The mix for corrugated sheeting is about 5 kg cement, 15 kg sand and 0.2 kg fibre, mixed well with water.The mix is poured into a mould where it hardens over 24 hours. It isthen placed in a damp, solar-warmed plastic caseto curefora month, or laid in water to cure for at least seven days (the curing must not occur in dry air). After curingthe sheets are dried (Parry,1984).
The Intermediate Technology Group (IPDG) in England developed a production systemfor corrugated roof sheeting which is highly appropriatefor small-scale produc-tion.Thefactorycanproduce2000tilesof50 x 25 cmperweekandneedsfourwork-ersinaf loor space of 25 m2 withacourtyard of about 40 m2. Afactory that produces 20 000 tiles a week, employs 30 workers on a factory loor of 400 m2 withacourtyard of 350 m2. In this way one can produce roofing at three quarters of the price of corrugated metal sheeting.These have been produced for 20 years, and the lifespan of the sheeting is estimated at 50 years.
Environmentally speaking, cement-based roofing can be considered better than the metal alternatives. However, roof sheeting is more economical in terms of material use than roof tiles. All of the products can be re-used, but the sheeting can be more easily damaged under demounting.
Was this article helpful?