Greetings from the Kingdom of Swaziland. I’d like to share a few comments on the ferro-cement tank in Footsteps 30. Since 1994 I have been involved with a tank-building programme with local churches and several hundred have been constructed, both in Swaziland and South Africa. We have a good teaching video available in Zulu.
We have found using a mould a great benefit. We use bent corrugated iron sheets and make the mould in four pieces which are then bolted together. Each quarter of the mould is reinforced on the inside with a triangular support of wood.
We use a pre-cast foundation into which we put the outlet pipe. A thin layer of old engine oil must be applied before use as otherwise the cement sticks to the mould. The only disadvantage of the mould is in transporting it from one home to another. We have used a pick-up truck but plan to use a donkey cart in the future. Each mould makes at least 40 tanks.
Through experience we have learnt that nearly every concrete tank will leak. We use two layers of bitumen-based paint (non toxic) on the inside of every tank to prevent leaks.
Any responses are most welcome.
Willem Klaassen, Rural Ministries Umnotfo Farmers, Association, PO Box 387, Veni, Swaziland.