Home and Building, Volume 37 Number 6 (1975)
Materials: Some Aspects of the Australian Scene
Materials: Some Aspects of the Australian Scene
This strongly product oriented report from Australia provides an interesting comparison for readers this side of the Tasman. The potential market size must inevitably lead to some larger product ranges being available in certain areas. However in general terms the market developments seem fairly similar to New Zealand although a few items will be of particular interest.
The variety, made possible by market size, would undoubtedly be of interest to many New Zealand specifiers.
Australia has just been through a period of intense activity in the building industry. One result has been that a highly developed, sophisticated building supplies industry has evolved.
Australia produces building materials which meet world standards of quality and design, and building industry manufacturers export their products to markets all over the world, whilst meeting local requirements. As well as the actual goods, companies have built up world markets for techniques and know-how developed in Australia.
Significant techniques have been developed in Australia, for example, in the field of high-rise buildings. The construction of buildings from the roof down, which is claimed to cut construction time by at least one third and reduce building costs by about ten per cent, has played an important role in several cities.
No conventional cranes, scaffolding or hoists are used. The building is erected from the top down, the roof being constructed first at ground level and jacked up to its final position off vertical elements. Within the roof structure, form work is set up and the service core and columns are cast. Each subsequent section of the work is jacked into position.
Pre-stressed concrete which allows the construction of larger unsupported areas and also makes possible lighter, shallower and more graceful structures without sacrificing strength, has been used to a high degree by the Australian building industry.
Pre-cast concrete, with its savings on erection time, has been called the most exciting of structural materials, and an unlimited variety of structural frames, beams, columns, floor-units and wall-panels for single and multi-storey buildings are currently in use. Additionally, significant use is being made on some buildings of light-weight concrete.
The useful life of pre-engineered formwork can be ten years or more, and the number of re-uses offers tremendous savings when measured against the costs of site-made, tailored form work. This factor has lead to broad use of pre-engineered form-work.
Prefabricated components have come to hold an important place in many types of construction. One Australian company producing modular panelised house offers nine different basic plans which can be constructed from the 22 standard panels in the system.
Designs are in keeping with modern home thinking and finishes are attractive. The homes can be taken from the completed floor to the lockup stage using only factory components.
The only stage of construction where a skilled tradesman is really required is for the layout of the sub-floor channel. Both the channel and the floor must be square and level, with the required degree of accuracy being comparable with that for a conventional home.
The channel, around the perimeter of the floor, is either bolted through to a joist in the case of a timber floor, or cast with splayed bolts into a concrete slab. With the sub-floor channel installed, the next stage in construction is the installation of bottom plates, following the sub-floor channel for external walls, and located according to the plan for internal walls.
The bottom plate for internal walls is a simple channel with skirting for either side of the panel wall already incorporated. External wall bottom plates have the same ready formed skirting for the indoor side of the wall, and a down-turned flashing to the outside. To prevent the ingress of rainwater, a rib more than 20 mm high and facing upwards is formed to create an impermeable water barrier.
The wall panels are installed next followed by the top plate. Final strengthening of the structure, which is already quite rigid because of the inherent stiffness of panels and corner fixings, is achieved with the tightening of integral top and bottom bolts. Since the sub-floor channel is bolted to the floor, the finished structure is highly resistant to wind pressure.
Final step in the construction process is the installation of the prefabricated roof system, which has been widely used on all types of housing and commercial buildings for many years.
The company provides a complete set of documents covering all aspects of construction, so that all the builder has to do is add a site and drainage plan and the drawings are ready for submission to local authorities.page 52
The house panels have an overall thickness of 50 mm, and comprise two skins of asbestos cement sheet filled with an expanded polyurethane foam. Panels are available with windows fitted already glazed, as well as with plumbing fittings in a variety of configurations. Nearly all are drilled for the inclusion of electrical wiring, and one panel even has a 100mm conduit to take the conglomeration of wires which run from the average home switchboard.
The modular panels have efficient insulating properties, and the foam core is fire resistant and self-extinguishing.
The same company has developed a continuous metal deck roofing to provide maximum protection throughout the life of a building. This decking, widely used throughout the building industry, is supplied for the prefabricated houses. Using" concealed fixing techniques, the decking has proved versatile, flexible and economical for large and small projects and a wide range of roof styles.
A number of Australian companies are producing variants of this type of roof decking, which is available in galvanised steel, prepainted galvanised steel, aluminium and copper to a proven standard of structured strength durability and economy.
For inside buildings, an Australian company has developed a rigid building slab for ceiling and partition applications. The boards available in many pre-fabricated painted and textured surface's, are strong, offer thermal and sound insulation, and a high degree of fire resistance. Two inches thick and four feet wide, the board is available in stock lengths to 16ft., or custom cut. Offering tremendous design flexibility, it requires only a one inch support around its perimeter and is ideally suited to many types of ceiling sysems and partitions.
Australia is a major aluminium producer, and the high strength-to-weight ratio, workability, corrosion resistance, high thermal and electrical conductivity, energy reflective and non-magnetic properties make this a versatile material, which is widely used in the building industry.
A major Australian aluminium fabricating company offers a comprehensive design-and-advice service to licensed manufacturers throughout the world. This company can supply a complete range of high quality aluminium extrusion systems for the manufacturers of windows, curtain walls, doors, insect screens and other building products.
They also provide expert advice on the establishment of factories and supply its licensees with detailed designs for hundreds of different aluminium windows.
Designs for aluminium-framed windows to suit both domestic and commercial architecture include double-hung awning types, casements, inward-opening awnings, sliding windows, fixed panes, and vertical and horizontal pivot reversible types. These can be manufactured in a wide range of sizes to suit local demands. Many of the windows have in fact, been specially designed for tropical and sub-tropical regions.
In the domestic range, the company has designed light-weight, single-glazed windows suitable for bungalow-style houses. For tropical and sub-tropical areas these are superior to windows with heavy, thermal-break frames and double-glazing. For commercial applications, the company's double-glazed windows provide a highly efficient thermal barrier. Venetian blinds can be fitted between the panes of glass to eliminate glare. The commercial style windows are readily developed into curtain-wall sections incorporating mullions and spandrel panels for high-rise buildings.
Other building products made by the company include steel and aluminium louvre frames, in 4 in., 6 in. clip sizes; aluminium balustrading in a wide choice of patterns; and "sun blades" to shield the exterior of buildings.
Aluminium is important in many areas of the building industry — in 1973 the page 54building and architectural market consumed 35 per cent of Australia's total usage of the metal.
Apart from window frames, the major items for which aluminium is used are wall cladding, curtain wall construction, shopfronts, balustrades and hand-railing, doors, roofing guttering and downpipe, accessories (such as Venetian blinds, flywire screens, sun louvres) and insulation materials.
However, aluminium sheet in the form of roof and wall cladding is finding increasing use in the building industry for both industrial and domestic applications. Building renovations are an important market for this product. While in low-cost modular housing and industrial buildings the uses of aluminium appear limitless.
A new finish developed by an Australian aluminium fabricating company is a permanent, anodised bronze, designed to complement contemporary building materials. This is the first economically priced, lightfast colour anodic finish produced for extruded aluminium products, the surface is hard and dense to resist abrasion and corrosion.
A new development in the ever popular louvre window is the louvre surround window, where the outer frame incorporates louvres fixed and fitted as the normal window.
Modern aluminium windows used in high rise buildings have special design features to avoid rain penetration, a problem in areas of high wind velocities and squally rain, or in very high buildings.
This is achieved by a pressure equalisation principle, or the rain screen principle, in which the outer building fabric eliminates those forces which drive rainwater into a building.
The outer skin or surface element of a building is backed up by an inner air space which can be pressurised in such a manner as to equal the outside pressures generated by wind velocity. This outer skin or rain screen is made resistant to water penetration, not by the normal method of sealing joints, but by eliminating the pressure differences between the inner and outer surfaces.
Plastics is another area where great developments have been made in the building industry. An example of the wide variety of products available is seen in the range offered by a leading Australian plastics manufacturingpage 56
organisation, which produces walling, flooring, furniture and awning materials.
Heavyweight vinyl wall coverings are produced to a fire retardant formulation. They are hard wearing, and are extensively used in hotels, offices, hospitals and schools. They are produced in more than 100 styles and colours to suit any interior design, and in textures ranging from linen to masonry and including many special effects.
Vinyl furniture fabrics are known throughout Australia and overseas for high quality, attractive appearance, durability and easy care characteristics. They include leather-look fabrics, brilliant coloured fabrics, and bright florals for outdoor furniture.
A three layer construction vinyl flooring made in Australia incorporates a durable, scuff resistant crystal vinyl wear layer locking in the print, a flexible expanded foam core, and a fabric backing. A wide range of colours and patterns is available.
Flooring and accessories from the same source have been installed in a number of buildings in Kenya while vinyl panelling foil made by this company was used on the walls of the Nairobi Hilton' Hotel. The laminating foils are a range of semi-rigid vinyls specifically formulated to provide a decorative surfacing material for lamination to porous building and furniture substrates.
Vinyl floor tiles made by another Australian company come in 44 colours and eight different patterns. The colours are protected by a tough, resilient surface of clear vinyl. Quarry tiles also are made in Australia from blended clays to produce attractive colours and surface finishes.
Australian manufacturers produce a great variety of building fittings and hardware. Lightweight, prefabricated louvre doors in fine grained timber which add elegance to any interior, as room dividers, cupboard doors or access doors. These doors can also be used outside. The timber louvres come in bi-fold doors, room dividers, adjustable window louvres, louvre panels for assembly into cupboards, walk-in wardrobes and other indoor fittings, as well as outdoor shutters.
These doors are available in full louvre, half louvre and full panel, on aluminium sliding tracks with nylon bushes.
A varied selection of elegant door furniture is made in Australia. Matching handles and backplates come in ceramic, stone, pottery, crystal and wood, in modern or traditional styles to enhance any interior. A feature of the range made by one leading manufacturer is a patented fixing method which eliminates the need for grub screws and visible fixing screws, resulting in smooth, rattle-free operation. This range is exported to many countries.
Light fittings are gaining increasing importance in finishing the interior of any building. One Australian company makes more than 300 different styles of lighting units for domestic and architectural use.
These include pendants and wall brackets, recessed downlights, complementary semi-recessed and surface-mounting units, and a wide range of shapes which can be mounted on or very close to the ceiling. In addition the company makes many types of outdoor or garden lights.page 62
Producing its own glassware enables the company to meet the special needs of lighting design. Clear sheet glass is cut, screen-rinted and bent to the required shape. A special method of bending glass has been developed so that very crisp square and drum shapes, which can also be decorated, can be made.
The development of colour-corrected mercury fluorescent and halogen lamps has allowed the production of new downlights using these highly efficient light sources. Architects find these fittings most useful; they can be as compact in size as the more familiar incandescent unit; they provide very good levels of illumination; and the rated life of the new types of lamp exceeds that of both incandescent and fluorescent types.
In the field of carpets Australia is well known for its high quality ranges and many manufacturers have supplied the carpets for important overseas build-ings such as office blocks and major new hotels. One Australian company recently supplied the carpets for the Nairohi Hilton Hotel.page 58