Building an outbuilding can be a practical way to create additional space at home. Whether you are considering a garden office, home gym, workshop, garage, storage building or another type of garden structure, it is important to understand whether outbuilding planning permission is required before starting work.
Some outbuildings can be built under permitted development rights, meaning a planning application may not be necessary. However, this depends on several factors, including the size and height of the proposed building, its position within the garden, its intended use and the type of property involved.
Understanding the relevant planning requirements at an early stage can help you avoid delays, enforcement issues and potentially costly changes later.
What Is an Outbuilding?
An outbuilding is generally a structure located within the grounds of a residential property and separate from the main house.
Common examples include:
Planning rules generally distinguish between structures that are used for purposes incidental to the enjoyment of the main dwelling and buildings that effectively create separate accommodation.
For example, a garden building used as a home office or gym may be treated differently from an independent residential unit containing its own bedroom, bathroom and kitchen.
The intended use of the building is therefore an important consideration when determining whether planning permission is needed.
Do You Need Outbuilding Planning Permission?
Not every outbuilding requires a planning application.
Certain outbuildings may fall within permitted development rights, provided that they satisfy all the relevant limitations and conditions.
Under the permitted development rules, outbuildings can generally be allowed where they are for a purpose incidental to the enjoyment of the dwellinghouse. This can include structures such as garages, sheds, storage buildings and other ancillary garden buildings.
However, permitted development rights are subject to detailed restrictions.
A building that exceeds the applicable height limits, is positioned incorrectly, covers too much of the available garden area or is intended to provide independent living accommodation may require planning permission.
It is therefore important not to assume that a small garden building automatically falls outside the planning system.
What Are the Permitted Development Rules for Outbuildings?
There are several requirements that should be considered when planning an outbuilding.
The Building Should Be Single Storey
Outbuildings covered by the relevant permitted development rules must generally be single storey. This means that a two-storey garden building will usually require planning permission.
The overall height of a permitted development outbuilding also depends on its roof design and its distance from the boundary.
Height Restrictions
There are specific height limits for outbuildings.
Where an outbuilding has a dual-pitched roof, the maximum overall height is generally 4 metres. For other roof types, the maximum overall height is generally 3 metres.
The maximum eaves height is generally 2.5 metres.
There is also an important restriction where the building is within 2 metres of the property boundary. In this situation, the maximum overall height is generally 2.5 metres.
These measurements can have a significant impact on the design of a proposed garden room or office, particularly on smaller plots.
Position Within the Garden
The position of an outbuilding is another important consideration.
Under the relevant permitted development rules, an outbuilding cannot generally be positioned on land forward of a wall forming the principal elevation of the original house.
This means that simply having enough space within the garden does not necessarily mean that an outbuilding can be positioned wherever the homeowner wishes.
The relationship between the proposed building, the main house, the garden and the road should therefore be assessed before construction begins.
How Much of the Garden Can Be Covered?
One of the important restrictions concerns the amount of land around the original house that can be covered by buildings and other relevant additions.
The calculation takes into account the buildings and additions that fall within the relevant permitted development rules. This can include existing and proposed outbuildings as well as certain extensions to the original house. The original house itself is excluded from the calculation.
This means that the available area cannot be assessed simply by measuring the proposed garden room or shed on its own.
Existing garages, extensions and other structures may also need to be considered when determining whether the proposal falls within the permitted development limits. For properties where the garden has already been substantially developed, this calculation can be particularly important.
Can You Use an Outbuilding as a Garden Office?
Garden offices are increasingly popular, particularly where homeowners want dedicated workspace away from the main house.
A garden office may be capable of being constructed under permitted development rights where it satisfies the relevant requirements.
However, its use remains important.
An office that is genuinely ancillary to the main dwelling is different from a building that has effectively become a separate residential unit.
The inclusion of facilities such as a bedroom, kitchen and bathroom may raise additional planning considerations, particularly where the building could be occupied independently.
The design and intended use should therefore be considered together rather than looking at the physical size of the building alone.
Can an Outbuilding Be Used as a Bedroom or Annexe?
This is an area where homeowners should take particular care.
Permitted development rights for outbuildings are intended to cover buildings used for purposes incidental to the enjoyment of the main dwelling. They do not generally allow the creation of a separate, self-contained living accommodation within an outbuilding.
A building designed to operate independently as accommodation may therefore require planning permission.
This can apply where an outbuilding contains facilities such as:
The planning authority may consider the overall use and function of the building rather than relying solely on how it is described by the homeowner.
If your intention is to create an annexe or independent accommodation, it is advisable to establish the planning position before construction begins.
Do Listed Buildings Have Different Rules?
Yes. Additional restrictions can apply where a property is a listed building or falls within the curtilage of a listed building.
The permitted development rules for outbuildings include specific restrictions affecting listed buildings. Planning Portal guidance states that an outbuilding within the curtilage of a listed building requires planning permission.
Listed buildings may also be subject to separate listed building consent requirements depending on the nature and impact of the proposed works.
If your property is listed, it is therefore important to consider the planning position before relying on permitted development rights.
What About Conservation Areas and Other Designated Areas?
Additional restrictions can apply to properties in designated areas.
These may include conservation areas, National Parks, Areas of Outstanding Natural Beauty, the Broads and World Heritage Sites. The precise restrictions depend on the designation and the location of the proposed development.
For example, the permitted development rules contain additional limitations concerning the amount of land that can be covered by certain buildings in designated areas, particularly where structures are located more than 20 metres from the house.
An Article 4 Direction can also remove or restrict permitted development rights in certain areas. Where permitted development rights have been removed, a planning application may be required even if the proposed outbuilding would otherwise meet the standard limitations.
Checking the planning history and local restrictions affecting the property is therefore an important part of assessing an outbuilding proposal.
Do Flats and Maisonettes Have the Same Permitted Development Rights?
The householder permitted development rights discussed above generally apply to houses rather than flats and maisonettes.
This distinction is important because someone living in a flat may not have the same permitted development rights as the owner of a conventional house with its own garden.
The legal and planning position can also depend on the ownership and use of the surrounding land. If you live in a flat or maisonette and are considering an outbuilding or garden structure, it is advisable to establish whether the relevant permitted development rights apply before proceeding.
What If the Outbuilding Is Already Built?
If an outbuilding has already been constructed without planning permission, the situation should be assessed rather than assuming that the structure is automatically unlawful.
The relevant questions may include:
Depending on the circumstances, it may be possible to establish that the development is lawful.
A Lawful Development Certificate can provide formal confirmation that proposed or existing development is lawful in planning terms where the relevant requirements are satisfied.
Where the building does require planning permission, a retrospective planning application may need to be considered.
Do Building Regulations Apply to Outbuildings?
Planning permission and building regulations are separate matters.
Even where an outbuilding does not require planning permission, building regulations may still apply depending on the construction, size, use and other characteristics of the building.
For example, a building intended for more substantial or regular occupation may raise building control considerations that would not necessarily apply to a simple garden shed. It is therefore important to consider both planning and building regulations before construction begins.
Obtaining permitted development rights does not remove the need to comply with other legal requirements.
When Is Planning Permission Likely to Be Required?
Planning permission may be necessary where the proposed outbuilding does not comply with the relevant permitted development conditions.
Examples can include:
The exact circumstances should always be assessed on a property-by-property basis.
What Should You Check Before Building an Outbuilding?
Before ordering materials or beginning construction, it is sensible to review the proposal against the relevant planning requirements.
Important points to check include:
1. The Property Type
Confirm whether the property is a house and whether the relevant householder permitted development rights apply.
2. The Planning History
Previous extensions or other development may affect the available permitted development allowance.
Planning conditions attached to previous permissions may also have removed certain permitted development rights.
3. The Property’s Designations
Check whether the property is listed, located within a conservation area, or affected by another designation.
4. The Proposed Dimensions
Measure the proposed height, width, depth, and distance from boundaries accurately.
Small changes to the design can sometimes affect whether the proposal falls within permitted development.
5. The Intended Use
Consider how the building will actually be used.
A storage shed, workshop or home office may raise different planning questions from an independent living space.
6. The Existing Garden Development
Consider existing extensions, garages, sheds and other structures when assessing the amount of land already covered.
7. Any Local Restrictions
Check whether an Article 4 Direction or a planning condition affects permitted development rights at the property.
How Can a Planning Consultant Help?
Planning rules for outbuildings can appear straightforward, but the details can become more complicated when several restrictions apply at the same time.
A planning consultant can review the proposed development against the relevant planning requirements and help establish whether planning permission is likely to be needed.
This can include reviewing:
At Expert Planning Consultants, we can provide professional planning advice tailored to your proposed outbuilding and property circumstances.
Obtaining advice before construction can help identify potential planning issues at an early stage and clarify the appropriate route forward.
Why Should You Check Planning Requirements Before Building?
Starting construction before establishing the planning position can create avoidable problems.
If an outbuilding does not benefit from permitted development rights and planning permission was required, the local planning authority may take enforcement action.
This can potentially result in the owner having to alter the building, submit a retrospective planning application or, in some circumstances, remove the structure.
Establishing the planning position before work begins can therefore provide greater certainty.
It can also help you design the building around the applicable requirements rather than having to make expensive changes after construction.
Frequently Asked Questions About Outbuilding Planning Permission
Do all outbuildings need planning permission?
No. Some outbuildings can be constructed under permitted development rights if they satisfy all the relevant conditions and limitations. The size, height, position, intended use, and characteristics of the property all need to be considered.
Can I build a garden office without planning permission?
A garden office may be possible under permitted development rights if it meets the applicable requirements and is used for a purpose incidental to the enjoyment of the main dwelling.
However, the building should not become separate self-contained residential accommodation.
How tall can an outbuilding be?
The permitted height depends on the roof design and the building’s distance from the boundary. Generally, the maximum overall height is 4 metres for a dual-pitched roof and 3 metres for other roof types, with a maximum eaves height of 2.5 metres. Where the building is within 2 metres of a boundary, the overall height is generally limited to 2.5 metres.
Can I use an outbuilding as a bedroom?
Using an outbuilding as a bedroom may raise planning issues, particularly if the building forms part of separate or self-contained accommodation. Permitted development rights for outbuildings do not generally cover independent living accommodation.
Can I build an outbuilding next to my boundary?
An outbuilding can potentially be positioned close to a boundary, but additional height restrictions apply where it is within 2 metres of the boundary. The precise measurements and other permitted development conditions must also be satisfied.
Do listed properties have different rules for outbuildings?
Yes. Additional restrictions apply to outbuildings within the curtilage of listed buildings, and planning permission will generally be required. Other forms of consent may also be relevant depending on the proposed works.
Can I get planning permission for an outbuilding after it has been built?
Depending on the circumstances, a retrospective planning application may be possible. However, it is preferable to establish the planning position before construction begins so that the proposal can be designed appropriately.
What if I am unsure whether my outbuilding needs planning permission?
If there is uncertainty, you can seek professional planning advice or contact the relevant local planning authority. Where a development is believed to be lawful, a Lawful Development Certificate may also provide formal confirmation of its planning status.
Understanding Outbuilding Planning Permission
Outbuildings can provide valuable additional space, but the planning requirements should be considered before construction begins. Although many garden buildings can benefit from permitted development rights, those rights are subject to conditions covering matters such as height, position, garden coverage, designations and intended use.
A garden office, garage or storage building may have a different planning position from an outbuilding intended to provide independent accommodation. Listed buildings, designated areas and properties affected by planning restrictions may also require additional consideration.
If you are unsure whether your proposed building requires outbuilding planning permission, obtaining professional advice before starting work can help clarify the planning position and identify the most appropriate route forward.
Contact us today to discuss your plans and find out how we can assist with your planning requirements. We can provide tailored planning advice based on your property, proposed outbuilding and intended use.