Crank System for Hempcrete Formwork by Belubula
Certainly one of Australia’s most experienced hempcrete builders, James Isaacs has developed a unique crank-based formwork system that materially improves how hempcrete walls are built on site.
Drawing on years of hands-on building experience, and an uniquely a background in sailing and rigging, the system allows large sections of formwork to be lifted smoothly in minutes using a series of mechanical jacks. The entire system can be operated by a small team.
After early builds where traditional formwork became heavy, awkward, and increasingly unsafe at height, the need for a better solution became obvious. The result is an interlocking slipform system that raises the formboards incrementally as each lift is completed, rather than requiring constant dismantling and rebuilding.
With the right planning, the formwork can be raised in minutes, significantly reducing downtime on site. On well-run builds, this enables 20-30 bags of hemp or 10-15 double hempcrete mixes per day. A meaningful improvement in productivity, particularly on volunteer or small-crew projects.
Why the Crank System Matters
On site, the benefits are immediately visible:
- Minimal visible joins
The continuous lifting process produces walls with a noticeably smoother, more consistent finish. - Faster and safer installation
Reduced manual lifting at height lowers fatigue and improves site safety. - Superior finish quality
Particularly evident on external walls, where the formwork is winched upward as the wall is filled. - Extended formwork lifespan
The system is designed for repeated use, reducing waste and long-term costs. - More efficient use of labour
Less downtime, fewer hands required, and smoother sequencing of mixes.
Internally, the system complements high-quality carpentry work, while externally it enables long, continuous runs of formwork to be raised progressively as the wall is packed, improving both speed and finish.
This system is a practical example of how incremental innovation, grounded in real site experience, can materially improve hempcrete construction outcomes.
Check out our Specs & Details page for more info about building with hemp.