Architect Greg Holman: natural stone in design

Natural stone is a striking and inventive feature across many architectural projects by renowned firm Harry Seidler & Associates. Project architect Greg Holman shares why natural stone is a go-to product for built environment design – from the ‘crackling’ green onyx at iconic Grosvenor Place, to the radiating lines of travertine at Riparian Plaza that are an homage to Harry Seidler himself. 

Interview with Greg Holman

When you think of inventive use of natural stone in architectural design, which of your projects come to mind?

At Grosvenor Place in Sydney [originally designed by Harry Seidler in 1982], we were commissioned to design large areas of the ground plane and create an internal lounge. The lobby features an internally illuminated Pakistan green onyx wall – designed not just as a visual feature, but with functional purposes. The stone sits in the back half of the lobby away from street – the idea was to have a striking element there, to draw attention. That side was always darker, and we needed something to generate light without using artificial illumination all day, burning power.

“When you look through the building you can see a crackling, bright green feature, almost like a fire, drawing people through.”

Now when you look through the building you can see a crackling, bright green feature, almost like a fire, drawing people through. The green onyx also acts as a supply air for the air-conditioning system; the wall is hollow and supplies fresh air through stone wall. Joints open by about 2mm to filter air through. It also conceals the audio system and provides an access duct. 

Stone is such a unique material; each piece is an individual. We had a couple of hundred slabs of the green onyx and no two are alike. It was a challenge to place all these ‘stone people’ with their friends, deciding which piece went where, and we had a lot of fun illuminating the stone.

Can you tell us about the distinct radiating lines in natural stone that are incorporated into Seidler projects such as Grosvenor Place, Shell House, Riparian Plaza and the QV1 Office Tower? How did this concept come about?

This is a classic Harry Seidler motif, which originated with Australia Square [completed in 1967]. It became Sydney’s first skyscraper and the world’s tallest lightweight concrete building. Because of the circular nature of the building, one way of breaking up the pavement was to make a feature of the subdivision lines. Harry took the centre of the tower and cast radiating lines around. He then repeated it at another project, the MLC Centre, and the use of this motif is something we’ve carried on in other projects at Seidler.

Mostly, the stripes are travertine. The lightness of the travertine glows brightly, without needing to throw large amounts of light onto the floor. [By up lighting the walls] and letting that light bounce off onto the travertine stripes, you get a perceived lightness much brighter than [with the use of] downlights. The white stripes run out from the building to the streetscape and beyond. It guides the eye right to the centre of it.

Travertine stripes are a recurring motif in projects by Harry Seidler & Associates that incorporate natural stone. Pictured is the exterior of 1 Spring Street (Shell House).

The interior finishes of these projects feature the use of travertine and a ‘black’ granite; why were these materials chosen? 

Using stone as a reflector of light is a pretty universal technique. It originates from the Mies van der Rohe Seagram Building [completed in 1958] – a beautiful, simple tower that influenced so many architects because of the ground-breaking way it expressed the office tower. It showed how modern lighting systems could be used in architecture. Lighting engineer Richard Kelly changed everything … washing the walls to light the building, lighting from concealed sources. It’s an enduring concept that works with any interior. 

Grosvenor Place Lobby. Photo by Wpcpey. WikiCommons. CC BY 4.0.

What has been the reaction from the public and architectural profession to your considered use of natural stone?

What amazes people is that it’s actually stone they’re looking at. Often people don’t realise that at first. There are some incredible pieces of marble that you could cut to size and call abstract art. It’s astounding that there’s such variety. A client once joked about putting a piece on the wall as art, and I said, ‘let’s do it, if you want it!’ Natural stone has an enormous range of visual possibilities, from plain and calm to wild-looking effects.

“There are some incredible pieces of marble that you could cut to size and call abstract art. It’s astounding that there’s such variety.”

What do you value about working with stone?

Stone doesn’t date, it doesn’t change; it ages in such a beautiful way. It’s not like paint that peels off or plastic that melts – stone is a very noble material. Glass is another building material like this. But stone has such character and personality. It can be decorative, structural, and used in so many surprising ways. Often architects don’t realise it’s flexibility and its endless potential, providing you have the imagination.

What needs to be understood when working with natural stone?

There are very important technical aspects that you need to understand. Some types of stone need to be sealed or protected; others stand on their own. As you use stone, you develop an understanding of the dos and don’ts. Jim at Stone Initiatives is a wonderful help with this. [When we use stone in a project] we require a fit for purpose review, to verify that our design and selected stone will do the job that we expect them to do. We supply samples to Stone Initiatives, who does a check for us, so we can dot the Is and cross the Ts.

“It is terrifically comforting to know there are people in the industry who have the knowledge to support the use of stone, to guide you and help when there’s a problem.”

It is terrifically comforting to know there are people in the industry who have the knowledge to support the use stone, to guide you and help when there’s a problem … It is also important to use experienced installers who understand the stone.

Have you faced any particular challenges when working with natural stone? 

There are no more challenges to working with stone than with any other material. It’s just about having knowledge of the material, of its potential and limitations. Whether you’re dealing with glass or bricks or stone, it’s the same. Develop a familiarity with it and understand it. There are a lot of resources out there, so it doesn’t need to be a mystery.

The Seidler office has a focus on aesthetic and physical longevity across all its projects. What part does the use of natural stone play in this?

In the end, visual sustainability is hand-in-hand with material sustainability. Often things look dated because they’ve been constructed using materials that don’t have the historical lineage of something like stone, which has been used for centuries. Many of our buildings rely on the knowledge that Harry Seidler developed and learnt through his experience with Bauhaus teachers and education with Josef Albers, which concentrated on what parts of creating things have enduring visual characteristics and what parts date.

This is very much embedded in the material you choose as well … [When you walk into a building made with stone], it makes you wonder ‘how old or how new is this’ – it could be a new building or one that’s still standing after 3000 years. Harry used to say, ‘Build buildings that last,’ and you can do that with stone. 

Many thanks to Greg Holman of Harry Seidler & Associates for his valuable time speaking with Stone Initiatives.

For more information about testing stone for new construction projects, see here.

Feature image at top: Riparian Plaza entrance. Photo by Kgbo. WikiCommons. CC BY-SA 4.0.