Module 1: Advanced Plastering Techniques
This module focuses on refining plastering skills to a professional standard, covering high-quality finishing, decorative work, and problem-solving for common issues. Below is a detailed breakdown of each topic:
1. Skim Coating to a High Standard
Skim coating involves applying a thin, smooth layer of finishing plaster (usually multi-finish or gypsum-based) to create a flawless surface.
Key Techniques:
Surface Preparation: Ensure walls/ceilings are clean, free of dust, and primed (with PVA or a proprietary primer) to prevent rapid suction.
Consistency of Mix: Achieve a creamy, lump-free plaster mix for easy application.
Application: Apply in two passes—first coat to fill imperfections, second coat for a smooth finish.
Trowel Technique: Use a stainless steel trowel at a slight angle, applying even pressure to eliminate ridges.
Timing: Work efficiently before plaster sets; polish with a damp sponge or trowel for a glass-like finish.
2. Ornamental Plastering (Mouldings, Cornicing, Arches)
Ornamental plastering requires precision to create decorative architectural features.
Methods & Materials:
Running Moulds: Pre-made templates used to shape plaster into cornices or ceiling roses.
Fibrous Plaster: Reinforced with hessian/scrim for durability in intricate designs.
Freehand Sculpting: For bespoke designs, using specialist tools (e.g., casting knives, profile gauges).
Installation: Secure with adhesive and screws; blend joints seamlessly with filler.
3. Specialist Finishes (Polished, Textured, Venetian Plaster)
These high-end finishes require advanced techniques for aesthetic and functional results.
Types & Applications:
Polished Plaster: Achieved by burnishing with a trowel for a marble-like effect; often uses lime-based mixes.
Textured Finishes: Created with sponges, brushes, or trowels (e.g., stippling, swirls).
Venetian Plaster: Multiple thin layers of tinted plaster, polished between coats for a glossy, depth-rich finish.
Marmorino & Tadelakt: Traditional polished plasters using natural materials like marble dust or lime.
4. Troubleshooting Common Defects
Even experienced plasterers encounter issues; this section covers prevention and fixes.
Common Problems & Solutions:
Cracking: Caused by rapid drying or poor substrate prep—remedy by dampening surfaces and using control joints.
Blistering/Bubbling: Due to trapped air or unprimed backgrounds—prick bubbles and re-trowel.
Efflorescence: White salt deposits from moisture; treat with a damp-proofing additive.
Uneven Drying: Avoid by controlling room temperature/humidity and using consistent plaster thickness.
Summary
This module equips learners with the expertise to execute flawless skim coats, intricate decorative work, and luxury finishes while diagnosing and rectifying common plastering flaws. Mastery of these skills ensures readiness for high-spec residential and commercial projects.
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