Class Q: agricultural buildings to homes

Up to ten homes from a farm building without a planning application

What Class Q is

Class Q is a permitted development right in Part 3 of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015. The Order itself grants permission for the change of use of an agricultural building to one or more houses (use class C3), with the building works reasonably necessary to convert it. You do not apply for planning permission. You apply for the council’s prior approval of a fixed list of matters, and if it approves, or fails to answer in time, you may proceed.

The current version of Class Q was substituted on 21 May 2024 by the Town and Country Planning (General Permitted Development etc.) (England) (Amendment) Order 2024 (SI 2024/579), article 3. It applies in England only. Wales has its own General Permitted Development Order and no equivalent of Class Q [TO CONFIRM]; converting a barn to a house in Wales needs a planning application.

The limits

Paragraph Q describes three forms of development. Q(a) is the change of use of a building that is part of an established agricultural unit, or a former agricultural building, to use class C3. Q(b) is that change of use together with an extension of the building. Q(c) is that change of use together with building operations reasonably necessary to convert the building.

Paragraph Q.1 lists the cases where the right does not apply.

Test	Limit in Q.1
Agricultural use (Q.1(a))	The site must have been used solely for an agricultural use as part of an established agricultural unit on 24 July 2023, or, if not in use on that date, when last in use, or, if brought into use after that date, for at least 10 years before development begins
Former agricultural buildings (Q.1(b))	A building that ceased agricultural use after 24 July 2023 qualifies only if it was part of a unit on that date and has not been used for a non-agricultural purpose since
Size of each house (Q.1(c))	No dwellinghouse may have a floor space of more than 150 square metres
Cumulative limit (Q.1(d))	Class Q development within the original limits of the agricultural unit may not produce more than 10 separate dwellinghouses or more than 1,000 square metres of floor space in total
Tenancies (Q.1(e) and (f))	On a tenanted holding, the landlord and tenant must both consent in writing; where a tenancy ended within the year before development for the purpose of Class Q, both must agree in writing that the site is no longer needed for agriculture
Recent Part 6 development (Q.1(g))	Not permitted if agricultural permitted development under Part 6 Class A(a) or B(a) (new or extended agricultural buildings) has been carried out on the unit in the 10 years before development begins
External dimensions (Q.1(h))	The building may not extend beyond its existing external dimensions except for the permitted extension, and for building operations protruding no more than 0.2 metres
The extension (Q.1(i))	Single storey, to the rear only, no more than 4 metres beyond the rear wall, eaves no higher than the existing eaves, ridge no higher than the existing building or 4 metres, not beyond the side elevations, and only on land that already had a hard surface on 24 July 2023
Building operations (Q.1(j))	Only the installation or replacement of windows, doors, roofs, exterior walls, and water, drainage, electricity, gas or other services, to the extent reasonably necessary for the building to function as a house, plus partial demolition to the extent reasonably necessary for those works
Protected land (Q.1(k) to (n))	Not on article 2(3) land, a site of special scientific interest, a safety hazard area or a military explosives storage area; not a scheduled monument; not a listed building
Space standards (Q.1(o))	Each house must meet the nationally described space standard (27 March 2015 version, with the 19 May 2016 notes)
Access (Q.1(p))	The building must have an existing suitable access to a public highway

Article 2(3) land, defined in article 2(3) and Schedule 1 to the Order, covers conservation areas, National Parks, the Broads, Areas of Outstanding Natural Beauty (now National Landscapes) and World Heritage Sites. A barn in any of them cannot use Class Q at all. An article 4 direction can also remove the right for a named area. The 1,000 square metre cap is cumulative per unit, so a unit that used the old Class Q for 450 square metres in 2019 has 550 square metres left.

Old Class Q and the transitional year

Before 21 May 2024 the right allowed up to 5 houses and 865 square metres [TO CONFIRM old limits], with no extension and a different set of size bands. Article 10 of SI 2024/579 preserved it for a year: where development was permitted under the old Class Q immediately before 21 May 2024 but would not be permitted under the new one, a prior approval application could still be made under the old rules until the end of 20 May 2025. That window has closed. Anyone with an old-style prior approval still has the three years from the prior approval date in which to complete.

The prior approval process

Paragraph Q.2 sets the conditions. For a conversion with building works (Q(a) with Q(c)), you must apply to the council for a determination as to whether its prior approval is required for:

• 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 for the building to change to a house
• the design or external appearance of the building
• the provision of adequate natural light in all habitable rooms

For a change of use alone (Q(a) only), design and natural light drop out. Where the development includes the extension, the council also considers the impact of the extension on the amenity of any adjoining premises.

Paragraph W of Part 3 sets the procedure. Under W(2) the application must include a written description, a site plan, floor plans with dimensions and elevations, contact details, a flood risk assessment where relevant, and the fee. Under W(3) the council may refuse where the development does not comply with any limit in Class Q or where it has too little information to tell. It consults the highway authority and, in flood zones 2 and 3, the Environment Agency (W(5) to (7)), and posts a site notice for 21 days or notifies neighbours (W(8)). Under W(10) it must have regard to the National Planning Policy Framework so far as relevant to the listed matters.

Under W(11) the development must not begin before one of three events: a written notice that prior approval is not required, a written notice giving prior approval, or “the expiry of 56 days following the date on which the application under sub-paragraph (2) was received by the local planning authority” without the council notifying you whether prior approval is given or refused. The 56 days run from receipt, so send the application in a way that proves the date. If the council misses the day the development is permitted by default, though it must still meet every limit in Q.1. The planning practice guidance (paragraph 030, reference ID 13-030-20140306) notes that the period can be extended by written agreement; do not agree to that lightly. Under W(12) the work must follow the approved details, and under Q.2 it must be completed within three years of the prior approval date.

The council may consider only the matters listed. It cannot refuse because the parish objects or because the site is outside the settlement boundary. It can and does refuse on location and siting, on the access, and on whether the works exceed what Class Q allows.

The fee is set by regulation 14 of the Town and Country Planning (Fees for Applications, Deemed Applications, Requests and Site Visits) (England) Regulations 2012 as amended and indexed each April; the current figure for a Part 3 prior approval that includes building operations is in the MHCLG table “Planning fees: annual indexation from 1 April 2026” [TO CONFIRM figure].

Conversion, not rebuilding

Class Q permits a conversion. In Hibbitt v Secretary of State for Communities and Local Government [2016] EWHC 2853 (Admin), decided by Green J on 9 November 2016, the building was an open-sided steel frame barn. The court held that “conversion” excludes works so extensive that they amount to a rebuild or fresh build, even where the existing frame could structurally carry the new house, and that the distinction is a matter of planning judgment for the council. The planning practice guidance (paragraph 105, reference ID 13-105-20180615) says the same: the building operations may include installing windows, doors, roofs, walls and services, and partial demolition only “to the extent reasonably necessary” for the conversion, not to rebuild.

In practice the council will ask for a structural report showing that the existing structure can take the loads of the converted building without new foundations, new frames or wholesale rebuilding of walls. A sound steel portal frame barn usually passes. A collapsing stone barn whose walls must come down and go back up usually fails.

What you can do under Q.1(j): new windows, doors and roof covering; clad or replace exterior walls; run in services; take down parts of the building where reasonably necessary for those works. What you cannot do: extend beyond the existing envelope except for the single storey rear extension; add a storey; build a new foundation; put up a garage, a boundary wall or a swimming pool. Anything outside the list needs a planning application. Many owners obtain Class Q prior approval first, which establishes the principle of residential use, then apply for the extras.

Agricultural occupancy conditions

Class Q brings no occupancy condition. That distinguishes it from a farm dwelling granted permission on the strength of an agricultural need, which usually carries a condition restricting occupation to a person solely or mainly employed, or last employed, in agriculture. Check that the barn is not within the planning unit of a tied farmhouse or named in its condition. A buyer’s solicitor should ask for the decision notice for any farmhouse on the holding.

Class R and Part 6

Class R of Part 3 allows an agricultural building to change to a flexible commercial use: use classes B2, B8, C1, E and F.2(c), or agricultural training. The date test under R.1(a) is different: solely agricultural use on 3 July 2012, or for 10 years if brought into use later. The cumulative limit is 1,000 square metres per unit (R.1(b)). Under R.3, up to 150 square metres needs only a notification to the council; above that, prior approval on transport, noise, contamination and flooding. Class R is not excluded on article 2(3) land, so a barn in a National Landscape that cannot use Class Q may be able to use Class R for a workshop or holiday let.

Part 6 is the agricultural permitted development that lets a farm of 5 hectares or more put up new buildings, up to 1,000 square metres of ground area since 21 May 2024, subject to prior approval of siting, design and external appearance. The two rights are linked in both directions. Class Q is not available if Part 6 Class A(a) or B(a) development has been carried out on the unit in the previous 10 years (Q.1(g)), and Part 6 Class A.1(b) bars a new or extended agricultural building where Class Q or Class S development has been carried out in the previous 10 years. The point is to stop a farm building a barn under Part 6 and converting it under Class Q.

A worked example

A holding of 30 hectares near a village in Somerset, outside any conservation area or National Landscape, has a steel portal frame barn of 400 square metres built in 2005 and used for hay and machinery until the owner retired in 2022. It stood empty on 24 July 2023 but its last use was agricultural, so it passes Q.1(a). No new agricultural buildings have gone up since 2016. The track to the lane is an existing access.

The owner proposes three houses of 130 square metres each, 390 square metres in total, inside every cap. Each meets the space standard. The works are insulated cladding on the existing frame, new windows and doors, a new roof covering, services, and a 3 metre single storey rear extension on the existing concrete apron. A structural engineer confirms the frame and slab will carry the loads.

The application goes in with plans, a transport statement, a contamination desk study, a flood map extract (flood zone 1), a noise note about the neighbouring grain dryer, and the fee. The council consults the highway authority, posts a site notice and has 56 days. It may refuse if it judges the location impractical or undesirable, for instance a mile from any services down a single track lane, but not because the local plan says no new houses in open countryside. If prior approval is granted the houses must be finished within three years, and the farm cannot use Part 6 for a new barn for ten years.

Sources

• GPDO 2015, Schedule 2, Part 3, Class Q (as substituted 21 May 2024): https://www.legislation.gov.uk/uksi/2015/596/schedule/2/part/3/crossheading/class-q-agricultural-buildings-to-dwellinghouses
• GPDO 2015, Schedule 2, Part 3, paragraph W (procedure): https://www.legislation.gov.uk/uksi/2015/596/schedule/2/part/3/crossheading/class-v-changes-of-use-permitted-under-a-permission-granted-on-an-application/paragraph/W
• GPDO 2015, Schedule 2, Part 3, Class R: https://www.legislation.gov.uk/uksi/2015/596/schedule/2/part/3/crossheading/class-r-agricultural-buildings-to-a-flexible-commercial-use
• GPDO 2015, Schedule 2, Part 6, Class A: https://www.legislation.gov.uk/uksi/2015/596/schedule/2/part/6
• SI 2024/579 (the 2024 amendment order), articles 3, 4, 7, 8 and 10: https://www.legislation.gov.uk/uksi/2024/579/made
• Planning practice guidance, When is permission required, paragraphs 026, 030 and 105: https://www.gov.uk/guidance/when-is-permission-required
• Hibbitt v SSCLG [2016] EWHC 2853 (Admin): https://caselaw.nationalarchives.gov.uk/ewhc/admin/2016/2853
• Fees: https://www.gov.uk/guidance/fees-for-planning-applications and https://www.gov.uk/government/publications/planning-fees-annual-indexation-from-1-april