Hemp-lime bricks - The Ecological Building Material of the Future

Hemp-lime bricks is a functional natural building material made from hemp shives, lime, and pozzolans or minerals. It not only has excellent building-physical properties, but also actively stores CO₂. With hemp lime bricks, you build not only healthy and efficient homes -

you invest in a sustainable future.

Learn everything here about production, benefits and applications:

CO₂-negative: up to 105 kg CO₂ stored per m³ of hemp brick
U-value: 0.18 at 38 cm wall thickness, 0.15 at 44 cm (without additional insulation)
Fire protection: 120 minutes already with 12 cm hemp bricks
Sound insulation: a 38 cm exterior wall reduces 48 dB
Circular & recyclable: very easy to reuse (as new hemp lime bricks)
Produced from regional hemp, cement-free

What is hemp lime?

Hemp lime - consists of hemp shives (hemp wood, the woody inner part of the hemp stalk), natural lime, and pozzolans (minerals) as a binder. After mixing, a lightweight, porous but stable building material is formed, which can be processed into blocks, insulation, or entire wall elements. Hemp lime combines the positive properties of both components: the insulating performance of hemp and the durability, moisture tolerance, and fire safety of lime.

In principle, Portland cement is an absolute taboo and has no place in hemp lime.

Other building-biology binders such as magnesite, alkali-activated binders, or geopolymer can also be counted as hemp lime products. There are also interesting mixtures made from hemp clay.

Hemp cement?

Roman cement is used as a binding agent in many hemp blocks, which technically is not lime. In this case, the correct term would be hemp cement. It can be recognised by its dark grey colour.

Although Roman cement facilitates production because it hardens quickly and achieves higher densities, it should be considered a significant compromise.

Where does hemp lime come from?

Hemp lime was further developed in France as a response to energy-intensive concrete solutions. France was a pioneer in this area because industrial hemp was never banned there. In the rest of Europe, industrial hemp was prohibited until the 1990s (which is completely incomprehensible, since the hemp used for building materials is pure industrial hemp), so the industry could not develop as strongly as in France.

Today, hemp lime is used across Europe. In principle, hemp is considered one of the oldest cultivated plants of humanity, and lime is one of the oldest binders.

We, the Schönthaler Bausteinwerk, were the first in the entire DACH region to produce hemp lime bricks in series, and we invested a great deal of time and energy in certifications and public relations.

In addition, we were the first to obtain a German approval for hemp lime products - thus pioneering ecological building with hemp and lime.

Acoustic Panels

Panels for Sound Absorption

Bricks

Bricks for New Construction and Renovation

Exposed Walls

Tamped Walls

Wall Elements

Prefabricated Hemp Walls

Benefits of Hemp Lime

Build without additional insulation (U-value 0.18 with 38 cm wall thickness)
Adds mass to timber construction
Excellent fire protection and fire behavior
Good sound insulation (48 dB with 38 cm wall thickness)
Summer heat protection
High phase shift and thermal storage
Highly diffusion-open
Extremely durable
Very easy to recycle, in theory and in practice
Fast renewable
Humidity regulating
Healthy indoor climate
Regionally available, also in many countries of the developing world

Properties of Hemp Lime

Highly insulating, thermal storage, good sound insulation
Lightweight & dimensionally stable
Humidity & temperature regulating (similar to clay)
Summer heat protection
Diffusion-open & capillary-active
Air-purifying & mold-resistant
Odor-neutral & antistatic
Very good thermal storage (18-hour phase shift at 30 cm)
High fire protection (B, s1, d0), EI 120 at 12 cm

Disadvantages of Hemp Lime

Not structurally load-bearing. A frame made of wood, steel, or concrete is required.
Hemp lime requires long drying times. This has disadvantages in logistics (storage, planning, pre-financing).
The long durability of hemp lime buildings is bad for the economy. Short-lived building materials are more profitable for companies.
Some standards are still missing.
Hemp still carries a bad reputation (prohibition).
Hemp lime must be transported dry, stored dry, and kept dry on the construction site until the building is plastered.
Sound insulation at 48 dB for the exterior wall is good, but heavy masonry or concrete is still somewhat better.

Application: standards are still missing.
Production: partially difficult in winter.

How can hemp lime be processed?

Hemp lime can be processed in many ways - depending on the requirements, it can be used as:

Building blocks (hemp bricks): for exterior and interior walls
Interior insulation: excellent building-physics, economical, and simple
In-situ casting (formwork filled on-site): for massive hemp lime walls, similar to hemp clay
Precast elements: prefabricated wall modules with a wooden frame - especially efficient in modern timber construction
Spraying: there are special machines that can spray hemp lime. However, this technique does not work well and causes a lot of waste/losses
Interior plaster & floors: also available as cement-free screeds or lightweight plasters

Hemp Lime Bricks Products / Product Lines

On Hanfstein we offer:

Solid blocks (6–44 cm width) - for new construction and renovation
U-blocks & hollow blocks - for ceiling edges and concrete supports
SAPPA acoustic panels - made from hemp and minerals, without cement
Prefabricated walls
Climate panels for heating and cooling
Interior plasters & insulation boards - cement-free, purely mineral

Mortar and Thin-Bed Mortar: Hemp bricks are relatively soft and therefore require a thick-bed mortar that behaves similarly to the hemp bricks. Thin-bed mortar with less than 5 mm does not work with pure lime mortar. Ideal are masonry mortars made from pure lime with fine hemp shives. This keeps the thermal insulation similar to the rest of the wall and improves sound insulation.

Our partner Uckermark Hanf also writes about this:

https://www.hanffaser.de/index.php/hanf-kalk-steine

Examples of applications for hemp lime

Single-family homes, multi-story buildings, building extensions
Renovation of half-timbered houses
Interior insulation of old buildings
Public buildings, schools, kindergartens
Acoustic solutions for schools, restaurants, studios (sound insulation)
Agricultural buildings

Where can you buy hemp lime products?

We produce various hemp lime products and are happy to advise you.

Regional distribution partners in South Tyrol, Switzerland, Austria, Germany (inquiries by email).

We deliver throughout Europe and beyond - for builders, architects, and retailers.

Contact us for more information.

[email protected]

From the hemp plant and natural materials such as foam glass gravel, an efficient wall system is created for both interior and exterior use. Our building materials offer excellent thermal conductivity, sound insulation, flexible processing, and a wide range of applications — from partition walls to renovation and new construction.

With improved bulk density, careful composition, and optimized component quantities, we ensure the best combination of functionality and aesthetics. Our broad range of solutions covers all areas of the construction industry and is continuously expanding its reach. A photo shows the harmonious integration into projects, tailored to growth conditions.

Thanks to the support of many universities and students and the full commitment of our partners, it has become a real alternative to conventional building materials, ready for further growth.