A dual occupancy building permit covers more than a single new house. It has to line up with your planning permit, separate the dwellings for fire and sound, and account for council consents covering drainage, easements and driveways.
Our building surveyors work with homeowners, investors, small developers and builders on dual occ, townhouse and unit developments across Melbourne and regional Victoria, including knock down and build two projects. We review the design early, issue the building permit, inspect each stage and issue the occupancy permit.
Yes. In Victoria’s residential zones, a planning permit is always required to build two or more dwellings on a lot, and it must be in place before the building permit is issued.
The Townhouse and Low-Rise Code, introduced in 2025, replaced the former ResCode provisions in Clause 55 for townhouses and apartment buildings of up to three storeys. If your design meets a deemed-to-comply standard, such as setbacks, site coverage or overlooking, that objective is treated as met. If it meets every applicable standard, objectors have no right of appeal. Zone rules and overlays still apply.
Since 16 October 2025, two dwellings that meet the listed standards can also use VicSmart: a 10 business day assessment with no notice to neighbours, unless heritage, flooding or certain other overlays rule it out. Our guide to building permits vs planning permits explains the difference.
The NCC classification drives most building permit requirements. Side-by-side townhouses are generally Class 1a, like a detached house, so much of our new home building permits advice applies. Where people live above and below each other, the building is generally Class 2, assessed under NCC Volume One with extra inspections of fire and smoke-resisting elements. See our apartment building permits page.
Attached Class 1a dwellings need a fire-resisting separating wall. Under the NCC Housing Provisions, it needs a fire-resistance level of at least 60/60/60 (or 90 mm masonry), must start at the footings or slab and can’t be crossed by timber framing.
Walls between dwellings must also limit noise. Under the NCC Housing Provisions, a separating wall between Class 1 dwellings needs an airborne sound insulation rating of at least Rw + Ctr 50, so choose a proven wall system and build it exactly as detailed.
Every new home must also meet Victoria’s energy efficiency standards, mandatory since 1 May 2024: a minimum 7-star rating plus a whole-of-home energy budget covering fixed appliances such as heating and cooling, hot water and lighting. Orientation, glazing and appliance choices are far easier to settle during design than after the planning plans are endorsed.
Building permit issues are cheapest to fix before the planning plans are endorsed, because the building permit must be consistent with the planning permit. That’s why we like to see a dual occ design early.
Send us the concept or planning drawings, the title and any planning permit. We check classification, fire separation, siting, drainage and easements, and flag anything that could force changes to the endorsed plans later.
Your team prepares construction drawings, engineering and energy reports. We confirm which council consents, protection work notices and demolition approvals your site needs, and check everything against the planning permit and endorsed plans.
Once the documents comply and the planning permit and any required consents are in place, we issue your building permit. It lists the mandatory notification stages your builder must call us out for.
We inspect the work in person at each mandatory stage, then carry out the final inspection. Once the certificates your permit calls for are in, such as plumbing compliance certificates, we issue the occupancy permit.
Planning approval isn’t the only council sign-off. Depending on the site, a townhouse building permit can also rely on:
Your council may also require an asset protection permit before work starts.
Two dwellings often push construction close to the boundaries, with excavation, footings or walls near a neighbour’s house or fence. When building work could affect an adjoining property, the building surveyor determines whether protection work is required.
If it is, the Building Regulations 2018 set out a notice process. A protection work notice goes to the adjoining owner, who can reply with a protection work response notice, and the building surveyor then makes a determination and gives notice of it. Allow time for this in your program, especially on narrow lots close to existing homes.
Your building permit lists the mandatory notification stages. At each one, the builder must notify us and must not cover up or continue the work until it’s inspected and approved. We inspect in person, not from photos or video, and Class 2 parts need extra inspections of fire and smoke-resisting elements.
Where the building permit requires an occupancy permit, a dwelling must not be occupied until it’s issued. Before issuing it, we carry out a final inspection and review the certificates your permit calls for, such as plumbing compliance certificates, so have them ready early.
JLN Building Consultants is a building surveying consultancy based in Niddrie, in Melbourne’s north-west. Our directors bring over 20 years of combined experience across construction and building surveying, and our residential work ranges from new dwellings and small second dwellings to multi-dwelling projects.
Whether it’s your first knock down and build two or one of several sites, you’ll get fast, practical advice.
Common questions from homeowners, investors and builders planning two or more dwellings on a lot.
Yes. In Victoria’s residential zones, two or more dwellings on a lot always need a planning permit, and it must be obtained before the building permit is issued. Two-dwelling proposals that meet the listed Clause 55 standards, with no excluded overlay, may qualify for the 10 business day VicSmart process.
Not always. Applications lodged before 6 March 2025 are still assessed under Clause 55 as it stood before that date, and so are section 72 amendments to permits whose original application was lodged before the code came into operation. Check which version applies before redesigning under an older permit.
Often, yes, subject to the zone, overlays and planning permit. Replacing one house with two needs a planning permit, and eligible proposals can use VicSmart. You’ll also need approval to demolish the existing house, and the building permit for the new dwellings can’t be issued until the planning permit is in place.
During design, ideally before the planning plans are endorsed. The building permit must be consistent with the planning permit, so a late problem, like a separating wall that doesn’t fit, can mean going back to council. Victoria adopted NCC 2025 on 1 May 2026, so we also confirm which edition applies to your application.
It’s the point, set in a council report, where stormwater from your lot must be discharged. Under regulation 133 of the Building Regulations 2018, the report is needed for a building permit involving stormwater drainage, and the drainage must discharge there. On multi-unit sites, council may also require a new drain or on-site detention.
Send us the site address, your planning drawings or permit and a short description of the project, and we’ll explain what your building permit will involve. Request a free quote, call 0422 234 951 or email info@jlnconsultants.com.au.
