Building costs in Perth have shifted considerably over the past few years, and homeowners planning a project in 2025 and beyond are dealing with a different pricing environment to what many guides written even two or three years ago reflect. Whether you’re budgeting for a new build, a major extension, or a significant renovation, understanding the key cost drivers helps you go into the quoting process with realistic expectations.
New Builds – What Drives the Cost
A new home build in Perth is priced either as a house-and-land package through a volume builder, or as a custom build through an independent registered builder. The two are very different propositions and comparing their costs directly is rarely apples-to-apples.
Volume builders price their products based on standardised designs, fixed inclusions lists, and high construction throughput. For a standard three or four bedroom home on a suburban block, volume build pricing in Perth currently starts somewhere around $250,000 to $350,000 for the structure, though this varies significantly depending on the inclusions tier selected and any site-specific costs. Site costs – the earthworks, slab preparation, and connection to services specific to your block – are often quoted separately and can add meaningfully to the base price, particularly on sloping or difficult blocks.
Custom builds through independent registered builders are priced differently – typically on a cost-plus or fixed-price contract basis for a design that is specific to your block and requirements. Per-square-metre rates for a well-specified custom home in Perth currently range broadly from around $2,500 to $4,500 per square metre of living area, though complex designs, premium finishes, and difficult sites will push beyond this range.
Extensions and Renovations
For existing homeowners, extensions and renovations represent the majority of residential building work in established Perth suburbs. Pricing for this category of work is harder to generalise because the scope varies so widely – a rear extension on a 1990s brick home is a very different job to a second storey addition on a Federation-era cottage in an inner suburb.
As a rough guide, single storey extensions in Perth currently range from around $2,000 to $3,500 per square metre depending on the specification and the complexity of integrating with the existing structure. Second storey additions are typically more expensive on a per-square-metre basis given the structural requirements. Bathroom and kitchen renovations – which often involve plumbing, electrical, and tiling trades in addition to the builder – can range from $15,000 for a basic refresh to $80,000 or more for a full high-specification refit.
Why Perth Costs Have Moved
The Perth building market has experienced significant cost pressures over recent years driven by labour availability, materials pricing, and sustained high demand across the residential sector. Trades that are in high demand – framers, bricklayers, concreters – have seen their rates increase, and this flows through to builder pricing regardless of project type.
For homeowners, the practical implication is that waiting for prices to fall before starting a project is a difficult strategy to rely on. Getting accurate quotes from registered builders for your specific project is more reliable than benchmarking against historical figures or broad per-square-metre averages that may not reflect current market conditions in your suburb.
Variations and Budget Contingency
One of the most common sources of frustration in residential building projects is the gap between the contracted price and the final cost. Variations – changes to the scope of work after the contract is signed – are a normal part of building, but how they are handled varies considerably between builders.
A well-structured building contract will specify clearly how variations are priced and approved. Before signing any contract, read the variations clause carefully and ask your builder directly how variations have been managed on recent comparable projects. Setting aside a contingency of ten to fifteen percent of the contracted value is standard practice for renovation and extension work, and slightly less for new builds where the scope is more tightly defined from the start.
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