Fine rendering is a thin, smoothly rubbed finishing coat of mortar or plaster, applied over a coarser base coat. After application the coat is floated or rubbed with a felt or sponge float, releasing the surface aggregate and creating an even, fine-grained texture. Fine rendering is a classic finish for interior and exterior walls.
Build-up of rendering
Render typically consists of three coats:
Scratch coat
- First coat on the substrate (stone or concrete)
- Levels out coarse irregularities
- Left rough so the next coat keys in
Float coat
- Body coat with larger grain
- Provides volume and strength
Finish coat / fine render
- Fine top coat with thin mortar
- Applied with trowel or smoothing iron
- After initial set, evenly floated
Application
Fine rendering is commonly applied on:
- Exterior walls — façade render with natural appearance
- Interior walls — base for wallpaper or paint
- Ceilings — smoothly prepared for paint
- Listed buildings — restoring historic render
- Farms and rural buildings — traditional façade with lime render
Advantages
- Smooth look — less relief than rough render
- Good base for paint — even substrate
- Vapour-open when using lime render — prevents damp issues
- Repairable — local damage easy to patch
Materials and mortar
For fine rendering the following are used:
- Lime mortar — traditional, vapour-open, suitable for old buildings
- Mixed mortar — lime and cement combined
- Cement mortar — stronger, harder, used outdoors
- Gypsum plaster — interior only, fast-setting
The grain size of the sand determines the final texture — for “fine” rendering, sand with a grain up to about 1 mm is used.
Related terms
- Plastering
- Render
- Scratch coat
- Lime mortar
- Façade render
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