On 14/11/2017 12:29, Murmansk wrote:


I'd like to support this cupboard using a long strip of wood at the back of the cupboard just under the top edge but my problem is how to attach this to a wall which is so insubstantial.


IME it is normally easier to put a batten under the *bottom* edge.
Although this will subsequently be visible, it may be a useful place to
put cup hooks to hang kitchen spoons, spatulas, etc.

The point is, with a strong bottom edge fitting you can rest the
cupboard on that and then either a reliable (but not necessarily strong)
pair of hands to hold it on the ledge while you fit something at the top
to hold it in place. Or you can even use props of some sort.

Others will comment on how to fit the batten. There are now quite good
plasterboard fittings, especially if it is 18 mm board. Finding
concealed battens, if there are any, is another option although
*personally* I would try to drill through them into the wall behind.
Similar for dot and dab. Recognising that this is more difficult if it
is a random stone wall.