In case you've been wondering, yes, it's possible to build a house extension without planning permission — and it’s all thanks to permitted development.
Nevertheless, there are rules and criteria that the extension must meet to qualify for permitted development. It is vital that you understand these rules and criteria before embarking on your project. This way, you can avoid getting into trouble with the law.
These rules control almost every aspect of your proposed house extension, from how high the extension can be to what to do if there's a highway nearby.
In this article, we’ll cover:
Plus a host of other tips and tricks! If you're about ready to add that extension, you can get your Resi quote here.
There are three primary conditions for extending your house without permission.
You cannot extend a house without planning permission if it has been extended before, either by you or its previous owners. This rule covers extensions made since the 1st of July 1948.
Listed homes and homes on designated lands (conservation areas, areas of outstanding natural beauty) have either limited or revoked permitted development rights. If your home falls under this category, we definitely recommend getting expert guidance when planning your extension.
Only houses are covered by permitted development. Other property types like flats and maisonettes will require you to apply for full planning permission. Also, note that if your house has been converted in the past, it may not be eligible for permitted development rights.
Before it was dissolved in 2020, the larger home extension scheme allowed homeowners to build single storey rear extensions that were larger than permitted development rights allowed. After it was dissolved, its allowances were added to permitted development rights. This meant that homeowners could still build larger extensions, but the way they would go about it now would be slightly different from when the larger home extension scheme existed.
Now, homeowners wishing to build larger extensions can simply apply for prior approval. With prior approval, you can extend a detached home as far as 8m for detached houses and 6m for other types of houses.
The rules set out in the town and country planning (General Permitted Development Orders) 1995 detail all the changes you can and can not make without planning permission
Here are some of them:
Permitted development allows you to extend the front of your house provided your front extension:
You can build your porch without planning permission provided:
You can convert your basement without seeking permission as long as
You don’t need planning permission to replace your window as long as the new windows are similar to the ones being replaced.
You probably won’t need planning permission to knock down internal walls as long as your house isn’t listed or in a conservation area.
For permitted development to cover roof light installation:
Most garage conversions fall under permitted development as long as the work is internal and no enlargement is involved. The only exception to this rule is a detached garage. However, if your garage is built after the house, it's worth checking in with your local authority to ensure that your home’s permitted development allocation has not been used up.
Conservatory extensions have the same permitted development criteria as house extensions. They must not be higher than the main house and must not occupy more than half of the surrounding land.
Sheds and garden rooms generally qualify as extensions under planning development rights. To build a shed or outbuilding without permission:
You can erect, construct and maintain your fence or wall under permitted development rights if:
Permitted development lets you build a swimming pool in your garden as long as it doesn't take up more than half of the garden curtilage.
You can add a solar panel under permitted development provided it does not protrude more than 200mm past the plane of roof or wall, and the highest part of the panel does not surpass the highest part of the roof.
This house extension was created using a loft conversion, which came under the homeowner’s permitted development rights - meaning no planning permission was required! The classic main dormer extension added bags of new space onto the household and includes not only new double bedroom, but an ensuite too.
In designing this house extension, our team used skylights to bring in plenty of natural light, along with a juliet balcony for an extra connection to the outdoors. While other balconies require planning permission, juliet balconies are exempt.
On using Resi, the couple had this to say: “We immediately liked the functionality of the platform. It was brilliant to be able to upload our inspiration ideas. We could brainstorm, but keep everything in one place - no more pieces of lost paper!”
Missing planning permission may affect the saleability of your home. How? Selling your property without providing the necessary documents could put the new owner at risk, as they will be held accountable for any breach in the law during its construction.
Although it’s more common to gain planning approval before starting on a project, there are some cases where the project had already begun before approval was sought (it may be that you made these changes without realising that they required planning permission).
In such a situation, retrospective planning permission is required. Retrospective planning permission allows you to file for approval after starting the project.
You should be careful, though, because if your application is not approved, you will be required to return things to the way they were.
Hence it’s always more advisable to apply for planning permission before embarking on the project.
This usually comes up when a seller cannot provide planning permission for the extensions or additions to the home at the point of sale. In cases like this, the buyer will be advised by their conveyance solicitor to get indemnity insurance.
Indemnity insurance protects the buyer from any legal issues that may arise concerning the building’s compliance, for example, building regulations and planning permission.
It’s worth mentioning that while indemnity insurance covers a legal defect with the property, it doesn’t cover repairs, replacements, or installations.
Resi offers an all-in-one solution platform to homeowners wishing to extend or renovate their homes. Our team of experts are equipped to handle everything from planning and permissions to financing solutions.
If you do need planning permission for your extension or renovation project to go ahead, it’ll benefit you to understand how the system works and what documents you’ll need for your project to have the best chance of being improved. For this, you’ll need to submit a full planning application. If you’re new to the process and you’d like some guidance, contact our experienced Planning team for a step-by-step approach to getting your work approved.
Alternatively, if you’re confident to go it alone, you can enlist the help of an architect to create detailed drawings of both your existing property and your proposed plan. The more detailed and explanatory these drawings are, the greater your chance of planning approval will be so it’s in your interest to secure a professional for the job.
Once you have your detailed drawings, contact your Local Planning Authority (LPA). They will be able to advise you on what actions are needed.
But in the meantime, you can use our calculator to find out how much your project will cost.
Please answer a few quick questions about your project to retrieve your quote.
What is the maximum extension without planning permission?
For extensions on detached properties you can extend as far as 8m from the existing property and for other types of properties the maximum distance you tend to be able to stretch from the original property is 6m.
What happens if you buy a house with an extension without planning permission?
If you buy a house with an extension that hasn’t been granted planning permission, you may be in breach of the law. This could, depending on the local council, result in the extensions on the property being demolished to regain the property’s lawfully agreed state.
What is the 4 year rule for retrospective planning permission?
This rule allows homeowners immunity from planning enforcement action for unauthorised extensions or renovations to their property that have been in place for over 4 years.
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