Ceiling Legends: How Australia Molded the Plastering World
How do you accurately identify and age a plaster ceiling? Understanding Australia’s role in the history of plasterwork used throughout the today holds the answer.
Decorations made from plaster in New South Wales (NSW) have their history between 1788 and 1939. The earliest known plaster cornice in Australia is 1816 in The Mint, Macquarie Street, Sydney[1]. In colonial Australia, a lack of limestone was a major disadvantage, not just for decorative plaster, but just to make mortar to hold stone and brick buildings together. With no limestone to mine, sea shells with a similar composition were found and burned. However, there was no substitute for gypsum. In England, lime plaster was used – made from limestone and gypsum – for decorative plasterwork. It was cost prohibitive to import into Australia as other economic challenges restricted imports to essential goods only. That is until 1830s when NSW experienced their first economic boom and luxury goods were imported for the first time. The lack of skilled craftspeople up to around 1840s, together with climate and mode of living, made the use of decorative plaster both inaccessible and inconsistent.
The Mint, Macquarie Street, Sydney NSW, contains the earliest known plaster cornice used in Australia
The 1850s saw an increase in migrants and with it an increase in demand for middle income housing. This encouraged plasterers to look for an alternative material to lime. Rather than sculpting by hand, in 1958 gelatin was used to create molds in which the existing materials could be molded into with an increased efficiency and accuracy. Due to the proliferation of gelatin molds, from the 1860s the variety of decorations increased and so did demand on modelers. Another building boom compelled the plastering industry to look for a material which would allow them to produce faster and cheaper. They looked to England again for the answer and found it in canvas plaster, also known as rag, stick and fibrous plaster. Made from layers of canvas which reinforced the plaster, strengthening it, and used less plaster lowering the cost. The first canvas plaster decorations where used in the YMCA building in Sydney in 1885. The 1880s is regarded as the “golden age” of Australian decorative plasterwork, following which pre-decorated metal ceilings began to rise, rivalling fiberous plaster panels.
In response to the now decrease in demand for their work, modelers once again looked to innovate. They considered replacing canvas plaster, experimenting with various additives, including straw, sugar cane also referred to as bagasse (manufactured under the name Bagasse), and cotton wool.
George Augustine Taylor was a cartoonist, inventor and publisher of several journals including Building: the magazine for the architect, builder, property owner & merchant. Around 1900 he invented and produced his own fibrous plaster for a new company he formed with merchant Alexander Knox. Taylor patented a new improved type of fibrous plaster for ornamental use on ceilings, walls, cornices and even temporary outdoor structures. It was first used to construct the ‘Citizen’s Arch’ in Sydney during Federation celebrations in 1901[2] but soon after installed in many commercial and domestic buildings.
Canvas reinforced plaster that could be produced in molds became popular in Australia from the 1880s as it was cheaper and less likely to crack than normal gypsum based plaster.
In the late 19th and early 20th centuries, several Australian companies experimented with making even lighter and stronger plaster by adding new elements like wood shavings, straw, millet, grass or wool. Taylor’s improved fibrous plaster contained bagasse, a by-product of the sugarcane refining process and he subsequently named his company after this material. It proved to be inexpensive, durable, easily molded and, according to Taylor, it could be cut or punctured without cracking, unlike most other plaster. The first true fibrous plaster was made in 1912 in West Richmond VIC: a layer of plaster reinforced by a layer of teased hemp, and sealed with a second layer of plaster. This was rapidly adopted throughout Australia until 1920s, when it was then copied by America and Britain. Today ‘plaster glass’ is made of plaster, which has been reinforced by either horsehair, copra fiber, hemp, coconut or glass fiber. The plaster glass panel is then secured in place by hessian straps to the ceiling’s timber frame.
Finally, two world wars devastated the plastering industry. Although a large deposit of gypsum was discovered in South Australia (SA), only a small amount of Australian plaster of Paris was ever made due to a lack of an established industry. The War progressed and the market for decorative plasterwork vanished, many modelling firms closed their doors for good.
Plaster glass ceilings remain present in public buildings and domestic homes today, especially prevalent in Western Australia. When speculating a house purchase, a diligent buyer will see that their pre-purchase inspection report makes comment on its status since dirt buildup over time will result in a sagging ceiling and increased risk of failure. As plaster glass ceilings are held in place by hessian straps, over the course of their life, re-strapping may be required. Ensuring regular maintenance of plaster glass ceilings mitigates issues. In 2015 a five-year-old boy was taken to hospital with minor injuries when part of a ceiling caved in at a Western Australian primary school in February 2015.[3] Other failures followed, well publicising the Department’s response, which included their cyclical program to re-inspect ceilings as part of the overall building inspections at public schools on a three yearly basis[4].
Be aware of anyone that can repair your plaster glass ceilings by re-screwing. Plaster glass ceilings should never be re-screwed as this is not how they were installed. The screw will break through the plaster glass ceiling sheeting due to the weight and the construction of the plasterglass board. Screws are only designed for use on gypsum based plasterboard panels, also known as gypsum board or drywall, where plaster is held in place between two sheets of paper. Aussies will be quite familiar with the Gyprock brand: Gyprock – Australian for plasterboard.
It’s clear the history of plasterwork is a great example of innovation being driven by necessity; in this case, by cycles in economic demand within a fledgling colonisation, followed by an urgency to maintain relevance and competitiveness. The use of gelatin molds is a non-obvious creative solution, where naturally one defaults their thinking to the status quo, as in replacing materials like for like, without considering an entirely different approach. Eventually, the conditions led to the method of historic plaster work that can be observed in countries like UK and America today.
CJLM
This is an excerpt from The Building Detective: Uncover building mysteries and solve them like a sleuth, a new book for problem solvers.
[1] Capon, Joanna. “Decorative Plasterwork in New South Wales.” Australasian Historical Archaeology, vol. 11, 1993, pp. 43–50, asha.org.au/pdf/australasian_historical_archaeology/11_04_Capon.pdf. Accessed 30 May 2024
[2] Lech, Michael. “George Taylor’s Improved Fibrous Plaster.” Museums of History NSW, 15 Oct. 2020, mhnsw.au/stories/general/george-taylors-improved-fibrous-plaster/. Accessed 29 May 2024.
[3] “Boy Hurt after Ceiling Collapses on Pre-Primary Class.” ABC News, 25 Feb. 2015, www.abc.net.au/news/2015-02-26/boy-hurt-after-ceiling-collapses-on-pre-primary-class-perth/6261848. Accessed 29 May 2024.
[4] “Education Maintenance Stimulus Package.” Www.wa.gov.au, 30 July 2020, www.wa.gov.au/organisation/department-of-finance/education-maintenance-stimulus-package. Accessed 29 May 2024.
