The Constitutional Court’s recent ruling on the private, recreational use of cannabis has renewed interest in the use of the Cannabis sativa plant in the construction industry.
Using hemp to build homes is a “step in the right direction”, says Mike Greeff, chief executive of Greeff Christie’s International Real Estate.
“Hemp is a natural product that is easily grown, is environmentally friendly and is exceedingly versatile in its applications. From oils to clothing, hemp has the potential to be a game-changer in the local manufacturing industry.”
In the construction industry, hemp is used to make "hempcrete", a hemp-lime composite building material, and to provide fibres for quilt insulation. It consists of hemp, lime and water and is an environmentally-friendly alternative to concrete. Not only is hempcrete waterproof, fireproof and 100% recyclable, Greeff says it can be repurposed as a fertiliser once demolished.
“Hemp is a revolutionary product and with its versatility, cost-effectiveness and low environmental impact, it has the potential to change the way we look at home construction. Hemp may become the material of choice for the discerning home builder or developer.”
Advantages of using hemp to build homes include:
Hemp regulates air flow:
Hemp insulation, which can be used in industrial and commercial situations, performs better than most modern insulators and has an exceptional lifespan. It allows greater breathability for humidity and moisture to escape. It is also more resistant to mould, mildew and rot.
It insulates:
Hemp has excellent thermo-regulation abilities through small air pockets that are naturally formed between the fibres. This would result in sustained savings on heating and cooling costs.
Hempcrete is cost-effective:
It drastically reduces cost and offers better tensile strength and durability. Hemp, unlike concrete, isn’t brittle and does not require movement joints incorporated into the building process.
Hempcrete is allergy friendly:
Hemp construction materials are appropriate for people suffering from allergies and contains antibacterial properties. New homes constructed using hemp as the base construction material will not have that "new house" smell that often affects individuals prone to allergies and respiratory ailments.
Hempcrete can be used for interiors:
The use of hemp products negates the use of glues, formaldehyde and sealants that hold together, preserve and finish most modern homes. In the event of a fire hemp does not burn in flames but merely smoulders. This ensures the fire-retardant properties of the construction material.