Hemp: Houses that breathe so you can too
Why should you construct your next home out of hempcrete? And how can Inwardout Studio help you to do that?
As a building designer, I am always looking for ways to create beautiful, functional and sustainable spaces for our clients. That is why I was intrigued by the idea of using hempcrete for one of our upcoming projects. Read on to learn about my experience using this building material in our design practice, and to find out how it could benefit your build too.
What is hempcrete?
Hempcrete is a natural composite made of hemp hurd (the woody core of the hemp plant), lime binder and water. Hemp has many advantages over conventional materials as it is:
Carbon negative, meaning it absorbs more carbon dioxide than it emits during its life cycle,
Fire resistant, termite resistant and mould resistant,
Breathable, allowing moisture to escape and preventing condensation and dampness,
Durable, flexible and recyclable, and
Possesses excellent thermal and acoustic insulation properties, creating a comfortable and healthy indoor environment.
Hempcrete wall close up, showing the hemp finish.
Hempcrete has been used for thousands of years in various countries. However, the use of hemp is still relatively new in Australia. However, I believe it has great potential to become a mainstream building material in the future, especially as we face the challenges of climate change and resource depletion.
How did I discover hempcrete?
I first learned about hempcrete when I was working on a garden design project for a hempcrete house in Westbury, Tasmania. The owners of the house, Sean and Mandy, are a couple who are passionate about sharing their experience of building their own eco-friendly home.
I was inspired by Sean and Mandy's story and decided to learn more about hempcrete. I helped Sean on a working bee one afternoon, mixing and temping the hemp for the house walls, which proved to be an invaluable learning experience.
At Sean and Mandy's house during the hempcrete wall working bee .
This home's beauty and simplicity continues to inspire me. The hempcrete walls have a natural texture and colour that blends in so well with the surrounding landscape. The house is warm in winter and cool in summer.
If you would like to know more about Sean and Mandy's house-building journey, read their blog. Or visit the house yourself! This couple organise regular eco-tours of their house and garden (the latter which we designed!).
The Campbell Town Hemp House
That is why I am excited when I was offered the opportunity to design a hempcrete house for one of my clients in Tasmania. The project is a new build on a rural property. The clients want to create a modern and energy-efficient home that will blend in with the natural surroundings and reflect their commitment to environmental sustainability.
3D renders of our design showing the eastern facade (left), and the northern facade with the sun room (right).
This design includes the following features:
Combination of timber framing and hempcrete infill for the walls to provide beautiful finishes
Single-storey layout with fully accessible visitor accommodation
Charging spot for electric vehicles
Central living area with an indoor garden to bring nature inside
Masonry heater place in the centre of the house for a consistent heat during winter
Sunroom along the north facade to provide solar gain in winter, with louvres to let the air flow into the house during summer
North-facing orientation to maximize solar access and natural light
Sloped roof with skylights to enhance ventilation and daylighting
Timber floor finish on timber batten for more flexibility (and they feel much better on your knees!)
Concrete slab to provide thermal mass, laid over pods made of recycled plastic (much better than the polystyrene ones)
Rainwater tank for water supply to the house and veggie garden
NB. The existing shed on this property was recently updated to include solar panels to provide for this household's electricity needs.
3D renders of the centre space showing the masonry heater and the indoor garden.
Wall Composition: In this project, the wall composition is 90mm of hempcrete on one side, a 90mm timber stud in the middle, and another 90mm of hempcrete on the other side. There is a 10 mm lime render in the outside and inside. It is very important to use a breathable finish for the hemp wall. This design provides both insulation and structural support. The R value of this wall is R3.0.
Challenges and rewards of designing a hempcrete house?
Designing a hempcrete house is a rewarding experience for me. I am learning a lot about this innovative material and how to use it effectively. I also enjoy collaborating with the clients, the builder, the Hemp Masonry Company, and other professionals involved in this project. We are lucky here in Tasmania to have a company which grows and processes the hemp for construction, X-Hemp is one of only a small handful of cannabis fibre processing mills operating in Australia, and they claim to be the only 100% female-owned and run hemp facility in the world.
Designing a hempcrete house also had some challenges. One of them was finding suitable contractors who were familiar with hempcrete construction. Hempcrete is still a relatively new material in Australia, so not many builders have experience working with it. Fortunately, I work closely with an experienced builder in hemp building for this project. Another challenge is dealing with the regulations and approvals for building with hempcrete. Hempcrete is not yet recognised as a standard building material in Australia, so it requires special performance solutions. This can cause delays and extra costs for any project. At this stage, I am still in the process of gaining building approval to ensure compliance with the relevant codes and standards. I will keep you informed of further developments in this space.
Future plans for designing with hempcrete?
Designing a hempcrete house is an exciting journey for me. I am proud of the outcome and happy with the feedback from the client. I think hempcrete is an amazing material that has great potential for creating sustainable and beautiful homes.
I am really looking forward to designing more hempcrete projects in the future. I want to explore different ways of using hempcrete for different types of buildings and contexts. I also want to share my knowledge and experience with other designers and builders who are interested in hempcrete.
Thank you for reading and I hope you enjoyed this blog post. Stay tuned for more!
Want more information about hemp?