The Hanging Gardens at Middle Path 1

For a year we had been regarding our second rainwater tank - a 10,000-gallon (45,000 litres) as a mixed blessing. It was becoming painfully (mid 2006) obvious that Australia was fast approaching a water crisis of unprecedented proportions. The extra water storage is a huge asset but, aesthetically, could be considered unappealing. Both tanks had developed cracks and the makers, North Coast tanks, cheerfully agreed to fix them under their 15-year warranty - a refreshing attitude in this day and age we thought. It seemed to me that if I could run some fencing wire around the tank and tension it it might offer some resistance to further cracking - I seriously doubt this would make any difference in fact - but it lead to the idea of building a trellis around the tank as a visual enhancement. One thought lead to another and the design evolved into a plan for a tank-top garden and trellis. The water in the tank would provide a significant thermal stabilising influence, winter and summer, while the garden & trellis would shield it from the warming influence of our summer sunshine.

A major influence over the design was that nothing could be fixed to the tank - no holes for screws or similar could be used and so the whole structure would need to be freestanding without fixings.

Other considerations were to minimise the time and expensive involved in the construction while building something which would endure. Wherever possible we would use what was lying around.

This is a section of the garden on top of the tank.

But first we needed walls to retain the soil around the base of the tank.

Which looked like this with the 4 long uprights in place. We chose to use champaigne bottles, not for their robustness, strength, appearance, durability, aesthetic appeal, recycling approved qualities so much as that they were lying around at the time.

And this is the space they created

The walls have holes for the lower wires to pass through.

The wires are tensioned with threaded rod

Ming inspecting progress on the tank top retaining wall around the manhole ~ or womanhole, whichever you prefer

The bottle layers are completed and 6~10 mm wire mesh is hand-formed around the top layer

which looked like this closeup

a generous capping of 40mm sandstone mortared in place to form a seat / workspsace

Waterproofing coats of emastak have been applied to ensure moisture does not seep into the reservoir

All the uprights are hanging in place. They range from 150X75 to 75 X 50 according to what was lying around at the time

An additionjal layer of 200 micron plastic membrane is added ion a "belts and braces" approach.

blocks for the sleeper walkway are in place and the first loads of coarse sand have been wheelbarrowed up the plank

a side view of the same time

the support block transfers the weight of the trellis onto the tank walls. We used left-over emastak to seal the end-grain as it was, at the time, lying around

the timber retaining wall, drainage layer

a layer of geofabric to prevent any soil-loss

Ready for the soil - the pots are for berry vines which we wanted to keep confined root-wise - and, at the time, they were laying around

The soil arrives .....

and came to here - the tank top has also been mulched

The front of the tank now looked like this - hardly the essence of elegance - passionfruit will cover it in time

Brace holding the above-tank top wire tension are held on merely by the tension in the wires around the tank - holding about 1 metre of the uprights. I was quite amazed to discover they felt stonger than had they been bolted to the tank

and the view from the top

We also discovered some recycled stakes and 200mm plant pots lying around and pressed them into service as mobile sprinkler stands

All the soil in place and a pile of mulch awaits spreading. a small (200mm) retaining wall is built around the 300mm concrete pipe intended to take any excess water down to the layer of gravel around the base of the tank and harmlessly into the surface drainage system.

and wouldn't you know it - there were a couple of grape vines lying around at the time

It came to pass that the heavens did open ... the rain was most welcome locally but as the tanks had just been repaired and needed to be kept dry at the time. As a consequence it became a baptism by deluge for a couple of days. The drain seemed overwhelmed by the abundance of it all and liberally shared her bounty with the garden.

2 months later ...........

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This document (www.middlepath.com.au/about/tanktopgarden_01.php) was last updated on Monday June 16th 2008  ||  email Please Note: While we believe the information we offer is true and valid through our own observations and experiences and we offer it freely with a sincere desire to help our fellow man, woman and child we feel it prudent to include the following as a precautionary device given various “authoritys” current attitude towards our work: Content on this site is provided for informational purposes only and is not a substitute for “professional” “medical” advice or diagnosis. You are responsible for your own health and therefore should make sure you have sought appropriate advice before embarking on any course of therapy or treatment for any condition you may consider that you might be experiencing. If you have or suspect that you have a “medical” problem, it is your responsibility to contact a ”qualified“ health care practitioner. Disclaimer: Information and statements on this site are not intended to diagnose, treat, cure, or prevent any disease.