What Your Builder Won’t Tell You: 8 Extension Mistakes an Architect Can Prevent
21/08/2026
Permitted Development in a Conservation Area: Can You Extend?
10/11/2026
Extending a House in a Conservation Area in Kent
An extension can give you a kitchen that works, somewhere to eat together or a better connection to the garden. In a conservation area, the starting point is understanding how those changes can sit comfortably alongside the character of your home and its surroundings. Conservation-area designation does not automatically prevent an extension — it means investigating the property carefully before settling on size, position and appearance.
1. Does a conservation area mean I need planning permission?
Some single-storey rear extensions can still qualify as permitted development. Under householder rules, extensions beyond a side wall and rear extensions of more than one storey face additional restrictions in conservation areas. The larger-home-extension prior approval route is unavailable there. An Article 4 direction or an existing planning condition may restrict rights further. Check the whole proposal rather than relying on depth alone.
2. Is your house also listed?
A conservation area and a listed building are different designations. A house can be within a conservation area without being listed, or be subject to both protections. Alterations or extensions affecting a listed building's special architectural interest require listed building consent, including internal work. Planning permission and listed building consent are separate applications; establish which your project needs.
3. Read the local appraisal before choosing a design.
Start with the council’s conservation-area information. Tonbridge and Malling publishes maps and appraisals (including West Malling). Sevenoaks publishes an area directory and design guidance. What features matter around your property? What views should your drawings explain? Take photographs from the garden, adjoining streets and public routes to understand the complete context.
4. Can a contemporary extension work?
There is no universal requirement to reproduce an old building’s appearance. Historic England recognises that carefully selected contrasting materials can work, provided an addition does not overwhelm the original house. Compare options: test a compact pitched roof against a lower, simpler form, or a generous single opening against several smaller windows.
5. What should the application explain?
An application must make the relationship between the house, extension and surroundings easy to understand. In Tonbridge and Malling, validation requirements include heritage assessment requirements for heritage assets or their settings. Assemble existing measured drawings, clear proposed designs, and a concise explanation of design decisions.
6. Remember the garden and the neighbours.
Show trees and boundaries when discussing the layout. Tonbridge and Malling advises that most trees in conservation areas have protection and require advance notification before pruning or removal. Review the extension from neighbouring properties: small adjustments to openings or roof edges resolve concerns while preserving the room you need.
7. What should I bring to an initial consultation?
Bring your address, photographs, existing plans or permissions, and a short list of what is not working in your home. Include an overall budget and preferred timescale. Explain which improvements matter most: another bedroom, a sociable kitchen, space to work, or easier access to the garden.
8. Establish the right route before fixing the design.
The commercial opportunity and peace of mind come from knowing where generic advice stops and property-specific guidance begins. Getting an architect to assess site constraints, boundary alignments and council guidance early protects both your budget and your timescale.
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Understanding conservation areas
Conservation-area status protects the character of an entire neighbourhood, not just individual buildings. Understanding local appraisals, tree protections and appropriate materials upfront turns planning from an obstacle into a structured, creative design process.
Planning an extension in Kent?
TP Evans Architects is based in Tonbridge and works across Kent, including West Malling, Sevenoaks and surrounding villages. We explore options in 3D before committing to planning. Get in touch to arrange an appraisal.
Extending a home in a Kent conservation area?
TP Evans Architects is a Tonbridge practice working across Kent. We guide homeowners through conservation area appraisals, planning applications and design options with clear 3D visualisations. Contact us to discuss your project.
