Compressed
earth block
Stabilised unfired earth block (±80% secondary materials) made from Brussels excavation soil + washed crushed concrete + 3.85% cement. 3 formats: 9/14/19 cm thick. Suitable for loadbearing walls up to 2 storeys or acoustic partitions. Laid in earth mortar · 100% reusable at end of life.
What is a compressed earth block?
The unfired earth block is a cold-compressed masonry unit made of local excavated soil, crushed concrete and sand, stabilised with a small proportion of cement. The earth forms the main matrix, the crushed concrete and sand provide the grading, and the cement gives resistance to moisture. Manufacture involves no firing.
The block is solid and breathable. Its weight gives the wall thermal mass, its vapour permeability regulates indoor humidity, and its density dampens sound transmission from one room to the next.
It is intended for loadbearing walls in buildings of up to two storeys and for non-loadbearing interior partitions. It is laid in clay mortar or conventional mortar, depending on the context.
Production takes place in Brussels, at BC Materials, from soil and concrete collected on neighbouring sites. The blocks come apart cleanly at end of life, and the producer organises their return for a new project.
Installation & uses
The blocks are laid like conventional masonry, with a clay mortar for a fully circular system, or a conventional mortar depending on site constraints. Joints are staggered from one course to the next, with a medium joint thickness to take up tolerances.
The block is cut with an angle grinder or a masonry saw to adjust finishes and openings. Its moderate weight keeps it manageable by hand in the smaller sections.
The finish can be left fair-faced to show the material, or take a lime or clay plaster. No prior treatment is needed.
At end of life, the blocks come away cleanly from the clay mortar and can be rebuilt into a new structure.
About the producer
BC Materials is a Belgian producer of unfired earth materials, based in Brussels, which puts urban excavation soil and local demolition streams to use. The company covers the whole of earth construction, from loadbearing blocks to decorative plaster, including mortars and rammed earth.
Its production follows a short supply chain, with materials recovered from neighbouring sites, processed in the workshop and delivered unfired. A take-back programme organises the return of the blocks for a new cycle.
Technical performance
EN 771-3 (blocks), EN 772-01/13/14/16/20, XPP13-901 (unfired earth block mortar), DIN 18945 (modulus of elasticity). Designation: BTCS – CL1 – RC 7 – Mv 2.0 – 13 × 9/14/19 × 29 – S 3.85% CEM III 42.5 – XP P 13-901. CE marking not applicable (unfired earth blocks are not covered by a harmonised European standard).
FAQ
Is the compressed earth block loadbearing?
Yes, in interior masonry. Compressive strength of the block 10 N/mm² to EN 772-1, class Rc 7. Built in the 14 cm format, unplastered, the masonry is characterised at 4.6 N/mm² with 10 mm Léém mortar, 5.9 with adhesive mortar and 6.2 with additive-modified lime-cement mortar, to EN 1052-1. The declared applications stop at interior walls and partitions.
Is it CE marked?
No. Unfired earth blocks are not covered by any harmonised European standard, so CE marking does not apply. The designation follows XP P 13-901: BTCS – CL1 – RC 7 – Mv 2.0 – 13 × 9/14/19 × 29 – S 3.85% CEM III 42.5.
What is its embodied carbon?
14.9 kgCO₂eq per m² of 14 cm wall laid with Léém Mortar, 20.3 with Léém Adhesive Mortar. GWP calculated to EN 15804+A2, technical data sheet of 10 November 2025.
Which thickness should I choose?
Three formats, 9, 14 and 19 cm, for a block 13 cm high and 29 cm long. Conductivity 1 W/m·K to XP P 13-901. The masonry strengths and the embodied carbon are measured on the 14 cm block.
What happens to the block at end of life?
It can be taken out of a wall and relaid: the product is declared fully reusable, and BC Materials runs a take-back programme. If not reused, the blocks are classed as non-hazardous inert waste.
Alongside
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Loadbearing block in Belgian recycled aggregates + low-carbon cement. Roosens · Familleureux.