Second-Storey Addition in Mentone, Bayside Melbourne
Adding a second storey to an existing single-storey home is the cheapest way to add bedrooms without touching your footprint or losing back-yard space. The catch is that many single-storey homes were not engineered to take an upstairs load. The structural upgrade often costs more than the new upstairs itself.
What to know about Mentone
Coastal south-east suburb with rebuild and townhouse activity close to the bay and rail.
This suburb has an active knockdown-rebuild market. Established blocks, real character stock, and buyers already paying premium prices for good design.
Cost snapshot
Second-Storey Addition build costs in Mentone
Base-build rate (mid-range)
$2,700 - $3,600/m²
RLB Q4 2025 — Melbourne, custom (excl. GST)
Typical added area
60–120 m²
Habitable area, indicative
Indicative build cost
$160,000 – $430,000
Base build only; excludes land, site works, fees & GST
Build timeframe
5–10 months
Design to handover
Approval pathway
10–16 weeks
Lodged with City of Kingston
Victoria average (ABS)
$485,292 · $1,914/m²
ABS Building Activity 2024–25, completed detached house
Indicative planning figures only — a builder's fixed-price contract is always final. Sourced from RLB Rider Digest (Q4 2025), ABS Building Activity 2024–25, Cotality Cordell CCCI.
Local build notes for Mentone
Council
City of Kingston
Where people are building
Mentone Centre, near Mentone Beach, Balcombe Road precinct
Typical lots
Coastal 550–750 m² blocks with knockdown-rebuild and townhouse activity near the bay and rail.
Council rules and overlays for second-storey addition in this area
In Victoria, a new build generally needs a planning permit (where the local planning scheme requires one) and a building permit issued by a registered building surveyor. Overlays such as Bushfire Management, Heritage, Significant Landscape and Development Contributions can apply, and growth-area blocks may attract the Growth Areas Infrastructure Contribution (GAIC). Confirm current requirements with your local council and the Victorian Building Authority before finalising a design.
The 3 decisions that shape your second-storey addition in Mentone
Structural upgrade scope
Get a structural engineer to assess the existing footings and frame BEFORE design. This determines whether a full second storey, a partial upstairs or a lightweight loft is realistic.
Staircase placement
The staircase eats floor area on both levels. Its location drives every other design decision.
Live in or move out
A full second storey usually requires removing the roof, which means moving out. A partial or lightweight loft can sometimes be done occupied.
Second-Storey Addition FAQs for Mentone
Can any single-storey home take a second storey?▾
No. Original engineering has to be checked. Some homes need major structural work first. A structural engineer can advise before design starts.
Is a second storey cheaper than moving?▾
Usually yes, especially in Melbourne's inner and eastern suburbs where you would pay a premium to buy a two-storey equivalent. The maths breaks down if the structural upgrade is major.
Do I need to move out?▾
For a full second storey, usually yes. For a partial or lightweight loft, sometimes not. Confirm with your builder.
Will my house lose character?▾
Only if it is designed poorly. Well-designed second storeys often lift a home's presence rather than detract from it.
Do I need council consent?▾
Yes. Second storey additions require both planning and building consent.
People also ask
Building a second-storey addition in Mentone
Which council approves a second-storey addition in Mentone?▾
Mentone sits in City of Kingston. That council administers the planning scheme and any overlays across the suburb, while your building permit and the mandatory inspections run through a registered building surveyor.
Where are new second-storey additions being built in Mentone?▾
Most of the building activity in Mentone is around Mentone Centre, near Mentone Beach and Balcombe Road precinct.
What lot sizes are typical for a second-storey addition in Mentone?▾
Coastal 550–750 m² blocks with knockdown-rebuild and townhouse activity near the bay and rail.