How to apply Venetian Marmorino plaster — a contractor's guide

Venetian Marmorino is a 3-coat lime-marble plaster that requires careful substrate preparation, controlled application and a precisely-timed burnishing window. This guide covers the full protocol contractors should follow when working with CALMURA Marmorino on standard drywall, cement plaster or masonry substrates.

1. Substrate preparation

The substrate must be sound, dry, level to ±2 mm over a 2 m straightedge, and free of dust, oil and loose material. Existing painted surfaces should be primed with CALMURA mineral primer (CMR-P-MIN) which provides a chemically compatible alkaline base. New gypsum board requires two coats of primer; cement-based render requires one. Allow the primer to cure 24 hours before the first marmorino coat.

2. Base coat (M-S sand grade)

Mix Marmorino M-S grade gently to break clumps — do not over-mix or you will introduce air bubbles. Apply the base coat with a stainless trowel held at 30°, working in 1 m² panels. The base coat should be 0.5–0.8 mm thick, levelled but not over-worked. Allow 4–6 hours minimum cure (24 hours in cool, humid conditions) before the body coat.

3. Body coat (M-S or M-F grade)

The body coat is the colour-defining coat. Apply at 0.4–0.6 mm thickness. For a satin finish, use the M-S sand grade and finish with a smoothing pass at 45° angle. For a high-polish finish, switch to M-F fine grade. Allow 6–8 hours cure.

4. Polish coat (M-F fine grade)

The polish coat is what creates the marble-like depth. Apply M-F at 0.2–0.3 mm in long sweeping strokes. Begin polishing 30–60 minutes after application — exact timing depends on temperature and humidity. Use a clean, dry stainless trowel and burnish in figure-eight motions, gradually flattening the angle of the trowel until you can see your reflection in the surface.

5. Beeswax soap finish

24 hours after polish, apply CALMURA Beeswax Soap (CMR-BX) with a clean cloth in circular motions, then buff with a soft cloth. This protects the surface, deepens the colour, and creates a soft satin sheen.

Common mistakes

• Over-thickness: Marmorino is a thin-coat system. Total dry thickness should not exceed 1.5 mm.
• Polishing too early: The polish window opens once the surface loses its wet sheen. Test by lightly pressing a finger.
• Single-batch tinting: For walls larger than 50 m², always order all material from a single production batch to ensure colour consistency.

Coverage and material planning

A 20 kg pail of M-S covers approximately 70 m² as a 2-coat base + body, plus 1 kg/m² of M-F as a polish coat for high-polish finishes.

For project-specific application protocols, contact CALMURA technical support — we provide on-site sampling and contractor training programs in major markets.