Build a complete budget
Project costs can be affected by design complexity, site access, soil and services, demolition, permits, approvals, finishes and landscaping. Ask every provider what is included and excluded in writing.
Compare like with like
When comparing quotes, line up floor area, specification, site works, permits, utility connections, timelines and provisional sums. A lower headline figure may not represent the final project cost.
What should a useful price include?
Ask for the design, floor area, specification, date, GST treatment and delivery scope behind every advertised figure. For a modular home, check whether transport, crane access, foundations and connections sit in the same contract or separate quotes. For an on-site build, clarify site allowances and the work still needed before occupation.
For example, Moncasa's published pricing structure separates building specifications from site and logistics considerations. It illustrates why headline prices need an inclusions check; it is one supplier's approach, not a market average or endorsement.
Considering factory construction? Compare prefab and modular suppliers serving Victoria, then ask each one to price the same complete scope.
Costs that are often outside the advertised price
- Feature and level survey, soil test, design, engineering and energy assessment.
- Planning advice, building permit, statutory fees and mandatory inspections.
- Demolition, tree work, excavation, retaining, access equipment and spoil removal.
- Foundations adjusted for the actual soil and site conditions.
- Water, sewer, stormwater, electricity, communications and meter work.
- Driveways, paths, decks, steps, fencing, clothesline and landscaping.
- Window furnishings, appliances and accessibility upgrades.
- Finance, temporary accommodation, insurance and contingency.
A simple quote-comparison method
Create one spreadsheet row for every scope item and one column for each provider. Mark each item as included, excluded, provisional or unknown. Ask providers to resolve the unknowns in writing and note whether each allowance includes GST. This exposes the difference between a shell, a standard build and a genuinely move-in-ready project.
Use the quote comparison checklist
How much contingency should you allow?
There is no universal percentage. The less site investigation and design work completed, the more uncertainty remains. Keep a separate contingency that is not consumed by upgrades before construction starts, and ask your designer or cost professional to calibrate it to the project stage and site risk.
Editorial review: 4 September 2026. This is a scope and budgeting guide, not a survey of accepted contracts. A future price comparison will need dated, permissioned quotes with consistent inclusions before we publish numerical benchmarks. TheGabin does not receive a referral fee from the professionals you contact.
This guide provides general information only. Costs vary by property, council, and provider. Always obtain written quotes and verify current pricing before making decisions.