Do I Need Planning Permission for My Extension in Hampshire?

When you’re considering an extension—whether it’s a sun-filled kitchen room, a side return, or an extra attic storey—it’s natural to ask: “Do I need planning permission?” In Hampshire and the surrounding counties, the rules can seem confusing, especially with different allowances for permitted development and special protections in places like the South Downs National Park (SDNP). Here’s a clear breakdown of what you need to know, what counts as permitted development, where local planning lies, and when to apply.

What Are Permitted Development Rights?

Permitted development rights (PDR) allow certain types of building work without a full planning application. They’re set out in law (for example the Town and Country Planning (General Permitted Development) (England) Order 2015) and give homeowners scope to make improvements, subject to conditions.

For example, a single-storey rear extension may in many cases be built under PDR rather than a full planning permission.

How Applied in Hampshire

In most parts of Hampshire, you should check:

• Whether your existing house is eligible for PDR (for example it is a house rather than a flat or other building).

• Whether the extension meets the size and height limits and other conditions for PDR.

• Whether there are local restrictions (for example Article 4 Directions) or conservation/designation issues which remove or limit PDR rights.

If your extension doesn’t qualify for PDR, or you want to build something larger or more complex (e.g., two-storey extension, changes to roof height, large footprint), then you’ll typically need to submit a full planning application to your local authority.

Special Case: Inside the South Downs National Park

If the property lies within the South Downs National Park (SDNP), the rules are stricter. While PDR can still apply, note that the SDNP is designated “Article 2(3)” land (in planning terms) which means extended PDR rights do not automatically apply in the same way as outside the park.

For example, the publicly-available guidance from the South Downs National Park Authority states that the extended householder permitted development rights introduced in 2013 do not apply within the National Park.

Additionally, the SDNP Local Plan (and associated Technical Advice Notes) place emphasis on conserving the natural beauty, wildlife and cultural heritage of the park, which can affect extensions and alterations.

Therefore, if your project is inside the National Park, even if it appears modest, it is wise to assume planning permission will be required (or at least pre-application advice should be sought) unless you’ve confirmed otherwise.

When to Apply for Planning Permission

You will need to apply for planning permission (rather than rely on PDR) in one or more of the following situations:

• Your proposed extension exceeds the size, height, or footprint limits for PDR.

• It changes the character of the house or area (e.g., side extension that doubles width, or front extension in a prominent position).

• The property lies within a designated area (National Park, Conservation Area, Area of Outstanding Natural Beauty, or similar) and PDR rights are removed or restricted.

• There is an Article 4 Direction in your area removing certain permitted development rights.

• You’re changing the use of the building or doing something not covered under PDR. In these cases you’ll need to submit a planning application via the Planning Portal (or direct to the relevant local planning authority) and allow for typical timescales of 8 weeks or more, depending on complexity.

How to Go About It (and How We Help)

Here’s a typical process:

1. Check whether your property is within the SDNP or other designations. If in Hampshire and near the boundary of the National Park, this matters.

2. Ascertain whether your proposed extension can use PDR: check size, height, footprint limits and conditions.

3. If PDR seems possible, notify or apply for a Lawful Development Certificate (in some cases) or carry out the building works with the understanding you must still meet building regulations.

4. If planning permission is required: prepare drawings (site plan, elevations, sections), submit via the local authority or Planning Portal, pay the fee, notify neighbours as required, await decision.

5. Once approved (or if PDR applies), progress to building regulations compliance, choosing your contractor, and project delivery.

As a contractor based in Hampshire with experience in extensions, refurbishments, structural alterations and new builds, we at Rogate Construction Limited are very familiar with the local planning and building regulations environment. We can assist by liaising with your architect, preparing application-ready plans, and coordinating the build so that the planning stage transitions smoothly into construction.

Key Take-aways

• Not all extensions automatically require a full planning application — many may fall under permitted development rights, but only if the conditions are met.

• If your property sits in the South Downs National Park (or other protected/designated area), you should assume the rules are stricter and “permission required” more likely.

• It’s wise to check early, ideally before committing to detailed design or contractors, so you avoid planning delays or unexpected refusals.

• Even where planning permission is not needed, you’ll still have to comply with building regulations, choose appropriate contractors, and possibly obtain a Lawful Development Certificate for peace of mind.

If you’re planning an extension in Hampshire, West Sussex or Surrey and would like guidance on whether your project requires planning permission (or how we can assist with the planning and build process), please get in touch with us for a no-obligation conversation.