I am eventually going to get a professional reskim carried out in my living room, however, I am doing as much preparation as I can prior to this. I am putting up some plasterboard around an arch that originally had a moulding around it. Should I put tape or mesh along the outside corners of the plasterboard? There are a few hairline cracks in the original top coat but the plaster is sound in these areas. Are these best just left as is or is it worth opening them out to allow the skim coat into the crack. Lastly, are additional corner reinforcing meshes ever fitted for a reskim ?