Concrete is well known to many New Zealanders as a building material. Being a country of ‘doers’ has meant that not only are we familiar with concrete but also many have had personal experience with it. Footpaths, garden walls, garages and sculptures stand as testament to this hands-on experience.
In the construction industry, concrete is the most widely used material both here and overseas. Commercial structures from single to multi-storey continue to be built in concrete. Most residential construction is based on the concrete ground floor slab and our infrastructure, from underground pipes to bridges, is largely constructed of the material.
The building industry in New Zealand is well resourced to construct in concrete. Raw materials are readily available throughout the country. The techniques for constructing formwork, placing concrete, erecting precast elements and building in masonry are to a very high standard internationally. The design of concrete structures by local engineers lead the world in many areas. The existence of several quality suppliers of precast structural systems and other proprietary elements in the marketplace allow designers and builders competitive pricing, extensive system choice and excellent technical support.
For all that, New Zealanders continue to favour timber framing for the construction of their houses. It is not unusual to see a design modelled on the massive homes of the Mediterranean, built using spaced timber studs with a thin cladding of stucco or acrylic plaster on rigid board. Many designers and homeowners in this country prefer to continue to use systems and techniques with which they are familiar.
Concrete construction has been widely used for housing throughout Europe and to a lesser extent in the United States. It would be difficult to think of the work by
Le Corbusier, Adolf Loos and more recently Herzog and deMuron without conjuring up images of concrete. Market research has been carried out in an effort to identify why concrete is not used more readily in the residential construction sector in New Zealand. These results indicates that there is inadequate information for those wanting to design and build concrete houses. There is also a lack of builders who are comfortable building concrete walls and suspended floors in the domestic context. The processes involved in building in concrete are different to those employed in timber framing and cladding. Builders comfortable with concrete have tended to become established in commercial construction. While the research pointed to an enthusiasm for concrete homes, designers and builders tend to stay with familiar materials and processes.
This publication seeks to bridge the knowledge gap for designers and builders of concrete homes. It does not however claim to fulfil all their information needs. It has been structured to give an overview of the principles and highlight the critical issues facing designers and builders. The construction industry has been widely consulted and research has been carried out both locally and internationally. The details have been prepared to present a broad range of construction scenarios. The designer or the builder using this manual may find the need to change relationships or sizes shown to suit their own purposes. The intention has been to present a starting point from which specific details can be developed. The details shown here have been checked for suitability for New Zealand conditions. Provided the detailing principles are adhered to, others should perform equally well.