A site assessment is the survey and inspection that establishes what your block will actually allow. It costs a small fraction of a build and it is the difference between a quote you can rely on and an estimate that moves. Almost every unpleasant surprise in a building budget traces back to something a site assessment would have found.
What gets assessed
The contour, meaning the fall across the building envelope specifically rather than across the whole block, because that is what drives earthworks and footings.
The soil, classified from a geotechnical test, which determines the footing design and whether piers are needed.
Services. Where power, water, sewer and stormwater are, and how far they have to come.
Overlays and constraints. Bushfire, flood, storm tide, character controls, easements, setbacks and protected vegetation.
Access. Whether a concrete truck and a crane can reach where they need to be, which sounds trivial until it is not.
Aspect. Sun path and prevailing breeze, which are design inputs rather than cost inputs but get recorded at the same visit.
What it costs, and what it saves
A footing design based on a guessed soil classification, or an earthworks allowance set without a contour, can move a budget by tens of thousands. The assessment is not a cost, it is the thing that makes the rest of the numbers real. Getting a survey done prior to plans being drawn is a good idea to get the actuals of the land. Engineering plans come once the client has approved the priced concept plans and given the go ahead to move into a prelim agreement.
The three things it most often finds
More fall than the block looked like it had, which changes the earthworks and sometimes the whole design approach. Reactive soil requiring a stiffer footing system than budgeted. And an overlay nobody mentioned, which changes the specification.
None of these are disasters when you find them before you sign. All three are expensive when you find them after.
Why some builders skip it
Because a quote off a floor plan can be produced in a day, and a quote off a survey takes weeks. If you are comparing two builders and one has a price for you immediately, ask what that price assumed about your soil and your fall. Then ask what happens to the price when the assumption is wrong.
How we handle it
We do not give a firm price without one. You get an estimate at concept stage built on what the block actually is, with site costs itemised rather than bundled into an allowance you will not understand until it is exceeded.
Frequently Asked Questions
What is a site assessment?
It is the survey and inspection that establishes what your block will actually allow. It costs a small fraction of a build and it is the difference between a quote you can rely on and an estimate that moves.
What does a site assessment check?
The contour across the building envelope, the soil classification from a geotechnical test, services (power, water, sewer and stormwater), overlays and constraints such as bushfire, flood, storm tide, character controls, easements, setbacks and protected vegetation, and access for a concrete truck and crane. It also records aspect, meaning sun path and prevailing breeze, which feeds how we design around your block.
What does a site assessment usually find?
Three things come up most often: more fall than the block looked like it had, which changes the earthworks and sometimes the whole design approach, reactive soil that needs a stiffer footing system than budgeted, and an overlay nobody mentioned, which changes the specification. None of these are disasters when you find them before you sign, and all three are expensive when you find them after.
Why do some builders quote without one?
Because a quote off a floor plan can be produced in a day, and a quote off a survey takes weeks. If one builder has a price for you immediately, ask what it assumed about your soil and your fall, and what happens to the price when the assumption is wrong. We do not give a firm price without one. See fixed price or allowance for how to read the contract that follows.
We build in North Lakes, Narangba, Newport, Samford Valley and Banksia Beach. Call 0483 949 127.
For the full picture on costs, timeframes, contracts and how to check a builder, read Building a Custom Home in Brisbane, The Complete Guide.
