Hi, I'm dividing part of a bedroom by adding a stud wall. I want to position the stud wall to come across level with the fireplace alcove wall. the alcove is 1140mm. The chimney breast is 230 deep where the new stud will start. Just wondering if I can set the stud wall 12.5mm back from the chimney breast so the plasterboard can sit flush with the solid chimney breast and then skim over?