Am I Allowed to Extend My Extension?

As home renovation specialists our work not only revolves around the design, but the planning aspect of a proposed build. Our lovely Home Tales team have years of industry experience, making the entire process as smooth as possible for homeowners wishing to improve their home. As trends change and families get bigger, clients come to us confused about whether they can add to a previous build.

It is absolutely possible to extend an existing ground floor or dormer extension in London, however, determining the right approval prior to carrying out the design and build is key. There is no finite number of extensions one can do as long as the size of the proposed extension does not become overbearing. As this is a grey area that may be confusing for some, we thought it would be a great time to cover scenarios in which this type of proposal will or will not be approved.

Things to consider

Whether you’re looking to add some much-needed space to your ground floor or loft, there are many reasons why homeowners choose to extend their properties. A ground floor extension is often used to add more space that you would use on a day-to-day basis, whether it’s a living area, kitchen, or dining room. A loft conversion is usually carried out to create extra bedrooms and bathrooms. As a ground floor extension requires new foundations, therefore digging into the ground, they tend to be slightly risker than roof extensions.

We believe it’s important to consider the cost and quality difference of altering an existing extension rather than rebuilding it. For instance, if the existing extension’s structure or foundations are not in a good condition, you may need to repair or restore it, which may rack up high costs. Therefore, to support the new extension, you may be better off replacing the entire thing. If your long-standing extension is full of charm and sentiment, it is entirely understandable if you would rather retain it. Furthermore, determining the type of permission your original extension may be helpful, as some authorities could want you to keep continuity by submitting the same type of application.

Permitted Development Rights

There are no exact rules against extending a previously built house extension as it all depends on the proposal itself. This applies to both roof and ground floor extensions. Under Permitted Development Rights, you are usually allowed a 3-4m ground floor extension, but by seeking prior approval under a Larger Homes Extension application, you are able to extend up to 6-8m. Therefore, allowing you to extend a smaller extension up to this length under PD Rights, meaning you do not require full planning permission. One risky thing about Larger Home Extensions is how much weight a neighbour’s disapproval carries. The council may refuse this type of extension if your neighbour is not in favour of it. For a loft, you can also seek a Certificate of Lawfulness to build an overall addition of 40-50m3 and raising of the roof height.

When dealing with an older extension, seeking to extend it further may be even more straightforward. PD Rights can change over time, so if your extension was built 10-20 years ago, there is a chance the rules now accommodate your larger extension proposal. Most planning matters related to roof extensions fall under Permitted Development Rights. This means permission is not often required to undergo any works, but we recommend seeking prior approval. Lastly, if your neighbour has built an extension larger than your own, you will be able to extend your extension further to match the size of their structure.

Planning Permission

Generally, it is safer to apply for Planning Permission when it comes to ground floor extensions, especially in the cramped streets of London. A ground floor extension is riskier than a loft conversion as it alters the property’s footprint and reduces the garden space. A Larger Home Extension application is great for places with a lower density of buildings, but cities require more planning consideration in order to prevent a cluttered space. Furthermore, digging into the ground to create the foundations for a ground floor extension can be massively disruptive for neighbours and the land.

Cases that do not fall under Permitted Development Rights will require Full Planning Permission from the local planning authority. This is a comprehensive permit that requires more intricate details about the site in question. If you are thinking of demolishing and rebuilding your extension to create a larger space, you may need planning permission, but this is dependent on your local authority’s rules. If you are living in a conservation area, you will definitely need Planning Permission for any external home improvement proposals. The process of obtaining planning permission can take from 8-13 weeks overall, which depends on the complexity of your proposal.

Seeking further advice

As this is a grey area in terms of planning, you also have the option of seeking advice from your local planning authority through the Duty Planner Service. This is a service that the council offers to provide homeowners with a pre-application determination. This means they will consider your proposal before you continue with a design or submit for planning, which can then be followed up with a written report. The service provides peace of mind for those worried about receiving a refusal for their project. Usually, the Duty Planner Service is priced at £100-£200, although some local planning authorities even offer it for free.

If you are thinking of undertaking a home renovation, we would love to help you on your project. You can speak to a member of our friendly team of professionals on 02070432378 or via email at hello@hometales.co.uk. It would be helpful if you could provide some details of the project you would like to discuss. Alternatively, you can book a free telephone consultation with us here, where you can see all available times.


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