Brisbane & SEQ Costs & Pricing
Room extension plans start from $3,490, with the price confirmed in writing after a scope review. This guide explains what affects the price, what’s included, and what additional fees to budget for.
Plan Draft’s room extension plans start from $3,490 for a straightforward single room addition on a standard residential lot. Room extensions are the one service we don’t price as a single fixed figure, because the drafting work genuinely varies from project to project.
What stays the same is the certainty: every room extension goes through a scope review, and the price is confirmed in writing before any work begins. Once agreed, that price does not change within the confirmed scope. No hourly billing, no open ended totals.
Size and layout of the addition: A single bedroom or living room addition sits at the starting price. Larger footprints and more complex layouts involve more drawing work.
Wet areas: Adding a bathroom, ensuite or laundry brings plumbing layouts and waterproofing notes into the documentation.
Roofline integration: An extension that continues the existing roofline is simpler to document than one that requires a new roof form tying into the existing structure.
Existing house plans: If your original house plans are available, documenting the existing dwelling is faster. Without them, we work from site measurements and photographs, which adds time.
Site conditions: Slope, access and existing structures all influence the site plan and sections required.
The drawing fee is not the only cost involved in getting a room extension approved and built. Here are the other fees to plan for:
Structural engineering: Room extensions almost always require engineering for footings, framing and any openings cut into existing walls. Engineering fees vary with complexity and are quoted by the engineer, who you engage directly.
Private building certifier: The certifier assesses the drawings and issues the building approval. Certifier fees are set and quoted by the certifier.
Site survey (sometimes): Where accurate boundary or level information is needed, a surveyor provides it and quotes the work directly. We advise at scope review whether this is likely for your project.
Construction: Building the extension once approval is granted is a separate cost entirely, arranged with your builder.
Some drafting services quote room extensions sight unseen and adjust the bill later. Others charge hourly, which leaves you carrying the risk of the job running long. We think both approaches put the uncertainty in the wrong place.
The scope review takes your address, photos and a description of the addition, and turns them into a confirmed written price. It costs nothing, it takes about a business day, and it means the number you agree to is the number you pay.
The service starting from $3,490 covers single room additions on standard lots. Projects that go beyond that scope include:
If your project lands in this category, we tell you at suitability review. We can often still quote the work, and if we’re not the right fit we say so.
Plan Draft’s room extension plans start from $3,490 for a straightforward single room addition on a standard residential lot. Every project is scope reviewed, and the price is confirmed in writing before any work begins.
Room extensions vary more than carports, decks, patios or granny flats. Size, wet areas, roofline integration and the availability of existing plans all affect the drafting work. The scope review accounts for those factors, and the confirmed price doesn’t change after it’s agreed in writing.
The drawing set includes a site plan with existing house context, existing and proposed floor plans, all required elevations and sections, basic specification notes, one round of revisions, and the digital PDF. Engineering reports and certifier fees are separate.
Beyond the drawing fee, budget for structural engineering, a private building certifier, and potentially a site survey. Each is quoted and paid directly to the provider. Construction is arranged separately with your builder.
Multi room additions, second storey additions, steep sites, heritage or character overlay complexity, and structurally complex briefs go beyond standard scope. We tell you at suitability review, before any commitment.
Our services
Brisbane & SEQ
Plan Draft provides fixed price drafting for carports, decks, patios, room extensions and granny flats across Brisbane and South East Queensland.
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From $3,490, scope reviewed and confirmed in writing. Send us your project details and we’ll respond within one business day, with no commitment required.