So far we have concentrated on the internal requirements but the design will also be shaped greatly by its "siting". Part of the design process involves gaining all the information you can not just about your site, but also neighbouring properties and the locality. The outcome of your analysis should be a scale site plan (preferably drawn on A2 size paper). The site plan should show the following:
- Any tree over three metres in height and its exact location
- Sewer, storm water, drinking water, electrical, and gas main locations and access points
- Various "Australian Height Datum" levels of adjoining properties (floor levels, ridge levels, gutter levels and deck levels.
- Neighbouring house "set backs"
- Boundary lengths, locations and junctions
- Contours at 5 metre intervals are necessary for sloping blocks
This list can be given to a surveyor for quotation. This will cost about $700 for a standard size block (as at Oct-2006). Photograph houses in the locality and research the local history - as similarities in existing houses in the area may influencing your design which may help formulate a design that is sympathetic to the surrounding architecture in the neighbourhood. Planning controls (local councils and others) will impact on your design and these must be considered at this time. Restrictions such as height limitations, preferred building forms and existing scale of architecture in the locality are all examples of planning controls that will impact your design. Have a good look at your local council's web site and veiw their development control documents. They are usually called Local Environmental Plans (LEP) or Development Control Plans (DCP). You may also like to view state environmental planning codes which can also affect what you can building and where.
It should be noted that if your site looks like it may have issues (e.g. unstable rocks, a very steep gradient, etc.) a geotechnical engineer should be engaged to advise you on the best location for your new home that will reduce building costs. Your site may also have restrictions that will be noted in your Section 149 Certificate, which is a document that forms part of your sales contract when you purchased your property. If you have owned the property for some time it is suggested that you apply to council for an updated certificate - as development requirements change over time. The Section 149 Certificate application form and many others can be found on your council's web sites but you will need to go to council chambers to lodge the application and pay the fee (approx. $120 as of the Oct-2006).
Call your local council and speak with the "on duty" building inspector and planner. Tell them you are designing a new home and ask them if there is anything that will affect the design of your new home.
This may sound like a great deal of work but if you do your research there won't be any surprises later, and your building will work the best it can on your particular site.
Example list of site restrictions
- Boundary set-backs: job north 900mm, east 6000mm, south 2000mm, west 5,000mm
- Site has an easement on southern boundary – special engineered footings required to support future house in zone of influence
- Geotechnical report will be required due to bolder outcrops and possible site instability issues, cost $2,500
- The site is zoned 7a (the bad 7 my builder tells me) we will require a flora and Fauna assessment ($3,000)
- The site is connected to sewer and water mains
- Site is home to the Perryman stand of Eucalypts and all tree at the back of the property and an assessment will need to be done during the application stage to see which ones will need to be retained
- Wind comes from the south in winter and neighbours say it is harsh
- Views from site to the east/northeast
- Called AGL there are no gas mains servicing the site, bottled gas only
- The section 149 (found in your Contract of Sale document) says that the site is
- Prone to flash flooding
- Bush fire prone
- Located in a slip zone
Add to this and find out as much as you can about the site, services to the site and anything at all that may impact on the design of your future house.
