how to install slate window cills

[Bitstreams]

My slate window cills have arrived yay!
What should I use to stick them in place? They're pretty heavy and 25mm thick. They're going on top of a mixture of stone uneven stone and bits of brick.

Simon

 

[chuckey]

I would use lime mortar. As I would also angle the cills downwards a bit to ensure that there is no standing water and I am intending to slot my cills into the wall at either side, so the finishing mortar course at the sides of the cill is in the vertical plane and not put the cill into the window recess, so the pointing at the ends of the cill is in the horizontal plane.
Frank

 

[Bitstreams]

I would use lime mortar.

Thanks - I have bags of Old House Store's Coarse Stuff (pre-mixed Lime Putty) - can I use that?

Simon