Light clay


Light clay - a heavyweight

Light clay is a comparatively heavy stuff and, compared to hemp, cellulose or wool, a rather solid material that can be used to insulate walls or the top floor ceiling. In contrast to the soft insulation materials, this allows a lot of mass to be introduced into the building in a simple manner. Loam or clay as a binding agent is mixed with a lightweight aggregate such as hemp shives, cork grist, expanded clay or expanded glass.

There are two different building materials or types of construction to choose from for wall insulation. On the one hand, there is insulating light clay as pre-dried building elements, light clay bricks that can easily be walled up with a light clay mortar. On the other hand, it can be used as a fill that is filled behind a formwork or in a cavity. It is common to install the light clay in one layer as a fill between the ceiling beams of the top floor ceiling or between the false ceilings. Because of its large mass, it perfectly combines the properties of insulation and soundproofing, even if the thermal insulation properties are not that high compared to fibrous insulation. A simultaneous sound and thermal insulation therefore requires somewhat thicker layers.

Light clay as insulation material

Moist or dry?

In old buildings, for example, light clay is usually used in a thickness of 12 to 16 cm. When installing, you have to pay attention to a good re-drying. Organic components, which are inevitably carried into the clay as dust by the surrounding air, could otherwise go moldy. The thicker the layers, the more carefully the required drying times must be observed and the drying monitored.

There are light clays as earth-moist, and less often as dry mixtures. Many of the dry products are hemp-light clay: clay powder mixed with hemp shives. These light clays are installed dry and slightly moistened. Due to the relatively short drying times, the very low level of installation moisture in these building materials means that construction can be progressed quickly.

Light clay as a building material

Light clay in old buildings

Light clay is a very popular insulation material, especially in the field of half-timbered construction and its restoration. 

This building material is ideal for the sometimes warped, crooked walls of a historical framework, which are also not necessarily of uniform thickness: light clay is perfect for filling in these unevenness, as it can be flexibly introduced into any cavity. The time-consuming and living space-reducing work of straightening a wall and creating levels is no longer necessary. This is necessary, for example, when using insulation boards that are glued to a flat surface. The light clay, on the other hand, doesn't care what size and format the cavity is.

Indoor climate and sound insulation

The advantage of the building material clay is its great ability to regulate the room climate: due to its diffusion-open property, it absorbs moisture from the room air and can either store it and release it again or pass it on through the wall to the outside - provided the wall exists consistently made of vapor-permeable building materials. 

To improve the sound insulation between two floors or when insulating the top floor ceiling, it is also possible to choose a slightly heavier material.


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