To allow for the flags dimensional tolerances and to create a gap to allow brushing in of kiln dried jointing sand flags installed unbound must have joints between 2-5mm.
Important: Straightness of lines is dependent on workmanship and any differences in sizes of the flags that result from the manufacturers permitted tolerances. Installing the flags using a 2-5mm joint can help achieve straight lines.
Tobermore do not recommend butt jointing flags. Butt jointing is when flags are installed tight together, touching. This will make achieving straight lines more difficult and causes the edges of the flags to spall.
Flags installed bound should have joints between 6-10mm.