Quick answer
Planning permission is one of the first questions homeowners ask about an extension. The answer depends on the property, the design and its planning history. This guide explains the usual route, the questions to ask and why building regulations remain relevant even when planning permission is not required.
For property-specific advice, speak to the appropriate planning, design or building-control professional and request a clear written scope from your builder.
Planning permission and permitted development are different routes
Planning permission is formal approval from the local planning authority. Permitted development rights allow certain work to proceed without a full planning application, provided every relevant condition and limitation is met.
Whether an extension qualifies can depend on its height, depth, position, materials and proximity to a boundary. Previous extensions also matter because allowances generally relate to the original house, not simply its current footprint.
When a full application may be needed
- The proposal falls outside permitted-development size or design limits.
- The property is listed or affected by an Article 4 direction.
- The house is in a conservation area or another designated location where rights are restricted.
- Earlier work has already used the available allowance.
- The project includes a prominent side extension, unusual roof form or materials that need closer assessment.
A designer or planning professional can check the property and prepare the drawings needed for the appropriate application.
Planning permission is not building-regulations approval
Planning considers the effect of development on the property and surrounding area. Building regulations concern matters such as foundations, structure, fire safety, insulation, ventilation, drainage, glazing and electrical work. Most extensions require building-regulations approval even when they are permitted development.
If the design creates a wide opening into the existing house, structural calculations may also be required. Our pages about structural alterations and load-bearing wall removal explain that part of the work.
A sensible order before asking builders to price the work
- Define the rooms, space and outcome you need.
- Check the property’s planning constraints and previous applications.
- Develop drawings detailed enough for contractors to price consistently.
- Confirm the planning route and building-control approach.
- Ask builders for written quotes based on the same information.
For a ground-floor project, also read our guide to single-storey extension costs and the page about single-storey extension builders in Colchester.
Related services and guides
Frequently asked questions
Can an extension be built without planning permission?
Some extensions may qualify as permitted development, but all relevant limits and conditions must be satisfied. Property-specific checks should be completed before work starts.
Does a kitchen extension need planning permission?
It depends on the external extension rather than the room’s intended use. A kitchen extension may be permitted development or may require an application.
Should I obtain a lawful development certificate?
A certificate can provide formal confirmation that proposed work is lawful. A planning professional or the local planning authority can advise whether it is appropriate.
Can a builder decide if planning permission is required?
A builder can flag practical considerations, but formal planning advice or confirmation should come from the appropriate planning professional or authority.
Planning work on your Colchester home?
Essex Builders can discuss the practical building work, arrange a site visit and provide a clear written quote for suitable projects across Colchester and nearby Essex areas.
Request a free quoteCall 07958 355936