The excitement of planning your custom built home is a rush. Yet, before settling on a design, it’s important you determine if all your wishlist items are possible. In particular, the type of home you can build may be limited by a number of environmental factors at the site.
The type of soil, topography of the site, the amount of sunlight and wind, the site’s drainage and other factors can all affect the type of home that can be built. For example, some soils are not as stable or well-draining as others. In this case, a three-storey home would not likely be legal or safe to build. Other factors like sun and breeze direction can limit the orientation options for the home, while topography may require a slope or geologic feature to become a major design element.
That’s why it’s best to consult with a custom home builder before you begin to determine your design. This will ensure you don’t land on a home that’s just not well-suited for the site.
Key Factors to Consider in Custom Home Design
When looking for a site on which to build a home, you should be aware of environmental factors of the site. A few to keep in mind include:
- Soil Quality: The soils in the Sydney area range from soft, sandy and unstable soils, which are typically near the coasts, to denser soils further inland. A soil test can reveal how “reactive” the soil is, which means how likely it is to move, shift or expand. Sites with highly reactive soils may be more costly to build on, require excavation to prepare, or place limits on the height and materials that can be used to build the home. Plus, since the Sydney area can experience earthquakes, softer, unstable soils may require abatement efforts prior to building to properly secure.
- Drainage: Strict building codes apply to homes built in floodplains. For example, the code in New South Wales requires residential floors of homes built in flood-prone areas to be of a specific height, and the design must also incorporate flood risk prevention features and flood-resistant materials and finishes. The site’s drainage characteristics may also influence soil quality, or require a proper drainage system to be built.
- Wind Strength: Wind can influence home design in a few ways. First, homes built in high-wind areas may have specific limits on height, roof pitch and floor-to-ceiling height, and special bracing may be required to properly secure the home. Also, wind is an important source of passive cooling, meaning cool summertime breezes can be harnessed to create draughts in the home for cooling. A site sheltered from the wind by ecological features or neighbouring properties will require careful orientation to achieve maximum passive cooling.
- Amount of Sunlight: Sunlight is very important in home design. A home that’s properly oriented to the sun will receive great natural light, and solar heat gain in the summer – when the sun can overheat rooms – will be greatly limited. In general, Australian homes are typically east-west oriented, with northern windows facing the sun. This maximises the amount of sunlight that reaches the home in winter, which acts as a natural heating source, and limits the potential heat gain in summer.
- Topography: Hills, slopes and rocky surfaces can all affect the design of the home. For example, a slope is a significant design factor, and the home must be properly oriented to achieve maximum sunlight. A home built on a south-facing slope, for example, might suffer from inadequate light in winter, spending most of its time in the shade, resulting in higher heating costs. Some topographies might also require excavation or fill before building can begin.
Before you start planning the custom home of your dreams – take a good look at the site you plan to build on. Typically, the best option is to design your home to properly fit the site’s unique environmental features.