BY ALEC SMART
In primary school, did you ever make a mask by inflating a balloon and coating it in strips of papier mâché?
When the sticky paper dried, you deflated the balloon and you were left with a firm, hollow shell upon which you could cut holes for your eyes and mouth, glue carpet on top for hair, and add additional paper and glue to sculpt the nose and ears. Finally, you popped it over your head to wear for costume parties.
A space-age design adopted by the NSW Dept Education in the 1970s. Photo: Alec Smart
Now imagine adapting the same method for a building. Place a giant inflatable circular bag (known as a Pneumoform) on a concrete slab foundation, cover it with a flexible frame of reinforced steel rods connected by springs, then slowly pour wet concrete over the top.
Then, as the concrete begins to harden, slowly inflate the bag to create a dome.
Once the concrete has set (around an hour or two later), deflate the bag and you’re left with a solid shell. Then the interior is ready for modification: add windows, doorway(s), ceiling supports, carpet for the floor and, if needed, subdividing walls for interior rooms.
Believe it or not, there is a word for this type of pneumatically-formed building: Binishell.
Inventor of Binishells
Binishells were named after their inventor, the innovative and progressive Italian architect Dr Dante Bini, who pioneered automated building techniques out of frustration with traditional slow, labour-intensive and costly concrete formwork.
Dr Bini was inspired after he played a tennis game on a court protected by an inflatable covering that was covered in a dense layer of snow.
In the mid 20th century Binishells often graced the illustrations of science fiction stories and appeared in the TV cartoon series The Jetsons.
Ku-ring-gai High School connection
The students and people associated with Ku-ring-gai Creative Arts High School are familiar with Binishells. One of these incredible, futuristic-looking structures exists in North Turramurra – inside the grounds of the school - in use since 1975 as a gymnasium and theatre.
The Binishell in the grounds of Ku-ring-gai High School, Nth Turramurra. Photo: Alec Smart
Between 1974 - 77, ten Binishells were built in Sydney metropolitan schools, another four in Newcastle and the Lower Hunter region, commissioned by the NSW Department of Public Works for urgently-needed gyms, libraries and assembly halls.
Their installation was supervised by the inventor himself.
Dr Bini arrived in Australia in 1974 and remained for six years to oversee the projects and train local building workers in their construction.
Two designs were utilised – single or twin shells. The initial domes were 18 metres in diameter, expanding later to 36 metres, and the first one appeared in Narrabeen Public School for a library and administration building.
One of the first of the larger 36-metre wide Binishells, in Fairvale High School, Fairfield, collapsed during severe weather conditions in Jan 1975, just three months after it was elevated, but its replacement still stands.
The Binishell at Ku-ring-gai Creative Arts High School was constructed in 1975. This reporter remembers the excitement surrounding its installation and scepticism regarding its strength and longevity.
National Heritage Listing for the Binishell
In an Oct 2019 Facebook post, Ku-ring-gai High School revealed “Our Binishell has been recommended for National Heritage listing!
“Named the Margaret Preston Hall, after Australian painter and printmaker Margaret Preston. Regarded as one of Australia's leading modernists of the early 20th century. The Binishell was lifted and shaped by air pressure in the mid-1970s, one of the first 36-metre Binishells to be constructed in schools around the state.
“Our Binishell has been home to magnificent art shows, marvellous musical concerts, sports events and hundreds of school assemblies. We hope to have many more memorable events to look forward to in this unique space.”
Ku-ring-gai High's Binishell is used as a gymnasium and theatre. Photo: Alec Smart
Futuristic dome's future and past
Over 1500 Binishells were constructed between 1970-1990 in 23 countries around the world, ranging in size from 12 to 40 metres in diameter.
Binishells are still in production under the guidance of Dr Bini’s son, Nicoló Bini, who has reinforced their structural engineering and modified them for international building compliance regulations. His construction company website, Binishells.com, also asserts, “The safety features characteristic of Binishells also make them ideal shelters in the event of natural calamities.”
Several of the original 14 Binishells erected in NSW educational institutions no longer exist.
The Pittwater High School Binishell collapsed in Aug 1986 (although an investigation found the concrete never cured properly). Others have also since been demolished, including Randwick Girls High, Georges River College in Peakhurst (June 2014), Hunter Sports High School in Gateshead (Jan 2016), Richmond High School (Dec 2018), Hunter School of the Performing Arts (Dec 2018), and Killarney Heights Public School (Feb 2019).
The first Binishell, a 12 metres wide, six metres high dome, was constructed in 14 July 1964, in countryside near the village of Crespellano on the outskirts of Bologna, Italy. It stood for 20 years and was used as an office but was eventually demolished because council edicts insisted the area was zoned for multi-storey residential dwellings only.
In 1967, Dr Bini demonstrated to the Americans the remarkable speed in which he constructed his shells by erecting a 15-metre high dome within a few hours in the grounds of Columbia University, New York.
In 1969, Dr Bini constructed a Binishell for the home of Italian film director Michelangelo Antonioni in Gallura on the north-eastern tip of Sardinia island.
Only 7 of the original 14 Binishells built in NSW schools still exist. Photo: Alec Smart
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