underfloor heating......do I have a potential problem ?

[jonjo]

Hi All

I recently had my home refurbished which included the majority of downstairs with UFH and a tiled surface.

There was the membrane for the UFH (a red plastic tray) placed everywhere downstairs and then the pipe laid in situ, then the screed and 3 weeks later the Ditramat or similar (was yellow) went down then the tile on top of that (600x600 porcelin)

the floor looks lovely and the UFH is excellent, its just over the last month i have noticed that certain tiles seem to creak....sounds like grit rubbing together in your hands and this has spread to other areas.....

is this me just being paranoid and this is natural movment as and when the heating goes through its daily cycle or not ? it's worth mentioning that the hallway which is also part of the downstairs area that is tiled does not have UFH and none of these tiles move.

any input appreciated from you pros before i speak to my tiler.

thanks

joe

[Dan]

Sounds like they're starting to de-bond to me, sorry to say that! Tiles shouldn't creak even with UFH. The expansion and retraction shouldn't be noticeable, it's a tiny amount but enough to fail if the wrong gear has been used.

Do you know what adhesive was used, and if the floor was commissioned before tiling?

[jonjo]

i know that the heating was not turned on until the tiling was all done

what would be the wrong gear for example ? i'm not sure what adhesive was used

will this only get worse or ?

[Dave]

Hi Joe..

Can i ask what screed it was please..?

[jonjo]

hi dave

im sorry i really would not know....what type should it be or do you mean thickness...not sure on that either

[Dave]

Was it a cement based screed as in laid and troweled out.. or was it a poured wet screed.?

[Sir Ramic]

Was the heating commisioned ( Run up to temp and back down) before tiling ?

[Dan]

Probably only get worse to be honest yeah. Wrong adhesive would be something not flexible. Doesn't sound like it's just grout issue either. If the floor is huge and no expansion joints have been used you may get away with putting some in now. That's a long shot and it's only if that is actually the problem.

You shouldn't turn on the heating right after the tiling is done, it needs a couple of weeks to really cure before turning it on. And when you do turn it on you're meant to gradually build the heat up and then gradually turn it down each day so it's expanded and restracted to it's fullest extend. And only then should you use it as you would want to, on and off each day.

Screeds are out of my league but Dave's spot on with 'em. And we have a member on here who works for Lafarge and they're all about screeds! So I'm sure we'll be able to help find the issue, but I don't think we'll manage to stop you re-tiling it the right way and / or with the right gear.

Got any adhesive bags lying around somewhere still by chance?

[jonjo]

yes laid down and trowled came on a tipper lorry...put on the drive and barrowed it in

[jonjo]

Was the heating commisioned ( Run up to temp and back down) before tiling ?

no 100% not

[jonjo]

Probably only get worse to be honest yeah. Wrong adhesive would be something not flexible. Doesn't sound like it's just grout issue either. If the floor is huge and no expansion joints have been used you may get away with putting some in now. That's a long shot and it's only if that is actually the problem.

You shouldn't turn on the heating right after the tiling is done, it needs a couple of weeks to really cure before turning it on. And when you do turn it on you're meant to gradually build the heat up and then gradually turn it down each day so it's expanded and restracted to it's fullest extend. And only then should you use it as you would want to, on and off each day.

Screeds are out of my league but Dave's spot on with 'em. And we have a member on here who works for Lafarge and they're all about screeds! So I'm sure we'll be able to help find the issue, but I don't think we'll manage to stop you re-tiling it the right way and / or with the right gear.

Got any adhesive bags lying around somewhere still by chance?

its 100sqm in total and is in one continuous run (kitchen through hall to l/room into diner) all ditra matted which the tiler said expelled the need for expansion joints ??

it had about 2 weeks after tiling done until heating was turned on.

i burnt all the bags !! bugger.....i remember them being white and blue with coloured stripes in the corner or something like that

[Dave]

yes laid down and trowled came on a tipper lorry...put on the drive and barrowed it in

Ok Cement based screed, then your issue is more than likely a non-commissioned floor as Neale has stated .. This can cause thermal shock to the adhesive bed and this in turn can De-bond from the substrate,, so what you have is the matting floating in areas on the substrate.. this might not be any more now than this crunching sound you have..but it is still worth calling back your installer..

[Dan]

Not sure ditra eradicates the need for expansion joints does it?

[Dave]

Not really no.. so 100 mtrs in a run might just add way too much lateral stress..

[jonjo]

Ok Cement based screed, then your issue is more than likely a non-commissioned floor as Neale has stated .. This can cause thermal shock to the adhesive bed and this in turn can De-bond from the substrate,, so what you have is the matting floating in areas on the substrate.. this might not be any more now than this crunching sound you have..but it is still worth calling back your installer..

thanks Dave

will it get worse do you think ? why would it de bond...wrong bond or ??

so your saying the ditra matting is not stuck to the screed properly ?

[Dave]

Too much lateral stress..( side ways movement) can cause them to heave.. are the loose ones or this creaking area towards the middle of the floor..?

[jonjo]

Not really no.. so 100 mtrs in a run might just add way too much lateral stress..

sorry if im not on topic here but its 100sqm accrued in 4 seperate areas but all are flowing into each other if you get me

[jonjo]

Too much lateral stress..( side ways movement) can cause them to heave.. are the loose ones or this creaking area towards the middle of the floor..?

no they seem to be here there and everywhere...no real pattern

[Dave]

So.. what is the largest separate area..? and i take it is doorways separating,.

[Dan]

You need expansion joints where different rooms meet, every 10 meters on large floors in length and width, and even if the rooms are knocked through, I'd still have one somewhere for the sake of each end of the room having slightly different heat-up and cool-down times due to all sorts of factors, oven at one end, patio doors at the other for example.

[Dave]

Less than 10 mtrs Dan with UFH.. Around 7 max i would say. and perimeter joints a must

[Dan]

Ta Dave. I'll remember that.

[Dave]

Even less with no matting....

[jonjo]

So.. what is the largest separate area..? and i take it is doorways separating,.

starting from the open plan kitchen it runs through to the hallway through what was a two seperate doors now knocked into one, then through the original doorway into the living room, from there through an open plan opening into what i call the sun room.

all was re screeded all be it the hallway was done seperatley to the kitchen and living room(sun room runs off living room) so the hall is in affect in the middle of the two large areas but tiles run smooth through the lot

clear or not ?

sorry i'm not builder / DIY'er !

the largest area if you like is the kitchen which is circa 50sqm but this does run through to the hall and living and sun room

[jonjo]

You need expansion joints where different rooms meet, every 10 meters on large floors in length and width, and even if the rooms are knocked through, I'd still have one somewhere for the sake of each end of the room having slightly different heat-up and cool-down times due to all sorts of factors, oven at one end, patio doors at the other for example.

i dont think i have these...i remember the tiler mentioning them but said ditra matting would eliminate the need for them ??

[Dan]

And did you say there's no UFH in the hallway?

That aside, sounds like you've found your problem. Two many rooms with different heat factors to cope with expansion with no expansion joints. Especially if tiles run from a heated floor, to one not heated, and then back to a heated floor the other side of the hallway (if I did read your earlier post correctly).

And you said the tiler said it's okay without strips when you have a de-coupling membrane, which isn't right. So you've got your culprit there too.

[jonjo]

And did you say there's no UFH in the hallway?

That aside, sounds like you've found your problem. Two many rooms with different heat factors to cope with expansion with no expansion joints. Especially if tiles run from a heated floor, to one not heated, and then back to a heated floor the other side of the hallway (if I did read your earlier post correctly).

And you said the tiler said it's okay without strips when you have a de-coupling membrane, which isn't right. So you've got your culprit there too.

yes he knew no ufh in hallway.....

i'm gutted, what should i do ?

he made it clear that he wanted to do the job properley and that he would not lay the floor without this ditra which as you know over 110sqm was a cost i was not expecting until he mentioned it (remember im no tiler) so i went the proper route or so i thought !

[Dave]

Have you contacted the tiler..?

[jonjo]

not yet

i want to get my facts stright or as best as poss so i dont get rolled over so to speak.

[Dave]

We appreciate that but this is deffo an installer error from what you have described..