In many instances, converting a garage can be done without the need for planning permission. However, there are several important considerations to be aware of before you begin organising the building work.

Follow the steps outlined below to determine whether you can proceed directly to construction.

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1. Check there are no legal constraints

Before we get into planning matters, if you live on a housing estate or in a new-build development, the first thing you should check is whether your title deeds contain any legal restrictions preventing you from converting your garage.

It’s not uncommon for developers to apply restrictive covenants to control future development and maintain the overall appearance of the area. These covenants can include restrictions on garage conversions and other renovations.

If your title deeds contain such conditions, you’ll need to consult with a conveyancing solicitor who will advise you on whether the works are possible and if any additional steps are required before commencing work.

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2. Check if your proposals classify as development

Next, determine if your plans qualify as ‘development.’

Under Section 55 of the Town and Country Planning Act 1990, internal works or changes that do not materially affect the external appearance of the building are not considered development and generally don’t require planning permission.

The term ‘materially affect’ lacks a precise legal definition but typically refers to changes to a building’s exterior. Many local planning authorities (LPAs) may view simple garage conversions (e.g., internal alterations, infilling the garage door with flush glazing) as non-material works, especially if the property is not on designated land like a conservation area or an Area of Outstanding Natural Beauty (AONB).

For detached garages, their use must be ‘incidental to the enjoyment of the dwellinghouse,’ meaning they can’t be converted into self-contained living accommodation without planning permission. Permitted uses include home offices, gyms, or hobby rooms.

Since LPAs may interpret legislation differently, it’s always advisable to check with your LPA before proceeding.

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3. Check for permitted development rights

If your proposals qualify as development, the next step is to check if your property benefits from permitted development (PD) rights.

PD rights outline what can be constructed without planning permission and apply exclusively to houses, referred to as 'dwellinghouses' in legislation. They do not extend to flats or houses in multiple occupation (HMOs).

If you live on designated land your PD rights may be restricted. Development is still possible, but additional rules will apply.

In some designated areas, the council may have implemented an Article 4 Direction, removing PD rights. Additionally, PD rights may have been removed by a condition on a previous planning consent. In such cases, you’ll need to apply for planning permission.

PD rights are also generally void for listed buildings, where you will need to obtain listed building consent to carry out any work.

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This converted garage in a conversation area in Edinburgh's Old Town by Izat Arundell required planning permission. Photo by Zac and Zac.

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4. Review permitted development guidelines

If your property has permitted development rights, the next step is to familiarise yourself with the relevant guidelines. Permitted development rules vary across the UK, so it's important to consult the regulations specific to your region.

The Town and Country Planning (General Permitted Development) (England) Order 2015 (GPDO) sets out guidance for England. Class A (extensions) and Class E (outbuildings) are the relevant sections for garage conversions.

Key considerations include:

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Attached Garages

If your garage is attached to your house, it will be considered an extension, and Class A will typically apply. The garage can be repurposed into living areas such as a living room, dining room, kitchen, or bedroom. Some key rules for external alterations include:

• Infilling the garage door with flush glazing or matching walling is usually permitted.
• If your garage faces the road, you cannot add a bay window, though a front porch may be allowed.
• External materials must be similar to the existing structure.
• You can extend the rear of a detached house by up to 4 metres (or 3 metres for other houses) without prior approval. Larger extensions of up to 8 metres (detached houses) or 6 metres (other houses) may be permitted with prior approval. These larger limits do not apply on designated land.
• You cannot extend above an attached garage if it’s on the front or side of your property. Two-storey extensions are not permitted on designated land.
• You can extend to the side but it must not exceed 4 metres in height or extend more than half the width of the original house. If the side extension is within 2 metres of a boundary, the height limit is reduced to 3 metres. Side extensions are not permitted on designated land.
• Extensions are not permitted to face the road.
• The total area of the extension must not exceed 50% of the site, excluding the original house.

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Detached Garages‍

If your garage is detached, Class E typically applies. Class E covers outbuildings, including detached garages, within the curtilage of a house. Stricter limitations on how the space can be used apply here.

Key restrictions include (non-exhaustive):

• Detached garages cannot be converted into self-contained living accommodation under PD rules.
• The use of the converted space must be 'incidental' to the main house's function. Permitted uses include a home office, gym, storage, or hobby room.
• Detached garages must be single storey.
• If you’re replacing a flat roof with a dual-pitched roof, the maximum height of the ridge is 4 metres.
• There is a maximum height of 3 metres for other types of roofs (e.g., flat or mono-pitched roofs).
• If your garage is within 2 metres of a boundary, the maximum height is restricted to 2.5 metres, regardless of roof type.
• The garage cannot extend beyond the principal elevation of the house that faces the road.
• The total area of all outbuildings must not exceed 50% of the site, excluding the original house.
• No verandas, balconies, or raised platforms are permitted.

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PD rules are largely similar across the rest of the UK. However, the larger home extension allowances apply only in England. For more information, please refer to the links below.

The Town and Country Planning (General Permitted Development) (Scotland) Order 1992

Town and Country Planning (General Permitted Development) (Wales) Order 1995

The Planning (General Permitted Development) Order (Northern Ireland) 2015

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The function of a detached garage must be incidental to the use of the main house in order to qualify as permitted development, as illustrated in this example of a home office studio by architect Paul Westwood. Photo by Chris Wharton.

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5. Apply for a Certificate of Lawful Development

Although PD rights provide clear guidance on what can be built without planning permission, some areas may be open to interpretation. Councils may view certain types of development differently, which could create complications later.

For this reason, it is always advisable to apply for a Lawful Development Certificate (LDC) before starting the building work. This certificate ensures that your project is legally compliant.

The process can take up to 8 weeks.

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6. Prior approval for larger garage extensions

If you live in England and you’re adding a large rear extension or an additional storey, you’ll need to apply for prior approval before building work begins.

This process allows your local authority to consider your designs and assess their potential impact on the amenity of the neighbouring properties.

As with LDCs, this assessment process can take up to 8 weeks.

For more information see our article below.

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READ: Permitted Development Rules for House Extensions

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7. Other consents

If your conversion affects an adjoining boundary, you will need to agree on a Party Wall Award your neighbours, which involves getting written permission before construction begins. You will need to notify your neighbours at least 2 months before the work starts. You can either do this yourself or through a Party Wall Surveyor.

Additionally, all garage conversions require Building Regulations approval to ensure they meet safety and energy efficiency standards. Simple construction work can be carried out on a building notice. For more complex projects, a full plans application is advisable.

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The information provided in this article is intended for general guidance and educational purposes only. Planning matters can be nuanced and difficult to navigate. For specific expert advice on your project, consult a skilled residential architect featured on Designs in Detail.

About the author

Aron Coates, an architect with over two decades of experience, draws upon a wealth of residential architectural expertise, encompassing projects ranging from the restoration of historic structures to the design of contemporary homes.

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