[Cob] supporting a tank

[Karey Harrison]

It is really common to have raised tanks like this in Australia

I have a 3000 litre tank above my laundry - I think that is bigger than the one you are proposing. Like most raised tanks, it is on a post and beam structure, with corrugated roofing over the beams, screwed down much more than for roofing so the corrugations don't collapse, to distribute the load.  It had to be engineered for a one in a hundred year earthquake event even though we don't live in our laundry.

The thing to think about with tanks, is that they ALWAYS eventually leak. I would not want to put one on top of a wall that would dissolve when it did so.

I would recommend incorporating post and beams into the structure so you weren't depending on the cob.

I live in Toowoomba where we had the inland tsunami in January - I don't know if you saw it but 10 & 20,000 liter concrete tanks got washed away. Polytanks, if they are empty, can blow away. Our tank is corrugated steel - it gives it a bit more weight in the wind.

cheers

Karey
Queensland

> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 6 Jul 2011 14:39:23 -0500
> From: John C Curry <curryjc at yahoo.com>
> Subject: Re: [Cob] supporting a tank
> To: "coblist at deatech.com" <coblist at deatech.com>
> Message-ID: <C0019871-51BD-4E03-9043-BBC9B0F25FD4 at yahoo.com>
> Content-Type: text/plain;	charset=utf-8
> 
> One can do anything, the questions is more economic. Not money but is there a more reasonable solution which meets your needs. 
> 
> That being said . . .
> 
> A concern is supporting the tank between the walls or span. The type of tank is also important in how it distributes the load over a given area. Most poly tanks are set into a bed of gravel and sand in order to keep the water load from rupturing the tank in an unsupported area. In other words the tanks are not structural. The bedding distributes the load. 
> 
> If you are gravity feeding water into the tank as well. Remember that the top of the tank must be below the intake. Also allow for over flow. 
> 
> I am fairly certain there is a way.  However, the reason you won't normally see this arrangement, large tanks above living space, is because any failure is catastrophic. 
> 
> I have always liked the idea of a foot pump, such as you might find in a boat. They make everyone conscious of water use. If you have a minor failure you won't necessarily pump or gravity feed precious water out of the system. 
> 
> More than anything, "do the math."
> 
> Good luck. I am interested in your solution. 
> 
> john
>