When the goal is to insulate a building thermally or acoustically without turning to synthetic materials, expanded perlite and expanded clay are two of the most widely used mineral alternatives. Both are lightweight aggregates of natural origin, but with different properties and applications.
Expanded perlite
Perlite is a volcanic rock that expands when heated to high temperatures, forming a very light, porous material. It is used in insulating mortars, as a horticultural substrate, and in industrial filtration applications. Its extremely low density makes it especially suitable for reducing a building's weight without sacrificing thermal insulation.
Expanded clay
Expanded clay is produced by heating natural clay until it forms lightweight, porous granules with a tough outer shell. It is used in lightweight concrete, green roofs, drainage systems, and as acoustic insulation in floor slabs and screeds, thanks to its ability to dampen impact noise transmission.
Which one should you choose?
As a general rule, perlite is preferable when minimising weight and maximising thermal insulation is the priority (for example, in spray-applied mortars), while expanded clay is better suited to lightweight structural applications and acoustic floor insulation. In many projects, both materials are combined depending on the area of the build.
Check out our range of mineral insulation materials to find the grain size and supply format best suited to your project.