Chopped material, regardless of which plant it is made from, is the optimal lightweight aggregate for an insulating lightweight clay. On the one hand, the chaff are able to buffer moisture, on the other hand, their rough surface and stability strengthen the internal cohesion of the insulating plaster.

Clay builders and home builders in particular, who make their own plaster and mortar, use the chaff to make insulating plaster and fill. "Normal" clay plasters or clay powder are suitable as binders. Such light-weight clay mixtures fill cavities, e.g. behind so-called lost formwork or behind a wall made of light-weight earth bricks. The thermal insulation properties depend on the specific weight of the respective light clay mixture, but the thickness of the insulation layer is usually determined by the prevailing structural situation. As with any light clay, good drying is absolutely essential. The lightweight aggregates made from hemp and thatch stand out from the usual straw in that they are more moisture-stable, which significantly reduces the risk of mold. In addition, the reed straw has an aesthetic added value: By washing the plaster surface free, it gets yellowish shimmering stains. The light clay mixtures can be processed more or less well with the plastering machine. If you like to experiment, it is ideal for you to try out mixing yourself and then find your optimal mix with the best processing.