Barn conversions – the structural issue

Anyone who has ever had to deal with a ‘barn conversion’ (i.e. the change of use of an agricultural building, usually to residential use but sometimes for other purposes) will be well aware of the structural problems that may arise, especially where the pre-existing building proves not to be sufficiently robust to allow conversion without substantial reconstruction and, in the worst case scenario, where the building collapses (or is demolished by well-meaning builders, or destroyed by fire or storm) before the project can be completed.

I have previously discussed these issues at some length in a series of five articles I published in this blog under the title “Barn Conversions again” in March 2013, and in a sixth and final article in December 2014. However, the considerable extension of permitted development rights for various changes of use introduced between May 2013 and April 2015 has given rise to further structural issues that can arise in these cases.

Some classes of permitted development within Part 3 of the Second Schedule to the General Permitted Development Order allow a certain amount of operational development in connection with some, but not all, residential conversions. However, the extent of the building operations that can be undertaken is strictly circumscribed by the terms of the Order. The changes of use in respect of which building operations are also permitted are Class M (formerly IA) (residential conversion of a shop or of premises providing financial or professional services), Class N (residential conversion of an amusements centre or of a casino) and Class Q (formerly MB) (residential conversion of an agricultural building). It is in relation to the last of these that structural issues are most likely to arise, especially if the pre-existing building is of unconventional, and perhaps insubstantial, construction.

In all three cases, the Order permits building operations reasonably necessary to convert the building to residential use (within Use Class C3 - dwellinghouses). In the case of Classes M and Q (but not Class N), development is not permitted if it would result in the external dimensions of the building extending beyond the external dimensions of the existing building at any given point. In the case of Classes N and Q development is only permitted to the extent that it would consist of 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. This stipulation is not made in respect of Class M, but in all three classes development demolition is prohibited, other than partial demolition to the extent specified by that Class. The wording varies slightly as between these three classes of permitted development. In the case of Class M, any partial demolition must be reasonably necessary to convert the building to residential use. In the case of Classes N and Q, it must be confined to the extent reasonably necessary to carry out the building operations permitted by that Class (as listed above). A developer under Class M thus has a slightly wider discretion with regard both to the building works carried out and as to the extent of any partial demolition, compared with a developer under Classes N or Q. A prior approval application must, of course, be made in all cases.

These statutory provisions represent the entirety of the legal constraints on the building operations that may be carried out as permitted development under these three Classes in Part 3. However, there is another important factor to be considered. Section 55(2)(a) of the 1990 Act provides that the carrying out, for the maintenance, improvement or other alteration of any building, of works which affect only the interior of the building, or do not materially affect the external appearance of the building, are not to be taken for the purposes of the Act to involve development of the land. It would be excessively legalistic, in my view, to argue that the words “for the maintenance, improvement or other alteration” of the building limit the scope of the works that are covered by section 55(2)(a). In particular I would not accept that the words “or other alteration” are to be construed ejusdem generis with “maintenance” or “improvement”; the purpose of such works may well be much wider than that. Thus I would contend that purely internal works (or works that do not materially affect the external appearance of the building) can be carried out to any building at any time and for any purpose, and that they would not amount to development under the Act provided that the completion of those works does not in itself constitute a material change of use.

Impey v. SSE (1984) 47 P. & C.R. 157 established that actual occupation of the converted building is not required in order for a material change of use to have taken place, if the conversion works have actually been completed. This was confirmed by the Supreme Court in Welwyn Hatfield v. SSCLG [2011] UKSC 15, where the contrary suggestion that had been raised in Backer v. SSE (1984) 47 P. & C.R. 149 was rejected. However, (short of completing the conversion works) any internal works that might be, or might be alleged to be, preparatory to a change of use for which a prior approval application has not yet been made would not constitute an unlawful commencement of the permitted development in the absence of prior approval, nor would they be a breach of planning control.

There may be some readers who are tempted at this point to cite Somak Travel Ltd -v- SSE(1988) 55 P. & C.R. 250, where an internal spiral staircase had been installed. By virtue of section 55(2)(a) this did not itself constitute development, but in this case it was part and parcel of the material change of use (or integral to the change of use) of an upper floor to office use, and so a requirement in the Enforcement Notice to remove the spiral staircase was upheld. The essential point, though, is that this case was concerned solely with the requirements of the enforcement notice. The breach of planning permission comprised only the unauthorised change of use of the upper floor of the building from residential use to use as part of the travel agency business which occupied the ground floor.

It was not alleged, nor did the inspector or the High Court find, that the installation of the internal staircase constituted development in itself. [The unlawful change of use would not have occurred, at the earliest, until all the works necessary for its occupation as an office had been completed.] However, in order to remedy the breach of planning control, i.e. the change of use of the upper floor, the removal of the staircase was seen as a necessary step in the restoration of that floor of the building to residential use. It was for this reason that the requirement in the enforcement notice that the spiral staircase should be removed was upheld by the Court. The case simply confirmed that the requirements of an enforcement notice can go beyond the scope of the breach itself, if the additional steps required to be taken (in this case the removal of the spiral staircase) are a necessary part of remedying the breach so as to restore the premises to their previous use. (This was in line with two earlier cases - Murfitt -v- SSE [1980] JPL 598 and Perkins -v- SSE [1981] JPL 755.) It does not, however, justify calling Somak Travel in aid in an attempt to argue that there are any circumstances in which purely internal works (or works that do not materially affect the external appearance of the building) are not exempted from the definition of development under section 55(2)(a).

Bearing in mind the clear legal effect of section 55(2)(a), it is difficult to reconcile this statutory provision with the statement in the government’s online Planning Practice Guidance, as amended on 5 March 2015, that it is not the intention of what was then Class MB(b) (now Class Q(b)) to permit the construction of new structural elements for the building and, accordingly, that it is only where the existing building is structurally strong enough to take the loading associated with the external works to adapt the building for residential use that certain building opera¬tions would be considered to come within Class MB(b) [Q(b)].

This advice clearly overlooks the fact that (so long as it is confined to purely internal works or works that do not materially affect the external appearance of the building) the installation of new structural elements in the building, such as a new floor, or the addition of a mezzanine floor, structural strengthening, including a new or augmented load-bearing frame, additional or strengthened roof trusses, etc. does not constitute development at all, and is not therefore governed in any way by the scope of the permission granted by Part 3, either in respect of the change of use itself, or in respect of the operational development that is also permitted under Classes M, N and Q. The latter can clearly refer only to any external works, or works that do materially affect the external appearance of the building. There is absolutely nothing in the Planning Acts, or in the GPDO itself, that prevents or inhibits other works within the building and/or which do not materially affect the external appearance of the building, whether they are carried out before, during or after any external works permitted by the GPDO.

The restriction of building operations under Classes N and Q to 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 applies only to the external works permitted by Part 3. It has no application whatsoever to purely internal works, no matter how extensive those may be.

On the other hand, if the existing structure, and the materials from which it is constructed, are so insubstantial that the building would require almost complete demolition and reconstruction in order to meet the requirements of the Building Regulations, then this clearly falls outside the scope of what Part 3 permits (particularly as regards the limited scope of the partial demolition that is permitted). In my book on Permitted Changes of Use, I have cited an appeal decision in Bedfordshire, issued in February 2015 that confirmed this.

There have, however, been other appeal decisions where inspectors would appear to have fallen into error in determining that certain agricultural buildings which comprise, for instance, a steel frame clad with light corrugated sheet, are incapable of conversion within the terms of Class Q. In one case, in August 2015, the proposal was to replace the corrugated sheeting with timber cladding, and a roof of slate. However, the Inspector doubted that the increased weight of the new materials could be carried by the existing steel frame, which was showing signs of corrosion. No structural report had been produced to confirm that the proposed conversion could be based on the existing steel frame, and so he concluded that the conversion could not be carried out within the limited structural parameters of the permitted development allowed by Class Q. A similar decision was reached on very similar grounds in another appeal in September 2015. What both these appeal decisions appear to have overlooked is that the necessary internal strengthening could (and quite probably would) have been carried out under section 55(2)(a), and would not therefore impact in any way on the limited extent of the building operations permitted by Class Q(b).

The two specific examples mentioned above are among a growing number of prior approval appeals that have been dismissed on these or very similar grounds. In our seminar in November, members of Keystone Law’s planning law team expressed their strong disagreement with this approach to the structural issues arising in prior approval cases under Class Q, and our guest speaker Sinclair Johnston agreed with us, and showed examples of structural works that in his view are entirely lawful in accordance with section 55(2)(a). We are all agreed that any future appeal decisions which conclude that the need for internal structural alterations and strengthening of an agricultural building takes the proposed development outside the scope of the development permitted under Class Q would be open to legal challenge in the High Court under section 288 and are liable to be quashed.

At the application stage, I am also aware of one case in which the LPA refused their prior approval on the grounds that internal structural works had been carried out to the building without prior notification having been given under Part 6. They therefore alleged that the agricultural building as it existed at the time of the prior approval application was unlawful, so that permitted development under Part 3 was now ruled out, by virtue of Article 3(5). Bearing in mind the effect of section 55(2(a), this reason for refusal is clearly nonsense.

A practical way forward in future in cases where internal structural works have either been carried out already, or where they will clearly be necessary in order to facilitate the residential conversion of the building, would be to give details of those works as additional information accompanying the prior approval application, so as to demonstrate the practicability of the proposed conversion, while at the same time making it abundantly clear that those internal works do not form part of the application for prior approval because, by virtue of section 55(2)(a), they do not constitute development and do not therefore require prior approval under Part 3. The LPA should then have no excuse for alleging that the proposed development does not comply with any conditions, limitations or restrictions specified in Part 3 as being applicable to the development in question. Nor, in light of the information given by the applicant as to the purely internal works covered by section 55(2)(a), would there be any excuse for alleging that the applicant has not provided sufficient information to enable the authority to establish whether the proposed development complies with those conditions, limitations or restrictions.

© MARTIN H GOODALL