Mixing old and new wall tiles... thicknesses...

[88v8]

I have some 6" Minton Hollins left over from tiling our bathroom in 1991.

I'd like to use them in our new bathroom, I can cope with the 6" not being quite 6" any more when I mix them with new tiles but I see that in the intervening 34 years, wall tiles have got quite a lot thinner, in fact about half the thickness.
Too much to adjust by double-buttering.

Is there anything I can stick behind the thinner tiles and then stick to the wall?

 

[DAZB]

Depends on the depth you have available but Jackoboard or similar may work if you can get the 6mm space. If not then Undercloak, used in roofing on the verges could work as that is thinner and is a cement based product.

https://www.toppstiles.co.uk/trade/wet-room/construction-boards/jackoboard-plano-construction-board-6mm

Undercloak Board - 1200mm x 150mm x 3.2mm | Alltype Roofing Ltd

A core component of any roofing project, undercloak is a strong tile or fibre cement strip that is fixed at the roof verge, beneath the batt...

alltyperoofing.com

 

[simplesteve]

You could also look at buying the plastic ‘mosaic backer’ grids. These are 300 x 300 x about 2.5 mm thick, and in your case you would trowel the wall, stick them on, then trowel flat. That would let you adjust the thickness, and they’re dead easy to cut to size.