LECA concrete or normal-weight concrete? When lightweight pays off

Expanded clay (LECA) concrete is concrete in which the natural aggregate is replaced with expanded clay — granules of fired clay. This single substitution changes three parameters at once: weight, thermal insulation and water absorption. Below is a comparison with normal-weight concrete where the difference matters in practice.

Weight — transport and the crane

A LECA concrete element is markedly lighter than its normal-weight concrete counterpart. More metres of wall fit on a single vehicle, and a smaller crane is enough on site. On a single-family house this can decide whether the installation can be carried out from a single crane position.

Insulation — wall thickness

Expanded clay traps air within its structure, so a LECA concrete wall conducts heat less readily than a reinforced concrete one. Our wall build-ups achieve U-values in the range 0,117–0,185 W/(m²·K) depending on the layer arrangement — comfortably below the WT 2021 limit. The details are set out on our LECA concrete page.

Strength — where the limits lie

We use structural LECA concrete in classes from LC12/13 to LC20/22. That is sufficient for the load-bearing walls of residential buildings, including multi-family ones. Where the calculations demand more — floor slabs, beams, columns, balconies — we use normal-weight concrete up to C35/45. In a single building the two materials work side by side, and that is the typical arrangement, not the exception.

The environment — EPDs

The carbon footprint of our products is documented in the verified environmental product declarations ITB-EPD 561 and 562 — you will find the documents and a discussion on our sustainability page.

If you are wondering which material suits your project, send your documentation through the quote form — material selection is part of the quote, not an extra service.