What tile adhesive is used for large format tiles?

[stevep1]

agreed but with tiles a meter long and walls far from flat and a client who wants tiny joints with no lips at all i'm gonna end up having to pack them out. the suction effect isn't going to always be viable. i always do skim the back of every large tile anyway. on a window sill in the first bathroom i spread the sill 6mm trowel and banged down marle mosaic. when i pulled them up after a week they came up with all the addy leaving the sill spotless. that was a benfer flex on primed sill. did't leave a mark.

 

[DHTiling]

Is it worth switching adhesives then..

I use Mapei Keraflex maxi and it grabs like a sex starved maniac..:lol:

 

[White Room]

Has the plaster been so highly polished allowing no suction to break thru the glaze

 

[stevep1]

lol. i've tried 4 makes now. bal,benfer,weber,palace. not mapei yet. worth a go. starting to lose the plot. like i said never had a problem with any of these makes before. have spoke to people who have been tiling alot longer than me who wouldn't use anything else. priced two jobs today foung myself asking the woman what make of plaster she had on the walls. she looked at me like i had two heads . amazing how a knock back can dent your confidence

 

[stevep1]

it might be the plaster.part of one wall had a mist coat which i primed and tiled over. when the tiles pulled off the mist coat came off the wall too. clean off. doesn't look like anything wants to stick to this plaster.

 

[Aston]

i know its the plaster and it will stick if sealed correctly...

seal coat leave over night
sbr, higher ration , leave a while then tile..

 

[DHTiling]

it might be the plaster.part of one wall had a mist coat which i primed and tiled over. when the tiles pulled off the mist coat came off the wall too. clean off. doesn't look like anything wants to stick to this plaster.

AHH!! Contamination...😳... sticking to emulsion is a no no..

 

[stevep1]

yeah i know . that doesn,t explain the other 95 % of the walls. if it's the plaster what's the next step. or do i keep trying adhesive til i get one to stick.

 

[DHTiling]

Not really...

Is the plaster polished,,? does the primer skin..

 

[stevep1]

the neat one definately did. like peeling sun burn. not the other coats though.

 

[White Room]

If the mist coat was'nt sticking to the walls as my previous post the plaster maybe over polished, even a mist coat won't soak into over troweled walls

 

[stevep1]

trouble is we electric sanded one wall to rough it up incase it was over polished. then tested on that every day along with the others.

 

[DHTiling]

Steve..

When priming try a 4:1 coat... priming to neat can cause it too skin.. watered down coats work better

 

[White Room]

Has the plaster been contaminated with something, did any of the primer seperate when applied to the walls.

Did you upset the plasterers by any chance ??

 

[stevep1]

we started with 1-4. only went to neat as a test when nothing else worked. and on the advice of palace tech. some people say dont make a barrier between tiles and wall and others say you have to because of the plaster and addy reacting. never had it before pray i dont again.

 

[Aston]

how long did you leave the 4 to 1 ratio ? before the next coat??

 

[stevep1]

dont think it seperated. they seemed like decent chaps (for plasterers). i know the house owner went through a spell of sacking plasterers. i dont suspect sabotage though.

 

[DHTiling]

The reaction is ettringnite and it can take 2 coats etc to fully protect and as i said before if you apply neat it can skin.

I am finding it difficult to give a reason now steve as all that i use works for me ..

Your failures haves lost me.. lets see if another set of pro eyes can recommend something..

 

[White Room]

The plaster can be very absorbant so thats a good reason to prime alone other than enttringnite

 

[stevep1]

the first 4-1 coat was dry in 15 mins . i would say the next one went on an hour later

 

[stevep1]

i've lost myself. everything i've ever done before this job has worked for me too. thanks for your time and suggestions its really appreciated

 

[White Room]

Is the plaster all gypsum, as in a float and set or sand cement then a finish

 

[stevep1]

gypsum. thats why we went with palace tilers primer. it says on their web site to use it neat when sticking to gypsum with a cement based addy. since then i have tried everything

 

[White Room]

No, what I meant steve was a browning, hardwall, bonding or sand cement backing used on the block walls before the plaster finish was applied

 

[DHTiling]

Steve.. my apologies.. i am kind of slurped.. i will ,if not resolved tomorrow have another sober look..

 

[stevep1]

a 3 mm skim coat of gypsum finish over plaster board. i explained the weight issue but was told to go ahead. that wouldnt explain the tests ive done with 300mm cuts from the ceramic tiles that wouldnt stick when stood up against the wall

 

[stevep1]

i'm having a few myself. been one of those weeks

 

[Aston]

steve
how long did you leave the 4 and 1 coat of sbr? before applying the 2nd coat
just answer that for me please

 

[stevep1]

about an hour

 

[Aston]

thats why!!!!!

you should have left the 4 and 1 overnight, 24 hrs preferably THEN
do your 2nd coat of sbr the next day, then tile........viola

1st coat seals and absorbs into the plaster, needs adequate time to set and take effect
next coat is the bonding coat, which then sits ontop of the sealing coat and adheres/fuses and stablizes..

 

[stevep1]

if that's the answer my friend i most definately owe you one. i will be there in the morning applying my first coat of 1-4. to a fresh new wall. the same monday and a test tile tuesday :hurray: