What is a contour survey?

by | Jan 24, 2023 | Advice & inspiration, Building basics & regulations, Building tips

You’ve bought a block of land and are looking to build, but people tell you to get a contour survey. If your first thought was, ”What the heck is a contour survey?”, you’ve come to the right place. This article is all about defining what’s the purpose of contour surveys, and how they help during the design phase of building your home. We’ll also discuss what to do once you receive the results of a contour survey, including how to read it and what knowing these details of your property brings to the table.

What is the purpose of contouring?

A contour survey (sometimes known as a site survey, detail survey or feature topographic survey) is a means of determining the slope of your land and picking up all existing features of your land (including trees, vegetation, adjoining neighbours, visible services and easements). Performed around the same time you would have a soil test done, and it is standard practice on any new block of land. Every land parcel is unique and that’s why it’s a necessity to perform a survey for all proposed buildings.

Contour surveying is a fundamental step in the building process and it’s vital to establish the design of your new home. Think of them like maps for your builder that provides an overall view of your property. Understanding the different elevations of a location helps a builder with measurements and determining features of your home design. It also plays a vital role in deciding a fixed price.

How and why?

Surveys use a range of tools and technology to perform a survey including surveying bipods, marking machines, GPS, robotic total stations, laser scanners, survey drones and many more. What a surveyor chooses to use will vary from property to property.

Before any build, it’s vital for architects, engineers, builders and designers to figure out how much site works is required before the building can commence. Along with a soil test, a contour survey plays an important role in getting to know the land and understanding what steps must be taken. The information gathered from these surveys also can be essential to avoiding problems later in development.

It’s worth noting that most local councils have made contour surveys a mandatory step for new home builders. So not only is it a good idea, it’s a legal requirement.

Why is a contour survey required?

The elevation data you gain from a contour survey shows the contour lines of your property. In layman’s terms, this helps determine the various elevations of your land and how steep it is in various areas. Knowing each different elevation helps your builder or architect design your house.

A contour survey helps

  • How your home will sit on the block of land
  • Whether you’ll need a retaining wall
  • Estimate the amount of soil to remove from your property
  • design a house that will meet all requirements of local councils

Why is a contour survey important if you are knocking down rebuilding

The information from a contour survey will help determine what designs are feasible for your new home. It also provides a layout of your property, providing builders with a heads-up on any potential barriers to the project.

A knockdown rebuild can impact your land in a variety of ways, so it’s important to perform a contour survey and soil test after the knockdown, to check how conditions have changed and whether there are any issues that need to be addressed.

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When is a contour survey done?

A contour survey happens early in the building process before any construction begins. It’ll happen at the same stage as other necessary procedures, such as soil tests.

How do you read a contour survey?

So, you’ve received the results of your contour detail survey, how do you read it? These points will get you started:

  • Any point along a single contour line has the same elevation.
  • Closely spaced contour lines mean that the land has a steep slope.
  • Contour lines that are widely spaced indict the land has a gentle slope.
  • Closed lines with higher elevation towards the centre of the block show higher ground towards the middle of the land.
  • Closed lines with reducing levels towards the middle of the block indicate lower ground in the centre of the property
  • Equally spaced contour lines means the land has a uniform shape.

Here’s a visual that shows how contour lines show different elevations. Though these surveys are showing mountains, the basic concept applies to all reports:

Below are a few examples of contour surveys to give you an idea of what to expect.

Example 1
Example 2

Find the best surveyor for your project!

A contour survey is an important part of any building project. It’s important to hire a quality, registered surveyor to ensure the accuracy of your results. Your surveyor must be accredited by the Queensland Building and Construction Commission (QBCC).

Buildi knows the building industry and can help clients find the right surveyor for them. We know the signs of a trustworthy company and also the red flags that your contour surveyor is not on the level.

Book your free, impartial, consultation to discuss contour surveys


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Knockdown Rebuild

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