Decoupler and anhydrite

[Gazzer]

It would be great if we all lived in an ideal world where everyone listened to each others concerns & advise & we went about jobs by the letter of the law!!! aye we all wish.
Sir Ramic you have a very good point there, i know very little about Gyvlon screeds, only what i have read on posts here, & it sounds a bit of a headache also.
We are running 3 sites just now but we havent heard anyone speak about new screeds yet. at least with these posts we will be prepared for if & when it does come.
I will keep you posted when this job goes belly up!!:nopity:

The builder who has had these 3 floors I am about to tile knew nothing of the concerns of floor layers regarding the Gyvlon. he went along with what the screeder suggested. Its early days for us all but we all need to know the score, the internet and forums like this are one of the best ways of keeping on top of things.

 

[Stef]

The builder who has had these 3 floors I am about to tile knew nothing of the concerns of floor layers regarding the Gyvlon. he went along with what the screeder suggested. Its early days for us all but we all need to know the score, the internet and forums like this are one of the best ways of keeping on top of things.

Totally agree with you there, This forum is worth its weight in gold, No matter how long you been at it theres always something to learn.

 

[Gazzer]

Totally agree with you there, This forum is worth its weight in gold, No matter how long you been at it theres always something to learn.

Amen to that, its the folk who think they know it all that I worry about. Times are moving and we all need to move with them .

 

[Ajax123]

I certainly hope anhydrite is the way forward...... My livelihood certainly depends on it. Robson, you can always ring me at work if you need some advice 07545 932723

 

[doug boardley]

Robson. If you use cement it WILL fail. If you use gypsum it MIGHT fail. If you use cement it will delaminate along with the tile thus leaving the tiles un useable. I have never seen a failure with a gypsum day yet but my understanding is that the failure due to moisture is at the tile addy interface. This means that the tiles would come away clean and be reusable. Not sure if this is true or not. This job could be the way to find out though cos sure as eggs is eggs if you tile it next week it won't be dry. The underfloor heating should also be commissioned. This one seems doomed. The trouble for you is that as a professional you are accepting a contract and carrying out an installation that you know to be incorrect. A disclaimer may not cover you and you could end up liable for the inevitable repairs. My personal advice ........ as a self confessed anhydrite expert....... Walk away from it or do it properly. At 70mm which itself is far too deep you will be looking at two months.

what is the optimum depth for a gyvlon screed Al?

 

[Ajax123]

As close to the minimum depth as possible.40mm floating commercial unheated35mm floating domestic unheated30mm cover to heating pipes so 45mm on 15 mm ugh pipe and 50mm on 20mm pipes30mm unbonded25mm bondedAnything more is un necessary but screeners are often forced to put more in by poor specifications and poor building quality.

 

[Stef]

I certainly hope anhydrite is the way forward...... My livelihood certainly depends on it. Robson, you can always ring me at work if you need some advice 07545 932723

Al, thanks very much for that, we will see the boss tomorrow morning & see how he wants to go about this. Talking to my business partner today & told him all about this scenario, we are going to try & talk him into putting down linolium for the time being then we will go back & tile once the floor has fully dried out. :mad2: (this is what i will be doing)

 

[doug boardley]

As close to the minimum depth as possible.40mm floating commercial unheated35mm floating domestic unheated30mm cover to heating pipes so 45mm on 15 mm ugh pipe and 50mm on 20mm pipes30mm unbonded25mm bondedAnything more is un necessary but screeners are often forced to put more in by poor specifications and poor building quality.

any chance of having that in english Al??:lol::lol:

 

[Ajax123]

Al, thanks very much for that, we will see the boss tomorrow morning & see how he wants to go about this. Talking to my business partner today & told him all about this scenario, we are going to try & talk him into putting down linolium for the time being then we will go back & tile once the floor has fully dried out. :mad2: (this is what i will be doing)

Then sadly you would be making a mistake.........no offense intended. The screed dries purely by evaporation from it's surface. Covering it with an impermeable covering would stop it drying......you coul put a breathable carpet down. It would be best though to commission the heating and force dry the screed over the next two or three weeks then tile it using a gypsum addy

 

[Stef]

Then sadly you would be making a mistake.........no offense intended. The screed dries purely by evaporation from it's surface. Covering it with an impermeable covering would stop it drying......you coul put a breathable carpet down. It would be best though to commission the heating and force dry the screed over the next two or three weeks then tile it using a gypsum addy

i wasnt sure if you could force dry the screed, wasnt sure if it would crack it. i assume the heating has been commissioned by now i will find out tomorrow.
i told you this was just going to keep being a nightmare for me, happy days. will speak to him tomorrow & see what he says about this.
thanks again Al for your help on this matter its appreciated.

 

[DHTiling]

Commissioning the screed is the quickest way.. These screeds are going no where, so get to know them and you will be fine..

We need to get some more training days sorted..

 

[Ajax123]

Commissioning the screed is the quickest way.. These screeds are going no where, so get to know them and you will be fine..We need to get some more training days sorted..

I'm up for that Dave. Just let me know when.

 

[Stef]

Any chance of doin a course up in sunny Ayrshire? ha. i would like to attend a course on this especially if its goin to get more common as a screed.

I take it anhydrite will not crack if you force dry it then? would a dehumidifier also help? need all the info i can get so i can show him this tomorrow.

 

[DHTiling]

These might help..

View attachment Calcium Sulphate Tech sheet Apr10.pdf

View attachment gyvlon screeds 2.pdf

View attachment Gyvlon screeds 1.pdf

 

[Ajax123]

Any chance of doin a course up in sunny Ayrshire? ha. i would like to attend a course on this especially if its goin to get more common as a screed.I take it anhydrite will not crack if you force dry it then? would a dehumidifier also help? need all the info i can get so i can show him this tomorrow.

Force drying is actually a recommendation. Take a look at some of the tech data sheets at Lafarge Gyvlon Anhydrite based Calcium Sulphate Flowing Screed. That would help you a bit. The one on drying a gyvlon screed section 3 gives you the procedure but alter it slightly so that you maintain the highest temperature for 7 days instead of just three. No reason to expect it to crack.

 

[Stef]

Cheers folks, if i show him all this then maybe he will realise that its a good idea to wait.

"ALL GOOD THINGS COME TO THOSE WHO WAIT"

 

[Ajax123]

Cheers folks, if i show him all this then maybe he will realise that its a good idea to wait."ALL GOOD THINGS COME TO THOSE WHO WAIT"

If he don't listen put him in touch with me and I shall talk him through it as a suppliers technical manager

 

[Stef]

these were the two floors we tiled over anhydrite screed, the boss wouldnt wait, he knows we are going to be back to sort them but he just wants the clients moved in & then deal with snagging in a couple of months.:mad2: we ended up just using a flexi concrete adhesive in the hope it would delaminate the adhesive from the screed & hopefully delaminate the adhesive from the tiles, we did a test patch & it lifted off the screed but adhesive is solid on the back of the tiles, the boss will just have to go back to porcelanosa & buy more of the same.

Good news is though the next conversion wont be ready for us to tile until the end of November & they are pumping the screed in next week so they are learning, slowly.

 

[White Room]

Client moved in and doing snagging, thats going to be a nightmare..

 

[Stef]

Client moved in and doing snagging, thats going to be a nightmare..

Tell me about it, its not really snagging though ripping up 2 floors to stick them back down. "CRAZY"
The boss is just looking at the £500 large in his bank account.

The joiners are fitting an engineered wood flooring tomorrow (floating over the screed, with all that moisture still in)
We wont be the only 1's doing snagging😳

 

[Ajax123]

As long as it does not bounce back on your pocket Robson. I can guarantee that given what you have done here the adhesive will not stick to the screed for more than a few weeks. It usually becomes noticeable after a couple of months when the grout starts to crack and break up. If you primed the odds are that new tiles will be needed. If you didn't prime the screed may have dried the addy before it had time to grab the back of the tile and it will come off here as well. You never know eh!

 

[Stone]

Hi there,
I was just reading this thread and found it interesting.
Are you saying that anhydride screeds should not be put into wet areas?

 

[Dan]

Just bumping some of the older popular (sometimes not so popular) threads. Probably wont be current discussion these days but I just need to do it. So just ignore the thread if it's not current for you.