Guides to the National Construction Code, the standards it references and Australian planning rules. Every figure carries its clause, so you can check the source rather than take our word for it.
Code and compliance
Building Commission NSW's Building Defects Library lists 40 defects its auditors find often on apartment sites. Here they are by building element, each with its NCC 2025 and NCC 2022 clause and the stage where it is cheapest to catch.
Code and compliance
Building Commission NSW lists six services defects its auditors keep finding on apartment sites, all in ventilation and ductwork. Here is each one with its NCC 2025 and NCC 2022 clause and when to catch it, plus a natural ventilation calculator.
Code and compliance
Building Commission NSW lists six building enclosure defects its auditors keep finding on apartment sites, from damp-proof courses and weepholes to flashings and cladding. Here is each one with its NCC 2025 and NCC 2022 clause and when to catch it, plus a weephole calculator.
Code and compliance
Building Commission NSW lists seven structural defects its auditors keep finding on apartment sites, from a missing lintel to cut reinforcement. Here is each one with its NCC 2025 and NCC 2022 clause and when to catch it, plus a lintel bearing calculator.
Code and compliance
Building Commission NSW lists eleven fire safety defects its auditors keep finding on apartment sites, from fire-rated walls and penetrations to fire doors, stairs and hydrants. Here is each one with its NCC 2025 and NCC 2022 clause and when to catch it, plus a fire door gap calculator.
Code and compliance
Building Commission NSW lists ten waterproofing defects its auditors keep finding on apartment sites. Here is each one with its NCC 2025 and NCC 2022 clause and when to catch it, plus the new NCC 2025 balcony rules and a floor fall calculator.
Product and industry
AEC Assistant keeps getting better: projects now open on a drawing workspace that reads every sheet as you add it, reviews a set against the NCC, pins each issue where it is on the sheet, and lays every consultant's drawings over the architecture. You can also now choose how each answer is made.
Code and compliance
NCC 2025 sends box gutters to AS/NZS 3500.3:2025: a constant fall between 1:200 and 1:40, a sole at least 300 mm wide (200 mm for domestic work), a depth from Figure H.1 with 30 mm of freeboard, no more than 16 L/s at one outlet, and an overflow at every outlet. With a box gutter depth calculator.
Code and compliance
On 29 October 2026 the ABCB issued Corrigendum 1 to NCC 2025. Most corrections are editorial, but several change a result: Class 8 joins the solar PV tables, a sign error in the Volume Three pipe sizing method is gone, and the Housing Provisions steel, Class 10b and glazing provisions are corrected. Every correction, clause by clause.
Planning
Victoria's minimum garden area is 25%, 30% or 35% of the lot. Since Amendment VC314 on 28 October 2026, uncovered driveways and car parking count in the planning scheme and the 1 m minimum width is gone, but where no planning permit is needed the Building Regulations still exclude them. With a garden area calculator.
Product and industry
AEC Assistant keeps getting better: product claims checked against the official registers and the manufacturers' own data, drainage calculators with a report for your building surveyor, and new reviews for house plans, energy, siting and site safety.
Code and compliance
Under NCC 2025 a Class 5 to 9 building that must have toilets needs an accessible unisex toilet on every storey with toilets (a small-building concession aside), at not less than half the banks where a storey has more than one, and an ambulant toilet for each sex at a bank where the accessible one has other toilets beside it (F4D5, F4D6). This guide covers when one is required, the count for each class, small cafés and small buildings, and the AS 1428.1:2021 layout, with a checker that counts them.
Planning
In Victoria a small second dwelling is a self-contained Class 1a unit of 60 m² or less on the allotment of an existing house (Building Regulations 2018 r 5), while the planning scheme defines it up to 80 m². This guide covers when a planning permit is needed, the three siting rules written for the unit (r 74A, r 86A, r 86B), how the council's report and consent works, and the appeal to the Building Appeals Board, with a checker.
Code and compliance
The NCC sorts every building by its use into Classes 1 to 10. This guide sets out each class and sub-class from Part A6, the tests that separate a Class 1a townhouse from a Class 2 apartment and a Class 1b guest house from a Class 3, how a building with several uses is classified, the 10% minor-use rule and its exceptions, and what the class decides in the rest of the Code. With a class finder.
Code and compliance
Table C2D2 of NCC Volume One sets a building's Type of construction from two facts: its class and its rise in storeys. This guide explains how C2D3 counts storeys on a sloping site, with basements, rooftop plant, mezzanines and tall industrial storeys, how effective height differs, the two-storey concession, and what Type A, B or C changes beyond FRLs. A section builder counts the storeys and gives the Type.
Sustainability and energy
Section J of NCC 2025 Volume One sets the energy efficiency rules for Class 3 and Class 5 to 9 buildings and Class 4 parts. This guide covers the four Performance Requirements, the Verification Methods (NABERS Energy, Green Star, a reference building and an air-tightness test), the Deemed-to-Satisfy Parts J4 to J9 with their key numbers, what a Section J report is, and a checker for the J7D3 lighting power allowance.
Sustainability and energy
A new house on the NCC 2025 energy rating pathway needs a NatHERS rating of 7 stars, inside separate heating and cooling load limits, and a whole-of-home rating of 60 (Specification 42). In climate zones 1 and 2 a qualifying outdoor living area lowers the star rating to 6.5, or to 6 with a ceiling fan. This guide sets out both pathways in Part H6, the elemental route in Housing Provisions Section 13, the state and territory variations, and a checker for your ratings.
Code and compliance
A house site's wind classification, N1 to N6 or C1 to C4 in cyclonic regions, is read from AS 4055:2021 Table 2.2 using four site conditions: the wind region, the terrain category within 500 m, the topographic class and the shielding class. This guide explains how each is found, with its clause, where the NCC uses the class, and a calculator that applies Table 2.2 to your site.
Code and compliance
What Class 10a, 10b and 10c mean in the NCC, which parts of the Code apply to a shed, garage or carport, and when a Class 10a near a boundary or another building needs a fire-rated wall under Housing Provisions 9.2.4 to 9.2.8. Every protection method the Code accepts, the open-carport test, garages under dwellings and the South Australian variations, with a checker that draws your site.
Code and compliance
What the ABCB Standard for Livable Housing Design asks of a new house or apartment: a step-free path no steeper than 1:14 with no more than 9 m of ramping at 1:14, an 820 mm entrance door with a 1200 mm landing, 820 mm internal doors and 1000 mm corridors, an entry-level toilet with a 1200 × 900 mm clear space, a hobless shower and walls reinforced for grabrails. Every clause, the state variations printed in NCC 2025, a printable checklist and a checker.
Code and compliance
A termite management system is required where a Class 1 or 10 building is in an area where subterranean termites are a known risk and a primary building element is susceptible to attack. This guide sets out the materials the NCC treats as not subject to attack, the options in Housing Provisions Table 3.4.2, the 75 mm exposed slab edge and 400 mm subfloor clearance of AS 3660.1, the durable notice, the Queensland and Northern Territory variations and what Volume One requires for Class 2 to 9 buildings.
Tools and calculators
Free calculators for roof drainage, box gutters, site stormwater and water supply, applying the methods NCC 2025 calls up, AS/NZS 3500.3:2025 and 3500.1:2025, and showing their working clause by clause. What each one sizes, where the Standard applies, and how the numbers were checked.
Product and industry
AEC Assistant keeps getting better: a new tuned model that follows a question through related provisions, a deeper read of your drawings and clause clips, answers that keep going when you close the tab, and longer-running work on the way.
Code and compliance
Where AS 1428.1:2021 asks for 30% luminance contrast (doorways, stair nosing strips, the line on frameless glazing, toilet seats), how the Bowman-Sapolinski equation in Appendix B turns two light reflectance values into a contrast figure, why LRV 40 against 70 fails while LRV 5 against 30 passes, the 45% and 60% for tactile indicators, and a calculator that runs the equation for your pair.
Code and compliance
How NCC Volume One D2D18 sets the number of persons a storey, room or mezzanine is assessed for: the floor area of each part divided by the Table D2D18 figure for its use, with lifts, stairs, corridors, lobbies, ducts and sanitary compartments left out; or a seating count; or another suitable assessment. The full table, the NSW version, a worked office example, the clauses that then use the number, and a calculator that runs the method.
Code and compliance
Clause D3D14 of NCC Volume One sets every stair dimension for a Class 2 to 9 building: 2 to 18 risers a flight, Table D3D14's riser, going and 2R + G limits, the 5 mm and 10 mm constancy rule, the 125 mm sphere, slip resistance, solid treads, the Class 9b 36-riser rule and winders. Every sub-clause explained, with the NSW variation, the Housing Provisions equivalent and a checker for your flight.
Code and compliance
Clause D3D17 of NCC Volume One is the trigger for a balustrade: a continuous barrier along the side of a stair, ramp, floor, balcony, mezzanine, accessible roof or path where the trafficable surface is 1 m or more above the surface beneath. The four locations, the four exclusions, the construction rules in D3D18 to D3D21 it calls up, the NSW variation, the Housing Provisions equivalent for a house, and a checker for your edge.
Code and compliance
Clause D3D22 of NCC Volume One sets the handrail rule for every stair and ramp in a Class 2 to 9 building: one side, both sides at 2 m wide, the top not less than 865 mm above the nosings, continuous between landings, the second lower rail in primary schools and early childhood centres, AS 1428.1 in an accessible exit, the health-care and aged care corridor rails, and the separate rules for a stair inside an apartment. Every sub-clause explained.
Code and compliance
The gradient an accessible ramp may have (1:14), where it becomes a walkway (1:20), how far it can run before a landing (9 m), the 1000 mm width, the 1:40 crossfall, handrails both sides with 300 mm extensions and the 65 mm kerb, with the step, threshold and kerb ramps that sit beside them. Every figure from AS 1428.1:2021 and the NCC clause that calls it up, and a calculator that checks your rise and length.
Code and compliance
How many closet pans, urinals and washbasins a Class 3 to 9 building needs under NCC Volume One Part F4: count the people, split them by sex, read the band in the right F4D4 table and round any part of the next band up. The tables for offices, factories, shops, restaurants and schools, the accessible and ambulant compartments that sit on top, the unisex and all-gender options, the state variations, and a calculator that draws the bank of fixtures for your numbers.
Code and compliance
How eaves gutters, downpipes and overflow measures are sized under NCC 2025: the 5-minute rainfall intensity for your locality, the gutter type from Table 7.4.3a, the 12 m per downpipe rule and the overflow volume the gutter must shed in a 1% AEP storm. Every table, the Code's own worked example, and a calculator that runs the method for your roof.
Code and compliance
A wall, column, floor or beam is a fire-resistant building element when it holds a fire-resistance level, and NCC Volume Two Specification 1 sets the six ways to prove one: the deemed thickness tables, a tested prototype, an assessment of a near-identical element, a design to the structural standard, a calculation, or the fire-protected timber route. This guide walks through each with the clause, reproduces the deemed tables for masonry, concrete and gypsum walls and for protected steel, explains the Specification 2 detailing rules that come with them, shows where a house needs one, and includes a finder for steel column and beam protection.
Code and compliance
An FRL is three numbers in minutes: structural adequacy, integrity and insulation, in that order, from the AS 1530.4 furnace test. Which FRL a wall, column, floor or roof needs comes from the building's class, its rise in storeys (which sets Type A, B or C construction) and, for external walls, its distance from a boundary or another building. This guide explains each step with the clause, and the finder below reads the Specification 5 tables for your element.
Code and compliance
The NCC handrail rule for a house is one rail, on one side, with its top at least 865 mm above the nosings. A commercial stair adds a second rail once it is 2 m wide, and an accessible stair adds a 1000 mm maximum, both sides, a 30 to 52 mm grip and 300 mm extensions. This guide sets out each rule with its clause, and the checker below draws the rail for your stair.
Code and compliance
The minimum insulation R-value for a house ceiling, wall or floor is read from the climate-zone tables in Part 13.2 of the ABCB Housing Provisions. This guide gives the headline NCC 2025 figures for the common cases in all eight zones, plus the thermal bridging, reflective foil, solar absorptance, edge-reduction and condensation rules around them.
Code and compliance
When a house wall must be fire-rated under the NCC: the 900 mm boundary and 1.8 m building-to-building rules in Housing Provisions 9.2.1, what FRL 60/60/60 means, openings and eaves near the boundary, separating walls to 9.3.1, service penetrations, garage exemptions, and the SA, NSW and WA variations.
Code and compliance
A BAL rating, or Bushfire Attack Level, grades how much ember attack, radiant heat and flame a building on bushfire prone land could face, in six levels from BAL-LOW to BAL-FZ. This guide explains what each level means, how AS 3959:2018 works it out from the fire danger index, vegetation, distance and slope, what each level requires of walls, windows, roofs and decks, where NCC 2025's state variations change the rules, and a calculator that estimates the level for a site.
Code and compliance
Every NCC balustrade figure in one place: the 1 m fall trigger, 1 m and 865 mm heights, the 125 mm sphere and 40 mm face gap, the 150 to 760 mm climbability zone above 4 m, wire barrier tables, AS 1288 glass rules and the 2 m and 4 m openable window limits.
Code and compliance
Every NCC minimum ceiling height in one place: 2.4 m habitable rooms, 2.1 m kitchens, bathrooms and garages, 2.0 m over stairs, the two-thirds rule for raked ceilings and attics, and the Volume One figures for apartments, offices, schools and hospitals.
Code and compliance
The eight NCC climate zones explained: what each one means, how to find the zone for any address (Sydney is two zones), why NCC and NatHERS zones differ, and what NCC 2025 changes between them for insulation, roof colour, wall membranes and the drained cavity now mandatory in zones 6, 7 and 8 (outside NSW and Tasmania).
Product and industry
The biggest release since launch: faster and more thorough answers, NCC 2025 answered by default in every state, projects that fetch zoning and overlays from the address, sharing across your firm, public answer links, an installable app and seven free NCC calculators. With screenshots.
Code and compliance
Every NCC 2025 stair dimension for a house and a commercial building, with the clause behind each figure: riser 115 to 190 mm, going 240 to 355 mm, 2R + G between 550 and 700, 865 mm handrails, 1 m barriers and the 125 mm sphere test. Two diagrams and a free calculator.
Code and compliance
NCC 2025 became available for adoption on 1 May 2026. Four months on, it is still not the code most Australian projects are assessed against. Who is on it, who is not, and what changed at clause level.
Code and compliance
AS 3740:2021 sorts every wet-area material into waterproof or water-resistant, in Clause 3.3. The lists as a working reference, the NCC clauses that decide which label applies, and the compatibility chain in Appendix E that most failures break.
Planning
Victoria's Townhouse and Low-Rise Code replaced ResCode at Clause 55 on 31 March 2025. Meet every applicable standard and the application is exempt from objector appeal. The numbers, the standards list, the documents to lodge, and the traps, verified against the May 2025 Guidelines.
Code and compliance
AS 3740:2021 is the edition NCC 2025 calls up in its wet-area provisions. What it covers, what changed from 2010 with clause references, which NCC clause calls it up for your building class, and the numbers to keep at hand.
Practice
AS 4000:2025, released in June 2025, replaced the 1997 general conditions. The headline changes with clause numbers: GST, PPSA, WHS principal contractor, dispute resolution, and what to fix in your templates.
Product and industry
We named the problem. We published the architecture. Now we've shipped it: AEC Assistant rebuilt around projects, memory and cited, project-specific compliance answers. There's a free plan, so bring a real question and put it to the test.
Practice
Three of the most credible analyst voices in construction technology published their theses within weeks of each other. McKinsey on agentic services. Andreessen Horowitz on the system-of-record era ending. Zacua Ventures on AI across the construction value chain. All three arrived at the same structural observation we articulated in The Infrastructure Beneath the Infrastructure in March: the industry needs an intelligence layer, not more tools. The question is no longer whether. The question is how you build one that actually works. This article is our answer. Decision Intelligence Infrastructure (DII™) is a six-floor architecture. Each floor compounds on the floors beneath it. Most of the industry sits between the ground and second levels. The key challenge is not technical but human: institutional intelligence leaves when a project demobilises or when staff depart. Australia serves as a rigorous test case for any architecture aspiring to reach the sixth floor. We are building from this context and publishing the framework openly.
Practice
By Matthew Secatore - Co-Founder of AEC Assistant 15 min read · Construction · Decision Intelligence · AEC Compliance · Infrastructure · AI
Code and compliance
The Block 2025 bathroom week: adhesive failures, high vanities and an unfinished room. Every one of those maps to a clause, and the clauses for a Class 1 house are not the ones most articles cite. A verified checklist for waterproofing, ventilation, livable housing, electrical and plumbing.
Code and compliance
NCC 2022 Amendment 2 took effect on 29 July 2025. It references AS 1428.1:2021 and rewrites D3D22, D4D4 and Volume Three E1D2. Every change, what did not change, and what to re-check.
Product and industry
Month one of AEC Assistant (July 2025): jurisdiction-aware search, multi-image queries, team plans and two new calculators. Superseded; see Update 3 for the current product.
Sustainability and energy
How a ventilated rainscreen wall works, why thermal bridging decides its real R-value, and where the requirements sit in NCC 2025: J4D3, J4D6 and Specification 37 in Section J, and F8D3 for condensation.
Practice
The ARBV and NSW ARB joint report on systemic risks in the architecture sector (October 2022): D&C procurement, client agreements, NCC compliance and the climate and technology disruptors, with what a practice can do about each.
Practice
On Mother's Day 2025 we look at the women balancing AEC careers with parenthood: participation figures, the parental leave rules from 1 July 2024, and what practices can do to keep them.
Code and compliance
AS/NZS 3500 is the plumbing and drainage Standard series: Part 1 water services, Part 2 sanitary plumbing and drainage, Part 3 stormwater drainage and Part 4 heated water services, with Part 0 as the glossary. What each Part covers, which edition is current, where NCC 2025 calls it up, and what changed in the 2025 editions clause by clause, with the free calculators that apply them.
Product and industry
Introducing our founders, Andrew Galea and Matthew Secatore, and why we started AEC Assistant.
Free for the NCC, state legislation, ABCB handbooks and practice notes, with citations, and planning information for any address in Australia. No credit card.
