Vacant building credit or a viability case for fewer homes
The credit is arithmetic, viability is argument. This compares what each achieves, how vacancy and abandonment are tested, what councils challenge, and which to run first.
Choosing between the vacant building credit or a viability case is a choice between arithmetic and argument. The credit is a policy mechanism that offsets your affordable housing requirement against existing floorspace, and if the facts fit, the calculation is hard for an authority to resist. A viability case asks the authority to accept that the scheme cannot carry a policy compliant contribution, which invites an independent review, a dispute about land value and a review mechanism written into the agreement.
Most developers should test the credit first. Many go straight to viability because their consultant is a surveyor.
What the credit actually offsets
National policy provides that where a vacant building is brought back into lawful use, or is demolished to be replaced by a new building, the affordable housing contribution should be reduced by a credit equivalent to the existing gross floorspace of the vacant building. The requirement then applies only to the net increase in floorspace.
Two points follow that people miss. The credit reduces the affordable housing contribution, not the Community Infrastructure Levy, which has its own separate provisions for existing floorspace in lawful use. And it is expressed as floorspace, so on a scheme that replaces a low rise building of substantial footprint with a taller building of similar area, the credit can swallow the requirement almost entirely.
The credit does not apply to buildings that have been abandoned. That single exclusion is where nearly every dispute lives.
Vacancy tested, and abandonment
National policy does not set a period of vacancy. There is no six month or twelve month rule, which cuts both ways: an authority cannot refuse the credit because the building has only been empty for a year, and you cannot claim it merely because a tenant left last month.
Abandonment is a different question with an established approach. Decision makers look at the physical condition of the building, the length of time it has not been used, whether any other use has intervened, and the evidence of the owner's intentions. A roofless shell with saplings growing through the floor, empty for 15 years, is abandoned. A sound building marketed continuously for two years is not.
Deliberate vacation is the sensitive case. Where a building was emptied specifically to generate the credit, authorities push back hard, and the policy is capable of being read against an applicant who has manufactured the vacancy. Where a tenant left for commercial reasons and the building has been marketed since, the position is much stronger.
Get the evidence before you exchange, because it is retrospective evidence that wins these arguments: business rates records, utility accounts, marketing particulars with dates, agents' enquiry logs, and photographs of condition over time.
Doing the arithmetic
The calculation is a floorspace comparison, and it needs measuring properly to a recognised measurement standard rather than scaling off a sales plan.
Illustrative example: a site with a vacant single storey workshop of 1,000 square metres gross internal area, proposed for redevelopment as flats totalling 2,500 square metres gross. The credit covers 1,000 square metres, so the affordable housing requirement is applied to the 1,500 square metre net increase rather than to the whole scheme. On a plan policy seeking 35 per cent, the practical effect is a requirement calculated on 60 per cent of the development.
Get the existing floorspace surveyed and stated on a drawing. Disputes about whether a mezzanine, a lean to or a covered yard counts are common, and they are resolved on the measurement convention and the lawful use rather than on assertion. And be careful about existing buildings that were themselves unlawful, because floorspace with no lawful use is a much weaker basis for a credit.
When viability evidence is the better route
Viability is the better route in four situations. Where there is no existing building, or it is properly abandoned. Where the existing floorspace is small relative to the proposal, so the credit barely moves the number. Where the problem is not affordable housing at all but the total package of obligations, abnormal costs or an infrastructure requirement. And where the scheme needs a reduction beyond what the credit delivers.
National guidance is clear that viability assessment at the decision stage should be the exception rather than the norm, because the plan is supposed to have tested viability already. So the first question an authority asks is what has changed since the plan was adopted, and the answer has to be about this site rather than about the market generally.
The guidance also sets the framework: a benchmark land value based on existing use value plus a premium to the landowner, a gross development value evidenced from comparables, costs evidenced from a cost plan, and a return to the developer which the guidance indicates may be in the order of 15 to 20 per cent of gross development value for plan making purposes. A price paid above benchmark land value is not a reason to reduce contributions.
| Vacant building credit | Viability case | |
|---|---|---|
| Basis | Floorspace arithmetic under national policy | Financial appraisal of this scheme |
| Main dispute | Whether the building is vacant or abandoned | Benchmark land value and costs |
| Cost to run | Measurement and evidence of vacancy | Appraisal, plus the authority's independent review |
| Outcome | A fixed, predictable reduction | A negotiated reduction, often with a review mechanism |
| Transparency | Modest | Assessment normally published |
How councils resist each
Against the credit, the arguments are abandonment, unlawful existing use, measurement, and local policy. Some adopted plans state that the credit will not be applied, or will be applied restrictively. A local policy cannot simply disapply national policy, but it is part of the development plan and it carries weight, so the outcome turns on the balance rather than on a clean win.
Against viability, the standard moves are to dispute the benchmark land value as reflecting an overpayment, to challenge the cost plan as unevidenced, to require an independent review at the applicant's expense, and to insist on early and late stage review mechanisms that claw back value if the scheme performs better than forecast. Expect the assessment to be published, because national guidance expects transparency.
Appeal decisions on both points are indicative of how inspectors have approached the issues rather than binding precedent, and where a case is heading that way the choice of procedure matters, as the note on choosing between a hearing and an inquiry explains.
The evidence each needs
For the credit: a measured survey of existing floorspace to a recognised standard, drawings of the existing building, evidence of the lawful use, and a documented vacancy history. Put it in the Affordable Housing Statement rather than in a covering letter, so the case is in a document the officer report can cite.
For viability: a full appraisal with transparent inputs, a benchmark land value with the existing use value and the premium justified separately, a cost plan from a quantity surveyor, sales or rental evidence, and an explanation of what is site specific about the position. A Viability Assessment is work councils expect from a suitably qualified author working to recognised professional practice, and professional review before submission is strongly advised.
Choosing which argument to run
Test the credit first, because it is faster, less expensive and less intrusive. Where the credit gets you close enough, take it and stop.
Run viability where the credit does not exist or does not reach far enough, and run it properly, with the expectation that every input will be examined. Running a weak viability case alongside a good credit case tends to damage both, because it invites the authority to treat the whole submission as an attempt to reduce obligations rather than as an application of policy.
One related route worth checking on a commercial building: whether conversion under prior approval is available at all, which changes the affordable housing question entirely. The note comparing Class MA and Class Q prior approval sets out where those rights apply.
Enter your postcode on PlanScope to see which reports a brownfield redevelopment is likely to need.
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.
Frequently asked questions
How long must a building be vacant to qualify for the credit?
National policy sets no period. There is no six or twelve month rule, so an authority cannot refuse the credit purely because the building has been empty for a short time, and you cannot claim it just because a tenant recently left. What matters is that the building is vacant and has not been abandoned, judged on the evidence.
How is abandonment assessed?
Decision makers look at the building's physical condition, how long it has been out of use, whether any other use has intervened, and evidence of the owner's intentions. A roofless shell empty for many years is abandoned. A sound building marketed continuously is not. Abandonment defeats the credit, so the vacancy history needs documenting.
Does the vacant building credit reduce the Community Infrastructure Levy?
No. The credit reduces the affordable housing contribution. The levy has its own separate provisions allowing existing floorspace in lawful use to be offset against the chargeable amount, with their own conditions about use within a defined period. They are different mechanisms and each has to be claimed on its own terms.
When is a viability case better than the credit?
Where there is no existing building or it is abandoned, where the existing floorspace is small relative to the proposal, where the problem is the whole obligations package rather than affordable housing alone, or where the reduction needed exceeds what the credit delivers. National guidance treats viability at the decision stage as the exception.
Will a viability assessment be made public?
Normally yes. National guidance expects viability assessments submitted with applications to be publicly available, with limited scope for redaction. Factor that into the decision, because an appraisal in the public domain becomes visible to landowners, competitors and the authority in later negotiations on other sites.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.