Patching A Ceiling (Wood Lath)

There are different ways that you can plaster patch on a wood lath ceiling. If the patch is quite small, it can be repaired by cutting a piece of plasterboard to size and screwing it. An undercoat might be needed to fill in the gaps around the edges of the plasterboard and the ceiling.
If too much material has been onto the patch, a scrim can be used to reinforce the edges and it will help to prevent cracking at the joint.