Residential Design series Ground works

June 26, 2018





All councils are now addressing storm water pollution with tougher documentation at the DA application submission. Some councils have very strict hard and soft landscaped percentages and if you are increasing your hard landscaped areas beyond these numbers then you will have to address the issues that your extra hard landscaping is creating.

Hard landscaping includes all roofed areas, concrete paths and driveways, paved areas and swimming pools. Councils probably with encouragement from the EPA are acknowledging that if you have excessive areas of concrete landscaping or massive mausoleums masquerading as cottages, then the flood like deluge that assaults the storm water system as a result of the removal of the soft landscaping must be addressed at it’s source. This could mean you will have to install a retention pit.

Finally the councils and the Water board have dropped their obstructionist policies that they vigourously pursued for decades and are now encouraging people to install rainwater tanks.

The two problems, storm water runoff and Sydney and Australia’s shortage of water are intertwined, however the authorities thinking has not progressed yet to the point of saving the water.

Despite the lack of leadership you can do something by properly planning your renovations to include a groundwork concept plan.

Most people are now aware that you can reuse tank water in toilets washing and for the garden.

As long as the top of the tank is below the level of the eaves you can gravity feed all of the roof water to the tank. Initially the cost of setting up the piping will be greater than if you were to run it straight to the street, however the long-term benefits to the community and environment are obvious.

After you have chosen the size and position of your tank, (an exercise that can be assisted by ringing one of the tank companies and getting there helpful sales person to visit) you need to plan the piping layout.

For most inner city cottages the positioning of the tank will not be an easy matter. If you plan to gravity feed your toilet then the tank will be best situated on a stand, close to the vicinity of the wet areas. Possibly this will be a smaller tank that has an overflow running to a larger tank situated either in the garden or perhaps half or totally buried under a deck.

The storm water concept plan will show all of your new piping running to the tank. The overflow from the tank will run to the street.

Rainwater tanks now are available in all shapes and sizes.  They range in size from 360 litres or 80 gallons 80cm long x 36cm wide x 114cm high to 27,000 litres or 6,000gallons. A tank this size will cost you about $2,600.00.

Most people install a tank with around 3,000litre capacity.

The storm water and associated ground works is a job that will need to be completed very early in your renovation project. You will need a licensed plumber or roof plumber to assist with the putting together of the macano set like pipe work, however all the digging can be done by any enthusiastic amateur.

Listening to the minister who was the lord mayor but is now the minister for resourcefulness it sounds like we are being prepared for larger government charges on water and possibly taxes on house designs that do not address the issue of excessive storm water runoff seriously. I strongly recommend that when you plan your renovations you take time to plan your groundwork at the same time.   

Good building and design!

This article was written in 2004 and needs updating.

Note: The views expressed in this article are of a broadly based nature and are in no way to be taken as the basis of an individual design. Should a reader wish to pursue the ideas expressed then at all times we recommend they consult with the appropriate professionals. 

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