Hempcrete blocks, the green bricks’ that revolutionize the building sector

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Text Marie Mathieu, Marketing & Communication Isohemp

A true green brick, the hempcrete block has the wind in its sails! Though it has been confined to a craftwork for a long time, this 100 % natural material has everything to revolutionize a building industry which needs to reinvent itself.

The advantages of IsoHemp hempcrete blocks

The IsoHemp hempcrete block is a nonload-bearing glued masonry product designed for the production of healthy and natural insulating envelopes, partition walls and counter-partitions. Very versatile, it is highly appreciated by professionals for both new construction and renovations, whether they are single-family, collective or tertiary projects. Choosing the hempcrete block means choosing an insulating material which combines five incomparable assets: thermal regulation, water regulation, soundproofing, fire resistance and a 100% natural composition. Hempcrete blocks indeed have exceptional insulation qualities: while many insulators only protect against the cold, hempcrete blocks maintain a constant temperature in summer and winter (thermal resistance of 1 to 5 m2K/W). They are breathable, allow water vapor to escape and naturally regulate humidity, a major advantage for successful insulation: no risk of condensation or moisture pockets. They are therefore the insulation par excellence for old buildings, protecting their envelope, and can be used to insulate any type of wall (concrete, wood, etc.), whether the walls are dry or damp. “The blocks maintain a very pleasant warmth inside, so we have to switch on the heating a lot less. What is noticeable here is that the blocks create a very healthy and very calm living environment” argues Tristan, happy owner of a wood and hemp house. Hempcrete blocks’ honeycombed structure also offers significant acoustic insulation (-44DB): the hempcrete blocks therefore protect against interior and exterior noise pollution. All of this contributes to a feeling of great comfort, which is often highlighted by the occupants. Conventional building materials often have a significant environmental impact (concrete alone emits 8% of the world's CO2). The hempcrete block, on the other hand, offers a 100% green balance sheet: during its growth, the hemp plant captures a large quantity of CO2. Every cubic metre of this material saves 75 kilos of CO2 on a long-term basis.

Stéphane, who is currently renovating his countryside hotel, explains why this green aspect was important to him: "We are carrying out a project in which one of the main objectives is to reduce the carbon impact at all levels, so we asked ourselves: why not work on a short circuit? While searching, we came across IsoHemp quite naturally”. Another advantage of hempcrete blocks is that they are very resistant in case of fire. Their composition makes them very fireproof, unlike some plastic-based insulators which can give off toxic fumes in case of strong heat.

The perfect balance between performance and durability

Made from the combination between hemp and lime, the IsoHemp block is a high-performance material which has been proving its worth for decades. For a long time, the techniques for processing hempcrete in the building industry have remained traditional: either by mixing the components on site and applying them in formwork, or by using a spraying machine requiring highly skilled labor. IsoHemp's response was to launch on the market an industrialized product that can be worked by all professionals, respecting construction standards. The product is also in compliance with all European and national standards.

The Hempro system for a 100% hemp construction

The Hempro system comprises two types of 36 cm thick hempcrete blocks: solid blocks and machined blocks (predrilled blocks and U-blocks). Located in the building envelope, the machined blocks serve as the insulating lost formwork for the structural frame made from the reinforced concrete poured into it. The pre-drilled blocks constitute the formwork for the columns, while the U-blocks allow the beams to be poured that subsequently support the floor and roof. From single-family homes to apartment buildings to ecodisctricts, you can easily build low-energy, very low-energy or passive buildings. The Hempro system offers many advantages. It provides a breathable and homogeneous envelope and ensures a high insulation value with reduced thickness. Its implementation is quick and traditional. Moreover, it has an excellent price/performance ratio.

A technical unit for specific projects For specific and tailored-made projects, the company has also developed a technical unit that carries out all the necessary dimensioning and is able to provide the necessary calculation sheets. “This upstream work is intended to facilitate the prescription of our product and its validation by the competent control offices” explains Jean-Baptiste de Mahieu, IsoHemp’s Managing Partner. A nice way to encourage virtuous projects.

About IsoHemp

Leader in the international market, IsoHemp is manufacturing those insulating blocks made of hempcrete. The goal of this Belgian company, which was started in 2012 by two young entrepreneurs: Olivier Beghin and Jean-Baptiste de Mahieu, is to offer an innovative and high-quality product and to democratize it. In the era of low-carbon building, IsoHemp is logically experiencing strong growth of 30 % per year, and with good reason: the hempcrete block ticks all the boxes. The material indeed shows a positive carbon balance, is accessible and is efficient in many regards. The enthusiasm of candidates for renovation or construction, as well as the enthusiasm of professionals, has enabled the company to double its turnover each year. Such a growth, that the company has just invested 10 million euros in advanced but energy-efficient production tools and in the expansion of its production site, which will now be extended to a two-hectare site. This brand-new plant will be producing more than five million hempcrete blocks a year, a quantity which is equivalent to 5 houses a day.

References

Construction of a single-family, very low-energy and CO2-neutral house – The Netherlands

Led by famous Dutch meteorologist Gerrit Hiemstra, this very low energy and CO2-neutral project was made with only ecological and healthy materials: Load-bearing masonry in stabilised cured clay (ARGIO) and insulated concrete block of hemp (ISOHEMP), framework in solid local wood (Douglas fir, chestnut), insulated shell flooring, ... The hempcrete blocks were chosen for their technical properties (thermal mass, acoustics, hygrometric regulator, comfort ...), but also for their very good ecobalance, their innovative character and their regional origin.

Construction of an industrial building intended to become the future Luxroutage logistics centre – Luxemburg

New construction of an industrial building resulting from the collaboration between IsoHemp SA and Contern SA. Building made of hempcrete blocks and load-bearing structure made of concrete blocks. Construction of a masonry in blocks of 30 cm by 25 m wide and 14 m high, separating the heated offices from the storage area. This single masonry allows the two spaces to be thermally and acoustically insulated and complies with fire regulations. The masonry was coated on one side and spray painted on the other for optimal sound absorption. The combination of concrete and hempcrete blocks to offer an efficient and innovative constructive solution for the future Luxroutage logistics centre.

Detached house realized with the Hempro System – Belgium

New construction realized with the Isohemp Hempro system, a constructive system of concrete column-beams directly poured into the 30cm hempcrete blocks. An additional 20 cm thick envelope is made to reach a passive standard dwelling.