Duratec has helped to restore a piece of yesteryear to the city’s busy urban centre, all while complementing its contemporary surrounds.
In early 2021, construction group Built began works on 60 King William Street – a $450 million commercial development. The project is due for completion in the coming months, at which point, the multi-storey structure will be the largest commercial real estate development in the Adelaide CBD, comprising close to 45,000sqm of office space and 3,600sqm of retail space.
The project has involved the demolition of an existing building and the construction of:
- A two-level basement car park
- Ground-level retail and commercial spaces
- 13 levels of office space
- A roof level containing plant space and a terrace
Also part of the works was the restoration of a heritage-listed, Art Deco building facade – the frontage of the former Sands & McDougall building, constructed in 1882. The facade and its awning canopy were listed on the South Australian State Heritage Register in mid-2020. Duratec was engaged to deliver the facade restoration works in mid-2022.
The scope of works consisted of:
- 3D modelling of the horse emblem and pressed cement details
- Restoration of the heritage facade, including rendering, consolidation and painting
- Restoration of the original canopy, including structural steel repairs, new roofing and remediation of the original flashings
- Restoration of the original pressed metal ceiling panels to match the original detail
- Restoration of the original window frames, and installation of new glass and putty
All existing original fabric was to be retained, wherever possible, and works were to be consistent with modern materials and techniques, without compromising the structure’s cultural significance.
The Sands & McDougall building – a brief history
Sands & McDougall was a firm of manufacturing stationers, printers and bookbinders. The original
building on King William Street in the Adelaide CBD was designed in a classical style.
Alterations to the premises were carried out in 1894, 1896 and 1924. In 1933, the building was refaced to a design by Russell Ellis, a pioneer modernist architect, in what is now recognised as Art Deco style. A 1920s-era street-level shop (possibly installed in 1924) was not altered in these renovations.
In the design, Ellis combined his rigorous architectural training with one of the only surviving
architectural drawings of the facade held in the University of South Australia Architecture Museum.
Few new buildings were completed in the 1930s, however, many older buildings were refaced in
contemporary styles as businesses sought to project an image of modernity to customers. The new facade of the Sands & McDougall building was an example of this, eschewing the revivalist decoration of the 1920s in favour of a contemporary aesthetic.
Importantly, unlike many other Art Deco structures, the Sands & McDougall facade has never been painted and displays its original coloured cement finish. Coloured Portland cement render was widely used in South Australian inter-war architecture as a cost-effective alternative to stone or brick.
The Sands & McDougall building is an outstanding example of Art Deco architecture. While many other Art Deco buildings were designed by architects without formal training, Sands & McDougall was designed by a professional from a leading architecture firm. The rigour of architectural training
and practice is reflected in the exemplary execution of massing, proportion, line and detail in the design.
While only three storeys high, the facade conveys the illusion of a much taller building. In South Australia, there are few remaining buildings that so effectively evoke the style of 1920s New York skyscrapers, which influenced architecture globally at that time.
The Sands & McDougall building facade appears to be the earliest known refacing of a recognisable Art Deco style and likely the earliest extant example of Art Deco architecture in South Australia surviving in a near-original condition.
When completed, it was the most strikingly modern building in the city. Flanked on either side by revivalist-style buildings, it made a bold visual statement and likely had a strong impact on the popular architecture of Adelaide over the proceeding years.
Investigations of a heritage facade
Prior to commencing works on the restoration of the heritage facade, it was necessary to conduct investigations into the materials that were contained in the original structure.
Paint scrape study
In order to understand the facade’s original colour scheme, Duratec undertook a paint scrape study of the pressed cement detail and canopy. This involved the evaluation of sample materials, as well as paint trials so that the facade colour scheme would complement its new surrounds.
Following the removal of the structure that was supporting the original facade, Duratec identified drummy render, which was particularly prevalent at the tops of windows.
Heritage architect Swanbury Penglase was engaged to formulate a detailed methodology with the following recommendations regarding the render repairs:
- Removal of biological accretions and cleaning of the facade
- Trial render repairs
- In-situ repairs to the spalling pressed cement details, including removal of corroded reinforcement, reconstruction of decorative details and consolidation of loose pieces
- Painting of the facade using a mineral silicate wash
Steelwork investigation and proposed repairs
Before Duratec was engaged, the canopy had been removed from the building using a quick-cut and oxy-cutter. This meant Duratec had to join the canopy together, review the structural steel integrity, and propose a solution to strengthen and restore the steelwork.
To access the canopy, a scaffold frame was built in Duratec’s yard and the two halves were suspended with block and tackle from an overhead structure. This allowed safe access to the underside of the canopy to undertake investigations.
Constraints and difficulties
In restoring the heritage facade, the project team came across various constraints and difficulties.
1. Heritage-listed horse emblem
The facade’s heritage-listed horse emblem was found to be in such poor condition that it was being held together with chicken wire. As a result, Duratec was not able to undertake the repairs as per the original documentation.
2. Heritage-listed canopy
The heritage-listed canopy, which had been removed by a demolition company prior to the engagement of Duratec, had been cut into two pieces, using an oxy torch and a quick-cut.
3. Other challenges
- The plaster facade required more consolidation than originally documented
- During demolition, the facade had been supported by a steel frame, secured into place via dozens of holes cored through the facade. Duratec was required to repair these holes once the facade had been reinstalled as part of the new building and the steel frame removed
- The existing, original window frames were twisted and damaged, which led to an increase in scope
- Low-pressure cleaning with soft brushes and PH-neutral detergent were required so as not to damage the canopy, however, this made it difficult to achieve a uniform finish
- Mineral silicate paint, tinted to 20 per cent of a pigment, showed up the layer of the substrate underneath
- The painting of architectural features required the expertise of an artist with access to specialist brushes
- The finish of the entry columns was to be changed from tiles to a green marble slab, which needed to be cut to size and installed by a stonemason
The project team combined its considerable knowledge and experience to come up with innovative solutions to constraints and difficulties faced.
1. Heritage-listed horse emblem
To restore the horse emblem, Duratec produced a 3D scan, which allowed the technical team to assess the structure off-site and devise an alternative methodology. Reinforced cement was poured into a latex mould of the horse, effectively reproducing the emblem, which was then installed on site.
The horse was painted in the facade’s original colours, previously determined by the paint scrape study and endorsed by the heritage architect.
2. Heritage-listed canopy
Duratec restored the canopy in its warehouse, where a scaffold was built around the two halves before block and tackle was used to suspend them from ladder beams.
Duratec removed the 100-year-old pressed metal ceiling and restored more than 70 per cent of the panels. Replacement panels were produced using moulds from the early 1900s. The canopy’s significant corrosion saw it cleaned, strengthened (with steel plates and gussets) and primed. The scaffold was then removed and the two pieces were taken to site and bolted together.
A new subframe was installed and the pressed metal ceiling reinstated. A heritage galvanised roof and gutter were put into place, as were restored flashings and coverings.
3. Other challenges
Following an increase in scope, Duratec collaborated with the heritage architect and client to price the additional works and deliver them within a tight timeframe.
With hundreds of workers on site each day and a work area located next to the main entrance of the development, Duratec exercised flexibility with regard to work hours and the provision of access to other trades.
The new floor levels on the inside of the building did not match the existing levels of the heritage facade, proposing a challenge – the windows, of course, could not have floors running halfway through them.
The architect’s solution was to design a dropped-down floor area inside the building, behind the facade, to allow the space to read well from the outside. This involved the installation of reclaimed timber floorboards and skirting to the original floor level. This was then covered over with trafficable glass to allow building users to see a small piece of the structure’s history from the inside.
Access was a challenge on this project as the end of the heritage canopy reached out to the edge of the footpath on one of the busiest roads in the CBD. To accommodate site restrictions, Duratec employees worked early-morning and day shifts, as well as afternoon and night shifts.
Builder – Built
Specialist heritage contractor – Duratec
Base building architect – Cox Architecture
Heritage architect – Swanbury Penglase