02 standards say that acceptable lippage for floor tiles with a grout joint width of 1 16 to less than 1 4 is 1 32 plus the allowable inherent warpage of the tile.
Ceramic tile lippage tolerance.
In the days before isostatic presses warpage was more common.
For ceramic tiles which includes porcelain tiles they are allowed to have 1 mm of lippage plus the actual warpage in the tile which is normally about 1 mm for grout joint widths between 2 to 7 mm.
So that means that 2 mm lippage would be acceptable to ceramic tile.
If there is no warpage the lippage should not exceed the value in the table.
Guide to the installation of ceramic tiles on page 53.
The residential performance standards guidelines states.
When a tile is warped but within standards all of the corners cannot be set in the plane of the adjoining tiles.
However the measurement at right shows that the ceramic tile lippage is less than 1 6 mm 1 16 in which is within standards.
Lippage greater than 1 16 is considered excessive except where tile is larger than 13 13 inches.
If the grout joint width is 1 4 or greater then the allowable warpage is 1 16 plus the allowable inherent warpage of the tile.
5 4 6 tile finish and joints a when measured with a straightedge the finished surface of the tiling should be flat and true to within a tolerance of 4mm in 2m from the required plane.
Accordingly the tolerance for variation from tile to tile includes the actual warpage of the tile.