Building an accessory dwelling unit (ADU) on a property where you already live takes planning as well as construction. You’ll need to make decisions about the design, access, utilities, and finishes while managing noise, deliveries, and temporary disruption at home. Knowing the usual stages helps you prepare and ask timely questions. The exact sequence can vary with the site, approvals, and project scope, but most builds move from early planning through foundation, structure, services, interior work, and final checks.
Plan the project and site
Before work begins, confirm the proposed layout, scope, budget, responsibilities, and expected schedule with your contractor. Discuss site conditions, property access, drainage, and connections for water, power, and wastewater. Ask which approvals or inspections apply to your project and who will coordinate them. In Auckland, requirements depend on the specific site and design, so verify them with the appropriate professionals and authorities rather than assuming every ADU follows the same path.
Make key design choices early where possible. Room layout, windows, storage, heating, lighting, kitchen and bathroom fittings, and exterior materials can affect drawings, ordering, and later work. Ask which decisions have firm deadlines and what changes might mean for cost or timing. Keep a written record of selections and agreed changes so you and the builder have one clear reference.
From ground to enclosed shell
Once the site is ready, the team may establish work areas, protect parts of the property, and arrange equipment and material deliveries. Groundwork can include excavation, service preparation, and foundation work, depending on the design and site. The structure then takes shape, followed by roofing, exterior walls, windows, and doors. Weather, access, and site conditions can affect the pace, so ask how progress updates and schedule changes will be communicated.
The enclosed shell marks a visible milestone, but it does not mean the build is nearly finished. Before walls are closed, important work such as framing and service installation may need review or inspection. Ask what will be checked, when you can expect access to the work area, and whether photographs or updates will be provided. Avoid entering active work zones unless the contractor has confirmed it is safe.
Services, interiors, and checks
After the structure is enclosed, the project typically moves through electrical, plumbing, and other service work, followed by insulation and wall linings. Interior stages may include cabinetry, bathroom fittings, flooring, paint, lighting, and final connections. Choices made earlier guide much of this work, but confirm the locations and specifications of visible items before installation. Raise questions promptly through the agreed contact so the team can address them before the work is covered or completed.
Near completion, the contractor will work through outstanding items and arrange any required final checks or inspections. Walk through the ADU with the builder, test fixtures and appliances, and note items that need attention. Ask what documents, operating instructions, warranties, or maintenance guidance you should receive. Confirm how any remaining work will be recorded and when it is expected to be completed.
Prepare for work at home
Agree in advance on working hours, parking, delivery routes, temporary fencing, site access, and the best way to reach the site supervisor. Ask how the crew will protect driveways, gardens, and shared paths, and where tools and materials will be kept. If your household includes children, pets, or anyone who needs a quiet or accessible route, discuss practical boundaries before construction starts.
Expect some noise, dust, vehicle movement, and periods when parts of the property are harder to use. Move outdoor furniture and valuables away from the work zone, secure items that could be affected by vibration, and keep windows closed during dusty tasks when practical. Plan around temporary interruptions to services, and ask for advance notice whenever possible. Keep a clear route for household members and emergency access.
A smoother ADU build starts with clear decisions, a shared plan for site access, and regular communication. Keep your selections and questions organized, and raise concerns as soon as they arise. Auckland ADU Works can discuss your property and help you understand the steps involved in planning a build.