weeks. Site trials are being carried out as we speak. Also Creative Impressions are now looking at increasing their own distribution network so at last the industry looks like it is listening to the need for gypsum on gypsum.

I think the weber stuff has been temporarily withdrawn due to the French packaging

Weber are going to make it in the UK.. should be out late this year to early next year.

I missed this thread first time round - Doh!
Yeah, I did around 80sqm of 600 x 600 porcelain with it at the beginning of the year. As Rich has said it is easy to work with, although you do need to clean your trowels regularly otherwise they will just get gummed up and trashed. I used it to stick tiles directly to the screed and to stick the "old style" Dural Ci in the wetroom.

I've got some pics of the coverage on the back of a tile and it is good; I'll try and find them.

But as Dave advises, the product is not actually available through the UK market yet so you'll need to source another manufacturer shorterm.

I will be trialing the N&C offering in approx 4 weeks time which I'm looking forward to. All the technical information and support that I have received from N&C to date has been excellent and I am satisfied that the product will perform well. I'll try and do a report once the project gets underway.

you changed your name Daz.......you speeded up a bit now then or what?? ;P

Alan, I thought Daz was more personal especially as that is how most regular contributors know me.

I had a chat with a Weber rep the other week and he told me that Weber were pulling their gypsum adhesive because they are very close to developing an adhesive that will bond to both cement and anhydrite screeds and they have had far to many people using it to tile onto sand and cement.

Geoff, I left that site before I could find out the results of my little experiment unfortunately.

Firstly I'm a DIY'er if that makes any difference but I'm also an industrial chemist and this bonding to calcium sulphate screed is really interesting....I'll get my coat ;0)

After having a chat with Ajax I've plumped for the Gyvlon screed, 35 square meters laid by these guys... TW Pump Hire - Liquid / Flowing Screed Application (ps thats not an advert as I'm not connected at all but merely recommending them from experience)

It's been in a while now and we've had the wet UFH on so it should be quite dry. Now as a DIY'er trying to find somewhere that did Gypsum based adhesive was neigh on impossible however by luck creative impressions is located about 20 mins from where I live. I took a drive down there yesterday and picked up some bags of their GBTA along with some primer.

I decided for the sake of the short while to prime the surface after ensuring all the laitence had been removed. The primer looks very much like PVA although it did smell like it had some type of ammonia based compound mixed with it. Two coats of primer went on easily and was no issue at all.

I'll report back as to the use of the GBTA and my experiences once completed.

Two tilters type questions first if that OK?

I'm putting Tavertine 60x40 stone down, what bed size would you plump for? I was going to work on 3mm however I'm not sure if thats sufficient?

Also the room is open plan so I was going tile half of the room, move the furniture, kitchen units etc to the other half once tiled and allowed to dry and do the other half... will this be OK?

Cheers for now..

Ant

Hi Ant & welcome to TF,

Travertine, 35sqm & wet UFH.....have you considered a decoupling membrane too?
A decoupling membrane will eliminate any lateral movement and therefore reduce the risk of the stone cracking with the UFH.

How thick is the travertine? This will help advise the most suitable trowel size to use.

As far as furniture is concerned, you will be fine moving things around provided everything has dried properly. Just be careful with regards to scratching, sealing etc..

Good luck,

Daz