Tank ready for final plaster. When there is no water there is very little else. That is why water is, with good reason, the backbone of land-based Permaculture design. As designers, we observe and create opportunities to catch and store water. There are many options available to us: in the soil, in biomass and in ponds, dams and tanks. There is lots of great tried and tested solutions out there that you could explore. Today, in this post, I will share with you my views on ferro-cement tanks.
Makeing the base. A ferro-cement tank is, in my experience, a very interesting option when you need drinking quality water but you are on a budget and have a bit of time for a DIY approach. It allows you to obtain a yield of rain water from the roofs of buildings and store it.
Ferro-cement was invented around 1840 in France. Ferro-cement structures are created by constructing a frame from thin steel rods (rebar) that is then covered in a metal mesh to create the form of the structure. Then thin layers of sand and cement are plastered over, resulting in a hard, strong finish, ideal for a water tank. Nearly all land-based projects have a need for water storage in tanks and ferro-cement offers a long term pragmatic solution.
Ferro-cement was invented around 1840 in France. Ferro-cement structures are created by constructing a frame from thin steel rods (rebar) that is then covered in a metal mesh to create the form of the structure. Then thin layers of sand and cement are plastered over, resulting in a hard, strong finish, ideal for a water tank. Nearly all land-based projects have a need for water storage in tanks and ferro-cement offers a long term pragmatic solution.
Metal work finished. The advantage of ferro-cement is that it can potentially be applied in many contexts, including remote areas or hard to get to places where other options are unrealistic (pre-cast concrete, metal or large plastic tanks) and are more expensive. This is because it is possible in most cases to transport small amounts of cement and some re-bar. Pockets of sand can be found in most soils, taken on a small scale from a river or purchased, making it relatively easy to acquire at low cost.
The tanks that I built are used for drinking water, harvested from the metal roof of a house located next to the tank. For catching drinking water use metal or tiled roofs and avoid thatch or wooden shingles. When the tank is finished the roof should be cleaned and a first flush system installed. This redirects the first part of the water coming out of the gutter away from the tank so any debris or leaves do not go to the tank (more about that in the designers manual).
The tanks that I built are used for drinking water, harvested from the metal roof of a house located next to the tank. For catching drinking water use metal or tiled roofs and avoid thatch or wooden shingles. When the tank is finished the roof should be cleaned and a first flush system installed. This redirects the first part of the water coming out of the gutter away from the tank so any debris or leaves do not go to the tank (more about that in the designers manual).
Plastering from inside and out. As well as channeling rain water directly into your tank, you can also pump water into it. Depending on how the water will be used, different levels of care is need when harvesting. For good quality water install a fine screen to stop insects and debris getting into the water, and a cover to stop direct sun light entering. To make cleaning easy, there needs to be a wash out pipe flush to the bottom of the tank.
It is a good idea to position the tank in a place that is shaded and easy to access. To maximise your harvest you can calculate the square meters of your roof and average rain fall in your area. There are several online calculators which make this easy. Then you will know the volume of the tank you can build. The tanks I built (shown in the photos) are 3000 liters and were built in workshops. If you build a tank of 1000 liters, it is still light enough to make it portable.
It is a good idea to position the tank in a place that is shaded and easy to access. To maximise your harvest you can calculate the square meters of your roof and average rain fall in your area. There are several online calculators which make this easy. Then you will know the volume of the tank you can build. The tanks I built (shown in the photos) are 3000 liters and were built in workshops. If you build a tank of 1000 liters, it is still light enough to make it portable.
Applying the final plaster. Everything has its place and decisions are made based on context, climate, project goals and budget. I believe this is a great technique available to people in most circumstances, easy and inexpensive. It is truly versatile and many useful structures can be produced employing this technique from boats to sinks, roofs and tanks for storing water, grey water filtering systems and aquaponics.
Matt Prosser 29.05.2017
Matt Prosser 29.05.2017
|
|
