Do I Need Planning Permission for a House Extension?
Planning a house extension in Surrey? One of the first questions you'll probably ask is: do I need planning permission?
The answer isn't always straightforward. Some house extensions can be built under permitted development rights, meaning you may not need to submit a full planning application. However, strict limits and conditions apply, and these depend on the size, position and design of your proposed extension, as well as the property itself.
At Newstock Developments, we understand that navigating the early stages of a building project can feel complicated. In this guide, we'll explain the basics of planning permission, permitted development and what you should consider before starting your extension.
Important: Planning rules can be specific to an individual property and local area. This article is intended as general guidance for homeowners in England and shouldn't replace advice from your local planning authority or a qualified planning professional.
What Is Permitted Development?
Permitted development rights allow homeowners to carry out certain improvements and extensions to their homes without making a full planning application, provided the proposed work meets specific limitations and conditions.
This can make the process of extending your home simpler, but permitted development doesn't mean you can build whatever you want without permission.
The rules cover factors including:
The size of the extension
Its height
How far it extends from the original house
Its position on the property
How close it is to the boundary
Previous extensions to the property
Whether the property is in a designated area
Previous extensions can also affect the calculation, so it's important to consider the total enlargement of the property rather than just your new proposal.
When Might a House Extension Need Planning Permission?
You'll generally need to consider a planning application if your proposed extension falls outside the permitted development limits.
For example, planning permission may be required where:
The Extension Exceeds Permitted Development Limits
There are restrictions on the size, height and position of extensions.
For example, under the current rules, a single-storey rear extension under permitted development can generally extend no more than 4 metres from the original rear wall of a detached house or 3 metres for other houses. Larger single-storey rear extensions may be possible under a separate prior approval process, subject to the relevant conditions.
You're Proposing a Significant Side Extension
There are specific restrictions around extensions beyond the side elevation of the original house.
Under permitted development, a side extension must generally be single storey, no more than 4 metres high and no wider than half the width of the original house.
You're Planning a Larger or More Complex Extension
If your design goes beyond the permitted development limitations, you may need to submit a householder planning application.
What About a Double-Storey Extension?
A common misconception is that all two-storey extensions require planning permission.
That's not necessarily the case.
Certain two-storey rear extensions can fall within permitted development rights if they meet the relevant conditions and limitations. However, there are additional restrictions, including how far the extension projects from the rear of the original house and its relationship with boundaries.
A two-storey extension to the side or front of a property is different and will generally require planning permission.
Because the rules are quite specific, it's important to assess your individual property before assuming your project qualifies.
What If My House Is in a Conservation Area?
Location matters.
Permitted development rights can be more restricted on designated land, including certain conservation areas, National Parks, Areas of Outstanding Natural Beauty and World Heritage Sites. Additional restrictions can apply to matters such as side extensions and external cladding.
This is particularly relevant for homeowners in Surrey, where there are a number of areas with additional planning considerations.
If your property is in a conservation area or another designated area, it's worth checking the position before progressing too far with your plans.
What If My Property Is Listed?
If your home is a listed building, planning permission isn't the only consideration.
You may also need listed building consent for works that affect the character of the building. The requirements for listed properties can be considerably more involved than for a standard residential property.
This is another reason why it's important to establish what permissions and consents apply before construction begins.
What Is Prior Approval?
You may have heard the term prior approval when researching permitted development.
This isn't the same as full planning permission.
Certain types of permitted development are subject to a process where the local planning authority must consider specific aspects of the proposal before the work can proceed.
For example, larger single-storey rear extensions can potentially benefit from permitted development rights but are subject to a prior approval process and neighbour consultation requirements.
So even when a project doesn't require a standard planning application, there may still be a formal process to follow.
Do I Still Need Building Regulations Approval?
Yes — planning permission and Building Regulations are separate things.
This is one of the most important points for homeowners to understand.
Planning permission considers whether the development is acceptable in terms of planning policy, design, location and its impact on the surrounding area.
Building Regulations deal with the technical and construction standards of the work, including areas such as:
Structural stability
Fire safety
Insulation
Ventilation
Drainage
Electrical safety
Energy efficiency
The fact that an extension is permitted development doesn't mean it is exempt from Building Regulations. Permitted development rights do not remove requirements under other regimes such as Building Regulations or the Party Wall Act.
What About the Party Wall Act?
If your extension involves work close to or directly affecting a shared boundary or party wall, the Party Wall etc. Act 1996 may also be relevant.
This is separate from planning permission.
Depending on your circumstances, you may need to serve the appropriate notices on adjoining owners before certain works begin.
It's another example of why planning your project properly before construction starts is so important.
Getting Your Extension Plans and Permissions Right
Understanding whether you need planning permission is just the beginning.
Before construction can start, you'll need a clear and well-developed design, appropriate technical drawings and, where required, planning and Building Regulations approvals.
This is where working with an experienced architectural design team can make the process much easier.
Fluent Architectural Design Services provides architectural design, planning and technical services for homeowners across Surrey and the wider South East. Their services include measured surveys, architectural drawings, planning applications, Building Regulation drawings and structural calculations.
Having the right information prepared before you approach a builder can help you:
Understand what you're able to build
Establish whether planning permission is required
Develop a design that works for your property and lifestyle
Obtain the necessary planning approvals
Prepare detailed technical drawings
Give your builder the information needed to price and construct the project accurately
From Design to Construction
At Newstock Developments, we believe that good construction starts with good preparation.
Once your design and approvals are in place, having detailed drawings and structural information gives everyone involved a much clearer understanding of the project. It can help reduce uncertainty, avoid misunderstandings and ensure the construction phase starts with the right information.
Fluent's Building Regulation service, for example, provides detailed technical drawings and structural engineering information intended to give builders the information they need to construct the project safely and in accordance with current UK standards.
For homeowners considering an extension, having the right professionals involved at the right stage can make the journey from initial idea to construction considerably smoother.
Find out more about Fluent Architectural Design Services
Can I Find Out If My Extension Needs Planning Permission?
Yes.
The first step is to establish:
What type of property you have
What previous extensions or alterations have been carried out
Where your proposed extension will sit
How large it will be
How close it will be to boundaries
Whether your property is listed or in a designated area
Whether there are any planning conditions or restrictions affecting the property
The Planning Portal provides guidance on permitted development, but where there is any doubt, it's worth checking your specific circumstances with your local planning authority.
You can also apply for a Lawful Development Certificate where appropriate if you want formal confirmation that proposed or existing work is lawful development.
What Should You Do Before Starting Your Extension?
Before committing to construction, make sure you have established:
✔ What You Want to Build
Have a clear idea of the additional space you need and how you want it to work for your home and lifestyle.
✔ Whether Planning Permission Is Required
Don't assume your project qualifies for permitted development.
✔ Whether Building Regulations Approval Is Required
Remember that planning permission and Building Regulations are separate requirements.
✔ Whether Other Consents Apply
This could include listed building consent, Party Wall matters or other local restrictions.
✔ What Your Project Is Likely to Cost
Understanding your budget early can help you make informed design decisions.
You can read our guide[How Much Does a House Extension Cost in Surrey?] for more information about the factors that can affect your project budget.
✔ Who Will Carry Out the Work
Choosing an experienced and trustworthy builder can make the entire process considerably easier.
For more advice, read our guide[How to Choose the Right Builder for Your Home Project].
Planning a House Extension in Surrey?
At Newstock Developments, we understand that extending your home is a significant investment.
From the initial consultation and planning stages through to construction and completion, we aim to provide clear communication and a carefully managed service.
Whether you're considering a single-storey extension, double-storey extension, kitchen extension, rear extension or structural alteration, we'll help you understand the practical considerations involved in turning your plans into reality.
Thinking about extending your Surrey home? Get in touch with Newstock Developments to discuss your project.