Rhinolite plastering and cement skimming are not the same job with two names. Rhinolite is a lightweight gypsum plaster for interiors. Cement skim is a sand-cement based finish that works inside and out.
Choosing the wrong one is a common and costly mistake, especially on exterior walls and in wet rooms.
What rhinolite plastering actually is
RhinoLite is a brand of gypsum plaster made by Gyproc, and the name has become the everyday South African word for gypsum skim in the same way people say Prestik or Jik.
- Material: a lightweight retarded hemihydrate gypsum plaster
- Use: a combined basecoat, finishing and multi-purpose interior plaster
- Applied: by hand or by machine
- Finish: very smooth, closed and paint-ready
- Set: controlled setting times, free from inherent shrinkage cracking
It goes onto interior walls, ceilings and drywall boards. It is popular because it produces a genuinely flat, hard, smooth finish quickly.
Where rhinolite must not go
- Outside. Gypsum is not for exterior use in weather.
- Directly onto painted walls. Gyproc is explicit that RhinoLite should never be applied to a painted surface without correct preparation.
- Permanently wet areas. Shower interiors and similar need a cement-based system.
- Mixed with cement or additives. The manufacturer’s instructions say not to add foreign matter to the mix.
That painted-wall rule catches out a lot of renovations. The full preparation route for that situation is in our guide to whether you can skim over paint.
Cement skim: what it does differently
A cement-based skim is a thin sand-cement finish over existing plaster or masonry.
- Works outside as well as inside
- Handles moisture far better than gypsum
- Harder and more impact-resistant once cured
- Slower to cure and slower to reach a paintable state
- Slightly less smooth than a gypsum finish, though a good plasterer gets close
It is the right answer for garage walls, boundary walls, exterior facades, bathrooms with real water exposure and anywhere impact is likely.
Rhinolite plastering vs cement skim: choosing
- Interior lounge, bedroom or passage walls: gypsum. Fast, smooth, paint-ready.
- Interior ceilings and drywall: gypsum, comfortably.
- Kitchens: gypsum is usually fine away from splash zones.
- Bathrooms: gypsum outside the wet zone, cement-based inside it.
- Exterior walls: cement, always.
- Garages, workshops, high-traffic corridors: cement for durability.
In practice most Cape Town homes end up with both: gypsum through the living areas, cement where weather or water is involved.
What each costs in 2026
Labour rates for skim work are broadly similar between the two, because the trowel time is comparable. The material and the preparation are where they separate.
- Skimming walls and ceilings: R40 to R80 per m² labour only, R140 to R180 per m² supplied and applied
- Skim over an existing plastered surface: R50 to R90 per m² labour only, R150 to R190 per m² supplied and applied
- RhinoLite multipurpose plaster: around R415 for a 40kg bag, or about R165 for 10kg at retail
Where quotes disagree, the drivers are preparation, wall height, access and whether the surface is painted. A full breakdown of those variables sits in our skimming plaster price guide.
Finish and painting notes
- Gypsum surfaces must be sealed with a suitable plaster primer or bonding liquid before painting
- Do not paint either finish before it has dried right through
- Gypsum gives the flattest result under side light, which matters in rooms with big windows
- Cement-based finishes take repeated knocks better in busy spaces
Common rhinolite plastering mistakes
Most problems with gypsum skim are not the material’s fault. They come from four repeat mistakes.
- Applying it over paint without preparation. The bond fails and the coat lifts in sheets.
- Adding cement or bonding liquid to the mix. The manufacturer’s instructions specifically warn against it.
- Getting the water ratio wrong. Too much water weakens the set and causes a dusty surface.
- Using it in a wet area. Gypsum and standing moisture do not co-exist.
A fifth one is painting too early. A gypsum skim can feel dry to the hand while still holding moisture behind the surface, and paint applied then goes patchy.
How to tell what is already on your walls
- Colour: gypsum skim is typically pale and chalky white, cement grey
- Sound: gypsum sounds slightly softer when tapped than a cement finish
- Location: anything on an exterior wall is almost certainly cement-based
- Drill dust: fine white powder points to gypsum, gritty grey to cement
Knowing which one you have matters when you patch. Repairing a cement wall with gypsum, or the reverse, gives you a visible patch that behaves differently to everything around it. Plaster and skim products are covered by standards published by the South African Bureau of Standards.
Getting the right specification
Ask your plasterer which material they are quoting and why. “Skimming” alone does not tell you whether you are getting gypsum or cement, and the two behave very differently in a damp Cape winter.
If a quote proposes gypsum on an exterior wall or inside a shower, that is a red flag worth questioning before any work starts.
We offer a free assessment with no call-out fee. Read the basics in our skimming plaster guide, see our skimming service, or tell us about your rooms and we will specify the right material for each surface.
Frequently asked questions
What is Rhinolite plaster used for?
RhinoLite is a lightweight gypsum plaster used for interior walls, ceilings and drywall board. It works as a combined basecoat, finishing and multi-purpose plaster, applied by hand or machine, and produces a very smooth paint-ready finish with controlled setting times and no inherent shrinkage cracking.
Is Rhinolite better than cement plaster?
Neither is better overall; they suit different places. Gypsum gives a smoother, faster interior finish and is ideal for lounges, bedrooms, passages and ceilings. Cement-based plaster is harder, handles moisture and works outdoors, so it belongs on exterior walls, garages and genuinely wet areas.
Can you apply Rhinolite on a painted wall?
Not directly. Gyproc states that RhinoLite should never be applied to painted walls without correct surface preparation. Paint is non-porous, so the plaster has nothing to bond to. The paint must be sound, cleaned and scuffed, and a suitable bonding treatment applied first, or the plaster will fail.
How much does Rhinolite cost per bag?
Retail pricing runs around R415 for a 40kg bag of RhinoLite multipurpose plaster and roughly R165 for a 10kg bag. Applied cost is what matters more: skimming generally runs R140 to R180 per m² supplied and applied, or R150 to R190 per m² over an existing plastered surface.
Can Rhinolite be used outside?
No. It is a gypsum plaster made for internal application and will not survive exterior exposure to rain and weather. Exterior walls need a cement-based plaster or skim. The same applies to permanently wet areas such as the inside of a shower, where a cement-based system is required.