How many layers on bonding/filler for hole in the wall

RaulSim

To cut a long story short, my wall had to be cut out as a hole was drilled into a pipe behind it. After cutting out the plasterboard wall we realised there was a plank of wood behind covering most of the area. Most likely for support. 

The hole is about the size and shape of a car driver, or passenger side window. 

The plumbers have fixed the pipe and had to cut out some of the wood to access it. We now have builders in doing the making good work, after much delay.
Work done so far:

1. They have put a new plank of wood which covers the majority of the area on top and adjoined it to the old piece
2. used fibre glass tape (think that’s what it’s called) around the edges of the hole
3. Used bonding/filler (white paste) over the whole area and smoothed out (only 1 layer/coat)

Bearing in mind the existing wall was plasterboard and I’d like to restore to as close to original state, is another layer of bonding/filler needed? Or can he just plaster over it and then paint it once dry (as he suggested he will do)?

there are also some cracks around the edges after some drying time. See images. 

Should I be concerned about this?

Any help, or even general suggestions would be greatly appreciated. 

Thanks

Martin_the_Unjust

You’ve employed someone to do the job, let them do it, if you now start telling him how to do his job it’s unlikely to end well.

Bendy_House

Hi RS.

Looks like they've got the depth up pretty close to finished surface level? So theoretically all it needs is a finishing skim.

These cracks look to be due to shrinkage, probably because a slightly too thick layer of plaster/filler was applied before. This shouldn't be an issue, as the new skim should both fill these gaps and cover them. They've used scrim (that mesh) to secure the edges of the hole, so all should be fine.

And they should achieve a finish that blends in to your existing p'board wall.