Do You Need Planning Permission for a Garden Room? The Definitive Guide

Are you considering adding a garden room to your property in the UK but unsure if you need planning permission? I’ve been through this dilemma countless times before, and it can be quite confusing. The good news is that, in many cases, you don’t need to apply for garden room planning permission in the UK. However, be sure to check each one of the permitted development rules below before you start building. For those interested in building a garden room from scratch, it’s essential to understand the planning permission requirements to ensure a smooth construction process.

If you’re confident your building meets the permitted development rules, there’s no reason you can’t continue with your garden room build. However, I would mention your intentions to your neighbours. Should there be any concerns, you can address them promptly and avoid issues later on. Later in this article, I’ll discuss common issues and best approaches.

Garden rooms are a fantastic way to create extra living space, a home office, or even a gym without the hassle and expense of a full extension. However, navigating the permitted development rules for garden rooms in the UK can be confusing. In this guide, I’ll explain everything you need to know about when planning permission is required, the key regulations to keep in mind, and how to ensure your garden room complies with local building laws.

I will begin by covering the most common restrictions, followed by a detailed breakdown of the complete list. After that, I’ll provide case studies, scenarios, and answers to frequently asked questions. I also want to touch on building regulations and when they will be required as not all garden buildings will be exempt from building regs.

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Does My Garden Room Require Planning Permission? – Permitted Development Rules

Your garden room will be considered permitted development, meaning it will not require an application for planning permission, providing all of these conditions are met. This list of UK garden room planning permission restrictions has been sourced directly from the .Gov website here.

Before I discuss all the rules in detail, I want to highlight the most common restrictions. These are:

1. The garden room is not to be used as separate living accommodation.
2. If within 2m of a boundary, the garden room cannot be taller than 2.5m.
3. The garden room (including any existing outbuildings) cannot take up more than 50% of the curtilage of the property.

I’ll explain each of these in greater detail to eliminate any ambiguity.

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One. Garden Room Not to be Used as Separate Living Accommodation

The structure must be incidental to the enjoyment of the dwelling house. This means it should serve as a space for hobbies, home offices, gyms, or general relaxation, but not as a self-contained living accommodation. If you plan to use the garden room as a living space with a bedroom or kitchen, you may need full planning permission.

For more detail on this section, including questions such as adding a toilet or kitchen, please see the FAQ section below.

If the purpose of your garden room is to be a fully functioning living space such as an annex, you will need to apply for planning permission. For further information about applying for planning permission please see the section below titled: Applying for Planning Permission

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Two. Height Restriction of 2.5m When Within 2m of a Boundary

In many cases, a garden room will need to be constructed near a property boundary. The garden room must not exceed a total height of 2.5 meters if located within 2 meters of the property boundary. This includes the base, walls and any roofing. The height must be measured from the natural ground level where it is built. (The base of the garden room)

In the above example, the garden room is very close to the boundary on both sides and therefore must not exceed 2.5 meters in height.

See point four below for garden rooms further than 2 meters from the boundary.

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Three. The Garden Room Cannot Take up More Than 50% of the Curtilage of the Property

No more than 50% of the land surrounding the original house (as it stood in 1948 or when first built, whichever is later) can be covered by additional buildings or extensions, including the garden room. This excludes the house itself.

The term “original house” refers to the property as it was initially constructed or as it existed on 1 July 1948 (if built before that date). Even if you haven’t added any extensions yourself, a previous owner may have done so.

In my example picture below, the red line depicts the curtilage of the property, the white % boxes indicate existing buildings within the curtilage and the light blue chequered box indicates the restricted area for garden buildings. (More on this below in section five).

The total area covered by existing garden buildings adds up to 19%. This means the addition of a garden room building cannot take up more than 31% of the total curtilage area. (Unless some of the existing buildings are removed).

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More Garden Room Planning Restrictions

With the three key restrictions addressed, let’s explore the remaining garden room permitted development rules. See the detailed descriptions below the following list.

4. Garden rooms must be single storey with a maximum eaves height of 2.5 metres and
   maximum overall height of 4 metres with a dual pitched roof, or 3 metres in any other case.
5. Garden rooms are not permitted development forward of the principal elevation of the original
   house. The term original house means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date).
6. On designated land, garden rooms to the side of the house are not permitted development.
7. In national parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the total area to be covered by any garden rooms more than 20 metres from ANY WALL of the house must not exceed 10 square metres to be permitted development.
8. Garden rooms are not permitted development within the grounds of a listed building.
9. To be permitted development, any new building must not have a microwave antenna.
10. Balconies and verandas are not permitted development. Raised platforms such as decking
    are permitted development provided they are no higher than 300mm.

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Four. Garden Rooms to be Single Storey with Height Restrictions

Garden rooms must adhere to strict height limits to avoid the need for planning permission. These rules ensure that the structures remain subordinate to the main property and do not adversely affect neighbours or the surrounding area.

I already mentioned the 2.5m height restriction when within 2m of a boundary but when building more than 2m away from a boundary you will have a little more height availability.

Single Storey Requirement

A garden room must be a single-storey structure under permitted development rules. This means:

• The garden room cannot include additional floors or mezzanines.
• Installing a staircase or ladder to access a second level, loft area, or storage space above the main floor is not permitted.
• Any use of the roof space must remain non-habitable, as it could otherwise classify the structure as more than single storey.

Maximum Eaves Height

The eaves (the lower edge of the roof where it meets the wall) must not exceed 2.5 metres in height. This restriction applies to ensure the structure maintains a low profile and does not overshadow neighbouring properties.

Maximum Overall Height

The total height of the garden room depends on the type of roof design:

Dual-Pitched Roof (e.g., gable or hipped): The maximum overall height is 4 metres. A dual-pitched roof slopes on two sides, which helps reduce the visual impact of the height while allowing for more internal headroom.

Flat Roof or Mono-Pitched Roof: For other roof types, such as flat roofs or those sloping on only one side, the overall height must not exceed 3 metres. Flat roofs are a popular choice for keeping the garden room compact and within height limits.

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Five. Garden Rooms are not Permitted forward of the Principle Elevation of the Property

Outbuildings are not permitted development forward of the principal elevation of the original
house. The term original house means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date).

The principal elevation typically refers to the front-facing side of your house, which usually includes the main entrance. This side is considered the most prominent, facing the street or open space, and it defines the overall orientation of your property.

A garden room cannot be located forward of the principal elevation of your house if your property fronts a highway. If your property does not front a highway, the restriction about placing a garden room forward of the principal elevation does not apply. This means you may be allowed to position a garden room in front of your house, provided it adheres to all other permitted development rules

Exceptions or Special Circumstances

In some cases, properties may have unique layouts that affect how the principal elevation or highway frontage is defined. For example:

• Corner Plots: If your property is on a corner, it may front two highways. In such cases, the restriction applies to both frontages.
• Setbacks: A garden room that is significantly set back from the highway, even if forward of the house, might require clarification from the local planning authority (LPA) to determine compliance.
• If your property is accessed via a private drive shared with other houses and not a public highway, the restriction on placement forward of the principal elevation might not apply. However, the LPA may still consider whether the placement affects the shared access or the character of the area.

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Six & Seven. Garden Rooms Restrictions When a Property is Located in Designated Land

If your property is located on designated land such as a National Park, Area of Outstanding Natural Beauty (AONB), the Broads, or a World Heritage Site, specific additional rules apply to the placement and size of outbuildings under permitted development rights. These rules are designed to preserve the unique character, natural beauty, and historical significance of these areas.

Garden Rooms to the Side of the House Located on Designated Land

• On designated land, garden rooms located to the side of the house are not allowed under permitted development rules.
• This restriction ensures that the visual appearance of the property, particularly from public viewpoints such as roads or paths, remains consistent with the surrounding area’s character.
• If you wish to place a garden room or outbuilding to the side of your house on designated land, you will need to apply for planning permission.

Limitations on Outbuildings More Than 20 Meters from the House

For properties in National Parks, AONBs, the Broads, or World Heritage Sites, additional restrictions apply to outbuildings placed more than 20 meters from any wall of the house:

• The total area of all outbuildings combined in this zone must not exceed 10 square meters to qualify as permitted development.
• This rule ensures that large or numerous structures do not overwhelm the landscape or detract from the natural or historic environment.

Implications of this Rule

If you plan to place a garden room or outbuilding farther than 20 meters from your house, it must be compact—typically used for storage or a small ancillary purpose—to stay within the 10-square-meter limit. Most garden rooms will exceed this size.

Larger structures beyond this limit will require planning permission.

Key Considerations

1. Cumulative Area: The 10-square-meter restriction applies to the combined total area of all outbuildings located beyond the 20-meter mark. If you already have existing structures in this zone, you may have limited or no space left for a new garden room under permitted development.
2. Boundary and Height Limits: All other permitted development rules still apply, including height limits (e.g., 2.5 meters for outbuildings within 2 meters of a boundary) and restrictions on use.
3. Designated Land Oversight: Local planning authorities may impose additional conditions specific to their area to further limit visual impact or preserve the setting.

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Eight. Garden Rooms are not Permitted Within the Grounds of a Listed Building.

If your property is a listed building, permitted development rights for outbuildings do not apply. This means that any garden room or similar structure within the grounds of a listed building will require planning permission, regardless of size, location, or use.

The restriction exists to preserve the architectural and historical significance of listed properties and their surroundings. When applying for planning permission, the design, materials, and placement of the outbuilding will be closely scrutinised to ensure it does not detract from the listed building’s character or setting.

To proceed, it’s essential to consult your local planning authority (LPA) early in the planning process and consider hiring a specialist familiar with listed building regulations to help design a compliant structure.

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Nine. Garden Rooms Must Not Have a Microwave Antenna

To qualify as permitted development, any new garden room, must not include a microwave antenna. This restriction ensures that outbuildings remain incidental to the primary property and do not serve as a base for telecommunication or broadcasting equipment.

If you wish to install a microwave antenna on your garden room or outbuilding, you will need to apply for planning permission. This allows the local planning authority to assess potential impacts, such as visual appearance, interference, and effects on the surrounding area.

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Ten. No Balconies or Raised Platforms Over 300mm

If you are planning to build a decking area around your garden rooms, anything over 30cm is not considered permitted development. These restrictions are in place to ensure privacy for neighbours and to maintain the visual harmony of the area.

Balconies and Verandas

Any garden room that includes a balcony (a platform projecting from the building and enclosed by a railing) or a veranda (a roofed platform attached to the exterior, typically open on the sides) will require planning permission.

Raised Platforms and Decking

Raised platforms, including decking, are permitted development as long as they are no more than 300mm (30cm) above the natural ground level.

Platforms exceeding this height are considered more intrusive and require planning permission.

The height of a raised platform is measured from the natural ground level, not any modified or excavated surface.

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Top Tips and Questions Surrounding Garden Room Construction, Design and Planning

I’ve compiled a list of what I believe to be some of the most commonly asked questions and my top tips for building a garden room. If I’ve missed your specific question please feel free to ask below in the comments section and I’ll answer it ASAP.

Talk to Neighbours or Local planning Authorities

My first and most important piece of advice would be to talk to neighbours. Even if you stick to all the above rules, if someone doesn’t like what you are doing, you’re opening yourself up to a visit from your local building inspector. And they may find something you’ve missed.

I understand this isn’t always an easy task, as for some, you might not get on with your neighbours. (I explain the best route to take if this is the case below). But for those who are friendly with neighbours, have a chat with them and explain what you intend to do. You’ll find that 9 times out of 10 there won’t be any issues and you can get started with your build. The thing is, if no one has an issue with your garden room and it doesn’t impact anyone, the planning authorities will never be notified. Now, I’m not saying you need to purposefully hide anything, as you will still need to keep everything within the guidelines listed above, but you will be saving yourself some time and effort should anyone have an issue with your garden room after it’s built.

Example of a Garden Room Build Issue

I have one example, where a garden room was built within the permitted development rules, but as the room was being used as a woodworking hobby space, the noise levels were noticed by neighbours, who decided to notify the local council. The council arrived, asking to inspect the building and found that it was in fact just 10cm over the height limit, based on the measurement taken from the original ground level. The trouble with this build was that a small platform made from sleepers was added to support the front of the build. Due to the slope on the original ground this meant the front of the building was in fact over the 2.5m maximum height.

This meant one of two things:

• Reduce the height of the building by 10cm. (This would potentially take days and over-complicate the design of the structure.
• Apply for retrospective planning permission.

In this case, a planning application was submitted and luckily approved. It goes to show that a simple mistake can end up costing. The worst case scenario here would have resulted in the garden room having to be taken down altogether.

In hindsight, the owner should have:

• Discussed the build with neighbours and addressed any concerns before the build.
• Designed and built the garden room strictly to the height limitations.
• Considered sound proofing the garden building with Rockwool sound insulation sheets.

I Don’t Get on With my Neighbours

What do you do if you don’t get on with neighbours? You might be in the position where you think your neighbours are going to be difficult about your garden room. in this case I would advise:

• Be 100% sure your garden room sits within the permitted development rules.
• If you’re still unsure, apply for a certificate of lawful development. There will likely be a small cost for this but it won’t be as much as a full planning application and will give you peace of mind that your garden room is lawful.

Always follow the rules and be polite and courteous to any neighbour that raises issues. This doesn’t mean that you have to give them too much information but it might alleviate any concerns or difficulties in the future.

Think About Your Garden Room’s Impact on your Neighbours

To avoid any issues with your garden room build, assess your site thoroughly and think about how your garden room might impact your neighbours.

• Does it block any views?
• Does it block any natural sunlight?
• Does the garden room overlook any neighbouring properties?
• Are there any nearby trees or foliage that need to be cut back?
• Would the garden room’s foundation and base divert or impact any natural drainage channels?

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Check Your Properties Title Deeds for Restrictive Covenants

Before building a garden room, it’s important to check if any covenants apply to your property. Covenants are legal restrictions tied to the land that may limit what you can do, even if your project complies with planning and building regulations. They might prohibit additional structures, restrict building near boundaries, or require approval from a third party, such as a developer or estate manager. To check for covenants, review your property’s title deeds or land registry documents, and consult a solicitor if needed. Ignoring covenants can lead to legal disputes or even the removal of your garden room, so it’s essential to address them early.

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How to Apply for Planning Permission

1. Determine the Type of Permission Required

You’ll need to complete a household planning permission application which applies for minor changes to a residential property, such as building a garden room.

2. Prepare the Required Documents

You’ll need to prepare and submit several documents to your local planning authority (LPA). These typically include:

• Application form: Complete the planning application form through the Planning Portal website.
• Site plan and block plan: Show the location of your property and the proposed garden room in relation to boundaries and nearby buildings.
• Existing and proposed elevations: Illustrate how the structure will look before and after development.
• Existing and proposed floor plans: Provide layouts of the space, including dimensions.
• Design and access statement: (If applicable) This outlines the design considerations and accessibility of the proposed development.
• Supporting documents: These may include flood risk assessments (if applicable) or ecological surveys.

3. Consult Your Local Planning Authority (LPA)

Consider consulting your LPA for advice if:

• Your property is on designated land or in a conservation area.
• The project may impact your neighbors, such as blocking light or views.

4. Submit Your Application

• Use the Planning Portal (planningportal.co.uk) for an online application. The portal guides you through the process and allows you to upload documents, drawings, and plans.
• Pay the planning application fee. The cost is generally £206 for householder planning permission in England but may vary by region.

5. Notify Your Neighbours

Once submitted, your application will be made public, and your LPA may notify neighboring properties about the proposed development. Neighbors have a right to comment, support, or object within a consultation period (typically 21 days).

6. Await a Decision

The LPA will assess the application based on:

• Local planning policies.
• The impact on the environment, neighbors, and area character.
• Compliance with national planning guidelines.

Decisions are usually made within 8 weeks for standard applications, though larger or more complex proposals can take up to 13 weeks.

7. Respond to Feedback

During the review period, the LPA may contact you for further information or suggest modifications to the plan. You can work with them to address concerns or objections.

8. Receive the Outcome

The LPA will either:

• Approve your application, often with conditions (e.g., specific materials or timelines).
• Refuse the application, providing reasons. You can:
  • Amend the plans and reapply.
  • Appeal the decision to the Planning Inspectorate.

9. Start Construction

Once planning permission is granted, ensure you meet any conditions imposed by the LPA. Also, check if building regulations approval is needed for your project.

Key Tips for a Successful Application

• Plan Ahead: Start early to accommodate consultation and decision times.
• Be Detailed: Provide comprehensive, clear drawings and documentation.
• Engage a Professional: Architects, surveyors, or planning consultants can help prepare plans and navigate regulations.
• Communicate with Neighbours: Proactively discuss your plans to address potential concerns.

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When Do Building Regulations Apply to Garden Rooms in the UK?

Building regulations ensure that construction is safe, energy-efficient, and suitable for its intended use. While many garden rooms fall outside the scope of garden room regulations UK, there are specific situations where compliance is mandatory. Understanding these scenarios will help you plan your garden room project correctly.

1. Size and Use of the Garden Room

• Small, Incidental Use: Garden rooms with a floor area under 15 square meters that are used for non-habitable purposes (e.g., a home office, storage, or gym) typically do not require adherence to building regulations.
• Medium-Sized Rooms: If the garden room is between 15 and 30 square meters in floor area, it must comply with building regulations unless it:
  • Does not include sleeping accommodation.
  • Is located at least 1 meter from any boundary or built with fire-resistant materials.
• Large or Habitable Rooms: Garden rooms larger than 30 square meters or intended for habitable use (e.g., bedrooms or self-contained living spaces) must comply fully with building regulations.

2. Connection to Main Services

• Electrical Installations:
  • If the garden room includes electrical work, such as lighting or power outlets, the installation must comply with Part P of the Building Regulations to ensure safety.
  • A qualified electrician registered with a competent persons scheme should carry out the work.
• Plumbing and Water Supply:
  • Adding plumbing (e.g., for a toilet, sink, or shower) requires compliance with building regulations, particularly for drainage and water supply systems.
• Heating Systems:
  • Installing permanent heating, such as radiators connected to your central heating system or underfloor heating, must comply with regulations to ensure energy efficiency and safety.

3. Structural Requirements

• Foundations and Stability:
  • If the garden room is large or located on uneven ground, the foundations and structure must meet regulations to ensure stability.
  • Garden rooms built close to existing trees, slopes, or retaining walls may also require professional assessment to avoid issues.
• Fire Safety:
  • Any garden room located within 1 meter of a boundary must use fire-resistant materials for walls, roofs, and floors to comply with fire safety regulations.
  • Rooms intended for sleeping or with multiple rooms may also require specific fire escape routes and smoke detection systems.

4. Insulation and Energy Efficiency

If the garden room is designed for year-round use, it must meet insulation and thermal performance standards under Part L of the Building Regulations to ensure energy efficiency. This includes:

• Wall, roof, and floor insulation.
• Double-glazing for windows and doors.

5. Height and Location

If your garden room exceeds 2.5 meters in height within 2 meters of a boundary, planning permission is required, and building regulations may also apply due to its size and impact on neighbours.

When to Contact Your Local Authority

You should contact your local building control department to confirm whether your garden room project requires building regulations approval. This is especially important if:

• The room will be used as a habitable space.
• It involves complex structural work, utilities, or exceeds permitted development limits.

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FAQ’s

Here are some commonly asked questions encountered when planning and building garden rooms in the UK.

Q. Do I need planning permission for a garden room with toilet?

A. As long as your garden room isn’t being used as a separate living space, you shouldn’t need to apply for planning permission. So you can add a toilet, including the plumbing without the need for planning, so long as the room is only used for activities such as hobbies, an office, a gym etc. As soon as you use the space to

Q. How much does it cost to apply for planning permission?

A. Expect to pay around £206 to submit a planning application to your local planning authority. LPA’s might differ in prices so be sure to check with your local branch.

Q. What size garden room without planning permission or building regs UK?

A. A garden room can typically be built without planning permission if it’s under 2.5m tall when within 2m of a boundary, doesn’t cover more than 50% of the garden, and isn’t located in front of the house if it fronts a highway. For building regulations exemption, the room should be under 15m², or up to 30m² if it’s more than 1m from the boundary, has no sleeping accommodation or plumbing, and uses fire-safe materials. Always confirm with your Local Planning Authority as rules may vary.

Q. Restrictions when building within 1 metre of boundary

A. Even when within 1 metre of the boundary, the structure can still be considered permitted development as long as it meets the height, size, and usage conditions. If it exceeds these conditions, planning permission may be required.

• Height Restrictions: The overall height of the structure must not exceed 2.5 metres.
• Total Floor Area: The garden room must not cover more than 50% of the garden area. Including all outbuildings and extensions.
• Construction Materials: If the structure is close to the boundary, using non-combustible materials (in the case of structures over 15m²) may be required to prevent fire risks. However, if the room is under 15m², building regulations may not apply.

Q. What is the 2.5 m rule for garden rooms?

A. The 2.5m rule for garden rooms refers to the maximum eaves height (the lower edge of the roof) when the structure is within 2 metres of a boundary.

When the garden room is more than 2 metres from a boundary, the eaves height is still limited to 2.5 metres. However, the overall height (from the ground to the highest point of the roof) can be up to 4 metres if it has a dual-pitched roof, without requiring planning permission

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Disclaimer

The information provided in this article is for general informational purposes only and should not be considered legal or professional advice. While I have compiled this content from publicly available sources, including the Planning Portal Government website, and shared insights based on my personal experiences, these may not apply to your specific circumstances or proposed garden room build.

I am not a qualified planning consultant, and I do not have the authority to provide advice tailored to individual projects. If you have any doubts or concerns about the regulations or requirements applicable to your design, it is crucial to seek advice from a qualified professional or contact your Local Planning Authority (LPA) directly.

By using the information in this article, you acknowledge that it is your responsibility to verify all details and ensure compliance with relevant laws and regulations.

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Thanks for reading.

If you have any questions on this subject, please feel free to reach out via the comments section below or start a thread in my forum.