A development appraisal can look complete while still missing costs that will have to be paid. A utility diversion outside the main contract, a phased infrastructure payment or a professional appointment excluded from the initial budget can materially change the result.
Bartons has created bespoke viability software to support the assessment of development costs. Its purpose is to help identify the full cost allowances relevant to a scheme and support a justifiable appraisal. The value comes from combining a structured model with careful professional analysis of the project and its evidence.
What does “full cost allowances” mean?
It means capturing each applicable cost once, at a supportable amount, with a clear explanation of why it belongs in the appraisal. An omitted allowance can overstate the capacity for contributions. A duplicated or unsupported allowance can undermine the credibility of the submission.
Government viability guidance recognises construction, abnormal works, infrastructure, policy costs, finance and professional and selling expenses. Contingency requires justification in relation to risk and developer return. These are categories to investigate, rather than automatic entitlements to a fixed percentage. Read the government’s viability guidance on costs.
Use the model to ask better questions
The important work starts with reconciling the scheme against its cost information. Does the construction rate match the proposed specification? Are external works already included? Has the drainage strategy changed? Does the utilities quotation cover the full connection scope?
A bespoke appraisal provides a framework for working through those questions in the context of the actual development. Useful checks include:
- Construction scope: reconcile quantities, floor areas, specification, preliminaries and exclusions against the cost plan.
- Site constraints: investigate demolition, remediation, retaining structures and other works supported by surveys or technical advice.
- Infrastructure: establish responsibility for roads, drainage, utilities and works outside the main building contract.
- Project and disposal costs: examine consultant appointments, warranties, marketing and legal budgets, including what is already covered elsewhere.
- Programme: check when expenditure is incurred and when sales or other receipts become available.
These checks are a professional review process. Software helps organise the appraisal; it does not establish that a quotation is reasonable or that a particular allowance will be accepted.
Separate completeness from duplication
Consider an illustrative drainage package. A contractor’s price includes £120,000 for drainage, while the engineer’s schedule identifies £180,000 for the complete works. The first task is to reconcile the two scopes. If the contractor’s £120,000 is wholly included within the engineer’s £180,000, the additional allowance is £60,000. Adding the full £180,000 again would overstate the total by £120,000.
This is an illustration, not a Bartons project result. It shows why finding a cost is only the first step. The appraisal must also establish where that cost is already recorded.
Give timing the attention it deserves
Two schemes with identical headline costs can have different funding requirements. Infrastructure may need to be paid for before the first completion, while affordable housing receipts may arrive at agreed milestones.
The supporting analysis should therefore connect the finance allowance to a realistic programme and explain the borrowing assumptions. Where a simpler allowance is used, its basis and limitations should be clear. Adding an unexplained percentage makes it harder for a reviewer to distinguish a reasonable funding cost from an overly cautious assumption.
Build the evidence alongside the figures
For each material allowance, the working papers should answer five questions: what does it cover, who supplied the evidence, when was it prepared, how was the amount calculated, and where have overlaps been excluded?
Uncertain items deserve particular care. An early estimate should be labelled as an estimate, with the information needed to refine it identified. Testing a reasonable range can show whether that uncertainty changes the viability conclusion.
This approach supports the emphasis on objective, transparent reporting in the RICS Financial viability in planning: conduct and reporting standard. It does not imply that Bartons’ software is certified or endorsed by RICS or government. Read the RICS reporting standard.
A stronger basis for negotiation
A full, defensible cost position gives a council’s reviewer something specific to examine. Where an allowance is challenged, the discussion can focus on its scope, evidence and calculation, with revisions made transparently.
Bartons combines bespoke software with viability expertise to help developers explain the costs their schemes must carry. If your appraisal may be overlooking legitimate allowances, contact Bartons to discuss your scheme’s viability.