Tiling Calculators Australia

AS 3958 and standard Australian tiling practice recommend: 10% wastage for straight lay patterns on simple rectangular rooms; 15% for brick bond (offset) lay patterns; 15–20% for diagonal (45°) lay patterns, which require significantly more cuts; and 10–15% extra for rooms with many obstacles (bathroom with bath, WC, vanity etc.). Always buy from the same batch number — tile colour can vary between batches, and ordering extra at the start avoids mismatched replacements later.

AS 3958 recommends a minimum joint width of 3 mm for most ceramic and porcelain floor tiles. Larger format tiles (600 mm × 600 mm and above) should use 3–5 mm joints to accommodate dimensional variation. Natural stone tiles typically use wider joints of 5–8 mm. Narrower joints than 2 mm are not recommended for floor applications as they are difficult to fill and prone to cracking. For wall tiles, 2–3 mm joints are standard. Match your grout choice to joint width — unsanded grout for under 3 mm, sanded grout for 3 mm and above.

Yes — under the NCC (National Construction Code) and AS 3740, all wet areas in Australian residential buildings (showers, bath surrounds, laundry wet areas) must have a compliant waterproof membrane installed before tiling. The membrane must be applied by a licensed waterproofer in most states, or by the tiler if they hold the appropriate licence. Common Australian products include Ardex 8+9, Mapei Mapelastic, and Sika MultiSeal. Tiling directly onto plasterboard or compressed fibre cement without waterproofing is non-compliant and will void your home insurance for water damage.