Tadelakt application protocol — from base coat to soap polish

Tadelakt is the most technically demanding finish CALMURA supplies — the result of 15+ centuries of Moroccan craft tradition. This protocol covers the full application sequence for contractors trained in classical lime work.

Substrate requirements

Tadelakt requires a sound, structurally rigid, vapour-permeable substrate. Acceptable substrates include:

• Cement render (NHL or OPC) cured 28 days
• Lime render cured 21 days
• Existing tadelakt (compatible re-application)

Unacceptable substrates: gypsum drywall (vapour-impermeable), painted walls, plywood, MDF.

Step 1 — Base coat (CMR-TD)

Mix base coat to a thick yogurt consistency. Apply with stainless trowel at 2–3 mm thickness in 1 m² panels. Texture with a wood float to leave a slightly open surface for mechanical key. Cure 24–48 hours.

Step 2 — Finish coat

Apply CMR-TD finish coat at 1.5–2 mm thickness over the cured base. Work the surface with a Japanese trowel to compress the lime. The finish coat is the colour and visual layer — apply in a single continuous session per wall to avoid joints.

Step 3 — River-stone polishing window

Approximately 2–4 hours after finish coat (varies with temperature and humidity), the surface enters the polishing window. Test readiness: the surface should be firm but accept slight indentation under fingernail pressure.

Polish with the CMR-RS serpentine river stone in firm circular motions, working systematically across the wall. The stone compresses the lime crystals, closes micro-pores, and develops the characteristic burnished sheen. Polish each panel for 15–25 minutes.

Step 4 — Soap saponification

After polishing, allow the wall to firm up for 4–8 hours. Then apply CMR-Hammam soap concentrate (1 part soap : 4 parts water dilution) by brush in liberal quantity. The soap reacts with calcium hydroxide on the surface to form calcium stearate — a hydrophobic, water-tight, mineral-soap layer.

After 30 minutes, polish the wall again with the river stone — the soap layer takes a second-round burnish that develops the iconic deep glow.

Step 5 — Cure window

Tadelakt requires 14–21 days to develop full water resistance. During this period, avoid water contact. After 21 days the surface is fully water-tight and may be re-soaped annually for ongoing maintenance.

Critical do's and don'ts

<strong>Do</strong>:

• Work each wall in a single application session
• Use only authentic CMR-RS serpentine stone (synthetic substitutes do not produce the same result)
• Maintain consistent room temperature (15–25°C) during application and cure
• Use clean tools — contamination causes spotting

<strong>Don't</strong>:

• Apply over gypsum or vapour-impermeable substrates
• Skip the saponification step (the wall will not be waterproof without it)
• Polish too early (smearing) or too late (no compression effect)
• Use synthetic detergents in place of olive-oil hammam soap

Coverage and ordering

A 12 kg pail covers approximately 8–10 m² when used as a complete base + finish system. For full project ordering — including river stones and soap concentrate — contact CALMURA technical support.