Build the budget in layers
Start with the land and site work, then design and consultants, council and utility charges, the building contract, external works, owner-supplied items, finance and contingency. State whether every figure includes GST and the same scope date.
Do not use an unsourced generic rate as the final allowance. Current written pricing tied to drawings and specifications is the evidence that matters.
- Survey, geotechnical and site investigations
- Design, engineering and other consultants
- Consent, development and utility charges
- House construction and documented allowances
- Driveways, landscaping, fencing and window coverings
- Finance, escalation and contingency
The main Christchurch cost drivers
Site levels, ground improvement, retaining, access, drainage and utility connections can dominate early variance. Within the house, plan complexity, structural spans, glazing, wet areas, heating and ventilation, joinery and finish selections move the price quickly.
Ask for alternatives that preserve the brief rather than simply deleting quality: simplify geometry, align structure and services, standardise openings and resolve selections before procurement.
Price at decision gates
Use an early feasibility budget, a design-stage estimate and a pre-contract price. Each should list assumptions and uncertainty. If the design changes, update the budget before proceeding to the next gate.
Shortlist questions
Ask before you appoint
- Which site and external works are excluded?
- Which selections are allowances rather than quoted products?
- What information would reduce the largest uncertainty?
- How are escalation and post-contract changes handled?