• Naomi CB

Permitted Development in Areas of Outstanding Natural Beauty (AONBs) or Green Belts

Updated: Sep 22, 2020

What is Permitted Development?

You’ve spent some time thinking about it and you’ve made up your mind; you’d like to extend, alter or refurbish your home – but you’re not sure whether you need Planning Permission for the works you’d need to carry out. You may not need to go through the hassle of seeking Planning Permission! Instead, you may be eligible to develop your property under ‘Permitted Development’.

The clients living at the Country House sought to create a family outbuilding for their property that would serve as a complimentary entertainment space. They were looking for something small-scale that remained visually complimentary to the style of their main home. The challenge: to achieve a design that could be built under the rights of PD on an Area of Outstanding Natural Beauty (AONB).

Area of Outstanding Natural Beauty, Waverley, Forest, Trees, Garden, Godalming, Beautiful

How is Permitted Development different to Planning Permission?

In short: works that require Planning Permission will require an application to be submitted to the council. Building under Permitted Development won’t. This means you’ll be saving on overall cost of project, as well as time, allowing you as a homeowner to tailor your property to your personal needs. We would advise you however to apply for a Certificate of Lawful Development (COL), so that you have proof that your development falls within your PD rights. Don’t forget that a COL application will take around 8 weeks –similar to the time taken to apply for Planning Permission – but is usually half the price of a regular planning fee.

In designing the Country House outbuilding, we used the COL application to address the challenging site location: within the Green Belt and recognised as an Area of Outstanding Natural Beauty. This was done alongside an acknowledgement of the existing PD guidelines from the local council and the Ministry of Housing. With the help of Planit Consulting, we made sure the project development always remained within the guidelines as set out by the council. The result was a project that successfully brought together respectful design, mindful of the immediate and wider context.


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What are the rules for permitted development?

You’ve decided you’d like to build under Permitted Development, and now you’d like to know a bit more. The criteria for a project to be considered PD are divided into a series of Parts; the most relevant to our Country House outbuilding project was Part 1, which deals specifically with development within the parcel, or ‘curtilage’, of a domestic property. In it, you’ll find details on a range of developments from antennae installations to building enlargements and alterations. You may find Class E useful, which covers the provision of non-domestic outbuildings, our main frame of reference and guidance in design. You can find further details in the Technical Guidance here.

I want to develop an outbuilding within the curtilage of my house; is this always Permitted Development?

Although you would usually require planning permission to build an outbuilding, there are certain criteria which may mean you could carry out your proposal under your PD rights. Here is a simple checklist that may help in deciding whether this is your case.

Checklist Fundamentals: Outbuilding Under PD Rights

1. My property is already lawfully listed as a domestic dwelling.

2. My proposed work will exist within the curtilage of my existing property.

3. My proposed works will not attach to a property that is not in my ownership.

4. I am not developing a flat or a maisonette.

5. My property is not a Listed building.

6. The permitted development rights of my property were not restricted or removed (if the property was built after 1948). We would strongly advise you to speak with your local planning authority for information about your property.

7. All my PD proposals relate to what is known as the original ‘principal elevation’ – in other words, usually the elevation with the most architectural detail on it and which often, but not always, includes the main entrance to the house.

8. My proposal will not build on more than 50% of the original curtilage.

9. My proposal will not be sited on land forward of a wall forming the principal elevation of the original, ‘main’ house.

10. My proposal is single-storey.

11. If my proposal is within 2 metres of the boundary of the curtilage, it does not exceed 2.5 metres in height.

12. My proposal does not include any primary accommodation.

By following the above checklist, we were able to extract the opportunities that these regulations brought forth to inform our brief. The result: a building with personality that responded sensitively to its immediate environment.

We always recommend working alongside local planning – this will ensure that your proposal has the best chance of being granted PD status. Throughout our process, we were guided by Planit Consulting, who served as an invaluable asset in our design process.



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I have a house in an AONB that is in a Green Belt zone; can I develop it?

The Green Belt is meant to curb urban expansion with the hope of protecting land. It is found around the majority of London, and includes many AONBs.

Areas of Outstanding Natural Beauty (AONBs) are included in Article 2(3) land: ‘a place whose distinctive character and natural beauty is safeguarded in the national interest to conserve and enhance it’. This means that PD rights within AONBs are reduced, but with the right approach, are definitely possible.

Before developing your property, it is important for you to get a good grasp on what rights you have as a property owner in an AONB and Green Belt zone. Your Permitted Development rights may be reduced, and planning permission grants may become more uncommon. However, these constraints can still be used to your advantage to create a beautiful project that will both fall under Permitted Development and fit your needs.

If you decide to develop your house in an AONB under Permitted Develpment, it would be useful to make sure that:

1. no part of the proposed work is between any side wall of the dwelling and the boundary of the curtilage; and

2. if there are buildings within your curtilage other than your ‘main’ property, and you want to build 20 metres away from your existing house, you need to make sure that, combined, these secondary buildings do not exceed 10 square metres.

It is important to remember that Permitted Development rights may be removed or declined by your local planning authority, issuing what is known as an Article 4 Direction. When adopted, you will then require planning permission to develop your property. Working with Planit Consulting allowed us to remain in tune with guidelines issued by the local council to propose a building that worked with their requirements.

You can find further guidance can be found within the Technical Guidance.


Case Study: Country Guest House, Waverley


Our Country Guest House is found within the boundaries of the Metropolitan Green Belt around London. It is also within an AONB and an AGLV (area of Great Landscape Value). Whilst the purposes of these designations are different, in planning terms, the controls on development are similar. They provide more weight to the effectiveness of planning control against major and inappropriate development with the aim of protecting the area’s natural and architectural beauty.

To achieve a design that would fall under PD rights and also respect its natural surroundings, we ensured that:

1. the total area covered by buildings within the curtilage would not exceed 50% of its total floorspace, excluding that covered by the original house;

2. our proposal would not be situated on land forward of a wall forming part of the property’s ‘principal elevation’-in our case, the front elevation;

3. the building would be single storey; a total of 4m in height and 2.5m to its eaves; and

4. the building had to be situated within a 20m zone from the back of the house where PD rights apply. Beyond 20m PD rights are very limited,

...as set out by planning guidance.

The client’s main house is found in a highly regarded location due to the number of properties built in the Arts and Crafts style. A consistent material language of brick, and exquisite craftsmanship exists throughout the area. This home is no exception. The repeated gabled dormers are a striking characteristic of the house. Our proposal needed to remain subservient to the grandiose architecture of the main house whilst also paying homage to it.

Under Permitted Development, the outbuilding was built within a 20 m radius of the existing property. The new building establishes an immediate relationship with its surroundings and with the existing house. To heighten this relationship, we remained faithful to the traditional building materials used, suggesting a high-quality brick to be used in different ways, ensuring a visual extension of the main house. In elevation, a swift transition from solid to perforated brick in a 2 metre high wall allowed us to lend a distinctive expression to the project, with the perforations reminiscent of Chinese lanterns – a nod towards the client’s heritage. That bit of ornament allows the building to take on a grander presence in the garden, reminiscent of a grand pavilion.

The need to build with a reduced overall height under PD brought forth the opportunity to express roof details; by lifting the tiles at the eaves, the client’s part heritage became a further innate quality in the design, perceptible from eye-level.

As part of the interior programme, the clients requested a series of hobby rooms, a home office and a storage space to serve as ancillary, flexible-use spaces to their home. Given the reduced size of the project, we aimed to ensure that each room was lent a distinctive character. Interplay in ceiling heights translates the typical Arts and Crafts interior to a modern, small-scale outbuilding, thereby maximising the constraint of having a reduced overall height of 4 metres. The result has been an inspired scheme that maximises the opportunities brought forth by the existing regulations.


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