Barn conversions - the new rules

NOTE: There have been significant changes to the law since this blog post was published, and so the material printed below (including the appended comments) does not accurately reflect the current position. For completely up-to-date and fully comprehensive coverage of this subject, we would strongly recommend readers to obtain a copy of the author’s new book - “A PRACTICAL GUIDE TO PERMITTED CHANGES OF USE” published by Bath Publishing in October 2015. You can order your copy by clicking on the link on the left-hand sidebar of this page.


The Town and Country Planning (General Permitted Development) (Amendment and Consequential Provisions) (England) Order 2014 was made on 10 March, laid before Parliament on 13 March and will come into force on 6 April. This is the long promised amendment to the GPDO that will allow the conversion of agricultural buildings to residential use (‘barn conversions’), and also some additional changes of use of A1 (shops) and A2 office premises. The Order applies to England only.

I will deal in a later post with changes of use of premises currently in use or including a use within Class A1 or A2, and go straight to the one you have all been waiting for – barn conversions.

Among other changes, the Order introduces a new Class MB into Part 3 of the Second Schedule to the GPDO. This new class authorises change of use of a building and any land within its curtilage from use as an agricultural building to a use falling within Use Class C3 (dwellinghouses). This new Class includes the authorisation of building operations reasonably necessary to convert the building to residential use.

As predicted, however, this new PD right is hedged around with important exceptions, limitations and conditions. First, development is not permitted by Class MB where the site was not used solely for an agricultural use, as part of an established agricultural unit on 20th March 2013 or, if the site was not in use on that date, when it was last in use before that date. Other agricultural buildings may qualify for residential conversion in future if the site was brought into use after 20 March 2013, and is used for that purpose for ten years before the date the development begins.

The cumulative floor space of the existing building or buildings changing use under Class MB within an established agricultural unit must not exceed 450 square metres, and no more than three separate dwellinghouses can be developed within an established agricultural unit. The 450 sq m limit is absolute, so that once any residential conversions carried out under Class MB have reached the 450 sq m limit, there can be no further such developments within the same agricultural unit.

Furthermore, this change of use is not permitted if the site is occupied under an agricultural tenancy, unless the express consent of both the landlord and the tenant has been obtained To avoid ‘winkling’ of agricultural tenants by rapacious farm owners, change of use is also precluded if less than one year before the date development begins an agricultural tenancy over the site has been terminated, and the termination was for the purpose of carrying out development under Class MB, unless both the landlord and the tenant have agreed in writing that the site is no longer required for agricultural use.

The amendment order also prevents this change of use where the erection or extension of agricultural buildings has been carried out under Part 6, Classes A(a) or B(a) of the Second Schedule to the GPDO on the established agricultural unit since 20th March 2013, or within 10 years before the date development under Class MB begins, whichever is the lesser. So you can’t put up new agricultural buildings or extend them and then convert them soon afterwards to residential use.

Although Class MB permits building operations reasonably necessary to convert the building to residential use, it does not allow development that would result in the external dimensions of the converted building extending beyond the external dimensions of the existing building at any given point; so it has to be wholly contained within the envelope of the original building. The type of building operations that are allowed under this heading are listed as the installation or replacement of windows, doors, roofs, or exterior walls, or water, drainage, electricity, gas or other services, to the extent reasonably necessary for the building to function as a dwellinghouse; and partial demolition to the extent reasonably necessary to carry out these building operations.

The inclusion of the two items I have put in italics in the preceding paragraph (roofs and exterior walls) seems to allow scope for some significant rebuilding or replacement of the existing fabric, although the reference to partial demolition would seem to indicate that wholesale demolition of the building and its entire replacement is not contemplated by this amendment to the GPDO. It would seem that there is potential here for disputes with LPAs as to the scope of ‘partial’ demolition that can be carried out within this class, and also the extent to which any such partial demotion and rebuilding is “reasonably necessary to carry out these building operations”. I would, however, suggest that it is very unlikely that the new PD right can be exploited in such a way as to build houses on the site of glasshouses or flimsily clad dutch barns and the like. But we shall see.

As confirmed in the Commons a couple of weeks ago, the development permitted by Class MB is specifically excluded on any site that is on “Article 1(5) land” (i.e. in a National Park, the Broads, an Area of Outstanding Natural Beauty, a Conservation Area or a World Heritage Site) or if the site is or forms part of a Site of Special Scientific Interest, a designated safety hazard area or a military explosives storage area, or if the site is, or contains, a scheduled ancient monument. Development under Class MB is also excluded if the building in question is a Listed Building.

As expected, the new PD right is subject to a prior notification procedure. In fact, there are two separate requirements, one in respect of the change of use and the other in respect of any associated building operations.

Before beginning the development, the developer must apply to the LPA for a determination as to whether the prior approval of the authority will be required as to —

(a) transport and highways impacts of the development,
(b) noise impacts of the development,
(c) contamination risks on the site,
(d) flooding risks on the site, or
(e) whether the location or siting of the building makes it otherwise impractical or undesirable for the building to change from agricultural use to residential use.

I have put the last of these in italics, because it seems to me that this gives the LPA a very wide discretion to resist such changes of use, without having to resort to an Article 4 Direction. The provisions of paragraph N of Part 3 (introduced in May 2013) will apply in relation to any such application, and this includes the requirement that the LPA must, when determining one of these prior approval applications, have regard to the National Planning Policy Framework as if the application were a planning application. I discussed the practical effect of this requirement in relation to office conversions (B1(a) to C3) in a blog post on Wednesday, 22 May 2013 (“Offices to residential – a further thought”). In relation to those conversions, there was some doubt as to whether this requirement had to be read in the context of the three criteria that were to be specifically applied to office conversions, but the inclusion in Class MB of the paragraph I have put in italics [(e) above] suggests to me that the NPPF can be applied on a much wider basis to these barn conversions. In fact, it would seem to turn the whole process into just another type of planning application – a sort of ‘planning permission-lite’.

As regards the building operations permitted by Class MB, this is subject to a separate an additional condition that before beginning the development, the developer must apply to the LPA for a determination as to whether the prior approval of the authority will be required as to the design or external appearance of the building. Again, the provisions of paragraph N will apply in relation to this application, including the requirement that the LPA must, when determining the application, have regard to the NPPF as if the application were a planning application. In this case, however, it would appear that the NPPF will only be relevant to the extent that it addresses design issues (in paragraphs 56 to 68).

There is no requirement to have regard to the development plan, so section 38(6) of the 2004 Act does not apply as such, but I have previously discussed, in the blog post mentioned above, the extent to which the reference to the NPPF may to some degree bring the development plan into the equation (due to the references to the development plan contained in the NPPF itself).

Other conditions in the GPDO amendment provide that this class of development is subject to the condition that the development must begin within a period of three years beginning with the date on which any prior approval is granted for that development, or beginning with the date on which the period of 56 days expires without the LPA notifying the developer as to whether prior approval for that development is given or refused, whichever is the earlier. This will work in exactly the same way as other time limits for determination of prior notification/approval applications (as previously discussed in this blog).

There are some consequential amendments to various existing provisions in the GPDO, which I may discuss on another occasion (including information requirements in connection with prior approval applications), but one point of clarification which resolves an issue that has been the subject of discussion, both in this blog and elsewhere, relates to the ability of an LPA to impose conditions on a prior approval (not only under Class MB, but on the other prior approvals under Part 3 governed by paragraph N). A further sub-paragraph has been added:

“(11) The local planning authority may grant prior approval unconditionally or subject to conditions reasonably related to the subject matter of the prior approval.”

This confirms that an LPA does have power to impose conditions on a prior approval under Part 3, but the scope of such conditions is limited. Any such conditions must be reasonably related to the subject matter of the prior approval, and cannot therefore be more wide-ranging. There would appear, however, to be some scope for dispute on this issue, and it may become necessary to pursue a section 73 application in some cases, and (if necessary) a section 78 appeal against the refusal of any such an application, coupled with an application for costs where appropriate.

FOOTNOTE (added on 7/8/14): The ‘barn’ (or other agricultural building) does not qualify for conversion under this provision if the site was not used solely for an agricultural use, as part of “an established agricultural unit” on 20th March 2013, or (if the site was not in use on that date) when it was last in use (or, if the site was brought into use after that date, for ten years before the date the development begins).

A correspondent has queried the fact that nowhere in my articles on this and related topics is the definition of an “agricultural unit” mentioned. I am happy to repair that omission.

By Paragraph 3(N)(7) of the Second Schedule to the GPDO (as substituted by Article 5(8)(c) of the 2014 Amendment Order) “established agricultural unit” means agricultural land occupied as a unit for the purposes of agriculture - (i) for the purposes of Class M, on or before 3rd July 2012 or for ten years before the date the development begins; or (ii) for the purposes of Class MA or MB, on or before 20th March 2013 or for ten years before the date the development begins.

By Paragraph 3(O) of the Second Schedule to the GPDO (inserted by the 2013 Amendment Order), “agricultural building” means a building used for agriculture and which is so used for the purposes of a trade or business, and excludes any dwellinghouse, and “agricultural use” refers to such uses. Note particularly that, in order to qualify as an agricultural building, it must have been used for the purposes of a trade or business. Non-commercial use of the building is a disqualification.

However, “agriculture” itself is not defined by the GPDO, and so the definition in section 336(1) of the 1990 Act prevails in the absence of any indication to the contrary. [viz: “Agriculture” includes horticulture, fruit growing, seed growing, dairy farming, the breeding and keeping of livestock (including any creature kept for the production of food, wool, skins or fur, or for the purpose of its use in the farming of land), the use of land as grazing land, meadow land, osier land, market gardens and nursery grounds, and the use of land for woodlands where that use is ancillary to the farming of land for other agricultural purposes, and “agricultural” shall be construed accordingly.”]

[NOTE: If you scroll down to the comments, only 200 are displayed on the page. We are (as of 9 March 2016) up to 202 on this post! If you want to see the latest comments, you will have to click on "Newer comments" at the bottom right-hand corner of the page. The commments on the second page start with an interesting discussion on the 450 sq m floorspace limit.]

© MARTIN H GOODALL