How Much Tile Adhesive Do I Need?

How We Calculated This

Tile adhesive coverage depends on the trowel notch size, which is determined by the tile size:

• Small tiles (<150mm): 6mm notch = ~2.5–3 kg/m²
• Medium tiles (150–300mm): 8mm notch = ~3.5–4 kg/m²
• Large tiles (300–600mm): 10mm notch = ~4–5 kg/m²
• Very large tiles (600mm+): 12mm notch = ~5–6 kg/m²
• Example: 20m² bathroom at 4 kg/m² = 80kg = ~4 bags (20kg)

Adhesive Types

• Standard powder (grey/white): Mix with water, cheapest, good for most applications
• Flexible powder: For substrates with slight movement (timber floors, underfloor heating)
• Rapid-set powder: Sets in 3–4 hours instead of 24, good for busy areas
• Ready-mixed (tub): No mixing needed, walls only (not suitable for floors)
• Epoxy adhesive: Chemical resistant, used in commercial kitchens and pools

Coverage by Product (20kg bag)

• BAL White Star Plus: 4–5m²
• Mapei Keraflex Maxi S1: 4–6m²
• Weber Set SPF: 4–5m²
• Dunlop Flexible Floor & Wall: 4–5m²

Back-Buttering Large Tiles

For tiles larger than 300 × 300mm, apply adhesive to both the wall/floor and the back of the tile (back-buttering). This ensures full coverage and prevents hollow spots. Increase your adhesive estimate by20–30% when back-buttering.

Tips

Always use a notched trowel at 45° to ensure consistent bed thickness. Mix only as much adhesive as you can use within its working time (typically 30–60 minutes). Use white adhesive for translucent or light-coloured tiles. Use flexible adhesive on timber floors, plywood substrates, and with underfloor heating.