Loz Posted March 29, 2022 Share Posted March 29, 2022 Hi, Had liquid screed poured about six months ago, was sanded a few weeks later, under floor heating was commissioned about 2 months ago and turned it up slowly and all been looking good and moisture was getting to the magical 0.5 so could tile. With a week to go was still reading 0.7 in places so decided to give it another week and given such nice weather had all doors open and whacked heating right up to max. Turned the underfloor off Friday so could be primed Monday (yesterday) and noticed a crack running across floor between the two heating zones underneath the opening which joins a new double height extension with existing single storey extension. Hadn't noticed a crack before and sure appeared when cooled down over weekend (wasn't at property). Plan was to use 60x60 porcelain tiles - tiler turned up today and said not happy about crack and said whatever he does reckons will case tiles on it to pop or crack and has said to use a different flooring - luxury vinyl tiles. Problem is all the tiles are here and kitchen goes in Monday. Been doing tons of stressing and reading, just not sure what sort of crack dealing with - thermal, movement, shrinkage - new to all of this, been reading about decoupling mats but tiler didn't seem to keen. Any advice greatly appreciated, reckon the crack is about .5 to 1mm. Pictures below Loz Link to comment Share on other sites More sharing options...
Temp Posted March 29, 2022 Share Posted March 29, 2022 (edited) Use some sort of decoupling mat. eg Ditra and a flexible adhesive (but you were probably using flexible anyway). Still a slight risk but not sure what choice you have. Edited March 29, 2022 by Temp 1 Link to comment Share on other sites More sharing options...
Loz Posted March 29, 2022 Author Share Posted March 29, 2022 35 minutes ago, Temp said: Use some sort of decoupling mat. eg Ditra and a flexible adhesive (but you were probably using flexible anyway). Still a slight risk but not sure what choice you have. Thanks for quick reply, tiler was going to use flexible adhesive, been looking at the decoupling mats - presume would need to do whole floor rather than just the crack ? They do add up a bit, my only other option is to return the tiles if I can and use a different flooring type - luxury vinyl tiles guess would never crack, bit of a nightmare all round - tilers feeling is whatever do there is a good chance of a crack in 60x60 porcelain tiles and couldn't be in a worse place from a looks perspective as right in middle and won't be covered by anything, Thanks Loz Link to comment Share on other sites More sharing options...
Conor Posted March 29, 2022 Share Posted March 29, 2022 Was there an edge insulation/expansion strip installed around all the walls? Usually a light strip of foam that's stapled or glued to all the walls before the screed is poured. Also along the edge of your patio doors. It's there to allow the screed to expand and contract without being constrained by the walls. 1 Link to comment Share on other sites More sharing options...
Loz Posted March 29, 2022 Author Share Posted March 29, 2022 Hi yes there was a foam strip all the way around the perimeter, been trimmed down now to floor level so not showing, strange in a way the crack is where there is no underfloor heating between the two zones, bit concerned I caused the problem by whacking it up to max (60 degrees) last week to dry and get last bit of drying done but after 5 months thought would be okay. Tiler has spoken to the matting people and they are saying don't guarantee it so he is not happy to do it so a bit snookered now. Tiling company won't take the tiles back as been more than 5 weeks so truly having a mare. Tilers advice is to ebay them and go with luxury vinyl tiles throughout. Not been a good day as all the other trades were lined up after this. Cheers, Loz Link to comment Share on other sites More sharing options...
Thorfun Posted March 29, 2022 Share Posted March 29, 2022 8 minutes ago, Loz said: Hi yes there was a foam strip all the way around the perimeter, been trimmed down now to floor level so not showing, strange in a way the crack is where there is no underfloor heating between the two zones, bit concerned I caused the problem by whacking it up to max (60 degrees) last week to dry and get last bit of drying done but after 5 months thought would be okay. Tiler has spoken to the matting people and they are saying don't guarantee it so he is not happy to do it so a bit snookered now. Tiling company won't take the tiles back as been more than 5 weeks so truly having a mare. Tilers advice is to ebay them and go with luxury vinyl tiles throughout. Not been a good day as all the other trades were lined up after this. Cheers, Loz can't you just ask the tiler to install them and tell him you accept any risk in 'that area'? 1 Link to comment Share on other sites More sharing options...
PeterW Posted March 29, 2022 Share Posted March 29, 2022 50 minutes ago, Loz said: bit concerned I caused the problem by whacking it up to max (60 degrees) last week to dry Yep.. you created the issue ..!! Drop it back to 35°C and it will be fine and not move. That crack is tiny and using proper flexible adhesive it won’t move at normal temperatures. 1 Link to comment Share on other sites More sharing options...
Loz Posted March 29, 2022 Author Share Posted March 29, 2022 Thanks for replies, I guess the thing that is spooking me is that the crack is on the line between the old and new extensions where movement between two sub floors was likely. It is also an area where there is no underfloor heating, if I caused the problem by whacking it up too much in final week which is I accept a possibility then wouldn't it crack where there is the under floor heating rather than where there isn't - very new to all of this as you can tell. Managed to speak to a dura mat technical person that from description said sounded like movement rather than thermal shock and he has very kindly offered to take a look in morning, if is movement from sub floors said mat wouldn't help but a movement joint might but crack is not straight. Duramat for whole area is £1200 plus extra labour for sticking it down and extra adhesive on top - probably the same as hit I would take ebaying the tiles - be interesting to see what he says tomorrow - will update, thanks for all help so far, been a bit of a nightmare, Loz Link to comment Share on other sites More sharing options...
Thorfun Posted March 29, 2022 Share Posted March 29, 2022 26 minutes ago, Loz said: Duramat for whole area is £1200 plus extra labour for sticking it down and extra adhesive on top - probably the same as hit I would take ebaying the tiles - be interesting to see what he says tomorrow - will update, thanks for all help so far, been a bit of a nightmare, don't forget the emotional cost of going for a flooring that you don't really want! if you'd wanted LVT then you'd have specified it to start with, right? so ditching the tiles (which is what you wanted) for LVT (which you didn't)* will have an emotional cost and impact. you might forever be thinking you really wished you had tiles? not sure you can put a financial cost on that. * assumed due to original decisions made about floor coverings 1 1 Link to comment Share on other sites More sharing options...
Loz Posted March 29, 2022 Author Share Posted March 29, 2022 My partner always wanted LVT ! I always wanted porcelain tiles largely as can't get my head round vinyl but mainly as thinking about ancient vinyl flooring from when I was young, also was thinking porcelain would hold heat well with the under floor heating and wear better, the Moduleo LVT been looking at in Transform range does say 20 years on wear but assume would be longer but guess a relatively new product, really don't know what to do as guess very difficult to tell whether is a thermal or movement crack, strange that crack only just showed up but chance it would diminish if turned heating on an experiment want to do after guy has seen it tomorrow. Just spooked now about movement and potential cracking elsewhere as there are other large openings into old house where we have historically had problems, to be honest deep down wish gone LVT from beginning as had a mare with tile company even before today. Loz Link to comment Share on other sites More sharing options...
Thorfun Posted March 29, 2022 Share Posted March 29, 2022 22 minutes ago, Loz said: My partner always wanted LVT ! Happy wife, happy life! 😂 (Happy partner, happy life doesn't really work though, sorry.) 1 Link to comment Share on other sites More sharing options...
Loz Posted March 29, 2022 Author Share Posted March 29, 2022 Thanks for all the replies, I have been doing quite a lot of reading in between posts, seems banging it up to 60 on the water temp and then turning it off ready for the tilers could well have been a mistake - the room never got above 25 degrees during all of that as an aside. I have been on trustpilot and read reviews of the moduleo LVT flooring and they are pretty bad - in fact appalling, then swapped to karndean which is a more expensive LVT and they were similarly bad - I know installation is likely to play a part as is people being more likely to leave a bad review but a hard sell reading those. Given I have the porcelain tiles paid for at property with tile company refusing to take them back (been more than 5 weeks - their policy and they are not budging) I am leaning towards finding a solution for them. That solution looks to be a decoupling matting and on internet found ditra 25 for £750 - durabase ci a bit cheaper but forums people seem to stick to the tried and tested ditra 25. I am tempted to risk it, wich I knew if crack was caused by movement or thermal shock of some kind - UFH been on for two months and crack only showed up when cold after weekend so no way of knowing I guess - could be the dry weather and the foundations settling, rep seemed to suggest if movement between the sub floors then matting won't help - thought would help a bit - any further thoughts greatly appreciated as will be pretty depressing to be a good few thousand in and a crack opening up across middle of room in most high traffic most visible area, Many thanks Loz Link to comment Share on other sites More sharing options...
AdamSee Posted March 29, 2022 Share Posted March 29, 2022 I have an extension with a liquid screed pour which has cracked in the same way. I've just given up worrying about it now. I want to it be right and perfect, but in the end I just want it done and without burning a bigger hole in my pocket than I already have. Do everything possible to minimise the chances of it cracking the tiles by using a decoupling mat, flexible adhesive and grout and then live knowing that you did everything possible without spending another fortune. I've used tile masters ultra flex s2 adhesive and anti fracture matting on a bathroom timber floor with UFH and I'm amazed that the builders didn't crack it when the fitted in a RSJ below it. So personally I have a lot of confidence in these products now. 1 Link to comment Share on other sites More sharing options...
Loz Posted March 29, 2022 Author Share Posted March 29, 2022 Thanks for reply, that is what starting to think as well, go with everything flexible and hope for the best ! Many thanks, Loz Link to comment Share on other sites More sharing options...
bassanclan Posted March 29, 2022 Share Posted March 29, 2022 You should calculate the cost in labour and materials and stress of retiling the cracked area and weigh it up against the membrane cost. May well be worth you getting a few extra tiles in as they may not make them in a few months time 1 Link to comment Share on other sites More sharing options...
Temp Posted March 29, 2022 Share Posted March 29, 2022 (edited) BAL adhesives/Tops Tiles have some advice.. https://www.toppstiles.co.uk/knowledge-base/how-to-tile-onto-a-screed-with-cracking Looks like they recommend DURABASE CI++ matting for cracks upto 3mm. £16 per sqm plus adhesive. Edited March 29, 2022 by Temp Link to comment Share on other sites More sharing options...
djkprojects Posted December 29, 2022 Share Posted December 29, 2022 On 29/03/2022 at 19:55, Loz said: Thanks for reply, that is what starting to think as well, go with everything flexible and hope for the best ! Many thanks, Loz How did it go? I seem to be having a similar issue except mine was caused by an incompetent plumber who was commissioning the ufh and turned it up to 65degs on a week old liquid screed! Thanks Link to comment Share on other sites More sharing options...
Loz Posted January 3, 2023 Author Share Posted January 3, 2023 I had a rep from Dural come round who was in the area and he came up with what should be done, decoupling mat, flexible adhesive and also went for expansion joints in the large doorways and also a couple of strategically placed micro joints (an epoxy sealant that is same colour as grout but more flexible) one of which followed large crack as best as possible as laid tiles such that there was a joint running mainly with it. The company that poured the screed also came back and ground out the crack a bit, poured resin in and put some metal cross stitches in - think this was particularly good for the crack that looked like might run some more in the future. We are 6 months back in property with UFH being used a lot in the recent cold snap and nothing appeared so far - I do worry a bit now and then a crack will appear but seems to be a good solution that is holding up - in fact think had a bit of a lucky escape as the original tiler who is a bit old school was not going to use a decoupling mat or any doorway joints as far as I could tell and this seems to be pretty standard for screed UFH nowadays. Good luck, Loz 1 Link to comment Share on other sites More sharing options...
scottishjohn Posted May 18 Share Posted May 18 I,m ging for stick down :VT and my man will not do job unless he uses floor levelling compound after he has sanded the sreed first and same fpr upstairs over the ufh flooring system all makes it an expensive job they won,t even fit click ik type lvt flooring on an area as big as mine they consider it a DIY system i got same advice form major flooring manufacturers they also do not fit the flooring till all other work is done inc skirtings and kitchen bathroon sanitary etc etc Link to comment Share on other sites More sharing options...
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