Hempcrete: Plastic-free walls for Plastic Free July
- Ludovic Vilbert
- 13 minutes ago
- 3 min read
Every July, millions of people take part in Plastic Free July, looking at ways to reduce plastic waste in their homes and daily lives. It is an important reminder that our choices matter, but in the world of building design, plastic can be harder to spot.
When we think of reducing plastic waste, we often start with straws, packaging, or shopping bags. But the built environment, particularly how we construct our homes, is one of the largest and least visible contributors to plastic use.
In most modern houses, plastic membranes, synthetic insulation wraps, and petrochemical sealants are hidden behind every finished surface. They are there to manage moisture and protect insulation, but they’re not without cost. These materials are energy-intensive to produce, hard to recycle, and often compromise indoor air quality.
This Plastic Free July, we are spotlighting a different approach: building with hempcrete, a breathable, carbon-storing, and plastic-free wall system that supports healthy, sustainable homes.
What Is hempcrete?
Hempcrete is a natural building material made from hemp hurd (the woody core of the hemp plant), lime binder, and water. It’s mixed on site and cast in place around a timber frame, where it cures into a light yet solid insulating mass.
Unlike synthetic wall systems, hempcrete is vapour-permeable, meaning it allows moisture to move through it without trapping condensation. It also offers high thermal mass, acoustic insulation, fire resistance, and natural pest resistance, all without the need for plastic vapour barriers.
See our other blogs about hempcrete construction: Hands-on with Hempcrete and Hemp: Houses that breathe so you can too.
Plastic-free construction, by design
In most conventional homes, plastic wraps are used to manage moisture and improve thermal performance. But these materials are not biodegradable, and over time they can degrade, tear, or contribute to poor air quality inside the home.
With hempcrete, we do not need synthetic barriers. The material naturally balances humidity and temperature, creating a stable and comfortable indoor environment.
Photo from a site visit of one of our residential projects in Hillwood, Tasmania built using hempcrete.
On a recent project here in Lutruwita/Tasmania, we used a wall system that eliminates plastic membranes altogether, relying instead on the intelligent moisture buffering of hempcrete walls. The result? A low-tox, low-waste, high-performance envelope that breathes.
Sustainable building starts with materials
At Inwardout Studio, we believe good design is about more than just aesthetics. It is about systems that respect the environment, and the people who live in them.
Hempcrete ticks many of the boxes we care about:
Made from renewable, regenerative resources
Sequesters carbon during growth and curing
Fully compostable or recyclable at end of life
Naturally insulates without the need for petrochemical foams
Reduces construction waste by simplifying the wall system
Every material choice sends ripples far beyond the building site. Choosing natural building materials like hempcrete is notjust about reducing waste, it’s about creating homes that support well-being, biodiversity, and climate resilience.
Let’s build differently
This Plastic Free July, take a closer look at the materials behind your walls. Could hempcrete be part of your next renovation or new build?
We are always happy to chat about low-impact design, healthy materials, and how to make your home more future-friendly.
Got questions about hempcrete? Drop us an email, we would love to hear what you are planning.
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