What is plastering?
Plastering is applying a coat of plaster to walls and ceilings to give a smooth, flat surface ready for painting or papering; indoors this is usually gypsum plaster. It is done by a plasterer, by hand or with a spray machine followed by trowelling. In the Netherlands the work is called stuc or stucwerk, the plasterer a stukadoor, and the verb stuken or stucen. Note that the Dutch “stuc” means ordinary smooth plastering, not the exterior render that English speakers call stucco.
Types and differences
- Gypsum plaster: the usual interior plaster. A thin coat over smooth concrete or plasterboard is a skim coat.
- Decorative plaster: a textured finish that stays visible, such as scraped or trowelled textures.
- Spack spray plaster: a sprayed, grainy finish, common on Dutch ceilings. It is not plastering in the strict sense.
- Lime and clay plaster: breathable alternatives with their own methods, suited to older buildings.
Application
- Assess the background. Smooth, non-absorbent concrete needs a bonding primer with grit first. Highly absorbent backgrounds such as aircrete or calcium silicate blocks are primed to control suction. Remove loose material, grease and dust.
- Fit corner beads. On external corners and window reveals, beads give straight, impact-resistant edges.
- Keep within the stated thickness. A skim on concrete is a few millimetres; a gypsum plaster on masonry is usually just over a centimetre. Minimum and maximum thicknesses are on the bag or data sheet.
- No standard gypsum in wet zones. In a shower or on splash-prone walls, use a moisture-resistant system such as a cement-based render or tiling on a suitable board.
- Let it dry properly. Fresh plaster is dark; it is dry when the colour is evenly pale. Ventilate, but avoid fierce heating, which can cause cracking.
- Seal before painting. Emulsion straight onto new plaster goes patchy and adheres poorly. Apply a mist coat or primer first.
Common mistake: painting plaster that is still damp. The paint flakes or stains and the wall has to be redone.
Related terms
- Gypsum
- Plaster coat
- Plaster base
- Clay plaster
- Corner bead
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