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A guide to Class Q planning permission

If you are in possession of a vacant agricultural building, for example a barn or warehouse, you may be able to utilise your Class Q Permitted Development Rights to convert the structure into a state of the art residential property, one of the most highly sought after typologies outside of London. Imagine waking up in the countryside with expansive glazing looking out over the rolling hills - this dream may be closer to reality than you might believe.

20 November 2023
12 minutes read
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Eugene Kim

Table of Contents

Table of Contents

Class Q was introduced in 2014 as a form of permitted development designed to help ease the pressure on housing in rural areas. This type of planning permission allows the change of buildings that meet certain criteria from agricultural to residential use.

As barn conversion architects in the UK, a disused agricultural building looks to us like a dream project, but to a land owner, they can become high-ROI investment opportunities. Whether you are in the London greenbelt or further afield, you don’t need to travel far to find a broken down, old barn with a stunning, natural backdrop – demonstrating the ample possibilities for transforming these redundant structures into new, sustainable housing.

That being said, barn conversion planning permission can be a difficult path to navigate, and it is important to speak to an expert to find out which route is best for you.

The criteria for Class Q permitted developments state that the building must have been used for agriculture on or before the 20th March 2013, however, some exceptions do apply. Class Q planning permission can not be granted for buildings in areas of natural beauty, National Parks, conservation areas or if the building is listed.

Existing suitable buildings with a total floor space of up to 450sqm can be converted into a maximum of three individual dwellings, however, under Class Q you cannot extend the building itself and the garden of the property cannot be more significant than the building’s footprint. What this means for your class q barn conversion is that you are limited to the existing footprint of the structure – any extensions to this, mean that you will need to apply for barn conversion planning permission which can be a tricky process, especially in rural areas.

Reasonable changes can be made to the building to allow it to be used as a home. These changes can include replacing windows, doors, roofing, water, drainage and other services. Under the same clause, you can undertake partial demolition. Find out more about rural barn conversions.

As part of the process, you will often need to have a structural appraisal to ensure that the current building can support the conversion without too many adaptations. Under Class Q, replacing foundations or load-bearing flooring isn’t allowed – and adding an additional floor to your barn can be a challenge. If any of these changes are likely to be needed, you would need to go through full planning permission rather than opting for Class Q.

What are the pros of Class Q development projects?

When compared to full planning permission, Class Q planning permission has a lower upfront cost and does not require quite the same level of technical detail as full planning permission does. Class Q also allows a route into developing homes in rural areas without having to meet an exception policy.

Here at Extension Architecture, we understand that urban planning is a large subject with a lot of confusing avenues. Our USP is that we combine architects with planning consultants and project managers under one roof, offering a completely integrated, turn-key approach from planning through to construction. If you are having trouble with your barn conversion project, or own a plot of land that you are considering developing, get in touch with our expert barn conversion architects today to find out how we can help you!
Barn Conversion Architects
* Barn Conversion Project in Epsom by Extension Architecture (Design by Zak Gilby & Dominique James)


What are the cons of Class Q planning permission?

Whilst the amount of technical information required for the application isn’t as extensive as it is for a full planning permission application, you will still likely need technical information on noise, contamination, flooding and more. Despite this technical information difference, a Class Q application is no faster than full planning permission. To qualify for Class Q, you must also be able to demonstrate that the building was used for an agricultural purpose on a specific date set in the legislation or the date when the building was last in use.

What does the future hold for UK Barn Conversions?

A review of the current planning permission system for rural projects was announced in 2016 and is likely to affect Class Q developments once the review has been completed. The proposals are considering changing the restrictions to allow for the conversion of properties up to 750sqm in size when being used for five individual properties whilst also increasing the allowable size when the conversion is creating three residential units.

Moreover, with increasing pressure from both the government and the public to increase housing supply across the country, our analysts expect a major turn-around in greenbelt planning policy to allow development on greenbelt land in the coming years.

If you are considering a class q barn conversion project in the UK, speak to our specialist architects today to get an insider view of the planning process and find out how we can help you!

Self Build Homes

 * Barn Conversion Project in Woking by Extension Architecture (Design by Eugene Kim)

Exploring the Scope of Class Q Planning

Class Q planning permission represents a significant opportunity for rural development, allowing the transformation of agricultural buildings into residential properties. This initiative, introduced to alleviate housing shortages in rural areas, has opened new avenues for sustainable housing development. The permission is applicable to buildings that were in agricultural use on or before 20th March 2013, with certain exceptions. However, it’s important to note that Class Q does not apply to buildings in designated areas such as Areas of Outstanding Natural Beauty, National Parks, conservation areas, or listed buildings.

Navigating the Limitations and Opportunities of Class Q

Under Class Q, eligible buildings with a total floor space of up to 450sqm can be converted into a maximum of three individual dwellings. However, the scope of modification under this permission is limited to the existing footprint of the structure. Extensions beyond this footprint require standard planning permission, which can be more challenging to obtain, especially in rural settings. Reasonable modifications are permitted, including changes to windows, doors, roofing, and essential services like water and drainage. Partial demolition is also allowed under specific conditions.

The Technical and Structural Challenges in Class Q Conversions

A key aspect of Class Q planning is ensuring the structural integrity of the building for residential use. This often involves a structural appraisal to confirm that the building can support the conversion with minimal adaptations. Importantly, Class Q does not permit replacing foundations or load-bearing floors, and adding an additional floor can be challenging. If significant structural changes are needed, full planning permission would be required instead of Class Q.

The Pros and Cons of Class Q Development Projects

Class Q planning permission offers a lower upfront cost and requires less technical detail compared to full planning permission. It provides a pathway for developing homes in rural areas without adhering to exception policies. However, technical information on aspects like noise, contamination, and flooding is still necessary. Despite these requirements, the application process for Class Q is not faster than that for full planning permission. Applicants must demonstrate that the building was used for agricultural purposes on a specific date set in the legislation or when the building was last in use.

Future Prospects for UK Barn Conversions

The UK government’s review of the planning permission system for rural projects, announced in 2016, is likely to impact Class Q developments. Proposed changes include allowing conversions of properties up to 750sqm for up to five individual units and increasing the allowable size for three-unit conversions. With growing pressure to increase housing supply, significant changes in greenbelt planning policy are anticipated, potentially expanding opportunities for rural development.

Ready to embark on your rural adventure? Class Q is your fairy godmother, but there’s more magic on the horizon. As the UK’s planning landscape evolves, bigger, better barn conversions may be on the horizon. We’re not just architects; we’re your partners in this exciting journey. Let’s chat about your barn-to-home dreams—because at Extension Architecture, we turn aspirations into addresses!


Navigating the Limitations and Opportunities of Class Q

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Eugene Kim

Eugene Kim, Founder and Managing Director of Extension Architecture, has led the firm for over 14 years, consistently delivering quality solutions. His dedication has been key to the company's growth and success.

Steph Fanizza, Architectural Design & Team Manager

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