If you are extending your home or converting a garage in Northampton, elsewhere in Northamptonshire, or across England, you will almost always need to think about planning permission as well as Building Regulations. They are not the same thing (we cover the difference in our companion article). This guide focuses on planning at a high level so you know what questions to ask before you commit to a design.
What planning permission is for
Planning permission is the local council’s formal consent for a change to the use of land or buildings, or for building work that affects the appearance, size or impact of development outside the limits set by national rules. Your local planning authority (LPA)—usually the district or borough council covering your postcode—checks proposals against the development plan, national policy and neighbour amenity.
Permitted development: when you may not need full permission
Many smaller householder projects can be carried out under permitted development (PD) rights set out in the General Permitted Development Order. If the work falls within the relevant limits and conditions, you do not need a full planning application—though the work may still need a Lawful Development Certificate (LDC) if you want written proof, and it almost always needs Building Regulations approval.
For extensions, PD rights are detailed: they depend on whether your house is detached or attached, how far the extension projects, height, proximity to boundaries, materials in some cases, and whether extensions or other works have already “used up” allowances. There are separate rules for single-storey, two-storey and certain larger single-storey extensions (which may need a prior approval application to assess impact on neighbours rather than full planning).
Important: PD rights can be removed or restricted. Common examples include listed buildings (where PD generally does not apply in the same way), properties in some conservation areas, Article 4 directions (which withdraw PD for defined areas or property types), and flats or certain converted buildings. Always check the current position for your exact address.
Garage conversions and planning
Converting an existing garage into habitable space without enlarging the building footprint often falls within permitted development provided no other restriction applies—but that is not automatic. Alterations to the front elevation, new windows, changes to parking provision, or sectional conversions in flats can all trigger planning considerations. If you are replacing the garage with a larger structure, or changing the principal elevation, you are more likely to need a householder planning application.
Separately, you will need to satisfy Building Regulations for structure, insulation, ventilation, means of escape and fire safety, damp proofing, and often energy performance—especially where thermal elements are upgraded.
Householder applications and validation
When planning permission is required, most domestic schemes use the householder application route. You will typically need clear drawings (existing and proposed), a block plan, and sometimes a design & access statement. Your LPA validates the application and consults neighbours where appropriate. Decision times are guided by national guidance but can vary with complexity.
Lawful Development Certificates
If you believe your scheme is permitted development, you can apply for a Lawful Development Certificate for a proposed use or development. If granted, it is formal evidence that the LPA agrees the work does not require planning permission subject to the facts stated. Many homeowners and solicitors find this helpful when selling a property.
How this applies to Northampton & Northamptonshire
Planning is decided by the council that covers your property after local government reorganisation; boundaries and council names change, so search for your postcode on the government’s Find your local council service. Policies on design, parking, sustainability and heritage can differ between authorities—always read the relevant local plan and supplementary planning documents.
How Kene Building Services can help
We are building contractors, not planning consultants. We can build to the drawings and specifications you provide and support you through the construction phase including liaison with building control. For planning strategy, we recommend working with your architect, architectural technologist or a specialist planning consultant, especially near conservation areas, on listed buildings, or for boundary-sensitive schemes.
Disclaimer: This article is for general information only. It is not legal or planning advice. Rules change and councils differ in interpretation. Confirm your project with your LPA and qualified advisers before starting work.
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