By Gareth Griffiths
Photos by: Robyn Walker, JD van der Walt, Betta Steyn and Gareth Griffiths
The repurposing of the former pumphouse utility building right next to Cape Town’s Liesbeek River, on the premises of the South African Astronomical Observatory (SAAO), was a remarkable heritage architectural achievement on many levels. TO BUILD celebrates this heritage achievement, this being the month of September and National Heritage Day.
This was fundamentally a remarkable repurposing and restoration of a bygone-era utility building on an extremely tight budget. The building dates back to Victorian times in the Cape. On another level, the property owners and the architects of record, SALT Architects, faced a number of building site geotechnical and structural challenges in the process. Significantly, however, this is an outstanding example of how South Africa’s colourful heritage can be recorded and preserved across multiple disciplines.
Typical of TO BUILD’s interrogative style, we unpacked some of the unique features of the project, including its materiality, design, and memorable details.
According to the architects of record, SALT Architects (www.saltarchitects.co.za), the existing building on the site earmarked for renovation was a Victorian pump house, initially used for pumping water from the weir in the Liesbeek River for irrigation purposes. Over the decades, the building underwent various renovations and transformations, serving as a workshop and an educational centre, among other things. The old mechanical workshop and the science educational resources centre had fallen into disuse. There was also the problem of the occasional winter flooding of the Liesbeek Canal.
Project and budgets
The client’s brief requested proposals for transforming the existing Victorian-era pump house into the new Visitors Centre for the SAAO. Challenges included the provision of modern ablution facilities, a reception area, varying exhibition spaces, and a dedicated room for housing an observation instrument known as a heliostat. In addition to modern ablutions within the visitors centre, an old outside toilet block located on a level above the pumphouse was given a substantial renovation, including a new sloping “skillion-style” roof fashioned from aluminium-zinc clip-fix roofing material as well as renovated exposed clay brick.
The brief also required general building maintenance, which, along with the renovation, had to be executed within a limited budget. The budget was “subsequently increased by 2.5 times”, says Principal Architect JD van der Walt, but was still “inadequate to cover the actual scope of work that needed to be done”.
However, Van der Walt and his team took on the challenge: “We saw the required transformation of the Victorian-era pumphouse into a Visitors’ Centre as an opportunity to uncover and showcase the site’s layered meanings”.
Heritage considerations and significance in Heritage Month
The former Royal Observatory Cape of Good Hope was founded on October 20, 1820 and is the oldest scientific institution in the country (source: www.saao.ac.za/). After 1971, a decision was taken to amalgamate the significant facilities for optical astronomical research in SA into one body, which became known as the South African Astronomical Observatory.
The South African Heritage Resources Agency (SAHRA) officially declared the SAAO a National Heritage Site on December 21, 2018. As a consequence of this, the pumphouse structure was categorised as a Grade 3C Heritage Building.
Apart from the adaptive reuse of the heritage building as an architectural challenge, the project also provided opportunities to recognise the diverse and rich cultural landscape that astronomy has engendered in South Africa. This is notably encapsulated in two breathtaking works of art and the preservation of the Victorian-era pump as a prominent piece in the new reception area.
Van der Walt notes that the oldest and more significant portions of the building were approached delicately, yet with enough targeted intervention to ensure the long-term use of the building.
Cultural heritage honoured
At the site walkabout, courtesy of Dr Daniel Cunnama, Project Manager and Science Engagement Astronomer from the SAAO, To Build’s Editor was drawn to an imposing and sculptured high-tech work of art, above which is the second artwork, a brilliantly back-illuminated ceiling piece which represents the night sky as seen by the Kora people, a nomadic group of the Khoikhoi.
These two signal works of art in the visitors’ reception area of the repurposed building are by South African artist Betta Steyn. They are explained by the exhibition board on site, interpreted and written by Dr Kerry Jones of African Tongue. This professional linguistic consultancy commissioned the artwork. Both of these honour the original people of the region, the Khoikhoi.
Jones’s interpretation explains: “One of southern Africa’s first tricksters and creators is known as |Kaggen in the |Xam language. |Xam is an extinct Tuu or !Ui-Taa language of South Africa, and is the same language you find on our coat of arms.”
“The ceiling is adorned by a striking sculptured figure, named |Kaggen, which was commissioned by African Tongue and created by me and my son Siemon,” says Steyn.
In 2021, linguist Jones extracted the Kora constellations to highlight the historical and cultural importance of the Kora data as documented by Lucy Lloyd, a linguist in Mowbray during the 1870 era and her brother-in-law. With the additional notes found in Lloyd’s notebooks, Jones collaborated with astronomer Daniel Cunnama, Science Engagement Astronomer, from the South African Astronomical Observatory (SAAO). Together, they identified which stars were likely to have been described during those summer evenings in 1874 by ǀXam storytellers ǂKāsing and Dīaǃkwã̰in, and Lloyd herself.
Steyn then collaborated with ǂKhomani artists in the Kalahari to gather their input, which was given by way of traditional “beenbrandwerk” or “bone burning work.” Subsequently, Steyn was able to create the artistic representations of the constellations as seen below.
The ceiling was made from perforated aluminium, the pinpricks of light representing the constellations seen during that era. Visitors move through the exhibition space to a dark room that houses a heliostat on a new concrete roof. This observation instrument tracks the sun’s movement and reflects its rays onto an interactive central table. The eastern wing acts as another space to host rotating exhibits.
Building technology
Due to its proximity to the river, managing the water table proved challenging and continues to be so. Heavy rainfall in July 2024 exacerbated matters.
“Our budget was very limited, restricting our efforts. To address drainage issues, we created hard landscaping on the higher north-eastern side of the building, which sloped away into a new concrete channel. Beneath this channel, a sub-soil drain was installed, but this was insufficient during recent rains,” says Van der Walt.
The original walls of that era had no damp courses, creating problems. One example is the Heliostat room (an instrument that tracks the sun) with a new concrete roof.
“We left the Heliostat room untouched. We should have lowered the existing soil below the surface bed level. However, the existing foundation is flush with the surface bed, making it impractical to lower the ground level without expensive underpinning and re-casting of foundations,” he explains, adding that this was a consequence of a tight budget. “Rising damp has been an issue in certain areas, though it is not a significant concern. Alternative methods, such as negative or positive waterproofing, could have compromised the integrity of the old bricks by trapping moisture on either side of the wall. Given that these are old, non-cavity walls, we decided it was better to manage the humidity rather than attempt a complete mitigation.
Hence, we chose a breathable wall solution to address this problem, allowing moisture to pass through the paint barrier. Paint manufacturer, Dulux, was consulted for their expertise on this approach.”
Walls and roofs
“Architecturally, our goal was to create a more expansive entrance area. We aimed to honour the original walls by exposing their cut surfaces, which we smoothed through grinding and sealed with Sikagard®-905 W.
“The new roof structure, featuring spruce beams, and the integrated oriented strand board ceiling, sealed with Rubio Monocoat, allowed us to introduce new architectural elements that complement, yet distinctly contrast with, the existing fabric of the building”, Van der Walt explains.
The old corrugated iron roof required considerable renovation and reimagination. Gables on the east-west axis of the former garage were removed and replaced with a low-pitch concealed fixed steel roof with a flat concrete slab roof replacing the slanted corrugated roof for the Heliostat room. The remaining pitch roof received a makeover of corrugated AZ150 pre-painted steel roofing, formed by Safintra, in matt colour, which closely matches that of the original roof and fits in with the heritage character.
Interior demolition was targeted at non-original portions of the building to enhance the spatial experience, emphasise the original structure and establish a more open plan for programmatic requirements. The former demolished items are hinted at and can be noticed in the building with expressions of the old positions of walls in the floor and wall detailing.
Contemporary interventions to the exterior approach of the building include three new windows for natural light. Two of these are inserted where a garage door used to be. These windows are similar in proportion to the original openings in the building but are expressed in a contemporary manner with deep but thin steel frames that form internal seating in the waiting area.
Professional team
Owner/project manager: SAAO
Architects: SALT Architects
Structural Engineers: AVCON Structural Engineers
Building Contractor: Boshard Construction & Benchmark Builders – JV
Heritage interpretation and concept by: African Tongue/Dr Kerry Jones
Artwork by: Betta and Siemon Steyn