Calcium silicate brick, also called sand-lime brick, is a man-made masonry unit made from a mixture of sand, slaked lime, and water. The mixture is pressed into moulds and then hardened under high steam pressure in an autoclave. During this process the lime reacts with the sand to form a firm, stone-like material. Calcium silicate brick has a naturally light grey to white colour.
Properties
- High compressive strength — making it suitable for heavily loaded, load-bearing walls
- Good sound insulation — thanks to its high mass (density)
- Dimensionally accurate and flat — the units and elements are precisely shaped, allowing fast and accurate laying
- Non-combustible — calcium silicate brick does not contribute to a fire
- Limited weather resistance on the outside — so it is used mainly indoors
Application
Calcium silicate brick is widely used for:
- Load-bearing inner leaves — the inner wall of a cavity wall construction
- Party walls — because of the good sound insulation between dwellings
- Non-load-bearing partition walls indoors
The material comes in two main forms: small masonry units (blocks) and large glued elements. The large elements are placed with a crane or vacuum lifter and stacked with thin-bed mortar, which greatly shortens the build time.
Difference from fired brick
Fired brick is baked in a kiln; calcium silicate brick hardens under steam pressure without being fired. Fired brick, thanks to its fired skin, is more resistant to the weather and is therefore used more often in the outer leaf, while calcium silicate brick is used mainly indoors.
Related terms
- Masonry unit
- Fired brick
- Cavity wall
- Load-bearing wall
- Sound insulation
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