Level 4: Recommended for most residential areas with non-critical lighting and satin, flat or low-sheen paints or wallpaper. Smooth and free of tool marks, but may have some minor imperfections. The most economical and common level of finish.
Level 5: Recommended for residential areas with critical lighting or gloss, semi-gloss or dark tone paints. Requires a skim coat to cover the entire surface and create a uniform texture. The highest quality and most expensive level of finish.
Level 3: For use in areas that do not require a high level finish, such as above ceilings and inside service shafts and other inaccessible spaces. All joints are to be taped with two applications of plaster and all screws are to be covered. The plaster is to be finished smooth, such as by scraping high points etc.
If the wallpaper has been stripped, the walls need to be prepared for plastering, which may include sealing the walls with paint. The plasterer will then tape and coat any joints and cracks, and skim the walls with plaster. The number of coats of plaster required depends on the condition of the wall.