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

 

[Deleted member 1779]

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?,

 

[Gazzer]

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

 

[White Room]

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.

 

[Spud]

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