The width of the gap may vary depending on the size of the tiles and the use required of the flooring. Closed joint laying is not recommended; a minimum gap of 2-3 mm allows the filler to adhere better to the sides of the slabs, as well as for better absorption of any movement in the bed/support structure and better adjustment of the slabs.In large areas, it is essential that expansion joints be laid regularly, while in smaller areas it is sufficient to leave a small space between the tiled area and the perimeter walls. This gap will then be covered by the skirting for a proper finish. In all cases, the design engineer or construction site manager will be able to provide appropriate advice/suggestions.