Extension and Renovation Building Permits — Melbourne & Victoria

Extending or renovating an existing house is a different job from building new. You are tying new structure into old, and often finding halfway through that the house was never built the way the old drawings say. The permit and the inspections keep that honest, and a residential building surveyor in Melbourne who has crawled through plenty of old roof spaces is worth having.

Cornerstone is a private building surveying practice issuing permits across Melbourne and Victoria. We take on every class of building work — residential, commercial and industrial — and extensions and renovations to existing homes are a large part of it. You appoint us directly, not through council, and one practice handles your job from house extension approval through the mandatory inspections to final sign-off. Fixed fee, quoted before you commit.

When you need a permit

Under the Building Act 1993, building work needs a building permit unless it falls within an exemption in Schedule 3 of the Building Regulations 2018. For an existing home, the line usually falls like this:

• Extensions and additions. Anything that adds floor area — a family room off the back, an enclosed verandah, a room in the roof — needs a permit. The new part has to meet the NCC, including energy efficiency.
• Second storeys. Always a permit, always an engineer. Existing footings and walls are checked for the new load, and overlooking and overshadowing of neighbours are assessed under the siting rules. In many zones and overlays a planning permit comes first.
• Internal structural renovations. Removing or cutting into a load-bearing wall, enlarging a window opening, replacing a wall with a beam — all permit work, with an engineer’s design for the new beam.
• Kitchens and bathrooms. Cosmetic work — joinery, tiles, fixtures, paint, floor coverings, a window replaced like for like in the same opening — is exempt. It tips into permit territory when a wall moves, a new or bigger opening is cut into a wall that carries load, or floor area changes.
• Reroofing. Patching or replacing part of a roof with the same material sits inside the repair and renewal exemption. Stripping and replacing the whole roof is treated as an alteration, which is still exempt if it is like for like and the frame is untouched. Swapping tile for steel or steel for tile changes the loads on the frame, so expect a permit and an engineer’s check of the framing and tie-downs. Skylights and changes to the roofline usually need a permit too.
• Dual occupancy conversions. Turning one house into two dwellings is a permit every time: fire separation between dwellings, separate services and exits, and nearly always a planning permit first.

Siting matters for every addition. Extensions must meet the siting provisions in Part 5 of the Building Regulations — setbacks, walls on boundaries, site coverage, overlooking, overshadowing. Where the design does not comply, council’s report and consent is needed before the permit, and we prepare and lodge that application. One more threshold, from regulation 233: if the alterations, with any others completed or permitted in the previous three years, relate to more than half the original volume of the house, the whole building must be brought up to the current Regulations unless the surveyor consents to partial compliance, which the Regulations only allow within limits. We flag that at quote stage.

What we need from you

Architectural drawings — site plan, floor plans, elevations and sections — showing the existing house and the new work. Engineering for any new footings, beams or second-storey structure. A 7-star energy rating report for the new part where required. A copy of title, and the planning permit with endorsed plans if one was needed. Owner-builders also need a certificate of consent from the Building and Plumbing Commission once the job is above the value threshold. Only have a sketch? Send it anyway and we will say what is missing.

What it costs

Extension and renovation permits are quoted as a fixed fee covering the assessment, the building permit, the mandatory inspections and the final certificate. The fee is set by the scope of the job and the number of inspection stages, not by the hour. Report and consent applications and council fees are itemised separately.

Things that catch people out

• Planning first. Where a planning permit is needed, it must be issued before the building permit can be. Check for heritage, neighbourhood character, bushfire and flood overlays early.
• Protection work. Building on or close to a boundary can trigger protection work notices to the neighbour under the Building Act. Allow time to serve and respond.
• Missed stages. The inspections depend on the job and are confirmed when we quote. A frame lined before we see it gets opened up again.
• Taking the back off the house is demolition too. It is normally covered by the extension’s permit, and Section 29A council consent applies if more than half the house or any street-facing facade goes — our demolition permits page explains the trigger.