To allow for the slabs’ dimensional tolerances and to create a gap to allow brushing in of kiln dried jointing sand, slabs installed unbound must have joints between 2-5mm.

Important: Straightness of lines is dependent on workmanship and any differences in sizes of the slabs that result from the manufacturers permitted tolerances. Installing the slabs using a 2-5mm joint can help achieve straight lines.

Tobermore do not recommend butt jointing slabs. Butt jointing is when slabs are installed tight together (touching). This will make achieving straight lines more difficult and causes the edges of the slabs to spall.

Slabs installed bound should have joints between 6-10mm.

For more installation guidance on our concrete slab range, please access our unbound slab installation guidelines or bound slab installation guidelines, depending on which laying method you have selected.