natural materials
In the current climate emergency it is up to architects to start specifying materials that are sustainable and offer additional solutions for clients regardless of budget.
Our Hemp House is a rear addition that is simple in form which borrowed from the pitched roofs of the existing home. The extension was built in timber and hempcrete - a bio-base material that absorbs and stores significant quantities of CO2 through its production. It is ‘breathable” and chemical free making it a great fit for the family.
We exposed hempcrete internally and set it against exposed timber in areas requiring a more robust finish. It’s lit by generous roof lights and fixed to an exposed timber structure. In order to reduce the programme and drying time we proposed using hemp both in-situ and as block construction. We worked with UK Hempcrete as well as with the structural engineer who had previous experience using the material. We used large scale samples to test the material, construction and finishes.
At our Supper Time project we used a natural clay plaster externally and internally by Clayworks to create a warm, inviting atmosphere, while large openings and skylights introduce abundant natural light, enhancing the sense of connection to the outdoors.
Natural clay plasters are more sustainable than gypsum plaster and paint, are non-toxic, with low VOC emissions and no synthetic, concrete or lime additives. The plaster is made from readily available, naturally abundant materials and require no processing. Clay plasters are the most sustainable wall finishes available and are recyclable, repairable and compostable. They allow buildings to breathe, attenuate acoustics and help regulate humidity and temperature.
Our Cork House project used cork to clad a new addition both externally and internally. Cork is a sustainable material, naturally water resistant, recyclable and will weather to a silver-grey colour over time. It has inherent insulating properties which meant we did not require any additional insulation on the external walls. It performs thermally as well if not better than expanded foam or any other crude oil derived insulations. It provides a high quality living environment during its use life time and perhaps as importantly can be reasonably simply composted down. Cork is breathable, free from chemicals, synthetic resins and carcinogenic materials and creates a healthy environment inside the house.
When using natural materials it is important to make sure these can also satisfy regulatory and practical requirements. It’s important to have a good team who can steer you through these challenges including a good Building Control Officer and other consultants, such as a structural engineer, to ensure the materials are fit for purpose. Getting this buy-in and assembling the team early is key.
We are seeing acceptance of unconventional building materials from our residential clients, Local Authorities and developers. More of our clients are becoming aware of low-carbon materials and innovative construction materials that are ‘better-than-zero-carbon’ whilst also reducing the heat losses of the building.
Natural materials, recycling and retro-fit needs to become more common and a viable option to clients. It should also be discussed from the outset of the project and become part of the briefing process. This process should bring clients and stakeholders inside the design process - empowering them to understand the challenges and issues that need to be resolved. This can help set a tone of collaboration and co-creation for the rest of the project and allow all to make unusual decisions, such as natural materials, retro-fit and recylcing, a more reasonable approach. Clients need to change their perception of the existing building / house and to recognise the energy already spent, and that which should be retained and maintained to prevent more carbon emissions and damage to our fragile climate.