Under a Perth backyard you will find one of four things: pale grey Bassendean sand, yellow Spearwood sand sitting on Tamala Limestone, wind-blown Quindalup dune sand on the coast, or the brown clay of the Guildford Formation out east. Which one you have decides how deep the excavator gets, what the base costs, and how the paving behaves in a Perth winter.
It is the biggest single reason two quotes for the same job differ. Well Laid Paving Perth has dug in all four, laying brick paved driveways in Perth from Spearwood out to Forrestfield.
The four ground types under the Perth metro area
Perth sits on the Swan Coastal Plain. W. M. McArthur and E. Bettenay mapped its landforms in CSIRO Soil Publication No. 16, The Development and Distribution of the Soils of the Swan Coastal Plain, Western Australia (1960): three dune systems running parallel to the coast, with river clays behind them. Running inland off the beach, that is Quindalup, then Spearwood, then Bassendean, then clay.
Three of those names are Perth suburbs Well Laid Paving Perth has worked in. Geoscience Australia’s Natural hazard risk in Perth, Western Australia (2005) records the Bassendean Sand as defined by Playford and Low in 1972 from its type area in the suburb of Bassendean.
| Ground type | Where it runs | What comes out of the hole | What it changes on a paving job |
|---|---|---|---|
| Quindalup dune sand | Closest to the water | Loose lime and quartz beach sand | Salt exposure; sand that will not hold an edge |
| Spearwood sand over Tamala Limestone | Coastal and north-western suburbs | Yellow sand, then limestone at unpredictable depth | Excavation plant, achievable levels, spoil weight |
| Bassendean sand | Central and inland sand plain | Pale grey quartz sand; coffee rock near the watertable | Compaction discipline and sub-grade bearing |
| Guildford Formation clay | Eastern suburbs and the Swan | Brown silty clay, wet from June to August | Drainage, seasonal movement, working weather |
Spearwood sand and Tamala Limestone: the coastal and north-western suburbs
From Cottesloe and City Beach up through Floreat, Karrinyup, Scarborough, Innaloo, Gwelup and Duncraig, the yellow sand under the lawn is what is left of a limestone dune. Geoscience Australia’s 2005 Perth Basin review describes the Spearwood Dune System as slightly calcareous aeolian sand remnant from leaching of the underlying Pleistocene Tamala Limestone. Dig far enough and you reach the parent rock.
How far down is the question nobody answers from the kerb. The same review records that the limestone’s upper surface is leached to the extent that the upper part of the unit comprises unconsolidated sand, and that the rock contains numerous solution channels and cavities and in places exhibits karst structures. Depth to hard cap rock varies street to street, not suburb to suburb.
So an excavation that takes an hour in sand can need a breaker, and the finished level is set by what is found, not by the drawing. Someone who has never hit Perth limestone prices it as sand and then varies the quote.
There is an upside. The City of Stirling’s technical specification for a residential brick paved crossover (revised 6 January 2023) calls for a 100 mm base course of crushed limestone — the same material, quarried and graded, that these suburbs already have underneath them.
Quindalup dune sand and the salt belt
The youngest ground in Perth is the strip nearest the water. Geoscience Australia’s 2005 review describes the Quindalup Dune System as wind-blown lime and quartz beach sand forming dunes or ridges generally oriented parallel to the present coast, which may also occupy blowouts within the Spearwood system. At Cottesloe, City Beach and Scarborough that is the ground closest to the water.
Loose, single-sized beach sand is also the worst bedding material there is, and the City of Wanneroo says so: its brick paved residential crossover sheet, correct as of July 2025, requires well-graded bedding sand passing a 5 mm sieve and rules out single-sized dune sands. Then there is salt — the Perth Groundwater Atlas, Second Edition (Department of Environment, December 2004) singles out the Cottesloe peninsula for its underlying salt water.
Bassendean sand: free-draining, and least forgiving of poor compaction
The pale grey sand across Perth’s central and inland suburbs — Morley, Bassendean, Gosnells, out towards Forrestfield — drains beautifully and holds a shape badly. Geoscience Australia’s 2005 review describes the Bassendean Sand as pale grey to white, moderately sorted, sub-rounded to rounded quartz sand, up to about 80 metres thick, inter-fingering eastward with the Guildford Formation.
Here, compaction is the whole job. Stirling’s specification (revised 6 January 2023) sets the sub-grade test at not less than seven blows per 300 mm on a standard Perth penetrometer — a Western Australian field test, used because this is Western Australian ground. Sub-grade that would fail it carries a car for one summer, then dishes where the tyres track.
There is a trap here that costs Perth homeowners money. What comes out of the excavation looks exactly like bedding sand and is not: Wanneroo’s July 2025 sheet requires bedding sand 20 to 40 mm deep pre-compacted, well graded, through a 5 mm sieve. Screeding the spoil back in is cheaper, quicker, and why a drive settles unevenly two summers later.
Geoscience Australia also notes a layer of friable, limonite-cemented sand, colloquially called “coffee rock”, through most of the Bassendean area near the watertable. Paving stops above it — but where soakwells go in the same visit, it is what the excavator meets.
Guildford Formation clay: Guildford, Maylands and the Swan Valley
East of the sand plain the ground changes completely. Geoscience Australia’s 2005 Perth Basin review describes the Guildford Formation as pale-grey, blue, but predominantly brown silty and slightly sandy clay, up to 35 metres thick, outcropping over much of the eastern Perth region — essentially a fluvial mud deposit, with its type area in the Swan Valley. Under paving it behaves nothing like sand.
Clay holds water and changes volume with it, and Perth’s rain arrives in a block. Bureau of Meteorology climate statistics for Perth Metro, station 009225, over 33 years to 2026, give a mean annual rainfall of 718.5 mm with 127.1 mm in June, 147.0 mm in July and 125.2 mm in August — more than half the year’s rain in three months, against 9.6 mm in December.
Australia’s residential slab standard puts a number on what that does. The National Construction Code 2022 Housing Provisions require foundations to be classified in accordance with AS 2870 (clause 4.2.2), and Explanatory Table 4.2.2 separates Class A, “most sand and rock sites with little or no ground movement from moisture changes”, from Class M, “moderately reactive clay or silt sites which can experience moderate ground movement”. That standard covers slabs, not paving — but on a recent house, its soil report is the cheapest read available on whether your ground moves.
On a clay site, water has to be taken away from the paved area rather than through it. The Perth Groundwater Atlas (Department of Environment, December 2004) records the eastern portion of the Swan Coastal Plain as associated with Guildford Clay, which has limited capacity to yield groundwater; on site, that low permeability reads as water sitting rather than soaking.
Why the same driveway spec behaves differently in Cottesloe and Forrestfield
The specification does not change; the work needed to reach it does. Stirling’s technical specification (revised 6 January 2023) asks for a 100 mm base course of crushed limestone or road base over sub-grade compacted to not less than seven blows per 300 mm. In Cottesloe you can hit rock before you reach that depth. At Forrestfield, on the plain’s eastern edge, the same sub-grade tests differently in July.
Council specifications checked: August 2026.
Edge restraint is where the ground shows itself again. Wanneroo’s crossover sheet (correct as of July 2025) requires a restraining barrier around the full perimeter, 250 mm wide and a minimum 80 mm deep, to prevent lateral movement of the bricks. Over loose sand it carries more of the load than over a limestone shelf. We cement the full perimeter of every driveway, in every suburb. Council by council: what your council requires for a crossover.
How to tell what you have before anyone quotes
Four checks, none of which cost anything. Read the colour of the sand in a garden bed — pale grey is Bassendean, yellow is Spearwood, brown and sticky is Guildford clay. Read the site classification on your soil report if the house is recent. Look your address up in the Perth Groundwater Atlas. And ask what the excavator hit when the pool or the soakwells went in.
Few Perth homeowners know the Atlas exists. Its Second Edition (Department of Environment, December 2004) states that the online version lets you search a property and calculate depth to groundwater there — on a low block, the number that decides how deep anyone digs in August.
The most reliable check is still a hole. Half an hour with a shovel, 400 mm down, where the paving is going, tells you more than any map: clean sand, clay under the topsoil, or rock. Contact Before You Dig Australia and pull the plans first, because paving often sits over the same ground as the sewer and the water service.
Neighbours are the other source. Well Laid Paving Perth has paved in Cottesloe, Karrinyup, Scarborough, Innaloo, Floreat, Morley, Bassendean, Gosnells, Forrestfield, Guildford, Maylands and the Swan Valley — all four ground types on this page.
What the ground changes in a paving quote
Four line items, and they are the four that move most between Perth suburbs: excavation and cart-away, the depth and material of the base, drainage, and the edge restraint. Well Laid Paving Perth publishes no rate per square metre. It publishes what a quote covers, so two Perth quotes can be compared line by line instead of on a single headline number.
Excavation is the one that surprises people. Sand comes out fast; limestone needs breaking and the spoil is heavier to cart; clay is worst in winter. Stirling’s specification (revised 6 January 2023) makes the property owner responsible for disposal of all spoil offsite, so removal belongs as its own line, not buried in a rate. A phone figure from an area alone prices the pavers, not the ground: what paving costs per square metre in Perth.
Get a quote from someone who has dug in your suburb
Marc Radaic measures and quotes paving across the Perth metro area, Monday to Friday, 7:00am to 5:00pm, and we never sub-contract — Marc is on site from the first quote to the last paver. Call 0448 440 229 or get a free quote. If it is a drive, start at driveway paving in Perth; everything else is under all our paving services.