Hardscape details and sections

A section through each built element showing what is under it: sub-base depth, bedding, edge restraint, footing size, drainage behind a wall, membrane, fixings. This is where quality is actually specified.

⏱ 4 hAdvanced🔗 11 resources (9 free)

The layout plan says where the paving goes. The section says whether it will still be flat in ten years. Almost everything that makes a Perth garden fail is buried: the base that was 40 mm of limestone instead of 100, the missing edge restraint, the retaining wall with no aggregate behind it, the deck post concreted straight into sand.

A detail is a drawing at large scale — 1:10 or 1:20 — cut vertically through one element, showing every layer from the subgrade up and every layer from the face back. You need one for each different build-up, not one per area. Three courtyards paved the same way share a detail. A courtyard and a driveway do not, because the base depth changes.

What a professional does at this stage

A landscaper who has been burnt draws details defensively. Every layer on the section exists because they have seen the version without it fail, and the numbers are there so nobody — including their own crew at 6am — has to make the call in the field.

The second reason is commercial. Once a section says “100 mm compacted crushed limestone sub-base”, the sub-base is a fixed quantity: cubic metres in the quantity take-off, a line in the quote, and a documented departure rather than an argument if someone lays 50 mm. Without the section, “base preparation” is just a word, and words get thinned when a job runs tight. Draw the details before you cost, not after.

Every detail answers the same seven questions

Any built element — paving, wall, step, deck, edge, water feature — is fully specified when the section answers all seven.

Question	What goes on the drawing
Subgrade	Stripped to what depth, compacted to what standard, and what happens to soft spots
Sub-base	Material, compacted thickness, layer depth if built up
Bedding / footing	Material, thickness, or footing dimensions and concrete strength
Wearing surface	Product, thickness, pattern, joint width
Edge / restraint	What stops it spreading, and how big that thing is
Drainage	Where water goes — falls, agi line, aggregate, outlet
Separation	Geotextile, damp-proof course, root barrier, movement joint

Two rules that apply to all seven. Show a dimension, not an adjective — “adequate base” specifies nothing. And show levels: the section is where finished level meets the levels and grading plan, and the two must agree.

Paving

Perth’s standard build-up is compacted crushed limestone sub-base, sand bedding, unit paving. The City of Wanneroo’s residential crossover specification is the most useful free benchmark in the state.

Sub-base: minimum 100 mm crushed limestone for a brick-paved crossover, thickness depending on ground conditions. CMHA’s equivalent figures are 100 mm compacted for pedestrian areas and 150 mm for residential driveways. On a renovation the existing subgrade is the risk: an old service trench, a filled soakwell or a ground-out stump will settle regardless of what you put on top. Note them on the section and specify removal and recompaction in layers.
Bedding: 20–40 mm pre-compacted, well-graded sand passing a 5 mm sieve. Bricklayers sand and single-sized dune sand are explicitly not suitable, and using them is the most common paving failure in this city. Bedding sand is a bedding course, not a levelling course — if your section allows 60 mm of sand to fix a bad base, it will keep settling.
Units: minimum 60 mm thick for anything a vehicle crosses, laid to 2–4 mm gaps. Compact with not less than three passes of a plate compactor over 12 mm plywood. Joint sand finer than the bedding sand, nominal maximum 2 mm.
Edge restraint: draw it on every single edge. Wanneroo requires 250 mm wide by 80 mm minimum depth; CMHA gives a minimum 200 mm by 200 mm cross section for a hidden poured concrete curb in residential work. A paved area without restraint spreads from the edges inward, joints open and sand washes out — and the failure looks like a base problem when it is an edge problem.

Poured surfaces — concrete, exposed aggregate, and the liquid limestone that is nearly a Perth default — need the same subgrade and sub-base discipline plus jointing. Show control joint spacing, depth and location, because an unjointed slab cracks where it chooses.

Retaining walls

A retaining wall is a structure, and above your council’s threshold it is engineered work. In the City of Stirling a building permit is required where any retaining exceeds 0.5 m, and a wall may only sit on the boundary if it is not more than 0.5 m above natural ground. The City of Joondalup publishes a 0.5 m trigger with additional conditions. Confirm your own council’s figure, and see retaining walls approval.

For a segmental block wall, the section must show:

Base. Not less than 150 mm of compacted crushed rock, cement-stabilised crushed rock, or lean-mix concrete of at least 15 MPa. Then 25 mm of washed sand to fine-level the first course.
Embedment. First course bedded roughly half a block below finished ground. Walls that start at ground level slide.
Drainage. 100 mm agricultural pipe with a sock, laid at 1 in 100 fall, and — the part everyone forgets — vented to daylight at a point you have actually drawn. A drain that discharges into sand behind the wall is decoration.
Backfill. 200–300 mm width of clean 10–20 mm aggregate against the back of the blocks, with block cores filled, placed one course at a time as the wall goes up.
Geotextile. Between the aggregate and the retained soil, so fines cannot migrate into the drainage layer and choke it. This is not optional on Perth sand.
Surface water. Show where water on top of the wall goes. It must not cascade over the face.

Hydrostatic pressure pushes walls over; drainage removes it. A wall that leans, bulges or cracks almost always had no functioning drainage layer.

Decks, structures and fixings

Deck footings are designed under AS 2870 or AS 1684; anything unusual — a spa, a tiled deck, poor ground — goes to a structural engineer. The details that matter on the section:

Galvanised stirrups with at least 75 mm clearance above finished ground, so posts are off the sand and termite inspection is possible. If a post is embedded directly, use no-fines concrete and slope the top of the footing away from the post.
25 mm separation from the building where a termite barrier under AS 3660.1 is the compliance method, and 10 mm between decking boards and the wall for drainage.
Timber grades: above-ground elements at natural durability Class 1 or 2, or softwood treated to at least H3. In-ground posts at Class 1 or H5. H2, H2F and H2S are not suitable for decks.
Fixings: hot-dip galvanised or stainless steel; electroplated fasteners break down early. Within 1 km of the coast, or within 1 m of a pool edge, fixings must be stainless steel — which in Perth captures most of the coastal corridor and every backyard with a pool.
Board gaps: 3–4 mm is the long-term target, adjusted at installation for seasoned versus unseasoned timber.

For roofed structures, note that from 1 July 2026 builder registration is not required in WA for Class 10a buildings under $50,000 — sheds, carports, patios and private garages. A building permit is still required and the structure still has to comply. See structures and building permits.

Where the hardscape meets the house

This detail costs the most to get wrong and takes ten seconds to check. A damp-proof course must be at least 150 mm above adjacent ground level, or at least 75 mm above adjacent paving, concrete or landscaping that slopes away from the wall. Raise a bed or a paved level against the house and you bridge the DPC; rising damp appears inside months later.

On a renovation, measure the existing DPC height before you set your finished paving level. If the numbers do not work, the answer is a drainage channel or a step down, not a hopeful 20 mm.

The safety notes that belong on the drawing

Details create hazards, so name them where the work is specified.

Silica. Since 1 September 2024, cutting, grinding or drilling any material with at least 1 per cent crystalline silica — pavers, blocks, bricks, tiles — is a regulated process in WA. Never dry-cut. Water suppression on the tool, P2 respirator, outdoors, off the wind. A pattern that generates hundreds of cuts is a design decision with a health consequence.
Trenches. Nobody works in an excavation 1.5 m or more deep without shoring, and spoil stays at least 600 mm from the edge, preferably two metres. Perth sand gives no warning before it collapses.
Working alone in heat. Deep footings in February, one person, no water. This kills people. Schedule it out.
Old structures. Anything pre-1990 you cut into may contain asbestos — see auditing an existing garden.

What happens to this next

The drainage plan must receive every agi line and outlet you drew behind a wall or under a paved area, and the specification and schedule of works turns each section into words a contractor prices and a client signs.

The next lesson takes the falls from your grading plan and the outlets from these sections and resolves where all that water actually goes.

Checklist

Draw a section through every different built element
Specify sub-base type and compacted depth for each surface
Show edge restraint on every paved area
Show drainage and backfill behind every retaining wall

Where to go deeper

Every link below was fetched and checked before it shipped. Nothing here is a guess.

Freegovernment15 minPerth / WA
Crossover, brick paved — residential: information sheet
City of Wanneroo
Why this oneThe most useful free WA paving specification in existence, because a council writes it to be enforced rather than to sell anything. It gives minimum 100 mm crushed limestone sub-base, 20–40 mm pre-compacted bedding sand that must be well graded and pass a 5 mm sieve, 60 mm minimum heavy-duty pavers, 2–4 mm gaps between units, joint sand at 2 mm nominal maximum, not less than three passes of a plate compactor over 12 mm plywood, and edge restraints 250 mm wide by 80 mm minimum depth. It also states plainly that bricklayers sand and single-sized dune sands are not suitable as bedding — the single most common paving failure in Perth.
Change this for Perth
Written for a crossover in the road reserve, so the loading is heavier than a courtyard and the widths, wing dimensions and 2% verge gradient are Wanneroo's own. Your council's crossover specification will differ in detail. Use it as a materials and workmanship benchmark for your own paving, not as an approval document.
Link checked 2 Aug 2026
Freearticle35 minOverseas — adapt it
Construction of Interlocking Concrete Pavements (PAV-TEC-002)
Concrete Masonry and Hardscapes Association
Why this oneThe layer-by-layer construction sequence with numbers you can put straight onto a section: minimum compacted base of 100 mm for pedestrian areas and 150 mm for residential driveways, a nominal 25 mm uncompacted bedding sand course screeded over rails, subgrade and base compacted to at least 98% standard Proctor density, and geotextile with a maximum apparent opening size of 0.60 mm lapped a minimum of 300 mm. It is the clearest free explanation of why bedding sand is a bedding course and not a levelling course.
Change this for Perth
North American. Ignore everything about freeze-thaw. Substitute compacted crushed limestone for the crushed aggregate base — that is the Perth material. Its geotextile trigger is saturated, clay or silty subgrade, which describes very little of the Swan Coastal Plain, so on clean sand most Perth builds omit it; keep it where you are working over clay, over old fill, or over a soakwell surround.
Link checked 2 Aug 2026
Freearticle20 minOverseas — adapt it
Edge Restraints for Interlocking Concrete Pavements (PAV-TEC-003)
Concrete Masonry and Hardscapes Association
Why this oneEdge restraint is the detail most often left off a drawing and the one that most reliably destroys a pavement, and this is the only free document that treats it as a design element. It gives a minimum 200 mm by 200 mm cross section for a hidden poured concrete curb in residential work, requires the base to extend beyond a spiked restraint by at least the thickness of the base, and explains why timber edging warps and rots. Read it before you draw a single paving edge.
Change this for Perth
Imperial units with metric conversions. The proprietary plastic and aluminium restraints it describes are less common in Perth than a poured concrete haunch or a course of bedded bricks, but the sizing logic transfers directly.
Link checked 2 Aug 2026
Freearticle1 hAustralian
Domestic Timber Deck Design (Technical Design Guide 21)
WoodSolutions / Forest and Wood Products Australia
Why this oneThe free Australian design guide that answers the detail questions a deck section has to resolve. Galvanised post stirrups with at least 75 mm clearance above finished ground so termite inspection is possible, a 25 mm separation between the deck and the building required by AS 3660.1 where a termite barrier is the chosen method, 10 mm between decking boards and the wall for drainage, 3–4 mm board gaps as the long-term target, above-ground timber at natural durability Class 1 or 2 or H3 treated, and in-ground posts at Class 1 or H5. It also states the rule that catches most Perth coastal jobs: fixings within 1 km of the coast, or within 1 m of a pool edge, must be stainless steel.
Change this for Perth
National, so it does not name Perth's wind region or bushfire requirements. If your block is in a designated bushfire prone area, decking material and sub-floor enclosure are additionally constrained by AS 3959 and you must resolve that before you finalise the detail.
Link checked 2 Aug 2026
Freearticle25 minAustralian
Your complete guide to DIY block retaining walls
Australian Paving Centre
Why this oneA supplier guide that, unusually, publishes the dimensions rather than the sales pitch. A facing built on a base not less than 150 mm thick of compacted crushed rock, cement-stabilised crushed rock, or lean-mix concrete of at least 15 MPa; 25 mm of washed sand screeded over that base; the first course bedded half a block below finished ground; 100 mm PVC agricultural pipe with a sock laid at 1 in 100 fall and vented to daylight; and 200–300 mm of clean 10–20 mm aggregate backfill with every block core filled, placed one course at a time. That is the drainage detail behind a segmental wall, written out in full.
Change this for Perth
This is a paving retailer's own document and it exists to sell blocks, so treat product-specific claims as advertising. It is South Australian, and unreinforced height limits are product-specific — the maximum heights in its diagrams are not a substitute for your council's threshold or an engineer's design. In WA, check the permit trigger first: most Perth councils bite at 0.5 m.
Link checked 2 Aug 2026
Freegovernment10 minPerth / WA
Retaining walls information sheet
City of Stirling
Why this oneA Perth council stating its own thresholds in plain language: a building permit is required where any retaining exceeds 0.5 m in height, a wall may sit on the boundary only where it is not more than 0.5 m above natural ground level, and all footings and associated works must be contained within the lot. It also reproduces the R-Codes Clause 5.3.7 site works table, where required setback matches wall height — 1 m of retaining needs 1 m of setback, 2 m needs 2 m, and so on up to 3 m.
Change this for Perth
Stirling's document, last updated December 2021, and thresholds vary between Perth councils. The City of Joondalup, for example, publishes a similar 0.5 m trigger but adds conditions about work for the protection of adjoining land. Confirm the current figure with your own council before you commit a wall height to the drawing.
Link checked 2 Aug 2026
Freestandard15 minAustralian
NCC 2025 Housing Provisions Part 5.7 — Weatherproofing of masonry
Australian Building Codes Board
Why this oneThe clause that decides how high you are allowed to finish paving, a garden bed or a raised deck against the house. A damp-proof course must sit at least 150 mm above adjacent ground level, or 75 mm above the finished surface of adjacent paved, concreted or landscaped areas that slope away from the wall. Landscapers bury this line every week by raising levels against a wall, and the result is rising damp inside the house.
Change this for Perth
The NCC is national but adopted state by state. Western Australia adopted NCC 2025 on 1 May 2026 with a 12-month transition, so a job documented earlier may still be assessed against NCC 2022 — the damp-proof course clearances are materially the same in both.
Link checked 2 Aug 2026
Freegovernment1 h+Perth / WA
Code of practice: Excavation
WorkSafe WA
Why this oneThe WA regulator's own code, last updated 25 November 2024, and the document that turns 'be careful in the trench' into a rule you can design around. It states that workers must not be required to work in an excavation 1.5 metres or more deep that is not protected by shoring, and that materials and equipment should be kept at least 600 mm from the edge of an excavation and preferably a minimum of two metres. It also covers battering, benching, spoil placement and the zone of influence around an excavation.
Change this for Perth
Written for workplaces under the WHS Act. A homeowner digging their own footings is not the regulator's target, but the physics is identical and sand collapses without warning. If your detail requires a trench approaching 1.5 m — a deep wall footing or a drainage run — redesign it or engage a contractor with shoring.
Link checked 2 Aug 2026
Freegovernment10 minPerth / WA
Crystalline silica substances regulations: information sheet
WorkSafe WA
Why this oneEvery hardscape detail you draw implies someone cutting something, and this is the WA regulator's statement of what that now means. Amendments to the Work Health and Safety (General) Regulations 2022 commenced on 1 September 2024, a crystalline silica substance is any material containing at least 1 per cent crystalline silica by weight — which includes bricks, blocks, pavers and tiles — and using power tools to cut, grind or drill those materials is a regulated process. Read it before you specify a paver that needs a lot of cuts.
Link checked 2 Aug 2026
Paid · $184.71 including GSTstandardReferenceAustralian
AS 3727.1:2016 Pavements — Residential
Standards Australia (via Intertek Inform)
Why this oneThe Australian standard that actually governs what you are drawing: design and construction of pavements for light, low-speed, non-commercial use by vehicles up to 10 tonnes gross mass, explicitly covering patios, paths, driveways, vehicle crossovers and cycleways. If a dispute over a failed driveway ever reaches a building surveyor or a court, this is the document they open. Published 13 December 2016 and still current.
Change this for Perth
Expensive for one garden, and it excludes Class H1, H2, E and P sites — reactive and problem soils — which is not usually a constraint on Perth sand but matters on the clay pockets in the eastern suburbs and the hills. If you are not buying it, the City of Wanneroo crossover sheet and the CMHA tech notes above give you most of the same numbers for free.
Link checked 2 Aug 2026
Paid · $308.30 including GSTstandardReferenceAustralian
AS 4678-2002 Earth-retaining structures
Standards Australia (via Intertek Inform)
Why this oneThe standard your engineer will design a retaining wall to, and the one a council will name in its conditions. It sets design criteria for structures required to retain soil, rock and other materials, in limit state format, including soil and rock reinforcement. Listed as current, published 26 February 2002. Worth knowing it exists so you can ask for a design certified to it rather than accepting a supplier's generic chart.
Change this for Perth
This is an engineer's document, not a builder's manual — it will not tell you how to lay a block. Do not buy it to build a wall. Buy nothing, and instead pay a structural engineer for a certified design on any wall over your council's threshold, over about 1 m, or carrying a surcharge such as a driveway, a pool or a neighbour's fill.
Link checked 2 Aug 2026

The rules, with sources

WA regulation changes. Each point below names its primary source and the date it was last checked — always confirm with your own council before you build.

In the City of Stirling, a building permit is required where any retaining exceeds 0.5 m in height. A retaining wall may only be built on the boundary where it is not more than 0.5 m above natural ground level, and all footings and associated works must be contained within the lot boundaries. Under R-Codes Clause 5.3.7, the required minimum setback matches the height of the site works: 0 m for 0.5 m or less, 1 m for 1 m, 2 m for 2 m, up to 3 m for 3 m.
City of Stirling — Retaining Walls Information Sheet ↗ · checked 2 Aug 2026
In the City of Joondalup, a building permit is not required for a retaining wall only if it meets all of the following: the wall does not exceed a height of 0.5 m; it is not part of, nor does it require, additional building work for the protection of adjoining land; and it does not adversely affect neighbouring properties in a way that would necessitate their consent.
City of Joondalup — Retaining walls and site works ↗ · checked 2 Aug 2026
A damp-proof course in a masonry wall must be not less than 150 mm above the adjacent ground level, or not less than 75 mm above the finished surface level of adjacent paved, concreted or landscaped areas that slope away from the wall.
NCC 2025 Housing Provisions, Part 5.7 Weatherproofing of masonry, Australian Building Codes Board ↗ · checked 2 Aug 2026
Western Australia adopted NCC 2025 on 1 May 2026, with a 12-month transition period.
Australian Building Codes Board — NCC 2025 state and territory adoption information ↗ · checked 2 Aug 2026
Workers must not be required to work in an excavation 1.5 metres or more deep that is not protected by shoring. Materials and equipment should be kept at least 600 mm from the edge of an excavation, and where possible a minimum of two metres.
WorkSafe WA — Code of practice: Excavation ↗ · checked 2 Aug 2026
Amendments to the Work Health and Safety (General) Regulations 2022 dealing with crystalline silica substances commenced in Western Australia on 1 September 2024. A crystalline silica substance is any material containing at least 1 per cent crystalline silica by weight, which includes bricks, blocks, pavers and tiles, and using power tools or mechanical plant to crush, cut, grind, trim, sand, abrasive polish or drill those materials is a regulated crystalline silica process.
WorkSafe WA — Crystalline silica substances regulations information sheet ↗ · checked 2 Aug 2026
From 1 July 2026 in Western Australia, builder registration is not required to construct Class 10a buildings — sheds, carports, private garages and similar roofed structures — valued under $50,000. The threshold for all other building work remains $20,000, and a building permit from the local government is still required before work starts.
Government of Western Australia media statement — Red tape cut for low-risk sheds, garages and carports, 14 June 2026 ↗ · checked 2 Aug 2026