Planning Permission When Buying a Property: What You Need to Know

Permitted Development Rights

Not everything requires a formal planning application. Permitted Development (PD) rights allow certain works to be carried out without planning permission — these are set out in the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended). Common examples include single-storey rear extensions up to 6 metres (terraced/semi) or 8 metres (detached), loft conversions that don't exceed the ridge height, outbuildings within certain size limits, and converting a garage into habitable space.

PD rights come with conditions and limits. For example, a rear extension under PD cannot be higher than 4 metres at the eaves, cannot cover more than 50% of the curtilage (garden area), and must use materials that match the existing house. For larger rear extensions (4–6 metres for a semi/terraced, 4–8 metres for detached), the Neighbour Consultation Scheme applies — neighbours can object, and the local authority can remove PD rights if there are objections.

Before extending or converting under PD, many homeowners obtain a Lawful Development Certificate (LDC) from the local authority. An LDC confirms that the proposed works are lawful without planning permission and provides a certificate you can show to future buyers or mortgage lenders. Applying for an LDC costs around £100–£200 and is highly recommended for works you want to carry out under PD rights.

What Requires Full Planning Permission

Beyond the limits of PD rights, any extension, new building, material change of use, or significant alteration requires a full planning application. Examples include extensions that exceed PD size limits, converting a house into multiple flats, changing the use of a garage or outbuilding to a separate dwelling, new dwellings on garden land, and works to listed buildings (which require Listed Building Consent separately from planning permission).

Planning applications are decided by the local authority's planning committee against their Local Plan policies, national planning policy, and any material considerations (including neighbour objections and heritage concerns). Decisions are not guaranteed — applications can be refused, and refusals can be appealed. The process typically takes 8–13 weeks for a householder application (smaller works) and 13–26 weeks for larger development.

One thing buyers often overlook: if you are buying a property to extend significantly, planning permission is not guaranteed. A property that looks like it has obvious extension potential may in fact have policy constraints — it may back onto protected green space, be in a conservation area with character guidelines, or have had previous applications refused. Always check planning history before assuming what's possible.

How to Check Planning History

Every local planning authority in England publishes its planning applications register online — this is a public database searchable by property address. Searching for a property's address will show all planning applications ever submitted for that site, their decision (granted/refused/withdrawn), and any conditions attached to granted permissions.

This is one of the most valuable free research tools available to buyers. It can reveal: whether extensions and conversions at the property had planning permission (and what conditions apply), whether the property has an interesting planning history (applications for additional dwellings, commercial use, or repeated refusals), and whether neighbouring or nearby sites have applications for development that could affect your enjoyment of the property.

Your solicitor will also carry out a local authority search that reveals official planning entries — but this is a point-in-time snapshot, not a full planning history. Searching the planning portal directly gives you much richer information and you can do it before making an offer, not weeks later after paying for searches.

Article 4 Directions

An Article 4 Direction is a designation that removes some or all Permitted Development rights from a specific area. They are commonly applied in conservation areas to prevent changes that would damage the character of the area — for example, removing the permitted development right to add satellite dishes, replace windows with different materials, or clad external walls.

For buyers, Article 4 Directions are most relevant in two contexts. First, in designated conservation areas where Article 4 means you need planning permission for works that would otherwise fall under PD rights — adding a porch, changing window materials, or painting external masonry. Second, in areas where the local authority has removed PD rights for converting houses into HMOs (Houses in Multiple Occupation) — typically in student-heavy urban areas. If you are buying to convert to multiple occupancy, an Article 4 Direction may make this impossible without planning permission.

Article 4 Directions are disclosed in the local authority search that your solicitor orders as part of conveyancing. Ask your solicitor specifically to flag any Article 4 Directions affecting the property and what works they restrict.

Planning Enforcement

If works have been carried out without planning permission and that permission was required, the local authority has the power to serve an Enforcement Notice requiring the works to be removed or the breach to be remedied. The local authority has 4 years to take enforcement action for an unauthorised extension or change of use of a dwelling, and 10 years for a change of use of a building to a dwelling (or any other enforcement matter not covered by the 4-year rule).

A planning enforcement notice on a property is a serious issue — it can render the property unsaleable or unmortgageable until resolved. Your solicitor's local authority search will reveal any outstanding enforcement notices. If enforcement notices are found, take legal advice before proceeding.

For works carried out without planning permission where the enforcement period has elapsed, it is possible to apply retrospectively for a Lawful Development Certificate (Certificate of Lawfulness of Existing Use or Development). This confirms the breach is now immune from enforcement. Some buyers negotiate with sellers to obtain this certificate before exchange.

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