FREQUENTLY ASKED QUESTIONS

The Australian Standard allows for a variance in tile dimensions of ±0.6% from the specified work size, with a maximum deviation not exceeding ±2mm. For example, a tile that is nominally 600x600mm can vary in size between 598mm and 602mm, resulting in a total variance of 4mm.

Tiles are categorised into three distinct sizes:

• Nominal Size: This size generally indicates the approximate dimensions of the product (e.g., 300mm x 300mm or 600mm x 600mm). The nominal size is also the measurement printed on each box.
  
• Work Size: This refers to the size that the manufacturer aims to produce. It is the actual size of the tile and should not be confused with the nominal size.
Note: Tiles of the same nominal size may have different work sizes (calibres). When using tiles with varying work sizes, wider grout joints may be necessary to accommodate size differences and tolerances.
  
• Actual Size: This is the final size of the tile, measured according to the Australian Standard.

To determine compliance, measure ten tiles in both length and width (a total of 40 measurements) to calculate the "average actual working size." The Australian Standards (tolerances) will then apply.

For instance, if the average work size of a tile is 297mm x 599mm, the acceptable range would be 295mm – 299mm in length and 597mm – 601mm in width. Tiles meeting these criteria are classified as acceptable and of First Quality.

The standard recommended grout joint width of 3mm, as specified in AS 3958.2023 (Guide to Installation of Ceramic Tiles), is generally sufficient to accommodate tile size variations and ensure proper placement.

Additionally, while a customer may choose a grout joint of 2mm or smaller, achieving this may be challenging if the substrate is not completely flat, plumb, or true.

Due to manufacturing tolerances, tiles of the same nominal size from different factories may have slight variations in their actual dimensions. Standards permit a variance in length and width from the nominated work size of ±0.6%, with a maximum deviation not exceeding ±2 mm. For example, a 600 × 600 mm tile can vary between 598 mm and 602 mm, resulting in a possible difference of up to 4 mm between tiles from different batches or manufacturers. Therefore, it's important to measure and determine the actual sizes of tiles before installation.

Professional tilers often encounter alignment challenges when working with such tiles. If there is a size difference between tiles of the same nominal size, the following methods can help achieve proper alignment:

Option 1: Align at Eye Level

• Focus on Eye-Level Alignment: Discrepancies at the bottom or top edges are less noticeable, so prioritise aligning tiles where they are most visible.
  
• Adjust Using Spacers or Grout Lines: Align the top edges of the tiles and use tile spacers or adjust grout lines to compensate for differences at the bottom edges.
  

Option 2: Start from the Midpoint

• Begin Laying from a Central Point: This helps distribute any size discrepancies evenly across the installation area.
  
• Combine Different Sized Tiles Carefully: When placing tiles of slightly different actual sizes (e.g., a 300 × 600 mm tile next to a 300 × 300 mm tile), ensure consistent spacing.
  

By carefully planning and adjusting tile placement, professional tilers can manage slight size variations and achieve a visually pleasing result.