How do I adhere a mirror on the wall when the base of the mirror has nothing to sit on?
Cut two lengths of timber to your desired height for the base of the mirror to sit on while the adhesive cures.
The mirror will not fall forward but would slide down the wall if there were no support on the bottom edge of the mirror whilst the adhesive is curing.
Adhesive usually cures in 24hrs at room temperature, please allow slightly longer if the room is cold, i.e fitting in an unheated room in winter.
Please see the image below for an example.