Start with one brief
Write down the suburb, intended use, approximate floor area, rooms, access constraints, target timing and any completed surveys or plans. Identify whether you want a supplied structure, an installed building or a completed home. Ask each provider to respond to that same brief.
A modular construction method and a granny flat use can describe the same project. A product name alone does not establish approval to live in it. Begin with the official Victorian small second homes guidance or NSW secondary dwelling guidance, then confirm requirements for your property.
Check these eleven parts of every quote
Copy the checklist into your notes. Beside each item record included, excluded, allowance or unconfirmed for each builder, plus the quoted amount and who is responsible.
1. Design and floor area
The same plan revision, bedrooms, internal area, ceiling height and specification. Separate decks and verandahs from internal floor area.
2. Site investigation
Feature and level survey, soil report, engineering and who pays if the findings change the design.
3. Approvals and inspections
The applicable state and council pathway, drawings, application fees, inspections and who coordinates them.
4. Foundations and site works
Footings or slab based on the actual site, excavation, retaining, drainage, spoil removal and demolition.
5. Factory supply and installation
For modular or prefab: delivery area, transport, permits for transport where needed, crane, traffic management, installation and joining modules.
6. Utility connections
Water, sewer or wastewater, stormwater, electricity and metering; the assumed distance to each connection.
7. Fit-out and comfort
Kitchen, bathroom, appliances, heating and cooling, insulation, glazing, flooring and window coverings.
8. External works
Steps, decks, accessible paths, driveway repairs, fencing, landscaping and making good after access.
9. Allowances and exclusions
Each provisional sum, prime cost allowance, excluded item and the process for agreeing a variation.
10. Timing and responsibility
Design, approval, factory and site stages separately; who contracts for and coordinates each part of the work.
11. Price and handover
GST treatment, quote validity, payment stages, required completion documents and the process for reporting defects.
Compare the known total and the unresolved work
Add the quoted contract price to separately quoted work that is needed for the same finished scope. Keep unresolved items visible. An unknown sewer connection cost is not zero, and a provisional amount is not a confirmed final price. Ask the relevant provider to price it or explain the assumptions in writing.
Five questions to send back to each builder
- Which items needed to complete this brief are excluded?
- Which amounts may change after the survey, soil test or design work?
- Who is responsible for each approval, connection and separate contractor?
- Does the total include GST and all specified delivery and installation work?
- What documents and works will be complete at handover?
Find the right specialist for the missing information
A builder can clarify their scope. A designer, planner, surveyor or certifier may need to resolve a site or approval question before a builder can price it. Compare Melbourne professionals or Sydney professionals, explore prefab and modular suppliers by state, and read the complete budget guide.
Prepared by TheGabin. Reviewed 4 September 2026. This editorial checklist helps organise questions; it does not assess contracts or establish a property's approval pathway.