The Advantages of Building on Sloping Sites
Sloping sites are common throughout Queensland. But why build on a sloping site? VHD Studio director, Craig van Heerden, shares his insights into the opportunities and strategies available when working with them.
Firstly, depending on the location of the lot, there can be many naturally occurring opportunities presented. Often, sloping sites may occur at the edge of an escarpment (e.g. within Toowoomba and surrounding areas) or in coastal hinterlands or headlands, with direct view access to the ocean. Land with excellent access to views and/or proximity to water, makes these considered ‘premium’ sites. In typical sub-divisions, there may be land available that has retained its natural slope, rather than being flattened via a cut and fill approach. Typical project home slab-on-ground dwellings are not easily applied to these sites, making them less expensive to purchase per square metre than flatter allotments. This can create opportunities for clever home owners and innovative building designers.
The Cut and Fill approach is the typical response of many home builders, as it creates a typical construction environment suiting generic house plans. The Cut and Fill approach is when a flat pad is created on a sloping block via a combination of retaining walls and earth batters. Whilst this is a reasonable approach, there are other opportunities present on sites such as these that this approach ignores.
Initially, consider the naturally occurring opportunities provided by the site by undertaking a site analysis. This can include trying to understand the sites orientation (specifically in relation to access to northern sunlight in both summer and winter), the direction and gradient of the natural slope, locations and impact of natural vegetation (some of which may not be able to be removed as it is on a neighbouring site or the like), locations of vehicle access, prevailing breezes (which can be extreme if they are working up slope across a site with no screening) and access to views both near and far.
It’s important to consider the basic impacts that the elements identified in the site analysis would have on a dwelling. In this way you are allowing the site context to impact the building mass rather than designing from inside out. I tend to identify access levels for both vehicles and pedestrians, heights / directions from which views would be available, impacts of the slope and access to and protection from the site’s solar orientation including northern sunlight / aggressive western light etc.
Start to develop a strategy for the massing of the dwelling on the site by implementing the strategies identified in the previous 2 steps. Consider where the building will be at ground level or where it may be suspended – the possible roof and floor levels and how they may interact with each other – as well as the possible preferred aesthetic outcomes.
At this stage the preliminary layout can be developed into a more detailed version – often using design modelling software. With more defined room sizes, locations, connections and infrastructure being applied – further design strategies are considered at this stage including vertical circulation, cross ventilation, access to natural surface levels etc.
Design Strategies to consider;
- Vertical Circulation
Centralised stairs to minimise travel. Possible use of intersecting floor plates with split levels and numerous smaller stair runs making it simpler to move between floors. Domestic lifts may also be an option.
- Natural Light Penetration
Natural light can be encouraged or excluded depending on its nature. Excluding Summer sun from internal spaces ensures the dwelling does not overheat, whilst allowing access to winter sun in the same locations encourages its warmth. 
- Access to Views
With the value places on views – we often try and allow spaces to look across each other to the view rather than placing walls in the view line – this often results in single use floor plan widths etc.
- Cross Ventilation
Cross ventilation is an important way to allow air to move through a building and create a natural cooling effect – this needs to be carefully managed on sloping allotments where wind can be an extreme factor.
- Access to the natural surface
Manage building floor levels to allow for direct access to ground levels for garages, laundries etc to try and minimise the number of times stairs need to be used to move through often used parts of the dwelling such as living areas.
- Managing building setback requirements and maximum heights above natural ground levels.
There are numerous codes and regulations throughout Queensland, including the Queensland Development Code and local government Town Plans, that restrict the proximity of a dwelling from its boundaries, as well as its height.
Additionally, we recommend utilising 3D modelling software during the preliminary design phase, to explore, in detail, the shape, articulation, and interaction with the ground level of the building.
Finally, when building on a sloping site, possible things to avoid include; excessive cut/till, steep driveways, extreme retaining walls, stormwater issues, and impacts on existing natural habitats.
If you are looking for a design solution for your next build, then reach out. We pride ourselves on creating innovative, responsive spaces that you will love.
All Images by VHD Studio.