Image: Glass House, Castlecrag, designed by Bill and Ruth Lucas. Photo by Richard Dunn. 
Lucas House
photo: David Moore

Site Overview

site name:
Lucas House
other/former name:
Glass House
Bill Lucas, Ruth Lucas
date of completion:
80 The Bulwark Castlecrag 2068 NSW
Residential / Houses (RES)
protection status:
– National Trust of Australia (NSW)
– NSW Heritage Register
– AIA (NSW) Register Significant Architecture
– DOCOMOMO Australia Register
current use:
Residential / House
editor Docomomo Australia fiche:
Noni Boyd in 2003


The Glass House, 80 the Bulwark, Castlecrag, designed by Bill and Ruth Lucas in 1957 is an excellent seminal example of the “shelter-in-nature” minimalist compositions constructed in Northern Sydney post World War II, by the architects of the “Sydney School” largely for their own use.

After their marriage in 1956, the Lucasí designed and built their first home at 80 The Bulwark, Castlecrag. The site is within the subdivision undertaken by Walter Burley Griffin and Marion Mahony Griffin in the early 1920s. Lucas admired Walter Burley Griffinís work at Castlecrag and was involved with attempts in 1961 to reclaim the network of public reserves and Haven amphitheatre established by the Griffins within the Castlecrag subdivision. The Griffins and the Lucasí both sought to integrate the built and natural environment using only natural, locally produced materials, which had minimal impact on the surrounding landscape. Additionally, both partnerships had a skill of designing houses to suit topographically awkward sites. The Lucasí timber-framed house clad completely with glass was intended to meet the Castlecrag design requirements established by Griffin, although not in the way that Walter Burley Griffin had intended.

The Glass House is single-storey residence built over a steeply sloping bush site. One corner of the house barely touches the natural sandstone outcrops, the remainder of the building and the decks are suspended over the gully in which the natural vegetation and rock outcrops were retained.

The rectangular plan is divided up into a grid of 12 squares, four by three. The central two squares being a deck and open well to the sandstone rock below, which now contains trees. When the Lucasí built the house there were no trees in the light well. A deck runs across the front (north) and the rear (south) of the house. Entry is from a path beside the carport. There is no formal hall, visitors enter straight into the first living room. This area was used by the Lucas’ for meetings with clients. A wall separates this area from the kitchen and a larger portion of living/dining room. The fourth cube along the front is a covered outdoor room, separating the living area from the studio. The studio has a small deck cantilevered over the trees below. This deck is now cut around a tree.

The living room and kitchen are entirely glazed, opening onto the front deck and the internal deck and light well. A passage leads from the living room at the entrance, past the laundry/bathroom to the series of bedrooms that run across the southern side of the building. A balcony runs the length of this elevation.

Initially, the central room on this elevation, like the living/dining room on the northern elevation was not partitioned. The salvaged septic tank that was tiled to form a bath survives. The floor is tiled with a slate that has cracked due to the movement of the structure. The house moves considerably in the wind.

The house is designed on a 4-foot module, with each cube forming the plan layout being 12 feet by 12 feet. The timber framework is braced with steel cross-bracing. Four slender steel posts (3 inch squareî) are the main structural elements, forming the corners of the internal court/lightwell. The steel structure extends to roof level and the floors being hung by steel rods from roof height. The decks/balconies are cantilevered.

The original construction is described in an article in Architecture in Australia, October – December, 1958. “The house is suspended on four 3 inch square columns which extend through to the roof. It is of composite construction with steel kept to the minimum for economic reasons being used for tension rods and spacing and joining members. All the timbers are rough-sawn creosoted hardwood inside and out. Wall timbers are restricted to mullions, and posts at 4’ 0” centres and the roof framing to purlins at 4‘ 0” centres on beams at 12 “ centres. The floor consists of 12’ x 4’ Stramit panels, being masonite faced on hardwood joists at 2’ 0” centres. Stramit is also used for the internal walls. To obviate the difficulty of local requirements for masonry all external walls are of glass sheeting. The internal walls are not structural and the arrangement of the bedrooms and living areas can be varied to suit changing family needs. The roofing is deep corrugated asbestos cement, having no roof battens. Safety mesh is stretched over the purlins and supports a 2 oz white fibre-glass blanket between clear Visqueen and double-sided isolation. This provides high thermal insulation, sound absorption and light reflection qualities, and has a pleasant quilted appearance. The laundry-bathroom floor is a lightly reinforced concrete topping over corrugated galvanised iron on joists 2’ 0’ centres, with the same insulation as the ceiling…”

The introduction to the exhibition: Architecture in the Third Millenium noted the ëpureí concept and realisation of the Glass House has similarities with seminal early modern movement buildings: Philippe Chareauís Maison de Verre in Paris and the Mies Van de Roheís Barcelona Pavilion, both c. 1929. The Glass House is minimalist in conception and execution and its modular design and use of industrial materials is reminiscent of the Eames House by Charles Eames in Santa Monica (1949). In a similar manner to the Eames House, and Peter Muller’s house and office at Whale Beach (north of Sydney) (c. 1955), the house is built from inexpensive off-the-shelf materials, often with an industrial character. The ‘modern’ architects working in the 1950s in Sydney were deliberately trying to avoid any stylistic references however their work has now been categorised as being a local variant of the modern movement: The “Sydney School”.

The house was intended to be low budget, however the lack of finishes, painting and decoration was deliberate. Bill Lucas noted in the Introduction to “Architecture into Millenium III” that he selected “materials that can be utilized to satisfy needs with as little effort as possible, self-finished, maintenance-free, that improve with wear, that merge with natural surroundings and that provide an appropriate background for living. I prefer the ‘construction’ to provide the ‘finish’“. None of the building elements were originally painted, not even the steelwork. Creosote was employed on the joinery. Lucas avoided chemical products wherever possible. The steelwork was also unpainted, retaining its factory undercoat. The Lucasí also used second-hand materials in the construction of the house.

The external glazing was composed of louvres or fixed panes of clear or opaque plate glass, each conforming to the 4 foot module. The original and the additional decking is timber and is in poor condition.

Current use

Residential: The building has continued to be occupied as a residence since its construction in 1957.

Docomomo Australia Evaluation

technical evaluation:

The Glass House is of technical significance for its unique engineering solution, designed to have a minimal footprint whilst retaining the sandstone outcrops, eucalypts and ferns below and for the conscious use, by the Lucasí of Australian made building materials.

social evaluation:

The Glass House is of historic and social significance as the residence and office from 1957 until 1962 of prominent Sydney Architects and Urban Conservationists, Bill and Ruth Lucas. It is one of a group of three low cost residences designed by the Lucasí in the Bulwark that retain both the natural landform and vegetation and utilize the restricted palette of building materials, re- interpreting the Griffinís garden suburb concept for Castlecrag.

cultural and aesthetic evaluation:

Initially published in Architecture in Australia in 1958, the Glass House has been visited regularly by architecture students since its construction and included in publications analyzing the development of post-war Australian Architecture. In her study of the Sydney School, An Australian Identity, Houses for Sydney 1953-1963 Jennifer Taylor notes that Lucas was one of a group of modern architects: Sydney Ancher, Peter Muller, Russell Jack. These designers, largely working in isolation during the 1950s, developed the local variant of modernism that is now known as the Sydney School. The general themes that Taylor has traced in the early Sydney School designs are “sympathetic materials, economy, simplicity and an appreciation of the beauty and harmony of nature“. The Glass House clearly exhibits these aspects of the work of the Sydney School designers and can be seen to be a seminal example of their work.

The design of the Glass House exemplifies the local application of Modern Movement concerns with the connection between internal and external space, the use of flexible internal space, moveable partitions and outdoor living areas. It is a carefully handled example of modular design, using standard, but chemical-free, low-cost off-the-shelf industrial products and second-hand building materials. The design and choice of materials indicate Lucas’ original design concept and the design philosophy that Bill Lucas continued to employ throughout his career.

Comparative Significance: canonical status (local, national, international)

The Glass House, 80 the Bulwark, Castlecrag, designed by Bill and Ruth Lucas in 1957 is an excellent seminal example of the ìshelter-in-natureî minimalist compositions constructed in Northern Sydney post World War II, by the architects of the ìSydney Schoolî largely for their own use. The Glass House is of aesthetic significance as a ëSydney Schoolí icon, that has continued to be visited and written about by architects and architectural students since its completion.

Peter Moffit (FRAIA) described the Glasshouse in his obituary of Bill Lucas in the Sydney Morning Herald (1/11/2001) as being “audaciously simple in its concept, it stands on tiptoes amongst the boulders and the ferns on four slender steel posts…The house appears to barely touch the ground, suspended amongst the trees.”

Neville Gruzman describes the Glass House in his obituary of Bill Lucas as “extraordinary in a deceptively simple way: if ever a house touched the ground lightly, it was this one.” He described the Glass House in his exhibition catalogue as being “the best Australian post-war house” and more recently, in his Obituary for Bill Lucas as being the “international seminal house of the Twentieth Century”

historic and reference values:

The design of the Glass House has featured in two architectural exhibitions, the Third Millenium Exhibition in 1993 curated by Neville Gruzman and an exhibition by the Historic Houses Trust: “Fifties Housing, Plus or Minus“.


archives/written records/correspondence etc.:

Current owners retain correspondence with Bill Lucas. Copies of some of which are held by the National Trust of NSW in their Archives.

principal publications:

Glass House published in Architecture in Australia, October – December 1958
Taylor, Jennifer (1972), An Australian Identity: Houses for Sydney 1953- 1963, Department of Architecture, Sydney
Curtis, William (1996), J. Modern Architecture since 1900, London, Phaidon.
Gruzman, Neville (2001), “Bright Thinker Pursued his Utopian Vision”, in The Sydney Morning Herald, 1/11/2001.
Moffitt, Peter (2002), “Bill Lucas Architect, 1924-2001”. In The Crag, Castlecrag Progress Association
Myers, Peter (2002), “Bill Lucas, 1924 – 2001”, in Architecture Australia, November/December 2002. Docomomo Journal Issue 27, Article by the Australian Working Party, June 2002.
McCartney, Karen (2007), 50/60/70: iconic Australian houses: three decades of domestic architecture, Murdoch Books, p. 230,
Margalit, Harry (2019), Australia: modern architectures in history. London. pp. 140–143
Lonergan, Peter (2022), “Bill Lucas: Architect Utopian”, Exhibition Catalogue, Tin Sheds Gallery

visual material

Drawings published in Architecture in Australia in October – December 1858 (reprinted Taylor, Jennifer, An Australian Identity : Houses for Sydney 1953- 1963, 2nd Edition, Department of Architecture, University of Sydney, Sydney, 1984

Photographs commissioned by the Historic Houses Trust of NSW for the DOCOMOMO/Historic Houses Trust of NSW Exhibition, Fifties Houses Plus or Minus? This exhibition examined the fate of some of the houses featured in the original 1961 exhibition held in Sydney and Melbourne.

Current photographs and the National Trust listing card are held by the National Trust of NSW in their archives

Audio Resource:
Sydney Living Museum “Two Point Perspective” Podcast on the Glass House
a tour of Bill Lucas’ renowned 1950s Glass House in Castlecrag with its then resident, Antony Gill