Many single-storey rear extensions in Cornwall can be built under Permitted Development (PD) rights without needing full planning permission. Under PD, you can typically extend up to 4 metres (detached) or 3 metres (semi/terraced) from the rear wall. However, PD rights may be restricted in AONBs, conservation areas and on listed buildings.
Full planning permission is required for extensions that exceed PD limits, for properties in conservation areas or AONBs, for listed buildings (which also require Listed Building Consent), and for any extension that affects a neighbour’s rights to light or privacy. We always check planning requirements before starting any project.
Much of Cornwall is designated as an Area of Outstanding Natural Beauty (AONB) or falls within conservation areas. In these areas, PD rights are often restricted or removed entirely. Extensions in AONBs and conservation areas require full planning permission and must be designed to be sympathetic to the local character.
A householder planning application in Cornwall costs £206 (2025 fees) and is submitted to Cornwall Council. The application includes drawings, a design and access statement, and supporting documents. Cornwall Council aims to determine householder applications within 8 weeks. We can recommend local architects and planning consultants.
Building regulations approval is required for all extensions regardless of whether planning permission is needed. Building regs cover structural safety, fire safety, energy efficiency, drainage and accessibility. We work with approved building control inspectors to ensure all our work meets current building regulations.
If your extension is within 3 metres of a neighbour’s property, you may need a Party Wall Agreement under the Party Wall Act 1996. We advise all our clients on party wall requirements and can recommend local party wall surveyors. Failing to comply with the Party Wall Act can cause significant delays and legal issues.
If your property is a listed building, you will need Listed Building Consent in addition to planning permission for any extension or alteration. Listed Building Consent applications are assessed by Cornwall Council’s heritage team. We have experience working on listed buildings and can advise on appropriate materials and methods.
A.V.A Building & Construction Ltd have extensive experience navigating the planning system in Cornwall. We can advise on whether your project needs planning permission, recommend local architects and planning consultants, and ensure all our work meets planning conditions and building regulations requirements.
A.V.A Building & Construction Ltd have extensive experience with planning permission for extensions across Truro, Falmouth and surrounding villages in Cornwall. As members of the Guild of Master Craftsmen, all our work is fully insured and guaranteed.
Contact us today for a free consultation on 01872 719546 or email avabuildingltd@outlook.com.
