Substrate preparation

The role of plastering walls and ceilings is to even out and level the surfaces being clad.

For leveling, a coarser-grain base plaster is used (Weber BC 15), while for smoothing, a finer-grain finishing coat (skim plaster) is used (Weber BM 15).

Weber BC 15 base plaster can be applied to any masonry, indoors and outdoors. It’s resistant to mechanical impact. Catalog consumption is 13-15 kg/m² for a 1 cm coat. Recommended thickness: 2 cm on walls, 1.5 cm on ceilings. Supplied as a powder in 30 kg bags. One bag is enough to cover 1 m² at a 2 cm thickness.

BM 15 (BM 15-W) finishing plaster smooths the base coat. It’s durable and lets the wall breathe. Catalog consumption is 3-3.5 kg/m², with a recommended thickness of 3-5 mm. Supplied in 25 kg bags, so one bag covers about 8 m² at a 3 mm thickness.

For natural stone cladding, plastering walls isn’t mandatory; stone can also be installed directly onto masonry (e.g. polygonal stone, which varies in thickness). However, plastering is recommended in most cases, since leveling the walls makes installation easier by providing a smooth, solid, clean surface (especially when tiles are rectified).