The Building Regulations and Historic Building Requirements: Resolving Conflicts
John Adams
Early in 1997 I read a report on the future of a major historic building where difficulty in finding a user is being blamed on the location of a staircase. It is claimed that satisfactory means of escape cannot be provided and that historic building legislation will not allow the stair to be relocated. On the face of it an impasse has been reached. It is a situation that every professional involved in work to historic buildings will recognise.
We always complain that the Building Regulations were drawn up with new construction in mind and that when applied to historic buildings they can result in unacceptable loss or alteration. In order to test the need for further guidance or legislation specific to the needs of historic buildings, the DoE recently commissioned an exploratory study which involved wide consultation with conservation officers, building control officers, architects, owners and other professionals. The results indicate that although there are several areas of conflict, the failure to overcome them is often due to poor understanding of the issues by all parties and poor communication. Building control officers (BCOs) sometimes do not understand the principles which drive historic buildings legislation; and conservation officers sometimes lack adequate knowledge about building construction and safety issues. Professionals may exhibit a lack of knowledge on one or both subjects. Knowledge and understanding is crucial because what is mostly being sought is the acceptable compromise.
Since the Building Regulations' requirements are written as a statement of performance rather than prescriptive solutions, conflict does not usually occur at this level. It is in the application of the Approved Documents (Parts A to L) that conflict sometimes creeps in. For instance, 'reasonable standards of health and safety' are required by the Building Regulations. BCOs will usually accept that when work is being done to a historic building it should certainly not result in a less safe environment, but significant improvements may not be necessary. However, if the solutions of the Approved Documents were applied, say on the height of stair and landing handrails, the historical integrity of the building might be compromised.
There is a distinction to be made between issues which are potentially life-threatening and ones which are more concerned with comfort or psychological well-being. Fire protection is obviously critical and much work has been done to find ways of meeting the performance requirements of Part B (Fire Safety) without compromising what we value in an historic building. However, the improvement of fire separation in floor construction, for example, which so often results in the replacement of traditional ceiling construction by plasterboard, makes sound transmission between levels worse. Such a dilemma and the difficulty of sound reduction in existing buildings is recognised in Part E (Resistance to the passage of sound) paragraph 0.14, which accepts that the prescribed sound reduction may not be achievable.
In fact the only part of the regulations which does specifically acknowledge the problems of historic buildings is Part B (paragraphs 0.11 - 0.14).
The promotion of an engineered approach to fire protection in relation to a thorough risk assessment for the building in question is one example of the change in the approach which has been developed by designers and others towards the Regulations, as the Regulations have moved away from prescribing solutions in favour of requiring performance standards. For example a door may not need to withstand a fire well beyond the time that it actually takes to evacuate the building, provided that the means of escape is reinforced by a reliable fire detection and warning system.
Historic doors have provided a regular bone of contention, which is recognised by the amount of research that the Building Research Establishment, English Heritage and others have carried out on the subject. Our understanding of the ways in which doors (and their frames) fail in fire has now improved significantly. The English Heritage guidance note, 'Up-Grading of Fire Resistance of Panel Doors' (to be published this year) should promote better understanding and help to avoid damaging alterations without compromise to performance.
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| Test loading the main staircase at Osborne House, Isle of Wight: if it had not been possible to prove the strength of this fine 'cantilever' staircase in this way, its use would have been restricted under the Building Regulations. |
Other 'life-threatening' issues centre on structural safety. Here in particular, a solution which is acceptable to the building control officer is often not acceptable to the conservation officer. For example, with the exception of mills and warehouses, few historic buildings are capable of sustaining the massive design floor loadings for offices suggested by BS 6399: part I: 1984 (General use = 2.5 kN/m2; Corridors = 4.0 kN/m2; File Rooms = 5.0 kN/m2). In order to achieve maximum overall flexibility for the user, the highest performance requirement invariably becomes the norm. However a careful analysis of actual space use requirements and loadings in relation to potential bearing capacity of historic floors can usually result in the satisfactory location of the activities without too much difficulty. Compare these with the designated loading of 1.5 kN/m2 for new domestic dwellings. Calculations of stresses and deflections often appear to show that historic timber floors are capable of carrying only small weight loads. However, English Heritage recommends that load tests and the past history of a satisfactory performance are an arguable test of adequacy.
Questions of structural strength often relate to parts of the building such as floor structure which are hidden and thus accorded less value, even though they are intrinsic and may be critical to the special interest or character of the overall building. So-called 'cantilever' stairs are also virtually impossible to justify by calculation. I have seen fine examples shored up unnecessarily on the recommendation of building control officers or engineers with professional indemnity in mind.
Questions of architectural character and appearance become particularly lively where external elevations are threatened by alterations to windows and doors. Changes to windows that are often generated by a perceived need to achieve a low U-value are often unacceptable in detail and appearance. Secondary glazing is rarely an answer where internal joinery (such as shutter boxes for example) are involved. The pressure to create hermetically sealed and well insulated environments which is fostered by Part L (Conservation of Fuel and Power) does not respect the fact that traditional construction needs to be well ventilated for its structure to breathe. The issue is not life threatening and Part L recognises the need to leave room for a relaxation of the requirements where traditional construction is concerned (0.50.7) and the need to protect historic window joinery (1.50f).
Part M (Access and Facilities for disabled people) does not apply to existing buildings unless a new extension at ground floor is planned, and provided that alterations do not worsen the situation. However, the Disability Discrimination Act (1995) will soon begin to exert pressure on building owners and users to improve access to services and facilities for disabled people and it is likely that the guidance given in the Approved Documents will be used as the benchmark for compliance by many professionals. This approach would not be appropriate for a listed building. English Heritage has publicised guidance entitled 'Easy Access to Historic Properties' which promotes a process for resolving potential conflict and better understanding of access and conservation needs that will result in acceptable solutions.
So far as the Building Regulations are concerned, the difference between new and old construction is that the former can be designed to conform whereas each old building has to be considered on its own pre-existing merits. It would be wrong to assume that this is not appreciated by the Building Regulation Division of the DoE; hence their caution in producing more Approved Documents or legislation. The study found that "the legislation is able to work well where the necessary skills and will exist" and that "avoidable and exacerbated difficulties were found to occur as a result of a lack of understanding and effective communication". In other words, more training is needed. There were too many cases of confrontation rather than collaboration and the requirements of conservation are often badly explained and not well understood. Even if the interpretation and application of the Building Regulations is not as clear cut as some would like, the existing situation provides a flexible framework for discussion and compromise in the right hands. If only all building control officers understood all about the aims, values and techniques of conservation! If only all conservation officers and other professionals made more effective use of the existing legislation!
The good news is that the Institute of Building Control Officers and the Association of Conservation Officers are making overtures to one another in recognition of the need to improve understanding between the two disciplines.
