84 Harrington Street

84 Harrington Street in Cape Town, South Africa is a 12-storey building featuring a total of 50 apartments built using hempcrete blocks and hemp construction materials. Hempcrete is a carbon negative material, meaning that it sequesters CO2 from the atmosphere. About 108kg of CO₂ can be locked away as biomass per cubic meter of hempcrete for the lifespan of the building.

Developed by Hemporium and Afrimat Hemp, the project has set new standards for constructing multi-storey buildings using alternative regenerative building materials, inspired by hemp blocks created in Europe. With its suitable climate, South Africa could allow for the large-scale cultivation of industrial hemp, considering that hemp is a versatile material that could be used in textiles, cosmetics and even processed to create an alternative to plastic. Hemp grows quickly and contributes to the purification of contaminated soils, requires little water, no pesticides or herbicides and is inherently pest resistant. Therefore its cultivation can be completely toxin-free. The material also has the capacity to maintain healthy indoor air quality.

The benefits of building with hemp in a multi-story building:

• Hemp is 100% natural, CO₂ absorbing, energy saving, very lightweight and durable. Using hemp blocks reduces the CO₂  footprint of a building as well as its operational CO₂ footprint. It has the potential to be a zero-waste material, as previously used hempcrete can be reused and added to new mixes.
• It has excellent thermal insulation values and good thermal mass well above regulation standards in South Africa, leading to substantial energy savings compared with conventional building technologies. The superior acoustic performance ensures privacy between units. It is simultaneously breathable and inherently airtight. As a vapour-permeable building envelope, it regulates internal relative humidity, eliminating condensation on internal faces.
• Hemp construction can be very simple and low-tech. It has the potential to create a whole new industry particularly relevant in a South African context.