Problematic Anhyrdrite floor!

[jonnyc]

Thanks Ajax...thats what I thought. As mentioned I didn't sand the floor as screed company said not to...I did try to sand and scrape a part but nothing came off...no dust...nowt. If moisture is the cause who is to blame? I don't do a bomb test and relied on dates given by customer and screed company who now say 120 days not 75 as previously. I told customer not to put up heating but he did so just my word against his. The heating to the travertine floors has been physically shut off for now so that if moisture levels are too high the floor can still breathe and hopefully be ok. Failed floors are porcelain. This type of screed obviously has some benefits...but not as regards tiling onto!!!!

i still havent seen any benefit at all in having these screeds except that they can be laid in a day. everything after that is aggro and more time.
even the notion that you dont need expansion joints through doorways is nonsense and has been proved to me many times unless the screed was badly laid

 

[jonnyc]

If the trav is solid and just the porcs came up after heating, then i think it is a strong possibility that it was heated to quickly.. if the heating was ran for 3 weeks then i doubt much moisture was left in the screed..

porcs will react a lot different to thermal shock than stone as porcs rely on polymers to hold the tiles where as stone with hold in the capillaries/structure of the stone backs.. so the thermal stress will make porcs pop easier if subjected to heat to fast as the adhesive would not be at full structural strength till at least 28 + days.

So don't be quick to blame moisture / sulphate delamination till you see how quick the floor was heated up.

this is a very good point dave. but if the screed under stone still has a bit of moisture in it do you think that if heating turned on say to 20 degrees over 4 days in equal increments held for 4 days and brought down over 24 days this might be ok.I only say this as it does seem that there are far more failures on porcelain than stone floors.

 

[jonnyc]

well i should have read from beginning before posting anything about this but it seems like the same old problem occurring.
now i respect the time you spend helping to educate us and your considerable experience with these screed ajax , but i do not accept your statement that these type of screed are here to stay and we should all embrace and learn or just not bother.
why should they be here to stay?
if enough tilers refuse to tile over them then they will not continue.
its not about being stuck in a time warp either . people of 40 yrs old and above and i would say that is quite a lot of the experienced tilers on this forum have dealt with and adjusted to massive changes within our industry and many of us would truly say that the changes in materials we fix whether finished stone/porcelain or even the prep work has given us a more interesting trade .

 

[jonnyc]

sorry had to start again for fear of losing post.
getting back, there are many instances of a bad product being brought to market and not succeeding.
why not because people did not like it!!
it is ridiculous to tell us that anhydrite is here to stay if we like it or not.
it seems to me there has been some very good sales pitch and patter to convince the average contractor that he is gaining by having one of these screeds.
I can say for myself only that i have counted 18 anhydrite screeds that i have stone and porcelain on to date.
without exception there is not as single contractor that used this screed that has done so again.
this is not because my tiles have failed but simply because beyond the obvious time saving of maybe doing 500 mts in a day in a big house top and ground. the waiting time and prep work they have to do is not worth the aggro. full stop.
perhaps if these screeds were laid in a professional manner as assumedly they are in germany/france then we might profit from an amazing level screed /latence problem sorted by screed company and we could all carry on as normal.
but this is certainly not the case here .

 

[DHTiling]

this is a very good point dave. but if the screed under stone still has a bit of moisture in it do you think that if heating turned on say to 20 degrees over 4 days in equal increments held for 4 days and brought down over 24 days this might be ok.I only say this as it does seem that there are far more failures on porcelain than stone floors.

heated to 20 degs or above in 4 days is IMO too quick.. but it is also how soon the heat is introduced.. not many wait a month to do this..

 

[jonnyc]

I got a full house on Gyvlonn LL to start next week.... nee bother at all.. ... what is the issue with these floors... you tile to skimmed walls . ? just think of a large skimmed floor.. same to prime , just longer to dry..

if only this was so easy dave.
what precautions have you made for this particular job,
have you tested this yourself and if so with what test meter.Or has someone else and if so, have they submitted a report in writing that would cover you in eventuality of any failure .

 

[doddy41]

Woudnt touch one of these floors with a barge pole too many things to go wrong

 

[DHTiling]

if only this was so easy dave.
what precautions have you made for this particular job,
have you tested this yourself and if so with what test meter.Or has someone else and if so, have they submitted a report in writing that would cover you in eventuality of any failure .

It is for a builder i have done tiling for, for a lot of yrs.. he force dries the floors.. last 3 have been done this way... easiest way to get them dry.. you can force dry a floor in 10 days... we run them for 3 weeks.. to make sure they are dry...

Some the damp testing methods are flawed IMO as they give a true reading at optimal conditions etc and not often that happens... we are told you need to do this and that.. then a few months later they change the goal posts and change their advice..

An example of this is the screed reps.. they say to make sure dry and use acrylic or epoxy primer.... NOW!! they say it is best to use a gypsum adhesive that are not even covered under BS..

So IMO force drying when they are heated is the option we go for , if the floor is not heated , then i don't touch .. but not tiled a none heated one yet..

These screeds are here to stay IMO , as they are quicker to lay and stronger than S&C screeds and of course cheaper as the speed of laying out ways the labour of a traditional screed.

When they first started to get mentioned on here , i had not even seen the in my neck of the woods but the past 2 yrs i have come across quite a few and this is the 4th for this builder as he likes these screeds..

This house is Gyvlon LL on both floor levels of the house.. and 3 bathrooms and over 60 mtrs i am told down stairs... the last one was 160 mtrs down stairs and when i first did one i bricked it because of all the scare mongering over this type of screed.. but the more i do the more reliant i am over them..

The biggest issue is the screeder .. they are a nightmare if not controlled properly as they over wet them to speed up the levelling out and this is what can cause friable surfaces and BIG failures.. make sure who ever is there when the screed is poured watches the slump test fro each pour to make sure it is the right consistency to get a nice strong hard screed.

 

[Ajax123]

It is for a builder i have done tiling for, for a lot of yrs.. he force dries the floors.. last 3 have been done this way... easiest way to get them dry.. you can force dry a floor in 10 days... we run them for 3 weeks.. to make sure they are dry...

Some the damp testing methods are flawed IMO as they give a true reading at optimal conditions etc and not often that happens... we are told you need to do this and that.. then a few months later they change the goal posts and change their advice..

An example of this is the screed reps.. they say to make sure dry and use acrylic or epoxy primer.... NOW!! they say it is best to use a gypsum adhesive that are not even covered under BS..

So IMO force drying when they are heated is the option we go for , if the floor is not heated , then i don't touch .. but not tiled a none heated one yet..

These screeds are here to stay IMO , as they are quicker to lay and stronger than S&C screeds and of course cheaper as the speed of laying out ways the labour of a traditional screed.

When they first started to get mentioned on here , i had not even seen the in my neck of the woods but the past 2 yrs i have come across quite a few and this is the 4th for this builder as he likes these screeds..

This house is Gyvlon LL on both floor levels of the house.. and 3 bathrooms and over 60 mtrs i am told down stairs... the last one was 160 mtrs down stairs and when i first did one i bricked it because of all the scare mongering over this type of screed.. but the more i do the more reliant i am over them..

The biggest issue is the screeder .. they are a nightmare if not controlled properly as they over wet them to speed up the levelling out and this is what can cause friable surfaces and BIG failures.. make sure who ever is there when the screed is poured watches the slump test fro each pour to make sure it is the right consistency to get a nice strong hard screed.

David... When was this one laid mate...if you know?

 

[DHTiling]

Around 7 to 8 weeks ago... heating has been on for 4 to 5 weeks... summit like he said 🙂