Need some advice on fixing porcelain tiles behind a multi-fuel stove.

The tiles are going onto standard 'brown' plaster, done by a local plasterer, who's also going to do the tiling.

What adhesive do I need?

I've come across 'Vitcas' on web-searches - any good? Over the top?

What's good for this location.

The stove is a boiler stove to run my central heating, so the walls of the stove will never exceed 100C (or if they do I'm in big trouble...), but the stove will be on 12 out of 24 hours, all year except summer.

The tiles are 300x300 Cotto Granito, unpolished porcelain.

Not sure which grout to use either - I'd like a mid-brown to match the tiles.

Thanks In Advance

I tiled behind a multi fuel stove a few months ago and used mapei keraquick,i asked the tile shop too what would be most suitable.For grout i use mapei ultracolour.No probs yet.

you'll be fine with that choice JoeIf you have the same availability Log Gatherer I'd recommend you get the same as Joe (Hillhead)

You may just want to check the weight of your tiles if going straight onto plaster. Max recommended safe weight for that substrate is 20kg/m2, including adhesive and grout.

Originally Posted by grumpygrouter

You may just want to check the weight of your tiles if going straight onot plaster. Max recommended safe weight for that substrate is 20kg/m2, including adhesive and grout.

with regards to "brown" plaster, I interpreted as sand/cement render, (hopefully with hydrated lime) but as Grumpy says, best check

Just checked - a pack of 11 300x300 weighs 15Kg - I reckon that's just about exactly 1 sq m, so I think with the adhesive and grout I'll be OK at 20 Kg per sq m.

Thanks guys!

yep, LG you'll be fine with that

just out of curiousity, can you find out what the "brown" plaster is?

Yep I'll ask tomorrow - George just calls it 'broon' (Scots for brown to you sassenachs...)

Apparently it's brown Carlite onto brick, with a multifinish top layer.

Dunno what that means, but it's been up for about 3 weeks and seems thoroughly dry.

I've gently tapped around it to check for any hollow sounds (I've been reading the forums you see...) - and it all sounds rock solid.

Got the Keraquick and Supacolour today, and George is going to put up the tiles on Wednesday.

YeeHaaaa!!!

don't forget to give it a coat of primer G first LG

Is that just PVA or something special?

Neil

it's the proper stuff to prime your plaster with Neil, you should be able to get it where you get your keraquick from, don't use PVA

If the temperature at the back of your stove is going to be high enough to require a fire proof adhesive I am afraid your substrate is not suitable. Carlite Browning and multifinish are both made from Gypsum. This is a crystaline substance which uses water as part of the crystaline matrix. If this is subjected to sustained elevated temperatures the "water of crystalization" is driven off from the gypsum molecule and it begins to "dehydrate". This will initially manifest itself as localised cracking or crazing which will potentially cause your tiles to crack. Ultimately it will fall apart and your tiles will simply fall off.

When dealing with Gypsum based materials e.g. screeds with under floor heating the temperature should be maintained below 55 degrees Centigrade.

I suspect however that your wall is unlikley to get that hot and a fireproof adhesive is not really necessary.

Well...

The stove has been on for about 6 hours now - the plaster behind it is not much more than comfortably warm. I can easily put my hand onto it and it just feels cosy. I guess around 28 - 32C.

The warmest part is around the place where the chimney pipe enters the wall, about 1200mm above the stove itself. Again, I can hold my hand on the wall and it's not uncomfortably hot. I'm going to put on a circular enameled steel 'rosette' to protect the plaster from over-heating.

Any particular brand of Primer G to get?

Thanks,

Neil

Mapei primer G...

Originally Posted by log_gatherer

Well...

The stove has been on for about 6 hours now - the plaster behind it is not much more than comfortably warm. I can easily put my hand onto it and it just feels cosy. I guess around 28 - 32C.

The warmest part is around the place where the chimney pipe enters the wall, about 1200mm above the stove itself. Again, I can hold my hand on the wall and it's not uncomfortably hot. I'm going to put on a circular enameled steel 'rosette' to protect the plaster from over-heating.

Any particular brand of Primer G to get?

Thanks,

Neil

Thought it would not get that warm. there are loads of primers you can use for this type of application - I personally would recomend an epoxy if you are using a cement based adhesive. This is becasue they are not particularly affected by the warmth and eliminate the risk of chemical interaction between the gypsum in the plaster and the cement in the adhesive. Acrylics do not seem as effective at this when there is heat involved.

I'll be out tomorrow at Tile Giant for some Primer G!

Thanks guys -

Neil

Originally Posted by doug boardley

it's the proper stuff to prime your plaster with Neil, you should be able to get it where you get your keraquick from, don't use PVA

Sorry to hijack for a second, Doing a wet room and the builder made the falls to steep into the drain and now has to build up and suggested putting PVA down before he puts extra sand/cement to build up the floor
Told him to use sbr, he's never heard of it

Thanks for the advice guys - the tiles and grout are up, primer G holding it all together!

Been running the stove fairly intensively for a week, no probs, and the tiles look great!

I'll post some pics when I can find out how...

Hi folks - thanks for all the advice, which I'm glad I asked for and got, cause I now have confidence my lovely new stove will keep its tiles in place!

It all looks great, and using a brown grout sets off the tiles nicely. Once the room is decorated, the whole 'ensemble' will look great.

As I hope you'll agree when you see the picture.

Thanks to all - and happy tiling!

Neil

Looks good...