Hemp Innovation01 Aug, 2026
Hemp Sauna Questions Answered: Binder, Render and What It Smells Like Inside
Hempco Admin3 Mins. Read
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Hempco Admin
Since sharing the progress of our hemp sauna, we have received plenty of thoughtful questions from our community.
Many people are curious about how the hempcrete walls are finished, what materials are used and whether the hemp creates a noticeable smell inside the sauna. These are all important details, especially when building a warm, enclosed space using natural materials.
Here are the answers to three of the questions we are asked most often.
We use a certified lime binder in our hempcrete mix.
Hempcrete is created by combining hemp hurd with a lime-based binder and water. The binder coats and holds the hemp hurd together, helping form the solid yet breathable wall system.
Choosing the right binder is important. Hempcrete needs a material that works with the natural properties of the hemp rather than sealing it inside a dense, non-breathable mixture.
The lime binder allows the finished hempcrete wall to remain vapour-permeable, meaning moisture can move through the wall rather than becoming trapped inside it.
This ability to manage moisture is one of the reasons hempcrete is such an interesting material for a sauna project.
Yes. The outside of the hempcrete wall is finished with a natural render.
The render protects the hempcrete while still allowing the wall to breathe. This is particularly important because covering hempcrete with an unsuitable, completely sealed finish could interfere with its natural moisture-management properties.
A compatible natural render provides a finished exterior surface without taking away from the qualities that make hempcrete so valuable in the first place.
It gives us the protection and appearance we want while allowing the hempcrete wall system to continue functioning as intended.
No, there is no noticeable hemp smell inside the finished sauna.
The internal face of the hempcrete wall is fully covered with a silver foil layer. A cavity batten is then installed to maintain an air space and support breathability before the interior is finished with cedarwood.
Because the hempcrete is contained behind these internal layers, you do not smell the hemp when using the sauna.
Instead, the sauna has the familiar, natural aroma of cedarwood.
The cedar lining creates the warm, timber-rich smell most people associate with a traditional sauna, while the hempcrete remains behind the finished surface as part of the wall system.
A sauna is a demanding environment. It regularly experiences heat, moisture and changing temperatures, so each layer of the wall needs to be carefully considered.
For our hemp sauna, the system includes:
Each material has its own role.
The hempcrete forms the main wall body, the natural render protects the exterior, the foil helps manage the internal sauna environment, the cavity creates separation and airflow, and the cedar provides the finished interior surface and familiar sauna aroma.
Rather than relying on one material to do everything, the sauna is built as a complete layered system.
Building with hemp is not simply a matter of placing hempcrete into a wall and leaving it exposed.
The surrounding materials need to be compatible, and the entire wall system needs to account for moisture, airflow, temperature and the intended use of the space.
That is why details such as the binder, render, cavity and internal lining matter so much.
Natural building materials can perform beautifully, but they still need thoughtful design and correct installation.
We have loved seeing how interested our community has been in the hemp sauna project.
It is a great example of how hemp can move beyond food, skincare and clothing and become part of the spaces we live in, relax in and enjoy.
As the project continues, we will keep sharing the materials, methods and lessons behind the build.
Because when people can see how hemp is being used in real projects, it becomes much easier to understand just how practical and versatile this plant can be.
