What is hempcrete and how is it used?
Hempcrete is hemp hurd mixed with a lime binder and water. It forms a light, breathable wall infill around a frame.
Hempcrete is a mix of hemp hurd, the woody inner core of the stalk, with a lime-based binder and water. It is packed or sprayed around a timber or other frame and left to cure.
What it does well
- Lets moisture move through walls, which suits older breathable buildings
- Adds insulation and helps rooms hold a steady temperature
- Resists mould and pests well thanks to the lime
- Stores carbon from the plant in the building fabric
What it doesn’t do
Hempcrete is not structural. The frame carries the load. It is also slow to dry, so walls may need weeks or months before plaster goes on, and timing matters in wet seasons.
Before you plan
Talk to your local building authority and a builder or architect with hempcrete experience. Rules, approvals and suppliers differ by region. Nothing here replaces professional building advice.
See how hurd fits with other hemp uses on the hemp materials page.