Whist visiting the Culburra Beach Hemp House I found this cool hempcrete demonstration wall in the garage. Check it out!
The wall was made by Kirstie Wulf and feature 2 different external renders.
Inside the Culburra Beach Hemp House: A Demo Wall Walkthrough
By Jeremy Thomas
On a visit to the Culburra Beach hemp house, designed by Kirstie Wulf of Shelter Building Design, I had the chance to explore one of my favourite teaching tools, a demo hempcrete wall.
This small wall section is a perfect way to see all the layers and materials that come together in hempcrete construction. Let’s break it down step by step.
The Foundations and Frame
Like any house, everything starts with the foundations. In Australia, that usually means a concrete slab or footings. From there, the timber frame is built.
- Studwork: Upright frames made of 90mm radiata pine, sustainably grown and widely available.
- Bottom plate & studs: The base plate sits on the foundation, with vertical studs rising from it.
- Formwork attachment: Using simple bugle bolts, temporary formwork is fixed to the studs, ready to be filled with hempcrete.
This formwork looks much like what’s used for concrete, but instead of cement, it’s filled with hempcrete while still wet.
Filling with Hempcrete
Once mixed, the hempcrete is packed into the formwork, layer by layer. It’s tamped lightly, just enough to bind together without losing its insulating air pockets.
The result is a solid, breathable wall that locks in carbon, regulates temperature, and manages moisture naturally.
Renders and Finishes
This demo wall beautifully shows the range of finishes possible:
- Exterior lime plaster: A Japanese-style lime plaster blended with fine hemp fibre. Smooth, crisp, and soft to the touch. With oxides, it could be coloured, or it can be painted with breathable paints.
- Rockcote clay render: On another side, a more textured finish that’s also fully breathable.
- Internal off-form hempcrete: Exposed hempcrete can be left raw for a natural look, sealed with breathable finishes, or rendered for a clean, modern feel.
Permanent Formwork Around Windows
For areas like windows, a magnesium oxide board is used as permanent formwork. This adds strength while keeping the wall breathable and fire-safe.
Why This Matters
This little demo wall at Culburra shows the whole hempcrete process in one neat package, from timber framing and formwork to hempcrete infill and breathable renders.
It’s a fantastic teaching tool for anyone curious about how hempcrete walls come together and why they perform so well.
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Disclaimer
HBD do not warrant the quality or experience of anyone listed on this directory.
We have relied on the information provided by the business and its representatives.
This site is not intended to provide and does not constitute building advice, or other professional advice.
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