Bench Project Report
by Daniel Birdsall
Since August at Permaculture Sydney Institute, construction of a bench has been underway as part of a Natural Building workshop that was held on the first weekend of October.
The Bench was built from earthbags with a glass bottle decoration and was covered with a lime render.
Figure 1 Simple Diagram of the project site with color-coded legend and measurement calculations.
First, land had to be excavated to accommodate the bench. Much of the land excavated on-site was further utilised in earthbags or to modify the landscape around the project.
Figure 2. A) & B) Clay and rocks being cleared out directly from site.
Earthbags were then filled with clay and sewn together. Once approximately 60 earthbags were arranged, a foundation was built outlining the perimeter of the bench. This was done using bricks and infilled with aggregate to provide structure and prevent moisture seeping upwards from underneath the bench.
L to R: Figure 3. Earthbags filled and drying out in PSI’s geodesic dome. Figure 4 Foundation placed in excavated hole using bricks and aggregate.
As outlined in the diagram below, a plastic fabric and agriculture pipe were placed around the back of the chair to divert underground water around the bench to prevent unwanted moisture build-up.
Figure 6. Diagram by Sam Vivers indicating the water diversion system. A water-proof plastic membrane and agriculture pipe catch underground water and send it around the bench rather than through it.
Next, bags were placed over the foundation providing the structure of the seating space. A decoration was designed in between two earthbags on the back of the chair using recycled blue wine bottles that had been cut in half and taped together.
Figure 7. A) First Layer of Earthbags being tamped down onto the foundation. B) Second Layer of bags placed. Waterproof plastic membrane is visible in A & B. C) Blue recycled wine bottles, cut and taped together, placed between earth bags to create a decoration within the seat.
To provide tension strength, a layer of fibreglass mesh was added to the structure before the final layer of render was applied and sponged over to create a smooth finish.
Figure 8. A) Instructor Sam Vivers teaching the workshop. Render has been applied to the top side of the bench seat and was being mixed in the cement mixer shown. B) The last layer of render being applied. Blue fibreglass mesh is shown in this image.
Figure 9. A) & B) Firepit Bench completed. The remaining ground of the site has been packed down with enviro-sand to provide an appropriate flooring.