pavers and walls with natural stones
We recommendedthe use of mortar or adhesive on a reinforced concrete slab. If calibrated 30 mm or greater, paver is to be used and a suitable crush rock can be used for pedestrian traffic, however, we recommend that the paver should be installed using a mortar bed rather than sand to give better stability to the finished product.
Natural stone come in different sizes starting from 3mm. Canadian Golbagh Landscape recommends to lay the stone from 5-8mm grout gaps.