Cracked tiles in my conservatory - HELP ME PLEASE

[Perry72]

Hi

Any advice would be most appreciated.

Last April we had a lovely conservatory fitted. Our builder (who was above excellent) recommended a local tiler. He persuaded us to have electric underfloor heating (Devimat Warm Floor System) as he could fit this as well as lay the tiles. He also helped the builder lay the concrete base. The tiler laid the underfloor heating mats on a Friday and returned the following Tuesday to lay the tiles. He left a testing device on the electric mains to ensure it was still working. He laid a protective screed on top of the mats. At no time did he tell us not to walk on the floor, but we kept off it for 24 hours and then we were very careful but he had cross the floor to access the garden. When he returned he said that the connection had broke and the mats might not work. After much deliberation we told him to lay the tiles and we'd take a gamble on the mats. The electrician advised him to just disconnect the earth. He then laid the tiles (did a lovely job) and the electrician came and did the final fix and the underfloor heating worked. much to our relief.

This was May time, so we didn't use the underfloor heating until September time. When we turned it on for a day we noticed that the first two tiles (from the patio doors leading to our garden) had cracked, I contacted the tiler and after a couple a calls he finally came back and replaced the tiles.

We left the heating off and turned it back on again towards Christmas time, same thing again, first two tiles cracked. We left in heating on thruogh Christmas and the cracked continued sometimes following the grout and sometimes making a small hairline crack in the tile, the cracks are thinner the further you get towards our house. The crack then goes up our wall towards the control unit for the underfloor heating (albeit a very thin hairline crack but still visable).

I've made numerous attempts to contact both my builder and tiler but neither are responding. The last time I spoke to the tiler he said that when he replaced the two front tiles he noticed that there was a crack in the floor underneath and suggested I ask my builder to have a look. I spoke to the builder that night and he said he would ring the tiler and arrange with him to come back and have a look - they're both now avoiding me.

I'm at a loss at what to do next, I did notice a crack in the concrete base, on the day it was laid, it was extremely hot day and the cement dried rapidly, the builder then laid a self-levelling compound to cover the crack.

Does anyone have any ideas what could be causing our problems? Is it the fact that the underfloor heating isn't earthed? Is it the crack in the concrete base? Has the tiler done something wrong when he laid the tiles? Its always the first two tiles that crack and there aren't any heating mats under these tiles as they are next to the outer conservatory door.

Another question as well, how long should it take for the tiles to warm up, the conservatory is 5m x 4m and there are mats under about half of it (he didn't put any where our sofa is or round the edges)?

I could do with some expert advice to arm myself for when I eventually get the builder and tiler back round, as they WILL return.

Paul

[Rich]

How long was the screed left for before the tiler went in? and can you tell us how you turned the UFH on? Did you wait a while and put the temp up slowly or just turn it on?

[Dave]

Hello Paul and thanks for the post regarding your tiling job.

A few questions first please..

1: How long was the falir down before tiling..as in the main floor before levelling the crack.?

2: Were any insulation boards used... this affects the warm up times and running costs.

3: When turning o n the UFH, how did you do this and was any advice given on this process.?

4: lastly any pics.

[Ajax123]

Another question - does the crack in the tiling have any relationship to where the noticeable crack was in the concrete?

[Perry72]

Thanks for your quick responses guys. I'll answer each question in turn:

How long was the screed left for before the tiler went in? and can you tell us how you turned the UFH on? Did you wait a while and put the temp up slowly or just turn it on?

The screed was left for at least 24 hours before anyone went into the conservatory.

A few questions first please..

1: How long was the falir down before tiling..as in the main floor before levelling the crack.?

The floor was laid on a Friday and the builder came back on the Monday and laid the self-levelling compound

2: Were any insulation boards used... this affects the warm up times and running costs.

No insulation boards, they put a polystyrene (I think that's what it was) down and said this would act the same as insulation boards and send the heat back up.

3: When turning o n the UFH, how did you do this and was any advice given on this process.?

We just tested that it worked with the electrician when he came one tea time, it came on we left it for a few hours and then turned it off, it was months later when we turned it in proper, it was just turned on high - no advice was given.

4: lastly any pics.

See attached - you can see the self-levelling compound quite clearly from picture 2 and this is right in the area of the crack tiles. It's a good job my wife took pictures at each stage!

Another question - does the crack in the tiling have any relationship to where the noticeable crack was in the concrete?

Yes, the crack is in a similar area to where the original crack in the base was -see picture 2.

[jay]

hi thanks for pics the heating should of been turned on very low heat first then increased slowly over the next 7 days but your problem with cracking is caused by the crack in the concrete was there any rio used in slab and no slc wont fix a cracked substrate by the looks of the pics it was a substatial crack which can be caused by rapid drying or lack of reinforcement in concrete plus several other reasons was concrete dampened to slow drying at any stage

[mikethetile]

Looks as if the crack in the slab is not surface but has gone through, the two halves will move independantly and crack the tiles

you need to take care when concreting in hot weather as the surface may dry too quick and crack, placing damp hessian on the suface and occasional damping will slow drying down

if the slab is cracked through it can be repaired with resin and retiled

nows a good time to talk to your builder about making a claim against his insurance