For this article we have classed a sloping site as a minimum 3.0m fall from front to back over a typical 500-700m2 residential site. A lower slope can usually be managed via retaining walls so that a simple site cut achieved.
For residential sites with 3.0m or more fall across the site, the slope becomes the key design consideration that the buildings design will respond to. Levelling the site either becomes very costly or highly impractical, so the slope must be incorporated in an aesthetically pleasing and architecturally responsive manner.
When designing a home on a sloping sites there are 7 key design drivers or considerations.
Sloping sites typically have a view, which should be the main focus of the design, and key spaces will be prioritised with the view. The rooms that typically take precedence are generally outdoor and indoor living, master bedrooms and suites, though any preference can be achieved with the right design team. For secondary bedrooms, a view is nice to have, but can often be attained by clever layout or alignment near the boundary, looking past the key spaces.
Access from below can come in under the house at basement level; typically, this access arrangement is at the front (when considering views) and the remainder of the house can focus on the views. Access from above would generally mean the access is at the rear of the site (when considering views), so you can have a high-level garage at the rear, with outlook to the front of the site. Where a site has access from a side road running parallel with the slope, the access point can be anywhere along the site.
Most residential code setbacks and height limits will require terraced forms – or a stepped building – down the site, rather than a large site cut. A terraced form enables a flowing building to cascade down the site, and clever planning can enable easy access from central living spaces to the more private spaces.
Generally, some amount of site cut will be required, at the minimum a pile type retention system should a stilt style home be desired or required. With access from below, the logical approach is to have the garage and entry off the street, and cut back into the site. Typically, a cut will be deep enough to allow a retention/retaining type situation, whereby the cut retains half a level below ground, and half a level above ground is filled. For steeper sites this may be a full level of each.
Depending on the slope, it may be that the home is spread over 3 or more levels. Where slopes are so significant that there may be a level change of 5 or more meters, internal access becomes a key consideration. Stairs may be broken up into 2 or 3 different flights in different positions to best suit the flow of the home and feel less arduous. In homes of 3 or more levels, a lift becomes more of a necessity then a luxury. With the possibility of a master bedroom or living area at the top of the site, and the garage at the bottom (or vice versa), the thought of climbing 3 or 4 flights of stairs when you forgot your wallet, phone or kids school bag multiple times a day becomes an inevitability.
On a front accessed site, it is typical that outdoor living spaces will be facing the view and in balcony or terrace form. This will generally give the ability to have a ground level lawn or garden to the rear. On rear accessed sites, typically the outdoor living spaces will be balconies or terraces to the front, with the ability to have a lawn or garden area to the front, at the bottom of the site. Side accessed sites may enable both front and rear garden areas, as well as balcony or terraced outdoor living spaces facing the view.
Light to underground spaces
Where some spaces may be completely below ground, clever ways to bring in natural light need to be considered. A stair with skylight, light court, or perhaps pushing out an external wall toward the boundary and adding a window may provide the solution. Alternatively, it’s possible a cave like feeling is preferred, such as for a theatre, wine store or the like. Subterranian spaces are ideal in this instance.
Yes, a sloping site will be more expensive to build on than a flat site; however, smart planning and early design considerations of key aspects will ensure the best construction processes to minimise cost, and the best design decisions to maximise the benefits afforded by the site.
When the design takes all considerations – from landscaping, to lighting, to maximising the views – into account, a sloping site can stop feeling like a challenge and more like an asset. Creative problem solving can make a home more unique and remarkable, especially in the hands of experienced architects. With our extensive experience with sloping sites, we have seen difficult pieces of land carved into truly marvellous homes.
If you have a building project with a sloping site and would like some guidance on how best to maximise it’s potential, Thextonsmith is ready to help, with years of experience at our disposal. Get in touch today for a no-obligation chat via email, phone, or social media.
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