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Material or Product

Hemcrete Hemp Walls

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Hemcrete is a building material that is carbon neutral - and actually carbon negative. Tradical® Hemcrete® is a bio-composite, thermal walling material made basically from hemp, lime and water, developed by U.K.-based Lhoist Group. Hemcrete is carbon negative because there is more CO2 locked-up in the process of growing and harvesting of the hemp than is released in the production of the lime binder.

Tradical® Hemcrete® is used to build walls. In timber frame buildings it provides the wall form, the racking strength and the insulation. In steel and concrete framed buildings, it provides the wall form and insulation in one monolithic product. Characteristics include:

- high thermal insulation;

- low density (down to 0.2 kg/m³ for Hemcrete used in roofing insulation)

- excellent air/vapour permeability

- high flexural strength

- high carbon capture

- very low energy building blocks

Among the important technical considerations for wall infilling materials of timber framed buildings, is that the excellent vapour permeability provided by Tradical® Hemcrete® is protecting the timber from deterioration mechanisms and extending its longevity. The light weight of Tradical® Hemcrete® means that lightweight timber framing and foundation structures can be used which can reduce costs and construction time making Tradical® Hemcrete® a very efficient building medium.

In steel and concrete structures, the vapour permeability also delivers a protective environment against corrosion.

The high thermal performance and air-tightness of the Tradical® Hemcrete® walls means that single skin structures are sufficient and do not require additional insulation layers. This avoids the need for cavity wall construction and makes construction speed and simplicity a very attractive feature of Tradical® Hemcrete® walling construction.

The ability of the walls to breathe and the store heat allows for a passive self regulation of the temperature and humidity within the building in general, often reducing the need for air conditioning.

As well as being ideal for new construction, Tradical® Hemcrete® is well suited for the renovation and repair of old timber-framed buildings as a viable and sympathetic replacement for the original wall in-fill.

The development of the Tradical® HB special lime binder specifically for use with Tradical® HF hemp shiv offers, to mainstream construction, materials that have the ability to make a very significant contribution in combating global climate change. Fast growing hemp stores carbon during its growth and releases oxygen into the atmosphere. The overall CO2 balance for Tradical® hemp and lime products is such that captured carbon is retained within the fabric of a building.

This sequestration of atmospheric CO2 offers an exciting opportunity to grow and produce sustainable, natural fibre, insulation and construction materials. Over ten years of experience in hemp lime technology has been gained by Lhoist companies in continental Europe and the transfer of this patented knowledge to the UK market comes through Lhoist UK with Tradical® hemp and lime products.