Typical Site Costs for Building on a Sloping Block

Typical Site Costs for Building on a Sloping Block

Typical Site Costs for Building on a Sloping Block

Typical Site Costs for Building on a Sloping Block

You’ve set your sights on having a view. It’s now time to find the right block - or should we say, the right sloping block. So what happens next? In this post, we outline the site costs for sloping blocks you need to consider.

Before jumping into the post, we’d like to offer a quick word of advice. Building on slopes can be expensive. If you find a sloping block you like, it’s imperative to get a professional building opinion prior to signing a contract.


Site Survey

A sloping block requires a more rigorous and costly site survey than a flatter block. Special attention needs to be paid to the block’s drainage, soil stability and wind exposure. In the case of extreme slopes, a structural engineer may even be required.

Structural Design

When it comes to sloping blocks, the structural design of the house is critical - particularly in relation to the foundations. There are several ways to approach foundation work on a sloping block: pour a single concrete slab; combine a slab with a timber sub-floor, or create a split slab. All three approaches have their pros and cons, and vary in cost.

A good builder will help you choose the right structural design and also outline the pros and cons to your individual situation, taking into account the block itself and your budget. To make things easier, G.J. Gardner Homes has a number of flexible designs in its Element Homes range which are ideal for sloping blocks.

Building Materials

Given that homes on sloping blocks are more exposed to the elements, particularly the wind, stronger and more costly building materials may be required. Unlike a home on a flat block, a home on a sloping block receives less protection from the surrounding topography.

Site Preparation

When it comes to sloping blocks, major excavation work is usually required. Your builder will need to cut into the slope to create a level platform for the slab. Your builder may also need to stabilise the soil on the slope by building retaining walls. This process of flattening, levelling and stabilising the ground doesn’t come cheaply.


Good drainage is essential when building on a slope, as water collecting at the bottom of a slope can cause soil erosion. Make sure you discuss the subject of water runoff with your builder. In some scenarios, you may require a pumping solution to remove excess water quickly.


Once the site has been prepared, you’ll need to start thinking about the cost of getting materials (eg. bricks, timber and steel) there. Depending on your block, access may be tricky and require a mobile crane to transport materials in.

A Final Word

Hopefully, this blog post has given you a good overview of things to consider when building on a sloping block, and made you start thinking about the possible costs. We don’t want to completely dishearten you, but arm you with enough information to make an educated decision. Just remember to do your homework and ask your builder lots of questions. After all, nothing beats a great view! If you require further information on sloping blocks, please don’t hesitate to contact us.

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