What are Class Q Permitted Development Rights?

What are Class Q Permitted Development Rights?

Planning permission and property development are often tricky areas to negotiate. If you are an agricultural landowner, you may be aware of Class Q permitted development rights. In short, these rights allow for the conversion of certain buildings from agricultural to residential use without planning permission. There have been many well-documented cases of dispute between planning officers and applicants due to high refusal rates and interpretation of the criteria. The guidance was updated in March 2018 with an aim to help both parties better understand the requirements for approval. This blog looks at what is currently permitted in terms of development and what steps are necessary to apply.

Further Details

Although Class Q removes the need for planning permission, a prior approval notice must still be bought to the attention of the relevant local authorities. Amongst other things, the notice must include details of any alterations to the external appearance. Refusal can be made on the grounds of it being undesirable or impractical, or if the authority does not feel that plans fall within the Class Q credentials. It is therefore often advised to employ the advice of a professional as they can also help you to appeal should your application be refused.

Am I Eligible?

You are eligible if you are a landowner who owns one or more agricultural buildings, that are currently categorised for use as agricultural buildings. There must also be reasonable access or plans to create equitable access that does not cause harm to the surrounding area. Agricultural buildings in a National Park, Area of Outstanding Natural Beauty and other Conservation Areas are excluded, and alternative planning measures should be considered.

light brown cow looking over fence in a green field

Class Q Development Eligibility Conditions


Up to Five

Previously the legislation allowed for the conversion of up to 450 square meters of building floor space into three dwellings. The updated criteria now allows for up to three larger homes with a combined floor space of 465 square meters, or up to five smaller homes at less than 100 square meters each. It is also possible to have a combination of the two, providing the total size and floorspace used at the end is no bigger than the above stated.

Internal Works

Works that include mezzanines and new flooring are not classed as operational development. Therefore, works that involve changes to the internal structure should not be taken into account during Prior Approval. In some regions, there continue to be issues involving objections on internal works. A professional planning advisor can cite relevant planning guidance and case law, and can usually overcome these hurdles.

interior of a rustic barn conversion


The guidelines regarding structural changes to an agricultural building lean towards allowing works considered necessary for a conversion, but not to the extent of a rebuild. What used to be a structural test is now considered a convertibility assessment. Subsequently, structural works to allow for the conversion of the building are permitted. However, the extent of these works is judged differently by each local authority, making each case challenging to predict. This is due to there being no specific rule when it comes to the building being initially strong enough to take on the proposed works, which means in some cases, reinforcement will be necessary. New or replacement roofing is also included under structural modifications. The structural soundness of a barn conversion is essential. Martin Perry Associates can carry out a professional survey of the building and report on its structural integrity to accompany planning applications and Prior Approval Notices.

The 56 Day Rule

The Prior Approval Procedure requests that local authorities must determine the result of an application within 56 days of receipt. Assumed consent, however, does not apply if authorities fail to meet this deadline. You should always wait to hear from the authorities before commencing any works.

For a structural engineer in Cornwall and the South West, Martin Perry Associates are a qualified and professional company. We can advise on many areas of Class Q Development, including the structural surveillance of the proposed building. We also work with a number of planning professionals who will be happy to advise on the planning implications of your proposed conversion. For more information on our services, browse through our website and for more related blogs, why not check out How Much Can I Extend My House Without Planning?

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