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Hi all
Interested in views from the trade world about how I should deal with a big floor tile **** up. Basically I'm wondering how far I should be pushing my builder to put things right. I've had porcelain floor tiles laid dot-and-dab (sorry, you must all be so bored of that topic) over under-floor heating and am now nearing a dispute of whether several grands' worth of back-pedaling is needed to put the job right.
Bit of background on me on this sort of stuff. Not a pro in the building trade but not blowing my trumpet to say I'm pretty handy on most things around the house - basic repairs, medium size building work, plumbing, electrics, tile, papering, plastering, and servicing the car until the things became so complicated that you don't recognise anything under the bonnet anymore. My missus says I'm a bit of a perfectionist but I just want to get things right as I don't like the idea of being a DIY botch merchant. Not the fastest in the world but I err on the safe side, ask when I don't know, and am prepared to rip it out and go back to the start when I've got it wrong - which as the years and experience go by is pleasingly rare. Big projects (loft conversion, extension, new central heating) I've had people in (time, effort, feeling older these days). I've had guys I've sacked off jobs when I know I could've done it better and guys I've just been blown away by. This is just to set the scene that I am not completely ignorant when talking to builders etc (relevance apparent later) and not prone to knocking tradesmen just for the sake of it.
Background on the mess I'm in now. Job was a kitchen extension - side return and old lean-to plus a few bits in the neighbouring utility room. Floor for old kitchen was and remains suspended timber, new floor to the side and end of this is concrete. Good job from the builder structurally, really good, would have him back but only for building. Part of the job price was laying the electric (loose cable) UFH and tile the floor.
In December he laid the UFH cable then the tiles dot-and-dab. Looks like UFH absolutely beyond a doubt has to be laid in a bed (no previous personal experience). For the tile, I have laid three floors - the old kitchen area twice and the utility room once. All three needed a power breaker to get them up. I'm not an expert but I know if getting them up doesn't break them, they weren't laid right. All mine were a sod to get up. I queried dot-and-dab method with the builder. Told me it'd be fine, done-loads-like-this-and-never-had-a-problem, plus floor not level etc. Apparently self-leveling compound wouldn't have been an option (?). Instinctively UFH cables surrounded by air struck me as pretty effective insulation (think secondary glazing, layers of clothes when it's cold) but he had some interesting ideas on hot air rising to the tiles that didn't really fit with my understanding of physics (I have a scientific background). Against better judgement and with time-constraints I was reassured that if there were any problems he would put them right. To be fair, he hasn't deserted yet.
Kitchen was then fitted on the floor - units along three walls with and an island. Stone work surfaces on top. Wasn't crazy money but far from the cheaper end of the market (that's my missus).
Floor was basically alright to begin with except that it sounded like walking on a xylophone with the different note of each tile with a void underneath. Then a tile started to knock when you stepped on where a dot was coming loose underneath, then another did it and so on.
To his credit he came round to look at it. I managed to dissuade him from his plan of drilling small holes around the edges of tiles and squirting in expanding foam to fill the void and adhere the tile. For me the insulation properties of the foam seemed a bad plan for UFH, and I wasn't convinced it would work anyway and managed to dissuade him on the lines of the possibility of hitting an UFH cable.
After some chats we agreed to try and get up some of the loose tiles. I offered to do that with him. After taking up a few it was apparent that it was only the grout keeping the tiles there. After cutting through the grout each tile lifted easily. Hardly a blob of https://www.tilersforums.com/forums/tile-adhesive/ has been left on the back of any tile - they look straight out of the shop (turns out he's not sure for certain what https://www.tilersforums.com/forums/tile-adhesive/ he used).
We just did a couple to start and I indulged him in his experiment to lay one by filing the void with expanding foam with Gripfill on the remaining https://www.tilersforums.com/forums/tile-adhesive/ dobs. Great experiment. It holds pretty well (but still sounds hollow) but the UFH beautifully heats where the dots are and the rest of the tile stays cold until the heat conducts through the tile. For anyone who lays UFH I'd be happy to chit-chat on some of what I'm seeing that absolutely confirms manufacturers' fitting instructions - except it should all be pretty obvious, it's a bit like bothering actually to test jumping from a plane without a parachute (never formally tested but we all know the result).
We agreed to lift all those that we could without disturbing the kitchen units and did so without damaging the UFH (they come up that easily).
There is/was a plan to remove some of the dots for each tile, leaving a dot at each corner so that a bed of https://www.tilersforums.com/forums/tile-adhesive/ could be laid in the remaining space but with the dot keeping the level for relaying with Gripfill on top of the old dots to hold the tile at those points. For tiles not lifted because they extend under kitchen units' end panels, they've have expanding foam squirted under (no UFH there) to fill the void, then as much https://www.tilersforums.com/forums/tile-adhesive/ pushed under as can be achieved, to hold the edge .
Last night after many hours of dissecting dots and dabs away from UFH cable and off the foam insulation tile backer boards stuck to the sub-floor, I started to lose it. In parts of the floor, the insulation is tearing badly and where foam has been squirted under less-accessible tiles, I can't hear a difference when I knock on them. Some of the dots that are due to have Gripfill on them knock against the floor beneath so, presumably lifting the tiles, however easy, is disturbing the adhesion between the sub-floor and the insulation boards. Gripfill on these dots is always going to knock unless by luck it gets held by enough https://www.tilersforums.com/forums/tile-adhesive/ around it.
This is about where I lost it. None of this is right. I'm looking at hours of work, much of which I have offered to do (not fundamentally opposed to that), in which I have decreasing confidence of an effective, long term outcome, for which I paid and questioned when it was in progress.
That was a long preamble but here is my dilemma. I am increasingly coming to the view that there is no way to get it right than to go back to where things started to go wrong. To do that I can't see a way other than dismantling the installed kitchen, getting the tiles up, leveling the floor (might include grinding off https://www.tilersforums.com/forums/tile-adhesive/ for the insulation boards), then UFH with insulation, tile the floor and reinstalling the kitchen. I have suggested this but it is understandably not well received. I have indulged/am still indulging in his suggestions of how to right things but I'm wondering if this is just pissing in the wind.
I do get my builder's reluctance. Shifting the kitchen will need to shift the stone work tops. It's likely these will break (cut for cookers, sink etc). I'd not be surprised that getting back to a floor that can be done properly will cost 2-3 grand for kitchen dis-assembly/assembly, 2 grand for work tops if they can't be saved, couple of hundred for insulation board, and around 700 for UFH cable. I'm not worried on a grand's worth of tiles - they're a doddle to get up as nothing's holding them. I get the costs involved of going right back to get it right but I'm looking at around 25k of units and kitchen machines, in a project that cost around 70-80k. Without fitting (which was in the price), the UFH and tiles come to less than 2k - which bit would I want to save?
What thoughts from the trade? How much more should we try foam, pushing in proper https://www.tilersforums.com/forums/tile-adhesive/, prayer, pixie dust? When is it reasonable to draw a line and say that we go back to where the wrong turn was taken, whatever the costs? Who should incur those costs? Am I being unreasonable or unreasonably fussy? Despite the numbers above, I'm not loaded - I took out a mortgage to do this and I'll be paying it forever.
Finally if anyone's got a great idea, I'm all ears.
Thanks if you bothered to read this far
Regards
Matt
 
OP
O

Old Mod

Glad u've had a productive meeting today, excellent news. Hope you're coming back to give us progress reports :)
Good luck.
 
OP
M

My dog's called Trevor

Football pfffttfft rather watch grout set .
As for your job, i hope all well matt, your patience is to be commended :sunglasses:

Thanks for your kind words as before. On the football, I see you're from Burnley, so that would be about right.
Take care and thanks
Matt
 
OP
M

My dog's called Trevor

Glad u've had a productive meeting today, excellent news. Hope you're coming back to give us progress reports :)
Good luck.

Many thanks and yes of course. Rude not to and hopefully will all be good news
Thanks again
Matt
 
OP
M

My dog's called Trevor

Is he going to attempt the retile himself, or is he getting in a professional in this time?
Good to see he wants a happy customer and happy to work right.

Not entirely clear on that detail. As all of this was in the preparation, just happy for the minute that that is where the focus is. Amazing today that talking to him, he knew exactly what to do but said he did it all super quick because the kitchen delivery date was set and by then not renegotiable (could have been and had already delayed it once to give him an extra week -during which we didn't see him). Bonkers. A couple of hundred quid for warehouse storage would have been a better plan. Real worry for him is whether he's learned anything. I'm not sure he has. Oh well.
Thanks for your interest.
Matt
 
OP
M

My dog's called Trevor

Brilliant stuff.

You can't leave before the climax, as the mrs says.

So take some snaps during the refit for us!

Can't wait for the finished working heated product!

Definitely owe you all some before and after snaps - as well as a pint
Following up on your UFH suggestions with a couple of suppliers. Much appreciated
Matt
 

Dan

Admin
Staff member
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Definitely owe you all some before and after snaps - as well as a pint
Following up on your UFH suggestions with a couple of suppliers. Much appreciated
Matt
Thinking about it.

I'd have a thermostat for each floor. And let them have their own cables. Your wood one won't take long to heat. It'll never get as cold as the other area. So you don't want it switching on with the concrete side.

I'd go with treating them as different areas. It might feel annoying only feeling one side warming on its own every now and again but on cold days the whole thing will be on. Warm days maybe just the concrete side.
 
OP
J

J Sid

Was thinking the same Dan, but if both have insulation boards there really should be no noticeable difference in heat up time.
But for the cost of a thermostat and the ability to have more control over the temperatures, then separate ones is good
 

Dan

Admin
Staff member
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Was thinking the same Dan, but if both have insulation boards there really should be no noticeable difference in heat up time.
But for the cost of a thermostat and the ability to have more control over the temperatures, then separate ones is good
Ahhhh while insulation boards have insulating values; they're not a material that will totally block out temperature changes.

Hence the varying thicknesses available. Even 4mm difference between 6mm and 10mm is noticeable.

I used to run Advanced Floor Heating. Waaaay back when only a few heating brands were available. Paul Short (of floor heating ltd) and then myself started this trend off of this blue insulation. I know quite a bit about it.
 
OP
J

J Sid

Christ Dan, is their anything you haven't done.
You should give a thought to a new avatar, some sort of cowboy.
 
OP
M

My dog's called Trevor

Thinking about it.

I'd have a thermostat for each floor. And let them have their own cables. Your wood one won't take long to heat. It'll never get as cold as the other area. So you don't want it switching on with the concrete side.

I'd go with treating them as different areas. It might feel annoying only feeling one side warming on its own every now and again but on cold days the whole thing will be on. Warm days maybe just the concrete side.

Interesting (genuinely, and a bit worrying that it is) as had come to that thought today.
Firstly, although maybe possible, struck me as difficult how you'd have two thermostats informing one control as to when it should/shouldn't allow power to the two separate systems. It would have to allow power to both. So it would be controlled preferentially by whichever area was coolest, 'telling' it to switch to on, and so activating both systems. I don't know this for a fact but don't think the controls are designed to need to be this clever in splitting two input signals and outputs separately. Might have this all wrong.
Something like a CH/HW control could handle it as basically it's taking two completely separate instructions from two systems. Even then its output is to signal the boiler to fire or not fire so there is still only one common outcome - in a heating/hot water system it'd be the room or cylinder thermostats shutting down the MCVs to isolate out that circuit so there is a plumbing shut out which separates the delivery of the control, and therefore boiler, response to the two systems. I'm sure an electrical equivalent is possible but starting to get complicated and would all have to be outside of the standard controls.
Started to think that two separate systems, which will just need setting for the same on/off times or temperature settings would let the whole room run almost as one system.
Or this is all too complicated. The system put down has a temperature sensor under the tiles and a thermostatic control informed by the air temperature in the vicinity of the control box. It'd be air temperature chiefly controlling the heating. Provided the floor sensor was coming from the area likely to be hotter, that would protect any cables from becoming excessively hot. That would tend to leave the less easily heated area cooler.
Anyway, haven't researched this sufficiently to my satisfaction to understand what happens when this and that occurs - eg are the floor sensors just to cut supply if there is excessive floor temperature build up? You wouldn't want to let the temperature under the floor limit the temperature in the room, same as you wouldn't want to let your boiler temperature limit room temperature, until the under floor/boiler temperature reached a level that might threaten the cable/boiler, so you have over-riding cut outs. Not asking you to answer this, just thinking out loud. Struck me it might not be the floor sensors controlling the heating rather than the thermostat in the control box which is effectively a room thermostat, in CH parlance. The box I've got has the facility to be set by room or under floor temperature - unless the under floor temperature gets crazy, you'd always opt for room temperature as that's the point of it. Just for your amusement, when our system was running for a couple of cold weeks in January, room temperature of around 24 needed an under floor temperature, with lots and lots of lovely insulating air around the cables, of a blistering 35.
Only other thing I wondered was that if the insulation under the cables is half-decent, does the difference in flooring beyond the insulation make that much difference? Again, not asking you to answer this but loose ends to sort out before mixing up the first batch of https://www.tilersforums.com/forums/tile-adhesive/ to lay the first tile.
I've got some homework to do to keep my best mate builder on the right track. Good at homework these days. Bought a big bloody ultra HD telly for the kitchen not having bought a telly for about 6 years. God, don't things change? So what I've discovered about Cat 5a vs 6 ethernet, HDMI 1.4 and 2.0, 4k TV signals and so on.... UFH can be cracked.
Thanks as ever
Matt
 
OP
M

My dog's called Trevor

Interesting (genuinely, and a bit worrying that it is) as had come to that thought today.
Firstly, although maybe possible, struck me as difficult how you'd have two thermostats informing one control as to when it should/shouldn't allow power to the two separate systems. It would have to allow power to both. So it would be controlled preferentially by whichever area was coolest, 'telling' it to switch to on, and so activating both systems. I don't know this for a fact but don't think the controls are designed to need to be this clever in splitting two input signals and outputs separately. Might have this all wrong.
Something like a CH/HW control could handle it as basically it's taking two completely separate instructions from two systems. Even then its output is to signal the boiler to fire or not fire so there is still only one common outcome - in a heating/hot water system it'd be the room or cylinder thermostats shutting down the MCVs to isolate out that circuit so there is a plumbing shut out which separates the delivery of the control, and therefore boiler, response to the two systems. I'm sure an electrical equivalent is possible but starting to get complicated and would all have to be outside of the standard controls.
Started to think that two separate systems, which will just need setting for the same on/off times or temperature settings would let the whole room run almost as one system.
Or this is all too complicated. The system put down has a temperature sensor under the tiles and a thermostatic control informed by the air temperature in the vicinity of the control box. It'd be air temperature chiefly controlling the heating. Provided the floor sensor was coming from the area likely to be hotter, that would protect any cables from becoming excessively hot. That would tend to leave the less easily heated area cooler.
Anyway, haven't researched this sufficiently to my satisfaction to understand what happens when this and that occurs - eg are the floor sensors just to cut supply if there is excessive floor temperature build up? You wouldn't want to let the temperature under the floor limit the temperature in the room, same as you wouldn't want to let your boiler temperature limit room temperature, until the under floor/boiler temperature reached a level that might threaten the cable/boiler, so you have over-riding cut outs. Not asking you to answer this, just thinking out loud. Struck me it might not be the floor sensors controlling the heating rather than the thermostat in the control box which is effectively a room thermostat, in CH parlance. The box I've got has the facility to be set by room or under floor temperature - unless the under floor temperature gets crazy, you'd always opt for room temperature as that's the point of it. Just for your amusement, when our system was running for a couple of cold weeks in January, room temperature of around 24 needed an under floor temperature, with lots and lots of lovely insulating air around the cables, of a blistering 35.
Only other thing I wondered was that if the insulation under the cables is half-decent, does the difference in flooring beyond the insulation make that much difference? Again, not asking you to answer this but loose ends to sort out before mixing up the first batch of https://www.tilersforums.com/forums/tile-adhesive/ to lay the first tile.
I've got some homework to do to keep my best mate builder on the right track. Good at homework these days. Bought a big bloody ultra HD telly for the kitchen not having bought a telly for about 6 years. God, don't things change? So what I've discovered about Cat 5a vs 6 ethernet, HDMI 1.4 and 2.0, 4k TV signals and so on.... UFH can be cracked.
Thanks as ever
Matt

Ok, since writing this, Julian and Dan have addressed part of what I queried. Sod it - I'm just going to leave the cooker on with the door open. It's got a timer apparently, although the book's so bloody complicated, none of us has worked out how to use that.
Matt
 
OP
J

J Sid

I would of thought the thickness of the insulation board over the two substrates will determine the answer wether to go with two thermostats and two controllers.
I have electric ufh in mist of my rooms controlled by probe in floor, have no idea if air temp control is better or not
 

Dan

Admin
Staff member
Reaction score
5,023
Interesting (genuinely, and a bit worrying that it is) as had come to that thought today.
Firstly, although maybe possible, struck me as difficult how you'd have two thermostats informing one control as to when it should/shouldn't allow power to the two separate systems. It would have to allow power to both. So it would be controlled preferentially by whichever area was coolest, 'telling' it to switch to on, and so activating both systems. I don't know this for a fact but don't think the controls are designed to need to be this clever in splitting two input signals and outputs separately. Might have this all wrong.
Something like a CH/HW control could handle it as basically it's taking two completely separate instructions from two systems. Even then its output is to signal the boiler to fire or not fire so there is still only one common outcome - in a heating/hot water system it'd be the room or cylinder thermostats shutting down the MCVs to isolate out that circuit so there is a plumbing shut out which separates the delivery of the control, and therefore boiler, response to the two systems. I'm sure an electrical equivalent is possible but starting to get complicated and would all have to be outside of the standard controls.
Started to think that two separate systems, which will just need setting for the same on/off times or temperature settings would let the whole room run almost as one system.
Or this is all too complicated. The system put down has a temperature sensor under the tiles and a thermostatic control informed by the air temperature in the vicinity of the control box. It'd be air temperature chiefly controlling the heating. Provided the floor sensor was coming from the area likely to be hotter, that would protect any cables from becoming excessively hot. That would tend to leave the less easily heated area cooler.
Anyway, haven't researched this sufficiently to my satisfaction to understand what happens when this and that occurs - eg are the floor sensors just to cut supply if there is excessive floor temperature build up? You wouldn't want to let the temperature under the floor limit the temperature in the room, same as you wouldn't want to let your boiler temperature limit room temperature, until the under floor/boiler temperature reached a level that might threaten the cable/boiler, so you have over-riding cut outs. Not asking you to answer this, just thinking out loud. Struck me it might not be the floor sensors controlling the heating rather than the thermostat in the control box which is effectively a room thermostat, in CH parlance. The box I've got has the facility to be set by room or under floor temperature - unless the under floor temperature gets crazy, you'd always opt for room temperature as that's the point of it. Just for your amusement, when our system was running for a couple of cold weeks in January, room temperature of around 24 needed an under floor temperature, with lots and lots of lovely insulating air around the cables, of a blistering 35.
Only other thing I wondered was that if the insulation under the cables is half-decent, does the difference in flooring beyond the insulation make that much difference? Again, not asking you to answer this but loose ends to sort out before mixing up the first batch of https://www.tilersforums.com/forums/tile-adhesive/ to lay the first tile.
I've got some homework to do to keep my best mate builder on the right track. Good at homework these days. Bought a big bloody ultra HD telly for the kitchen not having bought a telly for about 6 years. God, don't things change? So what I've discovered about Cat 5a vs 6 ethernet, HDMI 1.4 and 2.0, 4k TV signals and so on.... UFH can be cracked.
Thanks as ever
Matt
I think I can.

You seem to be a specific kinda bloke. And I think the one time the floor half heats up, you'd notice it. And it might be annoying.

You can change the pins inside the thermostat controller to inform it which sensor is primary.
Pretty sure you can just tell the stats these days which one is primary. I'm talking out my arse there assuming it's still 1999

So perhaps opt for air and run as you'd suggest. Allow the whole floor to heat at the same time.
 
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