Term: level of finish for plasterboard

The "level of finish for plasterboard" refers to a standardized classification system that describes the quality and smoothness of the surface treatment applied to plasterboard (also known as drywall or gyprock) before painting or other decorative finishes. This system is used to ensure consistency in appearance and performance, particularly in relation to lighting conditions and the type of final finish (e.g., flat paint, gloss paint, wallpaper).

In Australia, the levels of finish are defined in the AS/NZS 2311 (Guide to the painting of buildings) and AS/NZS 2589 (Gypsum linings – Application and finishing). The levels range from Level 0 to Level 5, with each level indicating a different degree of surface preparation:

Level 0

• No jointing or finishing.
• Used where the surface will be concealed or where no decoration is required.

Level 1

• Joints and interior angles taped with joint compound.
• Tool marks and ridges are acceptable.
• Typically used in areas not open to public view (e.g., service corridors, attics).

Level 2

• Joints and angles taped and coated with one layer of joint compound.
• Surface suitable for areas where appearance is not critical.

Level 3

• Joints and angles taped and coated with two layers of joint compound.
• Surface suitable for heavy texture or wall coverings.
• Not recommended for smooth painted finishes.

Level 4 (Most common for residential and commercial interiors)

• Joints and angles taped and coated with three layers of joint compound.
• Fastener heads and accessories covered with three coats.
• Sanded to a smooth finish.
• Suitable for flat or low-sheen paints in normal lighting conditions.

Level 5 (Highest standard)

• Same as Level 4, plus a thin skim coat applied over the entire surface.
• Provides a uniform surface for critical lighting conditions or high-gloss/semi-gloss finishes.
• Recommended for areas with strong natural or artificial lighting that may highlight imperfections.

Importance:

Choosing the correct level of finish is crucial for achieving the desired aesthetic result and avoiding visible imperfections, especially under critical lighting conditions. It also affects cost and labour, as higher levels require more time and skill.

In summary, the level of finish for plasterboard is a guideline that helps builders, plasterers, and painters determine the appropriate surface preparation based on the final decorative treatment and environmental conditions.