Anhydrite Screeds: Are You Confident When Tiling To Them?

[Dave]

As the market is growing very fast for Anhydrite screeds , are you as a tiler ok tiling to them and are you confident in doing so.

 

[Ian]

I am doing one as we speak. I am 100% confident on how to deal with them having done approx, 250 m2 now. Follow the correct procedures and you will be fine; remove laitence, then moisture test after this has been done, commission UFH, then moisture test again, use a suitable gypsum based adhesive to either stick tiles or any membranes and always tank any areas that are likely to get wet.

 

[Andy Tiler]

I am doing one as we speak. I am 100% confident on how to deal with them having done approx, 250 m2 now. Follow the correct procedures and you will be fine; remove laitence, then moisture test after this has been done, commission UFH, then moisture test again, use a suitable gypsum based adhesive to either stick tiles or any membranes and always tank any areas that are likely to get wet.

Are gypsum screeds/adhesive used in wet area bri?...

 

[Dave H]

Hi Dave, dont like tiling on them as allways an element of doubt, but have now laid in the region of 600m2 on to it, though
most has been hemihydrate screed (mayhew easyscreed), same beast/ different name! havent tried gypsum adhesives yet, but always use black pad on polisher to sand floor, hoover, check moisture content is at low enough reading and prime with Bal APD two coats, first diluted 1-1 neat 2nd coat, then lay ditra and tile. worked so far, but still worry about it!

 

[DHTiling]

I think we all have doubts now and again dave..

I like your method of using the black pads.. how long them they last mtrge wise.?

 

[Ian]

Are gypsum screeds/adhesive used in wet area bri?...

In the first house I did all the bathrooms were wet rooms and all of them had calcium floors, all waterproofed with dural ci++ and corners/joints taped, lapped 100mm up the walls as well.

 

[DHTiling]

In the first house I did all the bathrooms were wet rooms and all of them had calcium floors, all waterproofed with dural ci++ and corners/joints taped, lapped 100mm up the walls as well.

I have had a few wet floors now with Gyvlon and the latest was Gypsol .. as you , i fully waterproof them out to prevent any water getting to the screed.. these screeds are poured long before we get to know the use of the room ..

 

[Ajax123]

Some stuff in here that mit be helpfull. havent got round to addin tile master to the list of suppliers yet

Broken Link Removed

 

[Dave H]

I think we all have doubts now and again dave..

I like your method of using the black pads.. how long them they last mtrge wise.?

Normally last for about 200m2 depends how much laitance on floor less on hemihydate screeds

 

[Stef]

Having a moisture test done this week on a Gyvlon screed.
They (builder) are a bit apprehensive about it but I've told them to follow correct procedure & it will be fine.
Still trying to talk them into getting an order from Lee @ tile town for tile master adhesive.

 

[White Room]

I have'nt had the privilege yet but mention to other trades and they have'nt a clue and never heard of it.... :confused_smile:

 

[DHTiling]

I have'nt had the privilege yet but mention to other trades and they have'nt a clue and never heard of it.... :confused_smile:

Now that is very true..

 

[Diggy]

HOW is the moisture test done? Only ever done 1, was flat as a pancake. Did the latence removal and primed twice with "primer G' as i recall. Never had call backs from ir and that was around 8 yrs ago.

 

[Stef]

Question..
How do you know what the screed is?
Say the screed has been down a couple of years & no one knows who poured it, how do you test to find out if its concrete or a calcium screed?

 

[Ian]

Question..
How do you know what the screed is?
Say the screed has been down a couple of years & no one knows who poured it, how do you test to find out if its concrete or a calcium screed?

That is a good question Stef, I don't know if there is an official test that can be done but, they are a different colour to S&C, sort of a yellow colour. If the floor has been carpeted there's a fair chance the laitence will still be there as well, normally some around the edges where the sander couldn't reach, I had to do the edges on this one I'm doing, the sander the builder used left a 100mm band by the walls!!!

 

[Stef]

Bri, I've been looking at this floor I'm going to be doing for a couple of weeks now.
There is very little laittance coming to the surface of the screed & I would struggle to tell what it is.
I can't believe how hard the screed is.

 

[Ian]

Hopefully Alan can give us an answer to your question, it'll be something really simple no doubt.

 

[gamma38]

Same as Whitebeam for me, not had the pleasure as yet... It's just a matter of time for us all though i reckon. But by that time there will be a new screed out that's even better than the last...

 

[Stef]

Well Moisture test done today,



Start tiling tomorrow!!

 

[Ian]

Lol, how long has the screed been down?

 

[Stef]

Lol, how long has the screed been down?

Pumped in on the 9th of July.

They are pushing to get the floors tiled.
Be about another 6 weeks before the floor is probably ready for tiling.

Got asked today if we could fit some sort of Mat (membrane) to speed up the process.
Can anything be put on a Gyvlon screed to speed up the process?

 

[DHTiling]

NO!!! you can't , the only way to speed up the drying is to force dry it , is it heated,.?

 

[Stef]

It's getting forced dried just now Dave.
The heating has been on for just over 2 weeks.
I told them I didn't think you could do anything else to aid drying but I would ask the question.
It's not been sanded yet, I told them to sand it after 2 weeks but its still not been done.
We will see what they want to do..

 

[DHTiling]

How high have they got the heat..?

 

[Stef]

How high have they got the heat..?

Not sure as they rigged up a small cylinder heater to heat the floor.
It's running almost full pelt & the house is boiling.
The heating will eventually be source fed from below the field out the back of the house with a 10kw heater in the house.
One of these "Green" efficient heating systems.
The moisture in the house was unbelievable a couple of weeks ago, it was running down the insides of the windows.
Windows are open all day now to let the moisture escape.
Guys that were on site today reckon another 6 weeks before the screed will be anywhere near dry.

 

[DHTiling]

That seems a long time .. ? but this does depend on the heat of the screed though ... if it is only say 20dgs then it should be around double that to force it dry in 2 weeks or so , so the lower the temp and poor ventilation , then it will take longer.

 

[Stef]

Dave, I'm going to check in the morning & get them to get it turned up as far as possible.
As soon as the hygrometer was put on the floor it was registering 70+rh, wasn't even on an hour & it was up at 100%.
I reset the box & moved it about 6 feet & sanded a patch for it to sit on.
40mins later & we were almost off the scale again.

 

[DHTiling]

It is no good testing for RH whilst the heating is on .. false readings ..

 

[Gazzer]

The hygrometer needs to be in place for 24 hours before turning it on, then a further 24 before the reading is taken.

 

[Gazzer]

The heating should be off for 3 days IMO