The manufacturer's literature will explain if a product is suitable for interiors and / or exteriors as well as walls and / or floors. A recognised adhesive manufacturer will have a range of products each appropriate to different substrates / potential substrate movement. Cement based water mix adhesive is generally suitable on masonry substrates where no movement is anticipated. Where slight movement could occur through thermal or pedestrian loads a modified cement adhesive (probably two part) should be used as a minimum.

It is important that each pebble is embedded in the adhesive. Select a product suitable for application with a 10mm notched trowel, and apply no more than about 1m² of adhesive at a time.

Easier results are achieved with the lighter grade tiles 8mm, 11mm, 14mm thickness. The heavier grades 17mm & 20mm may have to be laid individually. www.mapei.it