When hemp hurd (the woody core of the stem) is mixed with a lime binder and water it petrified into a biocompsite substitute commonly know as Hempcrete. Hempcrete is lightweight cementitious insulating material weighing about a seventh or an eighth of the weight of concrete. Fully cured hempcrete blocks float in a bucket of water.
Hempcrete has significant advantages over concrete. It is breathable, fire resistant and a good insulator, and can be used as a fill around a timber frame, as a finishing plaster, or to build freestanding walls.
The Hemp plant absorbs atmospheric CO2 during the plant growth phase, and again as the material gains strength and matures. (100sq m with 300mm thick walls) will lock up 7.9 tons of CO2 in the walls. Estimated rate of carbon sequestration is 165Kg CO2 capture/m2. Therefore, building with Hempcrete reduces atmospheric CO2.
Hemp houses show superior thermal properties to the conventional homes: the exterior walls of the conventional homes were 4-6°C warmer than those of the hemp houses, indicating that loss of heat through the conventional brick walls was considerably greater than that through the “Hempcrete’ walls
Tests of the thermal conductivity of walls by Plymouth University led to an agreed reading of 0.08w/mK. These were taken on a 200mm thick wall that had been constructed a number of years earlier. The "R" value (thermal resistance) is 2.75 with plaster and surface resistances taken into account. "U" value (rate of heat loss or gain) derived from this would be in the region of 0.36 -0.37W/m2K. This empirical work confirmed a lambda value of 0.08 - 0.09 for hemp and lime and as this conservative figure has been confirmed by so many authorities that it seems to accept this when making building regulation applications. (Bevan and Woolley, 2008)
Hempcrete regulates the temperature and humidity of a building; in some cases completely eliminating the need for heating and cooling systems, resulting in huge energy savings. Hempcrete is carbon negative and the obvious choice for buildings aiming to achieve a low carbon footprint and the highest sustainable building code levels.
Hempcrete has very good acoustic components due to its open structure. Hempcrete has a low propagation rate, a figure of ~900Vson m/s against steel with ~6110 Vson m/s. Hemp concrete is characterised by its high porosity that combines the microscopic pores of its binder and its vegetable particles, and bigger pores between the particles. Thus, its sound absorption is intermediate between the excellent absorption of hemp shiv, and the reflexion of the binder.
Fire tests on a 300mm thick Hempcrete wall gave 73 minutes, for structural adequacy/integrity/insulative capacity. Further tests are being undertaken by the labs of Cesa, St Estier limes in France.
John French, a leading Queensland and international entomologist, has tested Hempcrete in the Northern Territory and Queensland found termite have no effect on the Hempcrete samples.
The material is mixed in mortar mixers for 1-2 minutes and stuffed by hand into the wall cavities. The wall is slip-formed with temporary wooden or plastic “shuttering” forming the inner/outer surface forms. The material is lightweight and can be moved easily about the site in tubs and passed up bucket-brigade fashion to workers filling the cavities. Site clean-up is easy. Simply till it into the soil.
The material is finished on the outside with a hard render coating about 20mm thick to protect it with a final colored topcoat finish added. The end result appears like any stucco finished building. The inside can be left natural or finished with lime plaster for a traditional look.
Hempcrete was discovered in a bridge abutment in France built in the 6th century. Since its rediscovery it has seen growing use in Europe. Industrial hemp is grown by certified commercial growers so the crop can be certified to be very low in THC. Hemp is not psychoactive. Given it has survived 14 centuries, people expect Hempcrete buildings will have a long life.
Hemp itself is a beneficial crop requiring no fertilizer, weed killer, pesticide or fungicide. It grows so thickly that weeds cannot grow. Farmers grow it in rotation with other crops such as barley or rye. The crop following the hemp requires no weed killer because the hemp has driven weeds out. The hemp seed is harvested as a nutritious food supplement rich in Omega-3 oil, amino acids, protein and fiber. It is considered a “super food”. The outer fibers are used for cloth usually as a blend with 45% cotton. The woody inner core is chopped to uniform size for our use. It has been traditionally used as animal bedding.
Ozhemp is the exclusive distributor for Tradical® Lime Binder/Render and Building Grade Hemp Hurd (shiv) from Chanvribat® and Hempflax® for Australia and New Zealand. Tradical® Tradical® Hempcrete are the only fully BCA certified hempcrete products and installation methods in Australia and New Zealand according to The Australian Building Codes Board (ABCB) and The Joint Accreditation System of Australia and New Zealand (JAS-ANZ).
Tradical® Hempcrete products have been developed in collaboration with professionals to meet their expectations and have been used on a wide range of construction sites for the past ten years with unrivalled functional reliability and with no distress observed to date.
These materials' characteristics have made TRADICAL® the benchmark in hempcrete construction. The conformity of the Tradical® Hempcrete with certified hemp hurd from Chanvribat® or HempFlax® blend by trained certified builders and tradespeople, in compliance with Professional Rules for the Construction of Hempcrete Structures ensures users will benefit from all the usual essential guarantees.
The vast majorities of experiments relating to hempcrete have been – and still are – conducted with Tradical® Hempcrete. The trusts that research institutions place in our products allow us to benefit from substantive knowledge acquired from experimental constructions and numerous development programs.
The ease-of-use, performance, and reliability that have contributed to the reputation of Tradical® Hempcrete are a result of the components' qualification and of the stability of their characteristics. The consistency of the Hemp/Binder blend is what enables us to ensure they are safe to use.
Beyond their technical performance, reliability, and conformity with the construction regulations in force, Tradical® Hempcrete also meet other requirements that have become just as indispensable; availability of renewable materials, ability to store CO2 in the long term, energy efficiency, and non-toxicity are decisive factors in choosing materials today.
Tradical® Hempcrete is the only fully certified hempcrete products and installation methods in Australia and New Zealand according to The Australian Building Codes Board (ABCB) and The Joint Accreditation System of Australia and New Zealand (JAS-ANZ).
Tradical® construction materials are developed products of the Lhoist Group based on high purity manufactured lime materials. The Lhoist Group is an international business focused on the supply of high purity lime products to many industries including the construction industry.
Tradical® Hempcrete is a unique, highly sustainable construction product for the creation of insulating walls as well as insulation layers for roofs. Tradical® Hempcrete is a blend of specially prepared hemp shiv and a special lime based binder Tradical® PF70. Together these products form a bio-composite building material that can be used both for the creation of buildings that have excellent thermal and acoustic properties as well as creating a healthy living and working environment.
Additionally, Tradical® Hempcrete has the ability to make an impact on the future of sustainable building. Helping to reverse the damaging effects of greenhouse gases, Tradical® Hempcrete locks up approximately 110kg of CO2 per m3 of wall and provides one of the best value materials for low impact, sustainable and commercially viable construction.
Produced mainly from renewable sources, Tradical® Hempcrete is mixed on site for fast track construction and delivers high levels of insulation, air-tightness and vapour permeability.
- is porous allowing the material to retain heat, requiring less energy for a building to maintain a stable temperature
- is an excellent insulator and does not require additional insulation,
- has excellent hygroscopic properties assisting in regulating the indoor humidity
- will not crack severely under movement and is three times more resistant to earthquakes than regular concrete
- is durable and fire resistant
- is naturally termite, pest and mould resistant, due to the use of lime
- is non-toxic and will not let off gas volatile organic compounds into the indoor air
- has good acoustic properties.
- can easily be designed to create different shapes and can be formed for precise openings for windows and doors, allowing water tight sealing to be installed.
Combining patented formulations of air-lime based binders with the chopped core of the industrial hemp plant stem, delivers a suite of new building products. These Tradical® Hemp Lime products have excellent performance characteristics for durable, healthy, sustainable and ecologically sound buildings.
Tradical® Hemp Lime products deliver excellent application, durability and aesthetic performance characteristics combined with sustainability, economic, comfort and health qualities that architects, developers, contractors and customers will value.
Tradical® PF: these ready-to-use pre-formulated binders combine air lime and hydraulic binders so that you get the best of both for your projects. To be used in brickwork and blockwork, rendering & plastering
Tradical® PF is a product line of different air lime-based pre-formulated binders to meet all needs in terms of building masonry, rendering and plastering in the renovation and new build market segments.
Tradical® PF incorporates in one mixed product all necessary ingredients to make high-quality/high performance air lime mortars compatible with all kinds of wall structures.
Tradical® PF brings all the necessary performances for a successful masonry work:
Note: Please note that cementitious or hydraulic binders that have not been designed to be used with hemp may produce unacceptable results. The failure is often related to the competition for water between the binder and the hemp. If the binder has insufficient moisture for the hydraulic components to set, then the result can be a mixture of damp hemp and/or dry powder.
Tradical® PF70 is the patented air lime pre-formulated binder "workhorse", to meet a wide range of applications and needs.
Tradical® PF70 has been developed to make a high-quality air lime binder with controlled setting. It is the binder for building masonry with all possible wall structures or roofing tiles, for rendering and plastering in both renovation and new build constructions.
Tradical® PF70 is ready and easy-to-use. Just add fine aggregates and water in the required proportions and you will have a mortar that is highly workable, of appropriate strength and flexible. In addition, it will bring breathability and long lasting performance that can enhance your building project adding values that any end-user will appreciate.
In combination with good design and construction, Tradical® PF70 mortars can lift the visual appearance of your brickwork and provide a durable, low maintenance end product of distinction.
Available in 20 kg bags
Tradical® PF80 is a binder prepared fat-based or lime (85%) and natural hydraulic lime (15%), intended after mixture with aggregates (sand) and mixed with water, soft masonry and stone achieve grout, body coating and traditional single-mass coating and repointing of old media, in accordance with the DTU 20.1 chap. 2.2, 4.21 and DTU 26.1. Chap. 11.
Available in 200 Liter bales
Chanvribat® is used to make hygrothermal renders and insulating concretes using Tradical® PF 80 and Tradical® PF 70 binders, with binder+hemp aggregate blends that comply with the French Professional Rules for the Construction of Hempcrete
Chanvribat® construction hemp aggregate is a plant-based material made from raw hurds, which – once verified as complying with strict specifications – can be used in the building sector as insulation and construction material.
Chanvribat® is designed for producing Tradical® Hempcrete: insulating walls, insulating lining, insulating roofs and hygrothermal renders, as well as brand-new constructions or renovations of all kinds: detached houses, residential buildings, public buildings, and more.
Available in 140 Liter bales
HempFlax® Building Grade Hemp Shiv are specially selected, processed and certified building grade quality hemp hurd (shiv) suitable for use in construction and insulation hempcrete using Tradical lime binder; insulating walls, insulating lining, insulating roofs and hygrothermal renders, as well as brand-new constructions or renovations of all kinds: detached houses, residential buildings, public buildings, and more
HempFlax Building Grade Hemp Shiv is made from 100% hemp straws after the fibers have been removed.
Tradical® Hempcrete that sets the standard.
Tradical® Hempcrete is the only hempcrete in Australia to be certified to the Building Code of Australia under the CodeMark scheme.
Considered to be the building industry’s highest level of product assurance, CodeMark is a certification scheme managed by the Australian Building Codes Board (ABCB).
CodeMark™ gives users the confidence that their building compiles. Building materials, forms of construction and designs can come under this scheme.
The BCA CodeMark allows the building industry to ensure nationally consistent, minimum necessary safety standards in building and construction. This includes fire construction, health, amenity and sustainability. The BCA CodeMark protects builders and clients alike, by imposing strict safety regulations that need to be legally met on every building project. BCA CodeMark is the only certification scheme that delivers this total compliance.
- Offering increased credibility and acceptance, boosting consumer confidence in, Tradical® Hempcrete as well as ‘certified builders”.
- Assurance, that the Tradical® Hempcrete system meets stringent national standards, encompassed by CodeMark™ Accreditation.
- Helps manage risk and legal liability.
- Increase confidence in building products and practices
It means total peace of mind. With CodeMark certification, home owners can breathe easy knowing that Tradical® Hempcrete delivers compliance to the BCA in relation to building requirements; while builders, architects, designers, and building certifiers can breathe easy knowing that they are indemnified from legal liability in relation to product
*Refer to conditions and limitations noted on certificate.
Click here to view BCA Certificate of Conformity. or click on the badge to access CertMark to verify our certification.
Hempcrete, or “hemp-lime composite building material” to give it its proper name, is a mixture of hemp shiv (the woody stem of the industrial hemp plant) together with a lime (or sometimes lime- based) binder. The material is usually wet-mixed and cast on site in shuttering, around a structural frame (hempcrete is non-load bearing) but it can also be pre-cast into blocks or panels.
Hempcrete is a non-load-bearing (although hard and self-supporting once set), medium density natural insulation material, which also has thermal mass, and it is breathable (vapour permeable). See below for more information.
In new-build, hempcrete is most commonly used to make walls, celling and roof insulation.
In contrast to conventional insulation materials (which tend to be installed in a cavity within the wall, or added to wall as an extra layer in the build-up) hempcrete in walls forms the wall and the insulation in one piece, with the only other materials being the structural frame. Wet finishes - a lime or clay plaster internally and 2 coats of lime renders externally - are the only other additions to the basic hempcrete wall, although cladding (timber, stone, brick etc.) can be used in place of wet finishes if desired.
In walls and roofs hempcrete is used in combination with other materials to provide an insulating layer, which can form all, or part, of the insulation layer depending on the building design.
In the restoration or retrofit of traditional and historic buildings hempcrete is often used to replace or repair infill panels in timber frame buildings, or to add insulation to solid walls in old buildings. It is ideal for use in traditional buildings because of its vapour-permeability and its ability (as a wet- mixed, loose-fill material which hardens once applied) to mould itself exactly to unevenly shaped walls in an old building, and support itself without sagging.
Hempcrete is a breathable (vapour permeable) material which is hygroscopic (it regulates humidity in the air by taking in water vapour and releasing it again when humidity levels drop). This is important, both for the health of the building’s occupants and in order to keep the fabric of the building in good condition.
In old buildings hempcrete works in harmony with the traditional materials, by allowing the building to “breathe”; meaning that water vapour can pass in and out of the wall rather than being retained within it to cause damp and damage to the building’s fabric.
Hempcrete is naturally fire and pest resistant, meaning that there is no need for potentially toxic chemicals to be added to it. This fact together with its vapour-permeability and hygroscopic nature means that hempcrete buildings are healthy living environments.
Hempcrete is a natural material. The hemp plant used as the aggregate in hempcrete absorbs so much carbon during its rapid growth that more CO2 is locked up in a hempcrete wall than is used in its construction. In other words, hempcrete has negative net carbon emissions – it’s a “better-than- zero-carbon” material. The exceptional eco-credentials of this natural, sustainable material (see below) make using hempcrete in your building the obvious choice if you want to reduce your energy bills, your carbon footprint and the overall impact of your building on the environment.
As a relatively new material, which is quite different from most conventional building materials, hempcrete can be tricky to work with unless some key concepts and techniques are understood. Unfortunately, due to its rapid acceptance as a building material across the UK, examples can be found where a lack of understanding of the material and construction techniques has resulted in problems with the build. This is especially common on large projects such as housing estates, where inexperienced contractors have expected hempcrete to behave in the same way as conventional building materials. However, such problems are not usually long term or serious, and with a little basic knowledge and some experience of using it, hempcrete is a straightforward and rewarding material with which to build.
Trades people with knowledge of the building code and building practices that have under gone a specific designed training in the installation of Tradical® Hempcrete to become a trained and certified Tradical® Hempcrete installers is of importance.
Architects who are not used to working with hempcrete and other natural materials may not find it easy to detail buildings correctly when using these materials. This is not an insurmountable problem and can usually be solved by the architect finding out about how to detail hempcrete; for example by reading around the subject, visiting existing buildings.
For more information on detailing hempcrete buildings, see: The Hempcrete Book: Designing and building with hemp-lime by William Stanwix and Alex Sparrow, published by Green Books in September 2014. Available at http://www.angusrobertson.com.au
As described above, hempcrete is a “carbon-negative” or ”better-than-zero-carbon” material; more carbon is taken out of the atmosphere by the growth of the hemp plant than is emitted as a result of its production and application on site. Various estimates for the amount of carbon sequestered have been put forward, and of course this varies depending on the exact type and source of materials, as well as on the application technique. However a leading UK manufacturer of hempcrete materials has suggested a figure of 165kg net CO2 sequestered per m3 for shuttered and hand-placed hempcrete, and 110kg CO2 sequestered per m3 for spray-applied hempcrete.
The reason the hemp plant absorbs so much carbon dioxide is because is a tall, fast-growing plant which needs to create a hard woody stem to support itself at its full height. It grows up to 4.5 metres in around 4 months in the UK climate. The strong woody cellulose of the stem is the part chopped up and used for building. Previously this was considered a waste by-product of the oil, seed and strong fibres for which the hemp plant which has long been grown. Now the whole pf the hemp plant can be used!
The other main hard-wearing cellulose material used in construction is timber which, depending on the species, takes many years to grow to a useable size. Compared to timber, the fast growing hemp plant, which replenishes itself every year in just 4 months, is a truly renewable, sustainable material. The protection which the lime binder in hempcrete gives to the timber structural frame means that faster-growing softwoods can be used for the frame, further increasing the sustainability of the building as a whole.
Hemp can be grown and processed all over the world, in a range of soil types, as long as the climate is not too arid, and so can be considered a “globally local crop”; cutting down on the energy used to transport hemp shiv for building. The hemp we use for building is grown in the UK and processed on the farm before being sent straight to the building site.
The hemp plant is naturally pest-resistant and weed-suppressant, eliminating the need for chemical fertilisers and insecticides. It requires very little fertiliser, and is deep rooting; returning nutrients to the soil and conditioning the ground for the next crop. This makes it an ideal break crop for farmers in the UK to use between sowings of other crops such as winter wheat.
Hempcrete binders are made from building lime (some are pure lime, and some are 70-80% lime), which is produced by burning limestone (an abundant natural resource) in a kiln. Compared to Portland cement (which is produced from building lime with a proportion of other minerals), lime is burnt at a much lower temperature (900°C for lime compared to 1200-1400°C for cement) thus saving energy. The finished, bagged lime also has a much lower density than cement, reducing the energy used in its transport, and when it is used on site lime will re-absorb some CO2 from the atmosphere as it sets (the amount of CO2 absorbed varies with the type of lime used). The lime binders we use for hempcrete are from Tradical® in France and the specially selected, processed and certified building grade quality hemp hurd from the Netherlands and France.
Once constructed, hempcrete walls, ceilings and roofs have extraordinary thermal properties (see below) which will continue to help the environment by bringing a massive reduction in the fuel used for heating and cooling during the lifetime of the building.
Hempcrete is completely natural and free from synthetic, fossil fuel based materials. Because hempcrete is naturally fire-retardant and pest-resistant (nothing eats lime!) there is no need to add chemicals to ensure its performance in these areas (as is usually the case with lightweight synthetic insulation materials). Chemicals added to conventional insulation materials often contain Volatile Organic Compounds (VOCs), which have been implicated in the recent rapid rise in incidence of asthma and severe allergic reactions in western countries as synthetic materials “off-gas” toxic chemicals into our homes.
Hempcrete, and the lime and clay plasters which are applied to its surface, are “breathable” (vapour- permeable), meaning that they allow water vapour to pass through them. In addition, thanks to the porous nature of both the hemp shiv and the lime binder and the air pockets created by the arrangement of particles in the hempcrete material itself, hempcrete is hygroscopic. This means that hempcrete absorbs moisture into the material during times of high relative humidity in the air, and releases it again when the relative humidity drops.
This ability to passively regulate the humidity in the internal space means that when there is excess moisture in the air (for example when cooking, or in bedrooms at night, from the occupants’ breathing) condensation does not get a chance to form on the surface of the wall. This in turn discourages the formation of damp and mould spores, which can be harmful to human health.
The regulation of humidity in the indoor environment to a healthy level (between 40-60% relative humidity) has been shown to inhibit the spread of viral and bacterial infections, allergic reactions, asthma and other respiratory conditions, and reduce the occurrence of mites, mould and fungi.
This ability of hempcrete to passively regulate indoor air quality reduces the need for mechanical ventilation systems, further reducing the energy required to maintain a hempcrete building.
The thermal properties of hempcrete are extraordinary. It provides insulation because of pockets of air trapped within the material; both in the spaces between particles of hemp shiv, and in microscopic pores in the hemp shiv itself. Compared to synthetic insulation materials, hempcrete is a less-effective insulator, For example 240mm thickness of hempcrete meets current UK building regulations for insulation (compared to around 80 mm of polyurethane insulation board). However because hempcrete is cheaper than synthetic insulation materials, and is used to form a monolithic wall, the usual thickness of hempcrete applied in a new building is 300-400mm for a wall.
The typical thermal conductivity of hempcrete is typically 0.06 to 0.07 W/mK. U-values for hempcrete vary depending on the thickness, the type of binder used, the exact specification, application techniques and the skill of the contractor, however a typical u-value (for a 350mm thick hempcrete wall) is 0.17 W/m2K.
Hempcrete also provides thermal mass, as well as insulation, due to density of the lime binder once it has set. This means that hempcrete is able to store heat within the fabric of the material itself (like a giant storage heater). In this respect it is unlike lightweight insulations which only store heat within the air trapped inside the material. The ability of hempcrete to store heat in this way as well as insulating has two important advantages.
Firstly, it allows for natural ventilation of the building. Whereas modern highly insulated buildings rely on airtightness alone to trap the air within the lightweight insulation layer (leading to the use of closed windows – to preserve the heat - with trickle vents and mechanical heat recovery systems to ensure indoor air quality), hempcrete stores heat (from the sun, or from internal heating) in the thermal mass of its walls, to be released slowly as the building cools down. This means that in a hempcrete home you can open the window if it gets a bit stuffy; safe in the knowledge that all your expensive heat is not going to flow straight out and be lost.
Secondly the slow speed at which a typical hempcrete wall stores and releases heat has the effect of “buffering” natural changes in internal and external temperatures, e.g. night and day temperature fluctuations, so that with very little heating or cooling a constant internal temperature is maintained. Hempcrete keeps your home cool in the summer and warm in the winter, with a dramatic reduction in fuel bills.
Hempcrete is unique in this mixture of insulation and thermal mass. It can be thought of (in terms of natural materials) as halfway between straw bale (which has loads of insulation, but very little thermal mass) and cob (which has loads of thermal mass and very little insulation). The combination of the two gives hempcrete an extraordinary thermal performance which works dynamically to maintain comfortable indoor temperatures with very little need for mechanical heating, cooling or ventilation. During in-situ testing, hempcrete consistently out-performs expectations based on laboratory tests and computer modelling.
Building with hempcrete should cost no more than building with conventional materials, however it will not be significantly cheaper either.
As with any material, costs vary depending on the complexity of the design, the exact specification, and a number of other factors. Broadly speaking though, the cost of building with hempcrete should be around the same as building with a conventional “brick and block cavity” construction including a high-spec insulation in the cavity.
Remember that this comparison is looking only at the construction costs. The extra thermal performance which hempcrete provides brings significant extra savings over the lifetime of the building, as well as improved health of the buildings occupants.
Please contact us for accurate example costs for the type of build you are considering.
There are a few certified Hempcrete builders, plasterers and contractors in Australia. We are happy to refer the various Hempcrete builders, plasterers and contractors within the vicinity of your project. Please contact us to discuss your individual requirements. http://www.ozhemp.com.au/contacts.html
The above Lets Talk About Hempcrete is provided with of courtesy www.ukhempcrete.com
For more information on detailing hempcrete buildings, see: The Hempcrete Book: Designing and building with hemp-lime by William Stanwix and Alex Sparrow, published by Green Books in September 2014. Available at Angus & Robertson Book Store http://www.angusrobertson.com.au or Amazon.
Q: How thick do the walls have to be to comply with Building Regulations?
A: We recommend 300mm for most domestic applications.
Q: Can Tradical® Hempcrete be used in a loadbearing capacity?
A: It is normally used together with a timber frame (or steel or concrete), with the frame transferring the vertical load of the roof and upper floors. The Hempcrete can be used to provide racking strength to the frame if required.
Q: Can Tradical® Hempcrete be used for other building purposes besides walls?
A: Yes. Contact us for test details.
Q: Does Tradical® Hempcrete need weather protection?
A: Hempcrete walls are normally finished with a lime render or covered with a rain-screen cladding (masonry or timber) of some sort to protect them from the weather.
Q: Is Tradical® Hempcrete fire proof?
A: Yes. Contact us for test details.
Q: If it is used as an external wall does it need a cavity?
A: No. Tradical® Hempcrete provides the insulation and is used as a monolithic (solid) walling material.
Q: How air-tight is Tradical® Hempcrete ?
A: Because Hempcrete is used to build monolithic walls, it is extremely air-tight and air leakage through the walls is negligible. The actual figure is approx. 0.75 g/m2/mmHg. Typical air leakage 1-3 air changes/hour @ 50 pascals
Q: Can Hempcrete be used as ceiling insulation?
A:Tradical® Hempcrete can be used for providing roof insulation within the thickness of the roof construction. The ultra low density, lightweight material is ideal for saving energy and contributing to a high level of hydro / thermal comfort.
Tradical® Hempcrete combines the low density (as low as 220 kg/m3) with excellent insulating properties, an exceptional elasticity (due to the composite effect of the hemp hurd and the lime matrix) and important vapour permeability. For these reasons and because of the simplicity of product placement (also possible with dry-spray machinery), Tradical® Hempcrete is a very practical solution for roof insulation in both new build and renovation applications
Q: Does Tradical® Hempcrete have a warranty?
A: Tradical® Hempcrete carries a manufacturers warranty covering the replacement of any defective material. Approved trained and certified Hempcrete contractor or sub-contractor installing Tradical® Hempcrete would warrant the work (subject to the conditions of the contract used).
Q: How much does it cost to build with Tradical® Hempcrete?
A: Cost obviously depends on scale and design, however spray applied Tradical® Hempcrete is comparable with conventional construction costs.
Q: Can Tradical® Hempcrete be used in the renovation of old buildings?
A: Yes, Tradical® Hempcrete can be used to form infill panels for historic timber framed buildings.
Q: How high can a building of Tradical® Hempcrete be designed?
A: The Hempcrete is not load-bearing, so the limitation is only on the structural frame and in the engineering work.
Q: How much CO2 is locked up in Tradical® Hempcrete?
A: Spray applied Hempcrete locks up around 110kg of CO2 per cubic metre. Shuttered and cast Hempcrete locks up around 110kg to 165kg of CO2 per cubic metre, depending on the level of compaction during construction.
Q: Does Tradical® Hempcrete breathe?
A: Yes. The word breathability is often used to describe Hempcrete buildings. There are various ways in which materials deal with moisture (water vapour permeability, capillarity and hygroscopicity). Tradical® Hempcrete performs well in all these areas in order to provide a healthy internal environment.
Q: Is Tradical® Hempcrete resistant to pests?
A: The Tradical® PF binder protects against rodent and insect infestation.
Q: How long will Tradical® Hempcrete last?
A: The use of plant based materials mixed with mineral binders such as lime or clay go back thousands of years. We know that the effects of the binder (high ph and good capillarity/vapor permeability) create a perfect environment in which to preserve the hemp shiv. Consequently we have confidence in anticipating a life-span of Hempcrete buildings measured in centuries.
Q: How do I know whether it is better to cast or spray the Hempcrete in my walls?
A: In general casting is used for smaller projects (less than 50-70 cubic meters) or where labor is provided by volunteers or selfbuilders. Casting becomes more economic for larger projects (in excess of 70 cubic meters).
Q: Can Tradical® Hempcrete be installed in the winter?
A: Yes, providing the temperature is not below 5°C and the material is protected from frost and heavy rain.
Q: How do I find a contractor to use Hempcrete?
A: Your Tradical® Hempcrete supplier will be able to give you a list of trained and certified Hempcrete contractors.
Q: How high can one build in a day with Tradical® Hempcrete?
A: There is no real limit other than practical arrangements on the site.
Q: Where can I buy Tradical® Hempcrete?
A: Tradical® Hempcrete can be purchased directly from Ozhemp the authorized distributor for Tradical® products Australia and New Zealand, contact us at Info@ozhemp.com.au
For technical details and sources, check out Tradical® http://www.tradical.com
For Hempcrete advice and consultancy: https://www.thehempbuildingcompany.com.au