Help!: Very hot conservatory

[heatonfan]

We are having our conservatory floor tiled with reasonable quality porcelin tiles and getting ride of the old Amtico that was laid about 15 years ago by previous owners. The Amtico is coming up, so we have been told, because it probably couldn't take the heat below.

It is a reasonably sized conservatory (so I reckon) - about 32 m2. In consequence it has lots of glass, and the heat in there is fierce on a sunny day, especially if we are not in and doors and windows are all shut.

Anyway, we are being quoted £250 for preparing the floor and £1,350 for fitting the tiles, arranged by the builder who has been sorting out a new kitchen, and who has to be fair to him had all the work so far done to a very high standard by the various tradesmen used. They are also tiling the kitchen and putting in underfloor heating there (separate quotation), so there is plenty of work in the job.

Given all that:

1) Is there anything in particular recommended for tiling rooms that get very hot? Just want to be able to ask informed questions of the tiler when he comes to do the work.

2) What should we look out for to be satisfied that we have got a high quality tiling job (which I hope we could expect for the outlay)? ie. what 5 things would you tell your old aunt on the other side of the country to check out before she paid over the cash!?

Thanks in advance!

[Dave]

what tiles are you having fixed...and what substrate..?

[heatonfan]

30 x 30 porcelain.

On concrete for the most part, but one small area is likely to be plywood put over old floorboards (a little conjecture, but that was part of the old house and so will probably be the same as the kitchen)

Hope that helps with the basic info.

[Ajax123]

Reason for amtico coming up is likely due to heat as you say. Most general purpose vinyl flooring adhesives cope with temperatures up to 27oC but I know my own conservatory gets well into the 40's if the doors are left shut.

As for the tiles - I would think that to take account of the differential levels of expansion and contraction in the two substrate types the best thing would be to use a decoupling mat.

Not sure about specific adhesives though.

[Dave]

You need to put a movement joint where the 2 substrates meets... they will expand and contract at different rates and a risk of deflection at the timber meeting point requires a joint..it canbe a pre-formed joint or a cold joint but deffoe needs to be a break..

[Ajax123]

You need to put a movement joint where the 2 substrates meets... they will expand and contract at different rates and a risk of deflection at the timber meeting point requires a joint..it canbe a pre-formed joint or a cold joint but deffoe needs to be a break..

Good point Dave. ...as I should very well know decoupling mats will not take account of deflection or vertical movement. Could still use one but seems less attractive now.

[beanz]

You need to put a movement joint where the 2 substrates meets... they will expand and contract at different rates and a risk of deflection at the timber meeting point requires a joint..it canbe a pre-formed joint or a cold joint but deffoe needs to be a break..

I'm glad i read this thread, as i thought a decoupling mat would be all that was needed in this situation!

Is there any point using a decoupling mat then, as the two substrates will be seperate anyway!?! Also, am i still going to be asking this many questions in 20 years? Every time i think i know how to handle a certain situation i find there's something else to take into consideration!!

[Dave]

If the tiles were stone then Yes i would use an uncoupling matt..stress cracks are more common with softer stones but porcelain should fine with correct adhesive and movement joint...

[heatonfan]

You need to put a movement joint where the 2 substrates meets... they will expand and contract at different rates and a risk of deflection at the timber meeting point requires a joint..it canbe a pre-formed joint or a cold joint but deffoe needs to be a break..

Well that is a good start - and I will definitely follow this through when the old floor is taken up.

But what about the heat - does any special adhesive or grout need to be used??

[Dave]

Most flexible adhesives will cope with 100dgs of heat and flexi grout will be needed...

Check with the manufactuer to clarify if unsure.