This spacer is not designed to be used in concrete structures. It is used to maintain distance of stones and tiles from the floor surface, 14mm height and 3.5mm. Between tiles, the purpose of using this part is to create a special stone or tile floor in order to prevent accumulation of water and rain on its surface and guide the water 14 mm beneath the surface…These pieces may also be used on the roof tops to prevent damage to the sealed surface. Meanwhile this is also used to prevent water accumulation in pedestrian crossing areas. Instruction for use: These base plates are placed under stones and tiles with corners of tiles to meet in the center of the spacer leaving 3.5 mm. distances from each other.