Loose tiles & underfloor heating...

[Dumbo]

Then he can use their report against the builder!

True . Never thought of it that way , but I'm not a canny northener . Just Wiltshire born and bred , strong in arm and thick in head .
Trouble is I'm not strong in arm .

 

[Old Mod]

Although the repair of your floors is the most important issue to be dealt with here, there is one thing that you’ve described that concerns me a little.
You’ve mentioned that
“In reality, the one that is worst was left at least 2 weeks before switching on, and has only been used approx 10 times?”
The reason that you have to wait before turning the heating on is to allow the adhesives to cure fully before heating, and 3 days is insufficient.
I appreciate you waited two weeks for the worst floor, but I instruct clients to wait 28 days, that’s the length of time it can take for cement based products to cure fully.
In fact adhesive doesn’t achieve its maximum bond strength until after 28 days.
Secondly, your method of operation, yes you were instructed to increase the temperature slowly at a rate of 1 degree a day, (which would be a good method for the first heating cycle,) but it should also be turned off in the same manor to complete the first cycle, before day to day use
However, was it explained to you that every time you turn the heating on and off, it should ALWAYS be done gradually?
There’s no need for it to be done in 1 degree increments after the first commissioning, but it should be done over a couple of days.
And the reasoning behind it is that you’re trying to prevent ‘thermal shock’ within the adhesive.
Thermal shock can happen at anytime!
It’s not unique to the first operation.
So if for example the way you use it is to leave it at operating temp on the thermostat and just switch it on via the fuse spur, it means it’s going from cold to operating temp straight away, or vice versa, this can possibly lead to thermal shock within the adhesive, which in turn can cause partial or catastrophic failure.
Just something to be aware of.
When the tiles are lifted and before they are
re-instated, look at the adhesive beneath them, typically thermal shock presents as ‘crazy paving’ or multiple micro cracks in the adhesive.

 

[jimthetiler]

It looks like you have cranked up the heat too soon,you need to raise the temp over at least a period of 3 days to 7 presuming the ambient temp is 10 plus degrees before you start.

 

[JMRolfe]

So that may be the case in the main bathroom as it's only been used a few times (although not at all in the last 2 months).

But the kitchen and ensuite have been built up per recommendations and kept at 22 degrees morning and night whilst we're home and allowed to drop to 18 during night / 20 day.

Also, at no stage had I been told that underfloor heating had to be kept on continuously?? Seem a bit extreme?

 

[JMRolfe]

Also, never been used but the thermostat (Warmup 4IE) offers geo tracking which will switch your floors off if you leave the house, and back on when you return home? Surely that would invalidate your gradual warmup routine?

 

[J Sid]

Also, never been used but the thermostat (Warmup 4IE) offers geo tracking which will switch your floors off if you leave the house, and back on when you return home? Surely that would invalidate your gradual warmup routine?

I pretty sure the warmup4IE will switch it to a lower temp, say 12c or whatever you decide rather the off.
why would you want to turn it right off, not an efficient way to run ufh.

 

[CJ]

You need to get the builders back first of all, how did they lay over the cables........Dot/dab??

You will also find it difficult to get another tiler to rectify the problem, as most of us do not like repairing other people’s work........especially not know it all/jack of all trades (master of none) builders.

 

[JMRolfe]

Sorry, let's start again none of them have ever been powered down. I just mean the temperature has been at its fallback temperature of 16 degrees (?). Floor always reads around 18 during this time presumably due to the central heating in the house. When I say on, I mean set to usually 22, sometimes 24 to give a to touch feel underneath.

 

[JMRolfe]

OK fallback is 12 degrees

 

[GoneGuy]

Have you tried tapping the tiles to see if they sound hollow? The builders might have dot and dabbed them and created hollow spots

 

[J Sid]

https://www.tilersforums.com/attachments/20190216_110433-jpg.104699/

 

[Andy Rhodes]

This is what it says on the bag , so by going to sealocrete all they will do is throw it back on the builder who did the job.
Sealocrete Rapid Set Flexible Floor & Wall Tile Adhesive is a cement-based adhesive for use on concrete, concrete block, cement render and brick. It can also be used on plaster, plasterboard, chipboard, wood and existing glazed ceramic or vinyl tiles and is suitable for use with most domestic underfloor heating kits. For internal and external use.
I know you don't want to get the builder back, but why pay out you hard earned cash to put something right that should been done right on the first time of asking.
If they refuse to make good mistakes seriously think about taking legal advice on the matter.

 

[JMRolfe]

Thanks all. I called the builder this morning, he's said he'll come and take a look.
He said the only time he'd seen it before was when moisture got into the chipboard...

Thinking about it, my mother in law showered with the shower door open (as you do) about a month ago in the room adjacent. At the time we ended up with water stains on the ceiling below. The tiles next to the flooded shower are fine, but it is the other side of the wall that they are all lifting so may be related?

Although that doesn't explain the ones in the kitchen ...

 

[J Sid]

evo-stik recommends priming with PVA

Underfloor Heating: 8. If using over underfloor heating elements, apply the adhesive according to the manufacturer’s instructions, leaving the correct length of time between laying the underfloor heating and applying the adhesive. Heating systems must be switched off for at least 48 hours before and after tiling.

9. Dusty or very porous surfaces should be primed with 1 part EVO-STIK Evo-Bond PVA to 4 parts water by volume and allow to dry prior to tiling. For wooden floors only prime if absolutelynecessary as it may reduce the porosity of the floor and increase the drying time of the adhesive.

 

[Andy Rhodes]

well it is evo-stik , & there word is law according to on e discussion i had with them many moons ago