From concept to a costed scope
Step 02 is where ideas meet numbers. Working from the agreed brief and a preliminary design concept, we develop a detailed scope of work that can be priced with genuine accuracy and compared meaningfully across different contractors or delivery options. The goal is not simply to produce a number — it is to produce a number you can rely on and understand.
Pricing residential construction is both a science and a judgement call. Material costs, subcontractor rates, lead times, and site-specific conditions all influence the final figure. At Century Built Homes, we document every assumption behind a price so that when you review the figure, you know precisely what it includes and what it does not.
What a comparable tender actually requires
A tender is only comparable if every party is pricing the same thing. This sounds obvious, but in practice it is the exception rather than the rule. We structure our scope documents to specify: the drawing revision being priced, the specification version, the nominated brands or performance standards for key materials, the inclusion or exclusion of provisional sums, the treatment of prime cost items, and any known site-specific requirements such as crane access, traffic management, or noise restriction hours.
When clients receive multiple quotes and one is significantly lower than the others, the explanation is almost always in what that quote has excluded rather than superior efficiency. We help clients read quotes critically — identifying gaps in scope, unresolved provisional sums, and assumptions that will become variations once construction is underway.
Scope splitting and work package structure
For larger projects, we recommend breaking the scope into clearly delineated work packages: siteworks and foundations, structure and framing, roofing and weatherproofing, external cladding and windows, services rough-in (electrical, plumbing, HVAC), internal linings and joinery, finishes and fixtures, and external works. This structure serves multiple purposes — it enables accurate cost tracking during construction, simplifies the variation process when changes occur, and provides clear payment milestones tied to measurable completion events.
For renovation projects, the scope split also distinguishes between work to existing fabric (demolition, remediation, structural alterations) and new work, which typically carry different risk profiles and pricing methods.
Provisional sums and prime cost items
Provisional sums (PS) and prime cost (PC) items are the two mechanisms by which uncertain costs are handled in a building contract. A provisional sum is an allowance for a defined scope of work whose full extent cannot yet be determined — excavation in unknown ground conditions, for example. A prime cost item is an allowance for a product or material yet to be selected — a kitchen appliance package, or a feature tile.
Both mechanisms are legitimate tools when used transparently. Problems arise when PS and PC allowances are set unrealistically low in order to present an attractive headline price, only to be reconciled upward once the contract is signed. We set PS and PC allowances at realistic market rates based on current supplier pricing, and we flag where the allowance is conservative versus where it carries genuine uncertainty risk.
Material grade clarity and upgrade options
Material specification has a profound effect on both cost and outcome. There is a meaningful difference between an entry-level aluminium window system and a thermally broken double-glazed unit; between a standard 20mm laminate benchtop and a 40mm engineered stone; between a Colorbond roof and a terracotta tile. None of these choices is inherently right or wrong — the right choice depends on your priorities, your budget, and how long you intend to hold the property.
For items where clients frequently upgrade mid-construction — kitchen and bathroom fixtures, flooring, roofing, external cladding — we provide side-by-side pricing at standard and upgraded grades at the tender stage. This eliminates the friction and cost of processing variations later, and it allows you to make informed decisions before the contract is signed rather than under time pressure during construction.
Tender validity and price adjustment conditions
All tender pricing is valid for a defined period — typically 30 to 60 days for residential projects, though this varies with market conditions. Beyond that period, material costs and subcontractor rates may have moved, and we reserve the right to review pricing accordingly. We are transparent about this: the validity period is stated on the face of the tender, and we will notify you promptly if any material cost movement occurs during the tender period.
The conditions that may trigger price renegotiation are also stated clearly: significant changes to the scope or drawings, changes to the approval documentation, material or product supply disruptions, and any site conditions materially different from those assumed in the tender. There are no hidden renegotiation triggers in our pricing.
Deliverables from Step 02
You receive a fully itemised scope of work with line-item pricing, a schedule of provisional sums and prime cost items with supporting market references, an upgrade options schedule for key specification items, a tender validity statement, and a list of exclusions and qualifications. Together, these documents form the basis for the Step 04 contract and provide a transparent record of what was agreed and at what price.
Business is governed by written contract, drawings, and approval documentation; this page is informational only and does not constitute an offer or guarantee.