Claytec is a German SME which produces a series of clay based products and systems. These include clay plasters, colors, boards, and blocks as well as interior insulation solutions. Within ISOBIO Claytec have investigated how adding bio-based aggregates could improve the properties and performance of their plasters. They have developed three new clay plasters that incorporate hemp powder as a bio-based aggregate. The plasters use earthen clay as a binder, and pumice and sand as the mineral aggregates. In addition, a silica based fire retardant additive was added in one of the plasters.
The Claytec plasters are packaged in the form of ready-to-use mixtures and are compatible with standard plaster machines. They are suitable for interior use. The three ISOBIO plasters were developed specifically for use as a fire protection layer on bio-based substrates such as rigid hemp insulation panels, compressed straw boards and wood fibre boards.
Clay in itself can be deemed advantageous as a construction material. It improves the indoor air quality, has a favourable environmental footprint, and is easy to use. The tailor made modifications developed in ISOBIO should improve their fire protection capacity and workability on bio-based substrates, while providing a constant moisture buffering effect (>65gr/m² (class III DIN 18947). These improvements are not expected to increase costs compared to standard clay plasters.