UK Grout Coverage Rates by Tile Size

It depends on the tile size, joint width and tile thickness. Small tiles (100x100 mm) with 3 mm joints need approximately 1.5-2.0 kg/m². Large tiles (600x600 mm) with 3 mm joints need only about 0.3-0.5 kg/m². Wider joints dramatically increase consumption — doubling the joint width roughly doubles the grout needed. Natural stone with wide joints (5-10 mm) can use 2-5+ kg/m².

For rectified (precision cut) porcelain tiles, joints as narrow as 1.5-2 mm are possible. For standard ceramic wall tiles, 2-3 mm is typical. For floor tiles, 3-5 mm is standard. For natural stone, 5-10 mm is common. Very large format tiles often use 2-3 mm joints. Always follow the tile manufacturer recommendation — joints too narrow can crack, and some tiles require wider joints to accommodate size variation.

Sanded grout contains fine sand and is used for joints 3 mm and wider — the sand provides bulk and prevents cracking in wider joints. Unsanded grout is smoother and used for joints under 3 mm and for polished or scratch-sensitive tiles (marble, polished porcelain). Epoxy grout is stain-proof and waterproof but more expensive and harder to work — ideal for wet areas, commercial kitchens and areas needing chemical resistance.

Formula: kg/m² = (joint width x tile depth x (tile length + tile width)) / (tile length x tile width) x grout density (typically ~1.6 kg/litre). All measurements in mm, result in kg/m². For example: 300x300 mm tiles, 8 mm thick, 3 mm joints = (3 x 8 x 600) / (300 x 300) x 1.6 = 0.26 kg/m². Add 10-15% for waste.