Self-Build Planning Permission: A Guide to Getting Approval
Learn how to secure self-build and custom-build planning permission, including prior approval, permission in principle, outline and full applications.
PLANNING APPLICATIONS
Andrew Ransome
10/5/202611 min read
Building your own home gives you the opportunity to create a property that is designed around your needs, rather than adapting an existing house or buying a new home from a developer.
However, finding a suitable plot and securing planning permission for a self-build or custom-build home can be challenging.
The fact that a proposal is for your own home does not, by itself, mean that planning permission will be granted. The site still needs to be suitable for housing and the proposal must comply with the development plan and other relevant planning considerations.
There are, however, a number of different ways in which a self-build project can come forward. The most appropriate approach will depend on the planning history and characteristics of the site.
This guide explains the main opportunities, application routes and planning considerations when seeking planning permission for a self-build or custom-build home.
What is self-build and custom-build housing?
Self-build and custom-build housing covers a broad range of projects.
The statutory definition includes homes where an individual or association of individuals builds or commissions a home to be occupied by those individuals.
This can range from someone managing much of the construction themselves to a person commissioning a contractor to deliver a completed home to their own requirements.
The important distinction is that the person who will occupy the home should have primary input into its final design and layout.
A conventional house purchased from a developer without such input would not normally constitute self-build or custom-build housing.
The distinction can be important because the planning system recognises the contribution that self-build and custom-build housing can make to housing choice. The National Planning Policy Framework requires development plans to consider the needs of people wishing to commission or build their own homes and to identify sites that can provide self and custom-build plots where there is an identified need.
The Self-build and Custom Housebuilding Act 2015 also requires relevant local authorities to maintain registers of people seeking serviced plots. It also places a duty on authorities to grant sufficient development permissions for self-build and custom housebuilding, subject to the statutory provisions.
These provisions should be considered alongside the normal planning policies affecting the site. But they do not provide an automatic right to planning permission.
Is your site suitable for a self-build home?
The first question should not necessarily be "which planning application should I submit?"
It should be:
Is there a realistic planning opportunity for a dwelling on this site?
This requires an assessment of the site, its planning history and the policies that apply to it.
The planning position can vary considerably between sites.
A plot within a settlement boundary may have a very different planning prospect from an agricultural field in the countryside or a site within the Green Belt.
Potential self-build opportunities can include:
a garden or backland plot;
an infill plot between existing houses;
a site on the edge of a settlement;
the replacement of an existing dwelling;
the conversion or change of use of an existing building;
redevelopment of previously developed land;
subdivision of a larger residential plot;
a rural building or barn capable of conversion;
a site allocated for housing;
a site identified on a brownfield register.
The planning merits of each opportunity will be different.
A site should therefore be assessed on its own characteristics rather than assuming that a particular type of plot will automatically receive permission.
Replacement dwellings
Replacing an existing house can be one of the more straightforward ways of creating a bespoke self-build home, particularly where the existing dwelling is lawful and established.
The fact that a house already exists does not necessarily mean that any replacement will be acceptable. Local policies may control the size, position and appearance of replacement dwellings, particularly in rural areas.
The planning assessment should consider, for example:
whether the existing dwelling is lawful;
whether it is capable of being replaced under local policy;
the size and footprint of the proposed replacement;
its position in relation to the existing dwelling;
the effect on the character of the area;
the impact on neighbouring properties;
access and parking;
trees, ecology and other site constraints.
Where the replacement dwelling is substantially larger than the existing property, the increase in scale will need to be justified carefully.
Garden and backland development
Large residential plots can sometimes provide an opportunity for a new self-build dwelling.
Garden and backland development can be particularly attractive because the site may already have access to roads and utilities and may be located within an established settlement.
However, the planning authority will usually consider whether the proposal represents a logical form of development or an unacceptable intensification of the site.
Important considerations include:
the relationship with surrounding buildings;
the character of the existing street;
access arrangements;
overlooking and privacy;
daylight and sunlight;
garden sizes and external amenity space;
parking and turning;
trees and ecology;
the position and scale of the proposed dwelling; and
whether the development would appear cramped or out of character.
The NPPF also encourages the effective use of land, while requiring development to maintain acceptable living conditions and respect the character of its surroundings.
Infill development
A gap between existing houses can sometimes provide an opportunity for a self-build home.
Infill proposals can benefit from being closely related to existing development and established infrastructure. However, it is important to establish whether the site genuinely represents an infill opportunity rather than an extension of development into an open area.
Local planning policies often contain specific definitions or criteria for infill development. These should be considered at an early stage.
Edge-of-settlement development
Land immediately adjoining an existing settlement can sometimes provide an opportunity for a new home, particularly where the site is well related to existing development and the local planning authority has policies supporting housing growth or where a local authority is short on its housing targets.
The assessment should consider the site's relationship with the settlement, rather than simply measuring its distance from the nearest house.
Questions include:
Would the development represent a logical extension to the settlement?
Is the site physically connected to existing development?
Can the site be accessed safely?
Are shops, schools and other services reasonably accessible?
Would the development result in an unacceptable intrusion into the countryside?
Is there an identified housing need or housing supply issue that supports the proposal?
Converting an existing building
Another potential route is to convert an existing building into a home.
Depending on the building and its lawful existing use, this may be possible through permitted development rights or a conventional planning application.
Examples can include the conversion of:
agricultural buildings;
offices;
commercial buildings;
shops;
industrial buildings; and
other redundant buildings.
Where permitted development rights apply, the project may be dealt with through a prior approval process rather than a full planning application.
However, prior approval is not a general alternative to planning permission. It is only available where a specific permitted development right applies and the relevant limitations and conditions are satisfied.
For example, certain agricultural-to-residential or commercial-to-residential conversions may be subject to prior approval requirements covering matters such as transport, flooding, contamination, natural light, noise and other specified considerations.
The existing use, planning history, building's physical characteristics and applicable permitted development right should therefore be established before relying on this route.
Which planning application route should you use?
There is no single planning application route that is best for every self-build project.
The main routes to consider are:
Prior approval
Permission in principle
Outline planning permission
Full planning permission
Choosing the right route can reduce unnecessary costs and help focus the application on the issues that need to be established.
Prior approval
Prior approval can provide a more streamlined route where the proposed development benefits from permitted development rights.
It is particularly relevant when converting certain existing buildings to residential use.
The advantage is that the principle of the development may already be established by the permitted development legislation, leaving the local planning authority to consider only the matters specified by the relevant permitted development right.
However, the eligibility requirements can be detailed. A building must satisfy the relevant limitations and conditions, and the development must fall within the applicable permitted development class.
Prior approval should therefore be considered as a specific legal planning route rather than simply a "simpler planning application".
Permission in principle
Permission in principle is designed to establish whether land is suitable for housing in principle.
It considers three fundamental matters:
the location of the development;
the use of the land; and
the amount of development.
The detailed design and technical matters are dealt with later through an application for technical details consent.
Permission in principle can therefore be useful where establishing the principle of housing development is the main objective before significant expenditure is incurred on detailed design.
It can arise through a brownfield land register or through the application route where the statutory requirements are met.
It is particularly important to understand that permission in principle is not the same as full planning permission. Development cannot proceed simply because permission in principle has been granted; technical details consent is required before the development can be implemented.
Outline planning permission
Outline planning permission is another way of establishing the principle of development before committing to the full detailed design.
An outline application can be appropriate where the key question is whether a site can accommodate a dwelling, or a specified amount of housing, but the final design has not yet been established.
The application can seek approval for matters such as:
the use;
the amount of development;
access;
layout;
scale; and
appearance
depending on which matters are reserved.
The remaining matters are subsequently dealt with through a reserved matters application.
Outline permission can therefore be particularly useful for landowners who want to establish the development potential of a site before undertaking the full architectural design.
It is important to note that an outline application will still require technical evidence, such as ecology and trees surveys.
Full planning permission
A full planning application seeks permission for the detailed development proposal.
The supporting information will depend on the site. It could include assessments relating to highways, drainage, flood risk, ecology, trees, heritage, landscape, contamination, noise or other matters.
The advantage of a full application is certainty.
If permission is granted, the detailed scheme is approved and can generally progress towards implementation, subject to conditions and any other required consents.
For a straightforward site, a full application may therefore be the most efficient route.
Building the planning case
Once the site and application route have been identified, the next step is to build a clear planning case.
Planning applications are determined in accordance with the development plan unless material considerations indicate otherwise.
The NPPF is a material consideration and provides national policies for both plan-making and decision-making.
For a self-build project, the planning case may include several different strands.
The local authority's self-build register can therefore be relevant evidence when assessing a proposal.
Local authorities are required to maintain and publicise registers of people seeking serviced plots for self-build and custom housebuilding.
The legislation also places a duty on relevant authorities to grant sufficient development permissions for self-build and custom housebuilding to meet the demand arising from their registers, subject to the statutory provisions.
This does not mean that an individual who is on the register automatically has a right to a planning permission on a particular site.
However, when considering a development proposal, it can be important to establish:
how many people are on the authority's register;
what demand has been identified;
the relevant base periods;
how many permissions have been granted;
whether those permissions meet the statutory demand; and
whether the authority has identified sufficient sites for self-build and custom-build housing.
Where there is a shortfall, this can form part of the planning case for additional self-build provision.
Design and local character
A self-build home does not have to look like a conventional house.
One of the advantages of self-build is the ability to create a home that responds to the site and the requirements of the individual occupier.
However, innovative design should still respond positively to its surroundings.
The best schemes are often those where the design has been developed in response to the site's characteristics rather than imposing a standard house design onto the plot.
Access, highways and parking
Access is often one of the first technical matters that needs to be investigated.
A self-build proposal may require a new access onto an existing road, improvements to an existing access or the use of a private track.
The application should demonstrate that safe and suitable access can be achieved.
Drainage and flood risk
Surface water and foul drainage can be important constraints, particularly on rural plots.
The appropriate solution will depend on the site and local infrastructure.
Ecology, trees and biodiversity
Ecological and arboricultural constraints should be identified early.
Trees can affect the position of a new dwelling, access and underground services. Similarly, protected habitats or species can place significant constraints on development.
Biodiversity requirements should also be considered at the beginning of the project rather than after the design has been completed.
For larger or more constrained sites, an early ecological appraisal can help establish what development is realistically achievable.
Heritage and landscape
Sites close to listed buildings, conservation areas, scheduled monuments or other heritage assets may require a heritage assessment.
Similarly, rural sites may need to address landscape character and visual impact.
These matters can influence not only whether development is acceptable but also where the house should be positioned and how it should be designed.
Planning obligations and Community Infrastructure Levy
A self-build home may be subject to planning obligations or Community Infrastructure Levy (CIL), depending on the location and circumstances.
Planning obligations must be necessary to make the development acceptable in planning terms, directly related to the development and fairly and reasonably related in scale and kind.
Self-build housing can also qualify for a CIL exemption where the statutory requirements are met.
The exemption is not automatic. There is a prescribed process for claiming it, including requirements that must be dealt with before development commences and evidence that must be provided following completion.
A person claiming the exemption must generally build or commission the home for their own occupation as their sole or main residence. There is also a three-year period during which certain events can result in the exemption being withdrawn.
CIL should therefore be investigated before a planning application is submitted and the exemption process should be considered from the outset.
Securing the self-build nature of the development
Where the planning case relies on the development being self-build or custom-build housing, it may be necessary to ensure that this is properly secured.
A planning obligation can be used to secure matters relating to the self-build or custom-build nature of the development where appropriate.
The exact mechanism will depend on the proposal and the requirements of the local planning authority.
The objective should be to make clear how the development qualifies as self-build or custom-build housing while avoiding unnecessary restrictions that could make the permission difficult to implement.
What if planning permission is refused?
A refusal does not necessarily mean that the site cannot be developed.
The first step should be to understand the reasons for refusal.
If the issues are capable of being addressed, it may be possible to submit a revised application.
Alternatively, where there are sound planning reasons why permission should have been granted, an appeal can be made to the Planning Inspectorate.
For some sites, the appeal process can also provide an opportunity to test the planning merits of a proposal independently of the local planning authority.
The key to securing self-build planning permission
There is no single planning policy that guarantees permission for a self-build home.
The strongest applications are normally those where the planning opportunity has been established before the design is finalised.
A successful approach should:
Identify the planning opportunity – understand the site's planning history, designation and relationship with existing development.
Establish the principle of development – determine whether housing is acceptable and what policies support or restrict it.
Consider all available routes – including prior approval, permission in principle, outline and full planning permission.
Choose the right development strategy – whether that involves a replacement dwelling, infill, backland development, conversion, brownfield redevelopment or another form of housing development.
Assess the constraints early – including highways, drainage, flood risk, ecology, trees, landscape and heritage.
Develop an appropriate design – create a home that responds to the character and opportunities of the site.
Use the self-build framework effectively – consider the local authority's self-build register, identified need and statutory duties.
Deal with financial and legal matters early – including CIL, planning obligations and any mechanism needed to secure the self-build nature of the proposal.
Submit a proportionate application – provide the information needed to demonstrate that the development is acceptable without commissioning unnecessary work.
The fact that a house is intended to be self-built or custom-built is only one part of the planning case. The key is to understand why this particular site can accommodate a home and which planning route gives the best prospect of securing permission.
Get advice on a self-build or custom-build project
If you are considering buying land for a self-build home, developing an existing property or seeking planning permission for a new custom-build dwelling, obtaining planning advice before committing to the site or detailed design can help identify opportunities and potential problems at an early stage.
A site assessment can establish the likely planning position, identify the most appropriate application route and advise on the evidence needed to support an application.
Get in touch with me to talk through your site.
Andrew Ransome MRTPI - Email: andrew@andrewransome.co.uk
About me
Andrew Ransome is a Planning Director and a Chartered Member of the Royal Town Planning Institute (RTPI), with more than two decades of experience in town planning.
He specialises in delivering strategic planning solutions for complex developments across both rural and urban environments, helping clients navigate planning challenges and unlock development opportunities. Connect with Andrew on Linkedin.
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