If you do not know how it has been done you can give a go with stud locator.
Securing heavy stone tiles to plaster walls.
Fit the item to be anchored over the bolt then insert the toggle and tighten.
We ve got some large stone tiles in a bathroom that are heavy as hell went on a skimmed wall and have been trouble free.
Add the elegance of natural stone to your bathroom walls for little more than the cost of standard ceramic tiles.
This is equivalent to ceramic tiles with a maximum thickness of 8mm plus tile adhesive or natural stone tiles with a maximum thickness of 7mm plus tile adhesive.
Some products are designed specifically for use between tile and plaster walls but any tile setting adhesive designed for thin set use will work.
A glue adhesive works better for installing tile over plaster.
For something especially heavy like a wall hung vanity she recommends having the wall built with a layer or two of plywood before putting on a layer of hardy board and then tile the wall this.
So make a small whole on both side of potential stud just to be sure.
The maximum weight of tiling which can be supported by a dry well adhered plaster background is 20kg m.
Stone tiles on a skimmed plaster board wall.
Hi the maximum weight limit for tiling direct on to plasterboard without skim is 32kg per sqr mtr using stone or in your case slate maximum thickness of 10 mm this includes adhesive.
How to hang things on a stone wall.
Stone accent walls and fireplaces can be a great design feature but hanging a picture on a stone wall or holiday wreath above a stone fireplace requires some care.
Home centers and tile shops carry a huge selection of marble limestone and granite and the installation techniques are virtually the same as for ceramic.
Then the next step would be to add an extra piece of 12 mm plywood on top of your wall attached to the studs.
Just please bear in mind they are not 100 accurate either.
Plastic versions hold medium loads in drywall and plaster.
450mm x 450mm tiles.
Bore a hole in the wall large enough to accommodate the toggle.
The surface of a plaster wall is too smooth for the cement to grip to.