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Arkhi's Simple Guide to Class-Q Permitted Development

Class Q Permitted Development was first introduced in 2014 and later updated in 2018. The legislation aims to benefit landowners, offering them a route to converting agricultural buildings into housing on their site.

But what is Class Q and how might you maximise the opportunities it presents?


What is Class Q?

The change of use of a building is categorised as ‘development’ in planning law and this usually requires ‘Planning Permission’ from the Local Planning Authority. However, there are now provisions in planning legislation that allow for specific development to be undertaken without express planning permission being granted – this is more commonly known as general Permitted Development (PD Rights).

Class Q is an example of a certain type of Permitted Development Rights and it refers to the change of use of an agricultural building into a dwellinghouse. Express Planning Permission is not required but it is subject to several criteria being met and certain conditions being satisfied.

The provision of this is set out in Class Q, Part 3 of the Town and Country Planning (General Permitted Development) (England) Order 2015.  This can be read at:

What’s Permitted?

The legislation in 2014 only allowed for the conversion of up to 450 sqm of agricultural building floorspace to a maximum of three dwellings. However, the new amendments that took effect in April 2018, increase those thresholds so that it is now possible to convert agricultural floorspace to create one of these alternatives:


  • Up to three ‘larger homes’, with a combined maximum floorspace of 465 sqm.
  • Up to five smaller homes (each less than 100 sq m).
  • A mix of both, with a total of no more than five homes, of which no more than three may be larger homes.


Whilst determining an application, planners have no discretion if a qualifying condition is not met. The list of ‘Development not Permitted’ in Class Q is inflexible and generally very prescriptive. However, each local authority brings its own interpretation for the Class Q rules, and some will be more rigorous than others in following the guidance.

Class Q Development Potential Sketch

Pros and Cons

One main advantage of Class Q is that a limited amount of technical information is necessary upfront - unlike a planning application, ecology and biodiversity considerations are not material to the Council’s determining of a prior approval application under Class Q. However, it often requires additional planning applications to follow-up in relation to other development if necessary.

Although applying for Class Q development is no faster than a standard planning application, the upfront cost is significantly lower (around £96 for change of use or £205 for change of use plus building operations). Developing this and submitting supporting planning applications, however, will incur further costs.


Common Pitfalls

Agricultural Use: Have you considered how the building sits within your holding and was it solely used for an agricultural use / is it part of an established agricultural unit?

Structure: Is your building incapable of conversion due to being structurally unsound, or does it need works above and beyond what is acceptable under the criteria of Class Q? Addressing these issues prior to submitting a prior notification can significantly increase your chances of success.

Desirability: Class Q applications can be refused on the grounds that it may be ‘impractical or undesirable’ i.e. near a slurry lagoon, intensive livestock unit or machinery shed. Therefore, its sometimes important to show the access and landscape details of the land surrounding the building to support your application.

The terms ‘practical’ or ‘undesirable’ are not defined in the regulations and the LPA should apply a reasonable dictionary meaning whilst making their decisions. This is an area where uncertainty and a slight degree of flexibility can be exercised by the LPA.

Curtilage: Does the area you wish to incorporate as a garden extend beyond the area allowed under Class Q? To combat this, you could consider a two-tiered approach?

Future Development: When you proceed through the process of Class Q, one of the main conditions applied centres around removing agricultural permitted development rights for the rest of the unit for 10 years. In other words, new agricultural buildings are permitted without full planning consent.

Building Operations / Demolition: Partial demolition is permissible to the extent reasonably necessary to facilitate works but cannot subsequently entail the rebuilding of the structure. There is a restriction related to the development of the external dimensions of the existing building. The supporting guidance provides zero scope to breach the existing building’s envelope.

Even seemingly small details such as a flue pipe can cause objections and delay, depending on how sympathetic the planning authority feels towards Class Q developments.

In practice, it would be necessary to apply for planning permission for such features once prior approval had been given. It is not the aim of these permitted development rights to allow the domestication of the countryside. Any conversion should utilise existing openings and minimise the number of new openings.

How Can We Help You?

As we have discussed, Class Q opens a whole new scope of rural development and like most alterations in planning policy it also presents several restrictions. Each Local Planning Authority (LPA) must be considered separately due the interpretation and variation of the policy. Nevertheless, development is achievable and out expert team can help you through the process and significantly enhance your chances of success.

At Arkhi we strive to design and develop a scheme which reflects your aspirations – we are simply here to facilitate your visons. As architects, we acknowledge and pride ourselves in our sensitive approach to construction and the creation of new dwellings in rural locations.