Siteworks are the costs of preparing a specific block to build on: soil classification, sand pad, fill, retaining, rock allowances, drainage and service connections. They sit on top of the design from-price and change by suburb. Across 102 Perth suburbs, The Property Plug data shows siteworks from $20,636 to $37,107, a $16,471 swing on otherwise identical builds.
Two buyers pick the same design, the same inclusions, even the same builder, and pay totals tens of thousands apart. Nothing went wrong. The difference is siteworks, the part of a build that depends on the dirt, not the design. It is the single most misunderstood line in a new home budget.
What siteworks actually covers
Siteworks is everything between a bare block and a slab the house can sit on. It is not the home. It is the groundwork that makes the home possible, and it is priced off your specific block's soil and contour report. The main components are below.
- Soil testing and classification. Sets the footing design. Stable sand is cheap, reactive clay is not.
- Sand pad or fill. Bringing the block up to the build platform height, with cartage and compaction.
- Retaining. Walls to manage level changes, priced by the metre on sloping lots.
- Rock and clay allowances. Excavation through hard ground, priced by the cubic metre.
- Drainage and service connections. Stormwater, sewer, water and power to the boundary and in.
Why the same home costs different amounts
The design from-price is fixed because the home is identical wherever it is built. Siteworks is not, because the ground is different on every block. Soil class, slope, fill depth, rock and service distance all change by location, which is why our data shows a $16,471 siteworks gap between the cheapest and dearest Perth corridors.
This is the honest reason a from-price cannot include siteworks. The builder genuinely does not know your siteworks cost until they see your block's reports. A flat, established, sand-based suburb tests cheaply and needs little preparation. A sloping hill lot needs cut, fill, retaining and sometimes rock removal, and the figure climbs fast. The home did not change. The dirt did.
What the Perth data shows
The Property Plug holds real siteworks figures for 102 Perth suburbs. The table shows the shape of that data as at June 2026.
| Siteworks band | Typical block | Figure |
|---|---|---|
| Low | Flat, established, sand | From $20,636 |
| Mid | Standard estate lot | Around the middle of the range |
| High | Sloping hill or valley, retaining | Up to $37,107 |
The complete ranked dataset for all 102 suburbs sits in the Perth Build-Cost Index, with a worked all-in example in our true cost to build by Perth suburb guide. We publish the from-price and the suburb siteworks figure together on every suburb page, so an indicative build estimate is visible before you enquire. We are paid by the builder, never by you.
IndicativeEstimate only, not a quote or an offer. Figures combine a home design starting price with the suburb siteworks and do not include land. Designs, builders, land and pricing change and are subject to availability. We confirm a fixed price with your matched builder on enquiry.
How to make sure siteworks hold
The risk is not siteworks existing, it is siteworks moving after you sign. Use this short checklist.
- Ask for a real figure, not an allowance. A provisional siteworks allowance can blow out when the soil report lands.
- Get the soil and contour report early. The figure is only as solid as the block data behind it.
- Compare the all-in, not the from-price. Two quotes are only comparable once siteworks is in both.
- Have it pressure-tested. A broker checks the siteworks figure against your block before you commit.
If a quote shows a from-price with no siteworks figure for your actual block, it is not a price yet. Ask for the siteworks number on your soil and contour report before you compare it to anything.