The board is a composite with a closed-cell insulating core and a cementitious skin on both faces. The skin gives compressive and bending strength and improves fire behaviour; the closed-cell core keeps water out and keeps the board light. Thicknesses run from 6 mm to 100 mm, in 600 × 2500 mm, 1220 × 2440 mm and 600 × 1200 mm formats.
What makes it usable on a prefabricated line is machinability. It can be cut with a knife, a hand saw, a jigsaw, a circular saw or a table saw on site, and formed on a CNC router or a multi-axis robot in the factory. Single-face grooving lets the board curve, which is how curved wall and counter details are made without a wet trade.
Fire classification is B1 under GB 8624-2025 — combustible but difficult to ignite. That is the correct class for this board, and it is not the same as the A1 boards used on the partition faces. Mixing the two up is a common specification error: a B1 board is right behind tile in a bathroom, and wrong as the lining of a fire compartment wall.
The typical application is the substrate for tiles in prefabricated bathrooms and kitchens, and behind tile or large-format porcelain on other interior walls and floors. The surface takes cement-based adhesive and structural adhesives, which is what allows the tile to be laid in a factory jig rather than on site.