How Much Tile Backer Board Do I Need?

How We Calculated This

For a standard shower enclosure (900 × 900mm, tiled to 2.1m height):

• Back wall: 0.9 × 2.1 = 1.89m²
• Two side walls: 2 × (0.9 × 2.1) = 3.78m²
• Total area: 5.67m²
• Plus 10% waste: 6.24m²
• Boards needed: 6.24 / 0.72 = ~9 boards

Common Board Sizes

• 1200 × 600mm (0.72m²): Most common, easy to handle
• 2400 × 600mm (1.44m²): Full height, fewer joints
• 1200 × 800mm (0.96m²): Less common but available

Board Thickness

• 6mm: Overlay on existing plasterboard or solid walls
• 10mm: Direct fix to timber studs as plasterboard replacement
• 12mm: Heavy-duty for floor use or high-load walls

Where to Use Backer Board

Tile backer boards are waterproof and provide a rigid, stable substrate for tiling in wet areas. Use them in showers, behind baths, around sinks, and for wet room floors. Standard plasterboard (even moisture-resistant) is not suitable for direct water exposure in shower enclosures.

Fixing

Fix with backer board screws at 300mm centres into timber studs or battens. Seal all joints with waterproof tape and flexible adhesive. Use a suitable flexible tile adhesive — standard adhesive may not bond properly to foam-core boards.