page 1 page 2
page 3
page 4
page 5
page 6
< prev - next > Construction Roofing and flooring KnO 100060_Micro concrete roofing tiles (Printable PDF)
Much attention has been paid to developing the small-scale production of concrete roofing
tiles as an affordable alternative to both traditional roofing materials, such as thatch, and
modern, mass-produced, often inappropriate, galvanized iron sheeting or asbestos cement.
These tiles are relatively low in cost, durable (with a life span expected to exceed 20 years in
most areas), aesthetically acceptable, able to offer adequate security and comfort, and
provide protection from both the heavy rain and the hot sun.
Concrete roofing tiles are now produced by small businesses in a number of countries in
Africa, South and Central America, Asia and South-east Asia, and in the former Soviet Union.
The key to the success of this technology was the development of equipment and techniques
to produce the tiles on a small scale. It typically costs US$5000 (excluding land and
buildings) to set up a concrete roofing tile workshop, and can be less than US$1000 in areas
where the vibration equipment and the moulds are made locally.
When the technology was first developed it was decided to make large roofing sheets similar
in size and shape to the corrugated asbestos or galvanized iron sheets used on many
buildings. These were reinforced with natural fibres such as sisal or coir. The fibre-cement
mortar mix was simply spread out by hand on a flexible plastic sheet in a large mould.
Afterwards the sides of the mould were taken away and the sheet with the mortar on top was
gently pulled over onto a corrugated mould where it took its shape.
Problems were experienced with decay of the fibres and cracking of the sheets after only a
few years, and so the production of fibre-reinforced concrete roofing sheets has been
abandoned in many countries.
The next development was production of fibre-reinforced concrete roofing (FCR) tiles. With
tiles (typically about 500 x 250 x 6 or 8mm) the performance of the fibre is less critical than
with sheets. The fibres are added largely to control damage caused by impact during
handling. Once placed on the roof, tiles are unlikely to crack if the fibres decay. In addition,
FCR tiles are vibrated during their production which gives them added strength and
durability. It has also been found possible to make fibre-reinforced semi-sheets (of size 600 x
600 x 8mm) by the same method without any adverse effects.
A more recent development has been to make concrete tiles without any fibre at all. These
are the so-called micro-concrete roofing (MCR) tiles. Greater care needs to be taken with
MCR tile production compared with FCR if the number of damaged or sub-standard tiles is to
be kept low. MCR tiles are also more brittle than FCR tiles, and can be damaged if dropped
or handled carelessly when transporting them or fixing them to the roof.
Practical Action, The Schumacher Centre, Bourton on Dunsmore, Rugby, Warwickshire, CV23 9QZ, UK
T +44 (0)1926 634400 | F +44 (0)1926 634401 | E | W
Practical Action is a registered charity and company limited by guarantee.
Company Reg. No. 871954, England | Reg. Charity No.247257 | VAT No. 880 9924 76 |
Patron HRH The Prince of Wales, KG, KT, GCB