HELP - floor tiles lifting!

[LisaK]

Hi
can anyone shed any light? My beautiful local slate floor tiles were put down about a year ago along with underfloor heating.

I've noticed that some of the tiles are starting to lift! They were put down by a proper tiler and been down a year but this problem has only started since the cold snap and I put on my underfloor heating for the winter....

Any ideas you experts out there?

Thanks
Lisa

 

[Softus]

You'll have to remove a tile and investigate why it isn't stuck down.

It could be the wrong adhesive, or too dry, or too wet, or not enough of it, or the wrong substrate.

Or it could be that the floor has become too hot. How is the temperature regulated within the pipework under the floor?

 

[LisaK]

Thanks for the reply.

The heating is regulated by a thermostat on the wall. It isn't pipes that heat the floor rather one of those flexi mats. IT has worked fine for a year.

I was wondering if the cold snap (its an old cottage extension done in the 60's with uninsulated floor) has made floor really,really cold (it was minus 12 outside this last few nights) and now we have put the floor heating on, it has caused shattering which is making tiles pop up?

Take your point about taking up the tile.....will have to get a builder in to take a look - expense I could do without right now.

Thanks
Lisa

 

[Softus]

It isn't pipes that heat the floor rather one of those flexi mats.

Ah, OK.

In that case, it still depends on the correctness of the installation.

If it was only a year ago then I'd get the installer back to determine why it has lifted. It should last more than a year, so it shouldn't cost you anything for it to be put right.

 

[LisaK]

Thanks and good point.

It'll be interesting as my Electrician supplied the mat and the tiler just fitted it.......

I'm worried that the waste water pipe for the washing machine that runs under said floor, is causing the problem somehow. That was put in last year too at the same time all the work was getting done. Could be water sitting in this pipe has frozen, expanded, shattered pipe and is causing tiles to lift - who knows.

I guess tiler/builder needs to come in to lift said tiles without damaging them and take a look underneath....

Fingers crossed.

Lisa

 

[Softus]

So I take it that this is a ground floor?

Regarding frozen water in the waste pipe, that's impossible if the waste pipe is at the correct gradient, because it wouldn't have any water in it.

What make was the mat? If you don't know, then is anything written on the thermostat, or were you given any documentation? If not, then can you post a photo of the 'stat?

Do you know what the mat was laid on, and how?

Do you know what tile adhesive was used?

 

[LisaK]

HI

It was a timeguard fleximat then fitted with a Heat Mat thermostat because the original timeguard thermostat went on fire (don't ask but Timeguard investigated their thermostat and decided to pay me off but not admitting it was their device at fault - goodwill payment they said but that is a different story)

Anyway and as the for the gradient of the waste pipe......I don't think that was fitted with any strict gradient in mind, I recall there was a channel cut out of the existing concrete floor and lets just say I didn't see any fine tuning of gradients going on so we could be edging closer to the culprit (standing water getting frozen!). Come to think of it, the tile that is lifting is directly above where I recall a 45% degree bend being put in the waste pipe in order for it to flow out to the drain out by my back wall.

Sounds like we could have a dodgy waste pipe! Might have to reroute that waste pipe out by some other route (not under tiled floors) if it is the culprit as I don't want to rip up my lovely floor.

PS the builder who put the channel into the floor is a builder who was paid good money to do the job but also a good friend which might make compensation tricky!!

PPS - don't know what adhesive was used.

Lisa

 

[Softus]

Anyway and as the for the gradient of the waste pipe......I don't think that was fitted with any strict gradient in mind, I recall there was a channel cut out of the existing concrete floor and lets just say I didn't see any fine tuning of gradients going on so we could be edging closer to the culprit (standing water getting frozen!).

Maybe, maybe not.

Can you measure the length of pipe run (i.e. as you imagine it running) under the floor, and the drop in height over that distance?

For example, if the pipe runs for 1 metre, then turns, then runs for another 1 metre, then it should drop a bare minimum of 44mm over that distance. That's the same amount as the outside diameter of 40mm waste pipe, so that should give you an idea of what you're looking out for.

PS the builder who put the channel into the floor is a builder who was paid good money to do the job but also a good friend which might make compensation tricky!

Let's not talk about compensation then, but if he's competent, and a good friend, then surely he'll scuttle straight back to put the job right?

 

[LisaK]

Good info.

Difficult to measure the height difference (I'll give it a go in daylight hours) but I know the pipe runs approx 2 m from washing machine to 45degree bend and then about half metre out to back wall. I would hazard a good guess (from memory) that the gradient isn't right on the pipe so standing water has been our problem.

I've got the underfloor heating on permanant now at about 15degrees so that, I hope, should stop the water from freezing anymore as the concrete that enclosed the waste channel/pipe wasn't that deep.

I guess the only way to know for sure now is to lift the tile. DO you know what we would expect to see if standing frozen water in the pipe has caused the problem...would it be visible underneath the tile i,e wet concrete or shattered concrete.

PS - it is wise to have an underfloor heating mat going if we suspect such a 'water' based problem......

L

 

[Softus]

I've got the underfloor heating on permanant now at about 15degrees so that, I hope, should stop the water from freezing anymore as the concrete that enclosed the waste channel/pipe wasn't that deep.

I know we have it easy down here in the south of England, but have you really had prolonged freezing conditions where you are?

I guess the only way to know for sure now is to lift the tile. DO you know what we would expect to see if standing frozen water in the pipe has caused the problem...would it be visible underneath the tile i,e wet concrete or shattered concrete.

There won't be any 'shattering', but if you can see the pipe you might see a crack. If this is what's happened then you won't need to lift the entire floor - just enough to deepen the channel and get the correct gradient.

Or is there an alternative route for the pipework so that you don't have to do more digging?

PS - it is wise to have an underfloor heating mat going if we suspect such a 'water' based problem.

I wouldn't worry - there's such a thing as being too cautious. However, the mat needs to be protected in the correct way electrically, i.e. connected to an RCD.