Butt Jointing Slate Tiles in a Hearth?

[neil b]

Hi All,

Newbie here!

I'm re-tiling a hearth using natural slate tiles 100mm x 100mm and they're approx 8mm thick.

I'm tiling the hearth and the sides and rear of the fire opening. We're then going to have a wood burning stove in the fireplace.

My question is, can I but joint them or should I leave a thin grout line for expansion? I get that they're all slighly different thickness and that's fine, just unsure about the expansion?

Any advice gratefully received

Cheers

Neil

[royaloakcarpentry]

Slate normally has a tolerance for overall given size of + or - mm. The amount depends on where they are made, as does how square they will be.

Chinese slate for example will be absolute cheap cack and not square, so you will not be able to butt them up.

If you want to try it, then dry lay them first and see if it works out.

[neil b]

Thanks for the reply.

The tiles all seem to be pretty much 100mm x 100mm but the thicknes varies... a lot

I'm not too botherd by that though, my main concern is whether I'll need to leave a gap so the tiles can expand when they get warm from the stove or whether butting them will be fine as you can never get them 100% tight togethr anyway???

Ta

[royaloakcarpentry]

If they haven't been graded to thickness then they will vary.

You will have to sort them in order of thickness and start with thickest tile first, working your way through them and laying the thinnest last. This way you will get a nice level, flush finish.

The heat will (should) not crack the tiles. Not sure that expansion will be a problem to cause cracking if they were butted up. They will suffer a certain amount of de lamination being in there natural state.

Personally I would not butt them up, and I wouldn't use 8mm slate for the hearth. Would want to put min of 20mm thick down.

[neil b]

Thanks for the advice. I'll lay them out an see what the wife thinks of how they look...

We all know she has the final decision!

[royaloakcarpentry]

No problem..............hope you check back, cos have edited since posting.

[tictic]

i would defo leave a gap of a few mm,

when you apply the addy to wall/floor and the tile fixed to it,there will be slight movement when the adhesive starts to bond to both subtrates,if they are butt jointed you will be putting pressure on all four sides of the tiles,which could lead to problems.