Page 17 - Tiling Guide Uniclass Index

11 GROUTING
BS 5385-1 recommends that for internal wall tiling in normal conditions –
1) For tiles with a facial area <0.1m2 with no side
Before grouting commences, ensure that the adhesive is fully hardened to avoid disturbing the tiles before they have bonded completely with the adhesive. Check the setting time of the adhesive used.
Where limited movement or vibration is expected, use a suitable flexible grout (check with the manufacturer for suitability).
When mixing a powder grout with water, always use the correct and consistent amount of water to avoid shade variation.
Apply the grout into the joints using a squeegee.
Once in the joint, the grout should be left to firm before cleaning down. This is to ensure it remains in the joint and does not absorb significant levels of extra moisture when the area is cleaned. Cleaning off too early can affect the colour consistency, creating a patchy colour appearance and can also affect the grout strength, leaving a weak, dusty surface layer.
over 600mm long, joints should be not less than 2mm wide;
2) Tiles with a facial area 0.1m2 to 1m2 with no side over 1,200mm long, joints should be not less than 3mm wide; and
3) Joints between tile panels should be increased pro-rata to panel size (e.g. for 3m long panels the recommended minimum joint width between 3m panels is 5mm).
BS 5385-3 : relates to the installation of internal and external ceramic and mosaic floor tiling in normal conditions and recommends that as a general rule, the width of joints in ceramic tiling should not exceed the tile thickness. The width should not be less than 3mm. Wider joints, for example 10mm wide, might be required to accommodate dimensional irregularities in the tiles, to maintain modular discipline or to provide a decorative effect. Wherever practicable, the depth of the joints should be at least 6mm.
15