polished porcelain problems?

[deankyall]

Hi everyone,am new to this site but have been a tiler for 26 years,as you all know tiling has had a lot of changes in the last few years,and after talking to various people in the trade there seems to be a recurring subject coming up,and i really want to find out if there is any further evidence at all,im talking about polished porcelain,and the fact that almost every tiler i have spoken too,myself included ,also a mapei rep,and my local tile wholesalers all report that after laying of the floor a lot of the tiles debond,nothing seems to really stick these well and the problem seems to be increased with underfloor heating,i have used mapei ,technik,bostik, opf,bal,ultra,no matter ,floors are always primed in my case and i would expect in the other people i have talked to,these are experienced tilers all of over twenty yrs working in the local area,they have all found ,no matter how they are cut, wet or dry that the tiles crack on L shapes, if there has been a tile chipped,when you take it up the tile comes up clean,wether you back it up or dont its the same ,i have tested it,now when i phoned mapei technical department last year they said ,that they had never heard of such a problem as did my local wholesalers,but this week when talking to one of their reps about another subject he mentioned that he had seen this exact thing??,also the local wholesalers ,when changing their displays say they take one knock and off it comes clean, adhesive still on floor or wall,but nothing on tile,now all the adhesives with porcelbond or porcelplus,what is it in these that makes them so,and they appear to make no difference,there is a problem with either the tile or the product,i see there is a few threads on here too,there is no real science to tiling,we all do the same thing ,we mix up, prepare ,and spread adhesive and lay a tile all pretty much the same way so,i look forward to listening to others about this,i have 200 m2 to lay in the next few weeks all on new screed on top of wet system underfloor heating,do i tell the builder that i need detra matting at a few grand? and all the floors will be higher than the rest of the house?or do i lay to screed with these products knowing that there could be problems?how flexible are these adhesives? the rep said they are to a certain extent,but they are cement based and are fairly rigid, his words not mine,combine that with a dense porcelain tile that do not allow moisture to penetrate then i see problems.tilers do not earn enough money to have these problems,if it goes wrong then its expensive ,and if there is something wrong then we should find out.thanks dean

[365drills]

Welcome to the forum and other members (tilers) will answer your questions.

Your concern seems to be that if you lay polished porcelain (I assume large format porcelain) then you fear the tiles will not stick correctly or come unstuck at a later point in time.

There is lots of advice on here and of course everything starts with cement based adhesive but manufacturers mix it with flexible properties to help in this area.

I think the only advice I can give is that if you know your substrate and you prepare well then you should not experience tenting, lifting, moving or debonding of tiles.

Others will guide you to the procedure including movement joints etc but I have to agree we have ALL heard of horror stories.

[hillhead]

Welcome along Dean, i have put down loads of polished porcelain floors and walls and i have not been called back to any or should that be yet? Interesting this as i'v heard nothing until now.
Single part flexi is all i use on them.

[nybor62]

im with hillhead recently did a 2500m2 floor all porc 600 x600, we did have to take a few up because of breakages , very little addy on tiles buts that what porc is like , imo i think its better to use ptb addy 100% coverage every time round notch trowel not 10mm not deep enough imo

[Stewart]

I've put 1000's of metres of porcelain down without a single failure. All the failures I have heard about are due to incorrect prep of substrate, bad fixing methods or incorrect adhesive.

[deankyall]

hi richard ,thanks for the reply,as i said all tilers i have spoken to about this have now experienced this problem,and in the replys below its stated that when one was taken up then there was no adhesive on the back ,why? this cannot be correct it wouldnt suffice for ceramics so why for porcelain?,

[Sir Ramic]

We can only report our own findings and I havent had any issues.

[deankyall]

you say very little adhesive on the back,this then cannot be right,this wouldnt suffice for ceramic tiles so why do people let it go wih porcelain?,i have laid at least 2000m of it over the last few years ,but evry time about a year later especially with underfloor heating the L shapes crack, when i take up a tile the adhesive is on the floor but none on the tile,this is worrying,we had one wher the builder turned up the underfloor heatingbtoo qiuck and blew all 130m2 ,luckily for us he admitted this to the tiling federation,or we were looking at bankruptcy,but nether the less ,i know many tilers ho ae now going back on jobs from over a year ago ,the other problem is proving that they turned heat up too quickly,anyway back to porcelain there are just too many times ive heard this for it to be coincedence,i think that because porcelain is so dense that it cannot absorb or bond to the adhesive,like if you wet the back of a porcelain tile it will never soak in??anyway i hope you dont have any probs,especially on 2500 m2,

[nybor62]

ive noticed in the past a few tilers dont have there addy wet enough , this can be a common cause of failure ,floors not cleaned enough i.e free from dust primed with the right primer

[deankyall]

bad fixing methods??? as i said we mix up spread and put down tile ,after 26 years its not rocket science,there is nothing different we do today than last year or year before

[whitebeam]

I always back skim the tiles if they have deep profile

[nybor62]

saw some tilers recently using square notch trowels on large format tiles , could'nt get it through to them that round notch is better

[deankyall]

i agree ptb is the best adhesive i have used on it too,also i find grey adhesive seems to bond a bit better than white,dont know why just a finding,
also dont forget this is just on porcelain every other type of tile no problems at all,and from different tilers ,the local wholesalers tilers , i have been asking around for a while just to see if anyone had experienced this., we always prime,always use correct adhesive etc.

[doug boardley]

got to say that I've never experienced this problem Dean and I've been tiling longer than you, as whitebeam I always tend to back skim too.

[garythetiler]

Hi Dean welcome to the forum, I believe( just a theory) its due to the fact of how the adhesive sets, like you say porcelain tiles and ceramic tiles are different ,the molecules in porcelain are tighter together and the crystals that form when the cement sets in the adhesive dont get pulled into the body of the porcealin tile in the same way that they do into the looser ceramic molecules I believe its called mechanical grip,porcelain tiles are adhered to by modifiers added into the adhesive this wont have same shear strength as say a terracotta tile stuck with rapid but is strong enough to take the normal traffic undertile heating ,In my opinion there should be a Standardised amount of polymer additive industry wide which all adhesive companies should meet for porcelain tiles I dont remeber being able to remove any tile that had been stuck with x7 and ardion 90 whether porcelain or not and i feel the the problem you are seeing is due to the fact the adhesive companies put the bare minimum additive in to do the job to keep cost down ,I agree with the L cuts often crack too but can only guess that minute stress cracks occur when cutting that grow bigger over time

[deankyall]

thanks ,i agree with that,when i had a call last year about a cracked tile the customer automatically assumed it was my fault,it was a 100m2 floor,i had already been back to remove 3 tiles that had been damaged due to other trades dropping hammers and the like on them,for nothing and this is when i phoned mapei and mentioned that when i took them up it was easy,came up clean,but the adhesive was another matter stuck fast to the screed,they said they had never heard that before,which i found hard to believe as i had been privy to this conversation when a collegue of mine had asked this before,anyway the cracked tile was taken up and the screed underneath had exactly the same crack through it,so i bonded screed back together with epoxy resin and restuck tile so far no comeback about that but i was there again until 2 o clock and they expect and always blame the tiler when it was not my fault,but it was really a day or so alltogether for nothing,anyway back to porcelain,i have and others have tried cutting with grinder and wet cut but ,still after a few months i have still seen the L shapes crack especially around door linings ,i think that when there is underfloor heating and they put the architrave down tight to the tile when the underfloor heating is in use,the floor rises and the architrave stops the tile or floor area rising with the rest,and so will crack,i think the adhesive is not good enough for porcelain the only one i find really sticking at all is the rubber based ones,ie fastflex,or topps version.The site i am doing at the moment is all polished wall and floor,they never use 15 ,or 18 mm ply ,but i will be telling them unless they do i cannot garauntee anything,but you have to tile on what they use because you need the work!!, i will do a test area on the floor with 2 different types of adhesive ,then take them up to show exactly what happens.

[deankyall]

ok update ,today a tiling friend of mine had to take up some pollished porcelain,because they had come loose,he sent me a video ,the L SHAPE into the door had split too,the vid showed him knocking them up and hey presto clean on the back,it took him 2 hrs to take the adhesive from the floor though,there was underfloor heating and i am beginning to think that this is the difference,the adhesive hardly bonds to the back of porcelain anyway,and when combined with underfloor heating,it dosent stand much chance,when he had taken tiles up and adhesive ,he did notice some hairline cracks in the screed,now the other thing he said was the floor temp was very hot ,boiler was running at 60 degrees,what is the max temp you can have a floor before it affects the tiling? especially if as with porcelain there is minimum bond,i then called bostik technical department,asked if they had heard of any probs,but of course not, then proceeded to say they recommend flexible stone and porcelain tile adhesive for porcelain,i asked what about opf single part flex? ,he said again the same as he said before ,i told him that my wholesalers sell opf recommended for porcelain ,containing porcel plus made by his company,as i also had a bag in front of me,he didnt know wether this was ok,i then proceeded to tell him of the problems i and others had been experiencing,and also asked what standards they test and what were the tests?as we just read and use what they recommend,essentially i just want to know how they test and under what conditions? but he could only answer to bs standard, "which is what "i said ,he didnt know but thats what we test to he said,anyway i said i would like to test his reccomendation and get a rep to witness the taking up of a tile ,but he said they wouldnt know anything!!, so he transferred me to sales to find the nearest place to me to buy his reccomendation,but the phone went dead and that was that,
Anyway my other question is this,when underfloor heating has been laid,you then tell them the proceedure of heating the screed slowly,if they then go on holiday 6 months later,and decide that whilst not there to turn off heating,when they return and find that theyre a bit chilly,and then turn up the heating directly to say 22 degrees ,would this then have any affect on tiles as its still a rapid change of temperature?just a thought,if the screed move s more than the adhesive can then surely that causes a problem,flexible adhesive i have been told by various reps is more for vibration than movement,so how flexible is something that is so rigid?try knocking it from a bucket in the morning ,rock hard,these are just thoughts,wonder what you guys think.?

[Dave]

Hi Dean..

Can you explain your fixing method.. say on a large format tile..?.. just curious.

And who is the tiling federation..?

[J2 tiler]

I would always lift my tile up after lying it on a bed of adhesive to see if the tile had addy on it for hollow purposes and to make sure that it had stuck properly to the back of the tile. I think that is a must on large format tiles on walls and floors with porcelain.
I can see where u would have the problem if you just lay away cause with large format tiles it hard to know if the tiles only has addy on one corner. I can't see primer your problem it seems you laying method needs changing. We all get the odd hollow one now and again but i never really had this problem from polished porcelain saying that i use alot of addy sometimes

[TilerJames]

never really had this issue with Porcelain, the only thing i can think of is the addy is mixed to stiff/dry

[deankyall]

hi,dave i think i should explain this is not just me i am basically talking for everyone ive talked to about this,the tiling federation was not my call the builder got them involved and we had to go through everything from floor construction to fixing method ,then take tile up for adhesive to be measured with micrometer,we were absolved completely and the problem was the underfloor heating being turned up too quickly, my fixing method is i mix with a rubi drill ,on a primed floor,with a ten mm notch depending on floor or tile ,spread the adhesive and tile it, ,

[Stewart]

hi,dave i think i should explain this is not just me i am basically talking for everyone ive talked to about this,the tiling federation was not my call the builder got them involved and we had to go through everything from floor construction to fixing method ,then take tile up for adhesive to be measured with micrometer,we were absolved completely and the problem was the underfloor heating being turned up too quickly, my fixing method is i mix with a rubi drill ,on a primed floor,with a ten mm notch depending on floor or tile ,spread the adhesive and tile it, ,

From this I take it you don't back skim the tile?

I have to say I'm a bit lost with this thread as I haven't come across this problem and 90% of my work is porcelain.

[deankyall]

lets be clear,of course i make sure there is enough bed,you always have to lift up tiles to check also you must pick up tiles and add adhesive if they are low,my point is polished porcelain when you do this always has loads on the back when wet,no argument there but!! when they dry ,if you knock one up it will come clean ok? right so my point is when the movement takes place in an underfloor heating example i think this debonds the porcelain from the adhesive,because the adhesive dosent mechanically bond to the porcelain,because of the density of it.

[Dave]

All i can say from what i do Dean is i always back skim porcelain.. fully bonded into the adhesive bed, you cannot rely on the tile getting fully coverage if the back is profiled ..

But you say it is the ufh.. if a customer turns on the ufh and wacks it up, then it shocks the adhesive.. bang up they come.. no wonder you have probs..

[deankyall]

i have tested this back skimming it makes no difference ,we had reps and the tile federation, all had no problems at all about the fixing method , with the right notch trowel and the adhesive correctly mixed it acheives the correct coverage, actually they take a sample away to test to make sure you have correctly mix,listen most work is porcelain nowadays,and ive done loads of it but if say someone drills something wrong and you have to take a tile off to repair,it will come of clean. in fact i was talking to aplumber on site last week and they told me they had chipped a tile and went to hammer it off and the whole tile came off with no adhesive on the tile ,now i dont kow who did it ,but this was a porcelain wall tile.

[Stewart]

As I said I'm lost, because I installed over a hundred floors with heatmats last year alone, and haven't had this problem. All my heated floor installs have a decoupler with them and the two floors I had to replace last year due to damage by other trades were an absolute $€^% to lift. I have come across a few L cuts fracturing, but I put that down to the tile having hair line cracks at time of fixing.

[deankyall]

that was just that job,they also had faults on the valves so it was running without stats full blast,anway as i said yesterday another tiler sent me a video yesterday and tiles came up clean and took him 2 hrs to take adhesive up,underfloor heating on that too,the adhesive bonds to the floor like sh.. to a blanket,but not to porcelain,dave have you ever taken one up?

[deankyall]

stewart would you use ditra on a new screeded floor with underfloor heating then? also which addy do you use?

[deankyall]

def not,always mix correctly,try a test would be intersting to see if porcelain comes up clean although you have to wait a bit maybe,also i think its when combined with underfloor heating

[doug boardley]

I can only say that in 30 years tiling I can't recall any instance where I've had a floor tile (most porcs) delaminate or crack.