Sometimes—but applying after construction does not guarantee approval. Whether an unauthorized building can be regularized depends on local law, planning rules, and whether it can meet applicable technical requirements. Planning permission and building-control compliance may require separate applications. The examples below cover England and France only; the rules elsewhere may differ.
What “regularizing” a building can mean
There may be two separate questions: whether the development is acceptable under planning rules, and whether the construction meets applicable building regulations or technical standards. A route that addresses one does not automatically resolve the other.
As an Amazon Associate I earn from qualifying purchases.
- Planning approval: asks whether the building or work is acceptable under the relevant land-use and planning rules.
- Building-control compliance: concerns technical requirements for the work. A certificate or approval in this area is not necessarily planning permission.
Local law may also treat a building erected without permission differently from later alterations to a building that was already irregular.
How retrospective approval works in England
Retrospective planning application
England’s planning guidance recognizes retrospective applications under section 73A of the Town and Country Planning Act 1990. The local planning authority assesses the development; permission is not automatic. The authority may decline to determine an application in some circumstances, including where an enforcement notice has previously been issued. The guidance says that a person who has undertaken unauthorised development has “only one opportunity to obtain planning permission after the event”; check the guidance and your case’s procedural history before relying on this route. Read the government’s planning enforcement guidance.
#1 Best Overall
In an area that charges the Community Infrastructure Levy (CIL), retrospective permission may affect eligibility for most relief or exemptions. Ask the authority how CIL applies to your case rather than assuming an exemption remains available. The enforcement guidance explains the CIL issue.
Building-work regularisation certificate
Separately, regulation 18 of the Building Regulations 2010 allows an owner to apply in writing to the local authority for a regularisation certificate for qualifying unauthorized building work carried out on or after 11 November 1985. This route concerns building-regulations requirements; it does not grant planning permission. The certificate is evidence, but not conclusive evidence, that the specified requirements have been met. Read regulation 18.
Rank #2
An application must describe the work and include plans so far as reasonably practicable, including any additional work needed to meet relevant requirements. The authority may require reasonable steps to assess concealed or uncertain work, such as exposing it for inspection, testing it, or taking samples. Remedial work may therefore be necessary before a certificate can be issued. Regulation 18 sets out the application and inspection powers.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Government consultation material discusses possible changes for higher-risk buildings. A consultation describes proposals, not necessarily rules in force; check operative legislation and the authority’s current process for the building concerned. See the government consultation on building-regulations regularisation.
How regularisation works in France
French government guidance says a request to regularize unauthorized work may be made at any time, but the town hall assesses it against the local planning plan in force. Depending on the case, the administration may regularize the construction, require compliance work, or refuse the request. Regularization is therefore not assured merely because the work is complete. The guidance was verified on 25 February 2026. Read the French government guidance.
The French guidance distinguishes a building erected without required planning permission from later work on an irregular building, and describes different limitation and enforcement issues. Those rules and any deadlines or penalties are specific to France; they should not be applied to a project in another country. See the guidance on regularizing unauthorized work.
Rank #4
What to establish before you apply
- Identify the applicable place and rules. Confirm the country, municipality, land-use designation, building type, and construction date. The authority and local rules determine which retrospective routes exist.
- Check the history. Gather any original permits, applications, enforcement notices or orders, and correspondence. A prior notice can affect whether an English retrospective planning application will be determined.
- Ask about each approval separately. Contact the local planning authority and building-control authority, or the equivalent bodies where you live. Ask which procedure applies to planning status and which applies to technical compliance.
- Assemble records and evidence. Collect ownership or land-right records, plans, photographs, construction dates, permits, and notices. For an England building-work regularisation application, plans and a description of the work are specifically contemplated; the authority may also require inspection or testing.
- Assess feasibility and corrective work. Ask what standards will be applied, what evidence is needed, whether opening up or testing may be required, and what changes would be necessary if the work falls short. For complicated cases, a locally qualified planning professional or building surveyor may help assess the application and evidence.
- Confirm consequences and timing with the authority. Ask about enforcement, fees, potential taxes or levies, appeals, and any time limits that apply locally. Do not assume that submitting an application pauses enforcement or resolves land ownership, safety, protected-area, or third-party-rights issues.
What happens if the building cannot qualify?
The authority may refuse the application or require work to bring the building into compliance. Depending on local law and the circumstances, enforcement action or financial consequences may also follow. For example, England’s guidance discusses enforcement options and possible CIL effects, while French government guidance describes possible penalties and orders to regularize or bring work into compliance. These are jurisdiction-specific examples, not a universal list of consequences. England enforcement guidance; French government guidance.
Recommended Free Tools
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
