Viability appraisal outputs: what to submit

A viability appraisal submission format that a reviewer can reproduce will save you weeks. The reviewer's first task is to rebuild your residual figure from your inputs, and if they cannot do that without asking questions, the questions arrive as a written request four weeks after submission and the negotiation starts a month late. Everything below is about removing that delay. None of it is about the assumptions themselves.

National guidance on viability sets the frame: assessments should be simple, transparent and proportionate, and prepared on the basis that they will be published. Write for publication and write for reconstruction, and most of the format questions answer themselves.

What a reviewer needs to reproduce the result

Four things, in this order. The inputs, with a source for each. The areas the inputs are applied to. The cashflow that turns them into a residual. And a statement of what is being asked for.

A reviewer who has those can test your figure against their own view and tell the council where the disagreement actually is. Without them, the exchange becomes a series of requests for information, and each round is a fortnight.

The most common gap is sources. A build cost of a stated amount per square metre means nothing on its own. The same figure attributed to a published cost index, at a stated date, rebased for location, with a stated allowance for externals and abnormals, is testable. Do that for every line.

The three documents to submit

Keep the submission to three parts, and label them.

The input schedule is a table of every assumption with its source and date: gross and net areas, unit mix, sales values per square metre by unit type, ground rent or commercial rent and yield, build cost per square metre, externals, abnormals, professional fees, contingency, finance rate and arrangement costs, marketing and sales costs, developer return and the basis it is expressed on, planning obligations, the levy liability, and the benchmark land value with its own derivation.

The cashflow shows the development programme and the timing: pre-construction period, construction period, sales or letting rate, and the drawdown and repayment of finance. It should be monthly or quarterly rather than annual, because finance cost on a two-year build is sensitive to phasing and an annual cashflow hides that.

The summary appraisal shows the residual result and the comparison with the benchmark land value, with a short sensitivity analysis on the two or three inputs that move the answer most.

Model file or printed output

Submit both. A printed or PDF output fixes the version for the record and is what gets published. The live model file lets the reviewer test sensitivities without rebuilding your work, which is what shortens the process.

Where the appraisal was built in specialist software the reviewer may not hold a licence for, export a full printout including the input pages and the cashflow, and supply a spreadsheet version of the cashflow. Where it was built in a spreadsheet, leave the formulas live and unlocked. A locked workbook with hard-coded values invites the assumption that something is being hidden.

Name the file properly. Scheme name, document type, version number, date. A folder containing three files called "appraisal final" wastes somebody's afternoon.

Redaction and publication

National guidance expects viability assessments submitted with applications to be publicly available, with only limited scope to withhold material. Plan for that from the start.

The workable approach is two documents. A public version, redacted only where necessary, and a confidential annex containing the material you are asking to withhold, with a short justification for each item. Typical candidates are individual comparable transactions subject to confidentiality, contract sums under a signed building contract, and funding terms. A blanket claim over the whole appraisal will be refused and will cost you credibility.

The position at appeal is tighter again, which we cover in viability at appeal. Assume any document you submit may be read by an objector and by a local journalist.

Version control across negotiation rounds

Viability negotiations run for months and produce four or five iterations. Without discipline, nobody can say which version the committee report refers to.

1. Number every version and date it, and never reissue a version number.
2. Keep a change log: one line per change, with the previous value, the new value and the reason.
3. Provide a reconciliation table between the previous version and the new one, showing the effect of each change on the residual.
4. Change one thing at a time where you can. Reissuing an appraisal with eleven amendments makes the effect of each impossible to see.
5. Keep the areas schedule constant unless the drawings change, and if the drawings change, say so explicitly.

That reconciliation table is the single most useful document in the whole exchange. Reviewers rarely get one, and they notice.

Reconciling the appraisal with the application

Inconsistency between the appraisal and the application documents is the fastest route to losing an argument you should have won.

Check that the gross internal area in the appraisal matches the area schedule on the drawings, and that the basis, gross internal or net internal or net sales area, is stated and used consistently. Check the unit mix matches the schedule of accommodation. Check the affordable housing numbers and tenure split match the draft heads of terms and the Affordable Housing Statement. Check the levy liability matches the form submitted with the application, including any relief claimed and any deduction for existing floorspace.

Then check the obligations. An appraisal carrying a figure for planning obligations that differs from the council's request needs a note explaining which version has been modelled. Where an obligation includes deferred or contingent payments, the cashflow has to show them at the right time, and the mechanism belongs in the agreement, which is where overage and clawback drafting comes in.

The covering note that saves weeks

Two or three pages at the front, and it should answer six questions without the reader opening the appraisal.

• What is being asked for, in specific terms: the obligations offered, the ones being resisted, and the amounts.
• What the residual result is, against what benchmark land value.
• Which inputs drive the answer, and what happens to the result if each moves.
• Where the figures come from, in one list.
• What has changed since the last version, if this is not the first.
• What is in the confidential annex and why.

Officers and reviewers read that note first. A good one earns the rest of the document a fair reading.

A Viability Assessment is a report councils expect from a suitably qualified author, normally RICS-qualified and working to the professional guidance on financial viability in planning, and professional review before submission is strongly advised. An AI-assisted draft can structure the document, set out the input schedule and draft the narrative. The valuation judgement, the comparables and the sign-off belong to the valuer.

One honest uncertainty: authorities differ on whether they want the live model at all, and some reviewers prefer to build their own from your inputs. Ask which the reviewing body prefers before you submit, because sending the wrong thing means sending it twice.

See PlanScope pricing: one free report, £50 per report, or Professional for unlimited reports.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.