How long does it take to build a granny flat in Brisbane?

Most people assume the build is the longest part of a granny flat project. In practice, most of the waiting happens before construction begins — and a realistic timeline accounts for both stages.

A typical completed project runs 4 to 6 months from an initial property check through to handover. How that time is spent matters more than the total.

Phase one: property, design and approvals

Property check (1–2 weeks). The first step is reviewing the address, backyard, access and obvious constraints to decide whether the project is worth taking further. This is where most surprises are caught.

Initial direction and budget (1–2 weeks). The brief, likely layout, level of finish and an initial view of the overall budget are discussed and agreed.

Design and investigations (3–6 weeks). This is where the property is properly understood — survey, site investigations, design development and engineering are coordinated for the specific block. This stage sets the foundations for everything that follows.

Approvals and confirmed scope (2–6 weeks). The required documentation is prepared and the approval pathway is coordinated. The scope and price are confirmed before construction begins.

Phase two: construction and handover

Construction (2–4 months). With the site, trades, deliveries, inspections and progress updates managed throughout the build, construction itself is the most visible — and often the most predictable — part of the timeline.

Handover. Final inspections and practical completion close out the project and hand the completed home over to you.

Why the pre-construction stage matters

The design and approvals stage is where quality is decided. Getting the plan, engineering and approvals right on paper is what keeps construction on schedule and avoids changes later in the project. A well-prepared project builds faster and with fewer surprises than one that rushes past this stage.