Dry Lining & Plasterboard Fixing

MODULE 7: Dry Lining & Plasterboard Fixing

This module covers modern drywall installation methods, focusing on efficient dot & dab adhesive fixing and professional taping/jointing techniques for seamless finishes.

1. Dot & Dab Techniques (Adhesive Fixing)

A. Suitable Applications

B. Materials Required

• Plasterboard (12.5mm standard, 15mm for fire-rated)

• Drywall adhesive (gypsum-based, pre-mixed)

• Plumb bob/laser level

• Notched trowel (10mm notches recommended)

C. Step-by-Step Process

1. Surface Preparation

• Remove loose debris/dust

• Apply primer (PVA or proprietary dab adhesive primer)

2. Adhesive Application

• Apply dabs (~50mm diameter, 25mm thick)

• Vertical spacing: 400mm max

• Horizontal rows: 3-4 per board (top/middle/bottom)

3. Board Fixing

• Press board firmly into adhesive

• Check plumb with level

• Leave 10mm gap at floor (for expansion)

• Temporary support (props or battens) until adhesive sets

4. Mechanical Fixing (Optional)

• Add drywall screws at 600mm centres if required

• Countersink screws 1mm below surface

D. Key Considerations

2. Taping and Jointing (Seam Finishing)

A. Materials Selection

• Paper tape (standard for most joints)

• Fibreglass mesh tape (for cracks/stress points)

• Joint compound (ready-mixed or powder)

• Corner beads (metal/plastic for external angles)

B. 3-Coat System (Professional Finish)

1. First Coat (Bedding Layer)

• Apply compound over joint (150mm wide)

• Embed tape firmly with 100mm knife

• Smooth out excess compound

2. Second Coat (Filling Layer)

• Apply after 24 hours drying

• Feather edges to 200mm width

• Fill screw dimples simultaneously

3. Third Coat (Skim Coat)

• Thin final layer (250mm feather)

• Sand lightly with 120-grit when dry

C. Pro Techniques

D. Common Mistakes to Avoid

Comparison: Dot & Dab vs Stud Partitioning

Health & Safety Notes

• Wear dust mask when cutting boards

• Use step platforms rather than makeshift supports

• Ensure good ventilation when sanding