Fibre-cement tiles

Building

Fibre-cement tiles and bricks are a relatively recent development. They use less cement than conventional tiles and bricks and make use of locally available fibres, reducing costs, and making light, strong building materials. A wide variety of fibre-cement building materials can be made – tiles, blocks, gutters and curved blocks for water tanks. A special machine called a vibrator and the appropriate moulds need to be purchased. For simplicity, we will just consider the tiles in this article.

Fibre-cement tiles will build long-lasting, strong roofs which can collect rainwater. They are usually cheaper and look better than metal sheets. However, a lot of careful planning and costing is essential before a group considers purchasing the vibrator and other necessary equipment. This requires a large capital outlay, and profits will only be made gradually. A regular supply of cement is essential. The cost of alternative roofing – corrugated metal sheets – will usually be the deciding point. If these are relatively cheap it will be very difficult to make a good profit. Technical skill is needed too to obtain good results. At first there may be a high rate of damaged tiles and breakages.

Two sizes of roofing tile are available. For new groups the smaller is recommended, as inaccuracies with this size are not too important. One badly formed large tile can throw the whole roof out of line.

The quality of the sand is very important. People assume that the locally available sand will be fine. However, if the sand particles are too fine or too coarse, the tiles will fall apart. Before investing in the machinery, check carefully the quality of sand available.

Sisal and jute fibres have proved very successful in tile manufacture. However, the processsing of the fibres is quite time-consuming. They have to be separated and chopped into small pieces. Other fibres (eg: banana fibre) may also prove successful.

The fibre-cement is mixed carefully from the recommended proportions of chopped fibre, sand, cement and water. The mixture is then placed onto the vibrator where the outline shape of the tile is formed in a mould.

Another important point is to consider the transfer sheet. This is the piece of plastic-like material which is used to transfer the newly made tile onto the form for drying. This needs replacing surprisingly quickly – often after only about 25 tiles. The replacement of these must be costed. Heavy duty plastic can be used as a substitute after being cut to size.

The newly formed tiles are left in the moulds to harden, usually overnight, to prevent them from drying out. The tiles can then be removed and the moulds re-used. To avoid breakages, it is important to follow carefully the instructions for curing the hardened tiles. They must be soaked in water for at least seven days.

Prices begin at about £1,400 for the basic machine and all necessary equipment, which can be obtained from…

J P M Parry Overend Road Cradley Heath West Midlands B64 7DD UK.

They are happy to answer serious enquiries and technical queries.