Hemp Green Building
Construction & Building
Hemp is a fantastic building material from an ecological, constructional, and financial perspective.
Carbon Footprint. Does Hemp absorb carbon?
Hemp is the most efficient annual plant for carbon sequestering. Regardless of the end use of biomass it´s roots binds few tons of carbon in the soil. It´s an ideal carbon sink.
One hectare of industrial hemp can absorb 22 tonnes of CO2 per hectare. It is possible to grow to 2 crops per year so absorption is doubled. Hemp’s rapid growth (grows to 4 metres in 100 days) makes it one of the fastest CO2-to-biomass conversion tools available, more efficient than agro-forestry.
Does 1 acre of hemp produce more oxygen than 25 acres of trees?
Only 1 acre of hemp is said to produce more oxygen than 25 acres of current forest. Wood pellets are very common, however hemp pellets for stoves and boilers are a much better solution.
Is Growing hemp environmentally friendly?
Industrial hemp is a very robust, competitive plant that will out-compete weeds. Bio-products made of hemp can produce environmentally friendly products that are easily recycled in compost or in landfills. Most hemp-derived products are non-toxic, biodegradable and renewable.
- Non-structural thermal insulation
- No off-gassing, non-toxic, low VOC, free of allergens
- Made from natural renewable raw materials
- Replaces layers of petroleum-based products
- Sequesters CO2
- Self-regulates temperature and humidity
- Durable, Breathable material
- Pest resistant & Mold Resistant
- Excellent acoustic performance
- Factory prefabricated with little waste
- Lightweight, Easy Installation. Self-Build friendly
How long will Hempcrete last
With these bricks, the need for a wooden frame is practically zero, and since they eventually turn to petrified rock they will last for hundreds of years.
HempCrete Recipe Mix
Wall-insulation hempcrete at a ratio of 1 part chopped hemp hurd by weight, with 1.5 parts of the binder by weight. After translating these weights to volume measurements, it approximates 4 buckets of hemp hurd going into the mixer with 1 bucket of binder (1/2 lime, 1/2 metakaolin).
Kevin McCloud on hempcrete
Hempcrete House Wanaka New Zealand
Hemp Key To Zero-carbon Houses
Hemp, a plant from the cannabis family, could be used to build carbon-neutral homes of the future to help combat climate change and boost the rural economy, say researchers at the University of Bath.
A consortium, led by the BRE Centre for Innovative Construction Materials based at the University, has embarked on a unique housing project to develop the use of hemp-lime construction materials in the UK.
Hemp-lime is a lightweight composite building material made of fibres from the fast growing plant, bound together using a lime-based adhesive. The hemp plant stores carbon during its growth and this, combined with the low carbon footprint of lime and its very efficient insulating properties, gives the material a ‘better than zero carbon’ footprint.
Professor Pete Walker, Director of the BRE Centre for Innovative Construction Materials, explained: “We will be looking at the feasibility of using hemp-lime in place of traditional materials, so that they can be used widely in the building industry.
“We will be measuring the properties of lime-hemp materials, such as their strength and durability, as well as the energy efficiency of buildings made of these materials.
“Using renewable crops to make building materials makes real sense – it only takes an area the size of a rugby pitch four months to grow enough hemp to build a typical three bedroom house.
“Growing crops such as hemp can also provide economic and social benefits to rural economies through new agricultural markets for farmers and associated industries.”
The three year project, worth almost £750,000, will collect vital scientific and engineering data about this new material so that it can be more widely used in the UK for building homes.
The project brings together a team of nine partners, comprising BRE Ltd, Feilden Clegg Bradley Studio architects, Hanson Cement, Hemcore, Lhoist UK, Lime Technology, National Non-Food Crops Centre, University of Bath and Wates Living Space. As part of the project the University of Bath received a research grant of £391,000 from the Renewable Materials LINK programme run by the Department for Environment, Food & Rural Affairs (DEFRA).
The Balehaus on campus.
Low carbon hemp house put to the test
Used to make paper, clothing and car body panels, hemp could also be used to build environmentally-friendly homes of the future say researchers at the University of Bath.
A consortium, led by the BRE Centre for Innovative Construction Materials based at the University, has constructed a small building on the Claverton campus out of hemp-lime to test its properties as a building material.
Called the “HemPod”, this one-storey building has highly insulating walls made from the chopped woody core, or shiv, of the industrial hemp plant mixed with a specially developed lime-based binder.
The hemp shiv traps air in the walls, and the hemp itself is porous, making the walls incredibly well insulated. The lime-based binder sticks together and protects the hemp and makes the building material highly fire resistant.
The industrial hemp plant takes in carbon dioxide as it grows, and the lime render absorbs even more of the climate change gas, effectively giving the building an extremely low carbon footprint.
Dr Mike Lawrence, Research Officer from the University’s Department of Architecture & Civil Engineering, explained: “Whilst there are already some houses in the UK built using hemp and lime, the HemPod will be the first hemp-lime building to be constructed purely for scientific testing.
“We will be closely monitoring the house for 18 months using temperature and humidity sensors buried in the walls, measuring how quickly heat and water vapour travels through them.
“The walls are breathable and act as a sort of passive air-conditioning system, meaning that the internal humidity is kept constant and the quality of the air within the house is very good. The walls also have a ‘virtual thermal mass’ because of the remarkable pore structure of hemp shiv combined with the properties of the lime binder, which means the building is much more thermally efficient and the temperature inside the house stays fairly constant.”
Professor Pete Walker, Director of the BRE Centre for Innovative Construction Materials, added: “The aim of the project is to provide some robust data to persuade the mainstream building industry to use this building material more widely.
Environmentally-friendly building materials are often more expensive than traditional materials, but the Renewable House project funded by the Department of Energy and Climate Change (DECC) and the National Non-Food Crops Centre (NNFCC) demonstrated a cost of around £75,000 (excluding foundations) to build a three-bedroom Code 4 house from hemp-lime making it competitive with conventional bricks and mortar.
The project is sponsored by the Department for Environment, Food & Rural Affairs (Defra) under the Renewable Materials LINK Programme, and brings together a team of nine partners comprising: University of Bath, BRE Ltd, Feilden Clegg Bradley Studios, Hanson UK, Hemp Technology, Lhoist Group, Lime Technology, the NNFCC and Wates Living Space. The high performance windows were kindly supplied by Janex.