Earth in non-loadbearing walls  

Earth infilling

Wall linings
- earth block
- light clay
- dry stacked brick

Clay panels

Clay building boards

A variety of different earthen building methods are suitable for use in non-loadbearing walls: unfired bricks, clay panels and boarding or light clay as moist fill mixture. Where non-loadbearing earthen building materials are used in loadbearing walls, a different material and construction carries the load. For example a timber-stud construction can be used in conjunction with an earthen infill material, both in new-build and traditional timber-frame constructions. Non loadbearing wall elements include infill panels, wall linings and separating walls which are not part of the supporting structure.

Likewise, interior walls should fulfil similar requirements to external walls. The thermal, physical and aesthetic requirements depend upon the function of a wall. For example, internal separating walls made with heavy and dense earthen materials store up warmth and give it up again to the air later as the room air temperature grows cooler. As a result, the room temperature remains more even throughout the day.

Important: All walls made with earthen materials must be protected against the weather during the building process. When planning new buildings it is advisable to protect earthen wall constructions against the effects of water at their base, both from below and from the side. A water impervious splash protection (min. 50cm above outside surface) protects against splashing rainwater, a damp-proof course against rising damp.


Earthen infilling
Wattle and daub infill
Earth brick "nogging"

In framed or half-timbered constructions, the spaces between the timber studs, rails and braces are filled with a non-structural walling “infill” or “nogging” in a variety of different techniques. One of the oldest methods is known as “wattle and daub”: Wooden struts are jammed between the timber members and woven with a wickerwork of split willow branches. This supporting “wattle” is then daubed from both sides with a clay straw mixture. This technique is used today only for renovation work.

Infill panels can also be filled with earthen brickwork or loose mixtures of moist clay straw or light clay. Where external walls are exposed to the elements, ‘green’ unfired bricks should not be used. As loose earthen materials dry the material can shrink leaving a gap between the timber members and infill material which should be plugged with more or the same material. Shrinkage gaps between the timber members and earthen brickwork is usually a result of the expansion and shrinkage of the timber rather than of the earth bricks. These will only become visible once the frame and infill have dried thoroughly.

Light clay infill panels that are exposed to rain should be protected by a double coat of external lime render. The adhesion between render and earth brick infill can be improved by scratching out the mortar joints to a depth of ½ cm to form a key. Render on walls exposed to heavy weather can be additionally strengthened by applying a plaster base to the brickwork.

Important: Whichever method is used, it is important that after the infill has dried thoroughly, it sits firmly within its frame and is not loose. Expertise is required in the renovation and rendering of historical infill panels in half-timbered constructions.

Wall linings

Wall lining (or inner shell) is a technique often used in renovation work to improve the thermal insulation, windproofing and noise insulation of thin existing external walls. A typical application is where external insulation is not an option, for example when half-timbered elevations should remain visible. Wall linings are also used to improve the thermal mass of modern light-weight timber-stud and timber-frame constructions.

Wall linings can be executed as masonry wall linings using earth blocks, as light clay wall linings using moist material or as a stacked lining using dry material. Clay panels and lightweight clay building boards can also be used.

Earth block masonry wall linings

Light clay block walling can be erected directly in front of the inner side of an external wall. Typically the earth blocks are erected slightly set off from the wall and the resulting cavity filled with a loose clay mortar mixture so that no voids result between wall and lining. This method is often chosen to increase thermal mass and insulation where no special workman’s skills are required and drying times need to be kept to a minimum. For added stability wall ties can be used where necessary to anchor the wall lining with the supporting construction.

Important: Heavy wall linings can require appropriate structural support or protection against rising damp or surface water.

Light earth wall linings

Insulating layers of light clay using moist loose material are most often used to even out uneven existing walls which may protrude or recede or where fittings or technical installations should be flush-fitted or hidden within the wall. A supporting construction of wooden slats is erected in front of the inner side of the wall and anchored with the wall, floor and ceiling. This is then used to fix or mount either sliding formwork or very often a permanent formwork (i.e. which is not removed) out of reed matting or laths. The moist light clay mixture is filled into the space between the formwork and external wall taking care that no voids result. The mixture is compacted so that it forms a stable and solid mass when dry. Drying times can be considerable.

Important: Moist constructions must be allowed to dry thoroughly and quickly and this should be considered during the planning of the thickness, construction and formwork material. The construction must be exposed to continual ventilation during the drying period or dried artificially.

Dry stacked wall linings

Earth blocks, bricks or ‘green’ unfired bricks are simply stacked without mortar against an existing supporting construction and then clad. This technique can easily be carried out as self-build method for new buildings without requiring special workman’s skills.

Important: To prevent the bricks from falling out, horizontal wooden battens are fixed to the supporting construction at intervals of approximately 50cm.