- Site Analysis
- New Zealand climate and environmental zones
- Plants, trees and landscape features
- Services and infrastructure
- Site conditions and ground stability
- Culture and heritage
- Site analysis checklist
- Site Use
- Passive Design
- Material Use
- Wet Areas
- Health and Safety
- Other Resources
Understanding all the features of a site, using and protecting the best, and minimising the impact of the worst.
Chemical contamination and pollution
Chemical contamination of a site may occur from past industrial, horticultural or agricultural activity (such as use of chemical sprays and pesticides) or use as illegal landfill (treated timber or asbestos products).
There have also been examples of contamination from organic material giving off gas or heavy metal deposits from industrial land use.
If chemical contamination is present, the site may not be safe to build on.
Surveying the site
A historical land use survey is the most effective method of identifying potential contamination from prior use. A land use survey will be more valuable than relying on soil analysis alone, which may be hit or miss depending on where samples are taken from, how many samples are tested and what they are tested for.
Survey data may be obtained by:
- checking local council records for previous uses of the site
- talking to long-term residents in the area who may provide information.
Testing for contamination
If contamination is suspected from a survey of previous land use, an expert consultant such as a geotechnical engineer or soil scientist will be required to perform tests to determine safety for residential use.
Surveying existing buildings
Existing buildings on a site may also be contaminated. Sources of contamination may include asbestos, old septic tanks, lead paint, CCA-treated timber and toxic moulds.