Our previous article covering the conversion of existing barns and agricultural buildings into residential accommodation set out the merits of doing so, and highlighted some key considerations. This article talks specifically about the Class Q planning policy that permits the conversion of certain redundant buildings under permitted development. If you own an agricultural barn, this makes it possible to convert it to a house or multiple houses without the need for full planning consent. It is important to note that Class Q does not apply to listed buildings, or buildings on article 2(3) land such as conservation areas and areas of outstanding natural beauty.

Class Q conversion permitted development In 2014, a permitted development right known as Class Q was introduced to planning policy in England to allow for residential conversion of agricultural buildings via ‘prior approval’. This process negates the full planning application process, should the redundant building meet the criteria of the policy. Class Q is therefore seen as a more assured and less onerous route to gain consent for a new home(s) in the countryside. In order to control development, the policy is necessarily restrictive. This can sometimes give rise to ill-conceived conversions, that whilst permissible can be of little architectural merit – especially considering many prior approval Class Q applications do not involve the rigorous design process associated with a typical full planning application. In short, there are both good Class Q conversions, and bad. With our experience as a practice, we can advise on where the potential lies, and how to best embrace the agricultural qualities of the building.

Top: Proposed visual of our current Class Q project which is in planning

Left: Exploded isometric view of the same project showing the existing barn, the demolished parts of the structure (in grey), and the proposed conversion

The policy was overhauled in 2018, and currently, the key things to be aware of are:

The site must have been used for agricultural purposes on the 20th March 2013 (, or it can be proven it was in use before that date, but not used since.)

If built or brought into use on/after 20 March 2013, it needs to have been in agricultural use for 10 years.

Your are allowed up to 3 larger dwellings (>100 sqm, but the cumulative total cannot exceed 465 sqm), or up to 5 smaller dwellings (<100 sqm). The maximum total of dwellings permitted is 5. The hypothetical maximum floor space (including new mezzanine floors) is 865 sqm (1 large dwelling + 4 small dwellings).

An agricultural tenancy of the site cannot have been terminated within 1 year of the prior approval application, and for the purpose of Class Q, unless there is prior agreement between landlord and tenant that the site is no longer required for agricultural use.

The building(s) cannot be extended in any way, though an independent first floor mezzanine may be constructed.

The building must be structurally suitable for conversion without new or reinforcing structure.

Partial demolition may be permitted.

Works to install or replace windows, doors, roofs, or exterior walls, or water, drainage, electricity, gas or other services are permitted to allow for the building to function as a house(s)

Class Q does not apply on article 2(3) land.

Additional to the above points which constitute policy Q1, the prior approval also requires consideration of Q2 relating to transport and highways impacts of the development, noise impacts of the development, contamination risks on the site, flooding risks on the site, whether the location or siting of the building makes it otherwise impractical or undesirable and the design or external appearance of the building.

The prior approval application should also be approved within 56 days, roughly in line with a typical planning timeframe, though approval is not given by default if this timeframe is not met.

Existing photographs of our current Class Q project

The main issue to be aware of with Class Q conversions is the interpretation of the local planning authority with regards to the distinction between ‘conversion’ and ‘rebuilding’. It is important to design the scheme in such a way that the existing structure and external envelope does not need to be substantively rebuilt, and is capable of fulfilling use a dwelling with only alterations to the building elements mentioned in the list above. Internal works are not typically considered as ‘development’ and are therefore less restricted. So whilst it is entirely practical, it is challenging to achieve a design that is of significant architectural merit, particularly with regards to the external appearance. With that said, we have extensive experience of agricultural and barn conversions which enable us to navigate this difficult balancing act.

For those with a qualifying Class Q building but seeking more of a clean slate, a topical issue is the newly-established ‘betterment’ principle. Owing to Mansell v Tonbridge And Malling Borough Council [2017], planning departments should now accept that Class Q consent is a valid ‘fall back’ argument. This means that should the criteria of Class Q policy be met, or better still consented, planning departments should subsequently be receptive to an application for a new house(s) that is of greater architectural merit and makes better use of the site. We will shortly be posting an article on the issue of betterment for further information and our project experience.

If you are looking for an architect for a Class Q barn conversion in Devon, Cornwall or further afield, New British Design would be delighted to talk to you about your project, so please get in touch