How to finish a internal wall shelf

[mrbg07546]

hi.

I am creating a to shelf in a chimney and wanted to know how to make the shelf flush and finished(as in attached picture I want to achieve)

I have created studding and put a plywood board on top and put plasterboard on outside. How do I achieve the shelf cleanly(as in pic) . I don't want to skim inside the shelf. And I don't want to use window board.

 

[Deleted member 174758]

When creating wall niches with metal lath it is quite usual to put in a horizontal plywood or OSB "shelf" patress then to board over the "shelf" with plasterboard and either skim or tape and joint then sand. Doing that ensures that there are no visible materil joints like you'd have with a separate plywood shelf. The illustration you link to shows something which could be achieved in that way as well