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  • Writer's pictureSam Nolan RIBA Architect

Barn Conversions: Class Q Permitted Development Rights

Updated: Oct 11, 2022

If you are considering converting an existing barn you own or are looking at a barn conversion development project there has never been a better time to do it.

Last year Government announced changes to the Class Q permitted development rights which allow the conversion of existing agricultural buildings in the countryside into permanent residential dwellings without the need for full planning permission.

Previously to meet the requirements of Class Q permitted development applicants were permitted to create up to 3 dwellings with associated garden area with a combined floor space of 450msq. More recent amendments to the legislation now also allow an alternative of the formation of either 3 dwellings with a combined floor space of 465msq or up to 5 smaller dwellings with a floor area of 100msq each or even a combination of larger and smaller dwellings.

In order to comply with the legislation, the main requirements are:

-The site must have been used solely for agricultural purposes on 20th March 2013


-if not in agricultural use on 20th March 2013 when the building was last in use


-in the case of a site which was brought into use after 20th March 2013 for a period of at least ten years before the development under class Q begins.

-The site must not be occupied by an agricultural tenancy unless the consent of both the landlord and tenant has been obtained.

-The development must not extend the external dimensions of the building beyond the external dimensions of the existing building at any given point.

-The garden area of the development must not exceed that of the footprint of the building itself.

-The development should only consist of building operations to allow the installation or replacement of windows, doors, roof, or exterior walls and water, drainage, electricity, gas and other services to the extent reasonably necessary for the building to function as a dwelling. Partial demolition is allowed in order to carry out those building operations.

There seems to be some debate and new case law about the extent of structural works allowed under the legislation but an addition was added to National Planning Policy Guidance in June 2018 with particular reference to internal works:

‘Internal works are not generally development. For the building to function as a dwelling it may be appropriate to undertake internal structural works, including to allow for a floor, the insertion of a mezzanine or upper floors within the overall residential floor space permitted, or internal walls, which are not prohibited by Class Q.’

Recent guidance seems to accept that internal structural works may be required to allow a conversion to function as a dwelling and as long as those works do not take the load of the external building they should be permitted under the legislation. Works to strengthen the existing structure would not be permitted.

There are also some restrictions in the location of the permitted development:

-The site cannot be within a SSSi (site of special scientific interest), a safety hazard area, National Park or an AONB (Area of Outstanding Natural Beauty).

-The site cannot be or contain a scheduled ancient monument or listed building or be in a conservation area or article 2(3) land.

How to formalise the Permitted Development:

An application for prior notification for the conversion needs to be submitted to the local planning authority prior to any works taking place. If the works have previously commenced an application for planning permission would have to be made.

When submitted the local planning authority will make an assessment as to the suitability of the conversion to a dwelling in terms of transport & highways impacts, noise impacts, contamination risk, flood risk and whether the location or siting of the building makes it otherwise impractical or undesirable for the building to change from agricultural use to a dwelling.

The permitted development right does not apply a test in relation to sustainability of the location of a conversion. It is generally accepted that most agricultural buildings will be in more remote locations and that vehicular transport will be required for daily needs.

Planning policy Guidance advises that impractical means that the location and siting would not be sensible or realistic and undesirable means that it would be harmful or objectionable.

The guidance defines examples of the definition of impractical as at the top of a hill with no road access, power source or other services and examples of undesirable as adjacent to intensive poultry farming buildings, silage storage or buildings with dangerous machines or chemicals.

What is required for the Prior Notification Application:

Although requirements vary across local planning authorities as a general guide for the prior approval notification most local planning authorities will require:

- A written description of the development, including the history and evidence of the agricultural use of the building.

- A structural survey demonstrating the structural soundness of the building and its suitability for conversion and a method statement describing how the building will be converted.

- A location plan at a scale of 1:1250 or 1:2500 with the site outlined in red and all other ownership outlined in blue. The location plan should identify the point of access.

- A block plan showing the extent of the application site and its curtilage.

- Existing and proposed plans, elevations and sections to a metric scale of 1:100.

- If the site is located within a critical drainage area or flood zone 2 or 3 a flood risk assessment. Check on the Environment Agency website on this link.

- A wildlife survey or statement outlining any potential impact upon protected species and a mitigation strategy if there are any.

- The completed application and application fee.

It usually takes up to ten days to validate an application and once that has happened there is a 56 day determination period in which the LPA should determine the application. The process is a relatively straight forward process which an architect or planning consultant can guide you through with relative ease. Once planning permission is achieved before any building work is carried out a building regulations application should also be made.

If class Q permitted development is not an option for your site all is not lost. There are specific policies in the New North Devon and Torridge local plan which (subject to certain conditions) are permissive of the reuse and conversion of disused and redundant rural buildings.

In spite of the restrictions it is possible to deliver some imaginative solutions with high design quality as we have done on recent projects. To check if your barn conversion project would be suitable or for some initial advice on how to get things started please do not hesitate to get in touch.

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