A finished tyre tank stand
You may remember reading about the work of FoodWaterShelter to develop a sustainable home for vulnerable women and children in Tanzania. And you may recall their innovative approach to water storage. Well here’s another innovative use for old tyres — and one that may alleviate some potential concerns of unwittingly contaminating the environment through alternative uses of tyres.
When installing a water tank, it is useful to keep it up off the ground; as high as practically possible. This provides greater water pressure, allows space under the tap to fit a bucket, keeps your clean water source up out of the mud, and makes it more difficult for livestock to damage piping. Achieving this height safely, cheaply and with the durability required to protect your precious water supplies and tank can be a challenge.
If price is no option, then a steel tank stand will be a good solution. Timber stands are common, but in an area with ferocious termites, it either requires treating the timber and concrete footings, or regular replacement. Circular tank stands can be constructed from cement blocks or bricks, but unless well made and braced, the weight of a full water tank commonly results in cracking and possibly complete failure.
Using the same, innovative principles as their tyre aquifer for storing water, FoodWaterShelter has begun to construct tank stands from old tyres. It’s an easy process and takes more of these challenging waste products out of the waste stream, while saving on the need for building materials. Tyre tank stands are durable and can be built several layers high. If you are worried about livestock such as pigs digging under them, then simply start with a row of buried tyres beneath ground level.
To build a tyre tank stand:
1) First determine the number and size of the tyres that you’ll need. Depending on the diameter of your tank and the diameter of your tyres, you’ll want to make sure that the tyres laid in a grid formation are larger than the tank.
2) Then go ahead and level the area where the tank will be sitting. If you want them embedded into the ground to prevent livestock digging under them, then simply dig down and make a level surface.
3) Determine the height you want your tank to be off the ground. It is likely that this will be limited by the height of your roof gutter, or the inlet pipe. It makes measurements easier if you can stack your tyres up empty to see how much space you’ll have for your tank. But be warned, this is not as easy as it sounds; as when you compact the tyres with soil at a later stage, the tyres will increase in thickness (hence height) by several centimetres. And to add an additional challenge, the amount each tyre increases by thickness will depend on the wall thickness and strength of each tyre. But the best thing to can do is be conservative with your space (allow an extra 10% to 20% or so), take your best guess, and then level things out at a later stage. In the worst case scenario you can tick it off as a lesson learnt and start again.
4) Once the bottom row of tyres are positioned where you want them, start adding some good, compactable soil, and start compacting. As usual when compacting soil, keeping it moist (but not wet) will improve this whole process. You want to make sure that soil is compacted right into the walls of the tyres to give them maximum strength. Similar to techniques that have been used for rammed earth tyre walls, it is easiest to compact into the tyre walls using a sledge hammer or something similar. Compacting the centre of the tyre is no problem with any basic compacting tool.
To make a tyre tank stand, tyres are simply laid in the
desired arrangement and soil is compacted into them.
5) Once the first layer of tyres has been compacted, simply add more rows if you want, and start compacting again.
6) Depending on how well your measurements worked out, and depending on how well the tyres cooperated with their increases in thickness, then you may need to use some sand or friable soil to level the top off to provide a good, solid and level base for your tank.
And there you have it. A durable tank stand made for a few dollars and with minimal tools.
If you want to see the tyre tank stands in action, or learn more of FoodWaterShelter’s Tanzanian approach to permaculture for meeting basic needs of water, sanitation and food security, then you may be interested in coming to their Permaculture Design Certificate (PDC) in June, 2012.
A completed tyre tank stand, two layers thick and embedded into
the soil to prevent pigs from digging under.