Cement and Concrete Institute

	Adéle de Lange, a professional architect specialising in housing, has been appointed Technical Marketing Consultant: Human Settlements. She will promote concrete as building material for housing on behalf of both C&CI and CMA, offering the best solutions - whether in-situ or precast construction - for human settlements. C&CI has formalised a new marketing focus area: Human Settlements.
The Focus Area will deal with sustainable concrete solutions not only for housing, but across the entire infrastructure associated with housing e.g. roads, drainage, lighting, fences, hospitals, and retail facilities. Contact Adéle on adele.delange@cnci.org.za Tel: 011 315 0300 Fax: 011 315 0584 or the C&CI Information Centre on info@cnci.org.za

A compilation of basic leaflets, technical papers, and presentations from CMA, C&CI and CSIR are available on CD format.
To order your copy click here.

Aimed at the small builder, DIY enthusiast and home improver, the booklet explains the important factors to consider when making and using concrete, mortar and plaster. It discusses how and why choosing the best materials, using the correct mix proportions, and ensuring good site practice, will improve the strength, durability and economy of the finished concrete. The publication covers concrete materials, storage of materials, estimating and ordering materials, and concrete floors for residential applications.

There is a material that offers it all. It's the most widely used and proven construction material in the world. It's been used for centuries, but is also right up to date. This versatile material is. concrete.

For most people a home is one of the biggest single investments they make in a lifetime. The building material chosen will have a major impact on the performance of a house - on its quietness, comfort and durability. In all these, concrete contributes to the quality of life.

Of the many materials available for house construction, concrete is the only one that is fire-resistant, rot-proof, durable and can be used in a wide variety of applications.

Concrete in housing is found from top to bottom - from foundations, floors, structural frames and walls to roof slabs and cladding. This adaptable material also makes its appearance in partitions, paths, patios, driveways, drains, retaining walls and fences.

Concrete is almost unique in being an inexpensive, readily available building material which is intrinsically fire resistant, needing no additional application of fire protection, and at the same time having structural and aesthetic qualities.

Noise is really unwanted sound. When sound waves strike a barrier such as a wall or a floor, they are reflected, absorbed or transmitted to varying degrees depending on the form of construction of the barrier. To control the level of noise between rooms the most important factor that a barrier must have is good sound insulation characteristics. The heavier the material the better, and thus concrete is an excellent material in this regard.

In recent years, reduction in site size has resulted in houses that are closer together and transfer of noise between houses is therefore greater. This is more easily contained by a concrete or concrete masonry structure compared with dwellings constructed of lighter materials. Quietness is a feature of a house with a concrete floor. The density and mass of the floor makes it vibration-free, and sound is confined to one room. Concrete floors are very good sound insulators, especially when combined with a soft covering such as carpet. Roof covering with concrete tiles also contributes to more peaceful living, particularly when it rains or hails.

Outside the house, concrete also has an important role to play. Increasing traffic volumes and weekend lawnmowers add to the volume of unwanted noise assaulting the outsides of dwellings. The techniques of sound insulation using heavy walls are equally valid in insulating noise from the outside of the house as they are between rooms. Because of the need for windows to provide light and ventilation, it is a little more difficult to achieve this in outside walls. However, to help reduce the amount of sound reaching these openings, one can utilise the 'sound shadow' cast by a concrete or concrete masonry wall on the property boundary. Although such walls will not be a complete noise barrier, it is very effective for noises in the upper frequency range (such as squealing tyres and screeching brakes), which are most grating on the nerves.

For the best sound attenuation, such walls should be as high as regulations allow, free from penetrations and as close to the property boundary as possible. Boundary walls, as well as providing some relief from outdoor noise can be skillfully planned to provide intimate courtyards and garden spaces that add to the privacy, security and attractiveness of a home.

Careful design can ensure that concrete and masonry walls absorb and store the heat of the winter sun by day and allow it to dissipate at night, while in summer these same walls can be shaded by eaves to keep the house cool. In this way concrete and masonry walls assist in maintain interior temperatures at comfortable levels all year round.

The mass of a concrete internal wall is just as important a property for passive solar design in buildings as it is for sound isolation. Combined with good building orientation and sufficient roof insulation, concrete masonry walls with their high thermal storage capacity can even out the effects of outside temperature fluctuations. The result is a comfortable inside temperature level achieved with minimal use of heating or cooling systems, thereby reducing energy costs.

A concrete floor may be used to carry a floor heating system in which heat is provided by embedded electrical cable or hot water piping. The heat can be stored within the mass of the concrete and dissipated to the rooms of the house over many hours

Concrete roof tiles too, have good thermal insulation properties and afford the homeowner a good measure of protection from extremes of temperature. They are also more affordable than most other roofing materials.

Of the main elements of a residential building, walls probably require the most frequent maintenance. This can be minimised by the careful selection and use of one of the many concrete products available for wall construction. The alternatives include concrete masonry, precast concrete and brick veneers.

A wide variety of concrete masonry - manufactured to very strict standards to ensure dimensional accuracy - is readily available in South Africa. Masonry is one of the few materials that, thanks to colour, texture and strength, can meet structural and aesthetic requirements and, at the same

time, give the advantage of low maintenance, safety and a sense of security. An example of this is roof tiles. These are manufactured to SABS specifications and carry the SABS mark of quality. They are exceptionally strong and durable and are virtually maintenance free.

A concrete floor will provide a home with a solid base that will last a lifetime. It will not rot, burn or assist the spread of fire, and is resistant to chemicals, fungi, vermin, and insects. It helps eliminate movement as a result of ground settlement. This reduces the likelihood of jammed doors and windows, the warping of walls, and small cracks that allow draughts to enter a home through the floor. An added advantage of a concrete floor's lack of movement is the extended life it brings to floor coverings.

Concrete's advantages for the homeowner include direct and indirect cost savings. It is an economical material which needs little maintenance. In addition, the variety of products, possible colours and textures available enable it to meet all practical and aesthetic requirements.