Guide to Conversion of Traditional Buildings

3.0 How to use the Guide to Conversion of Traditional Buildings

The principal aim of this guidance is to assist in creating constructive dialogue between practitioners (surveyors, architects, engineers and other building professionals) and verifiers when obtaining permissions for the adaptation of traditionally constructed buildings. Where warrant considerations might affect the character of listed buildings, the guidance may also be useful in reaching agreement between practitioners, verifiers and planning officers.

It is expected that this guidance will mostly be used as a reference document, and users will therefore find a perceptible degree of repetition if reading across the sections in Part 1.

3.1 Layout of guidance

Parts 1 and 2 are summarised as follows.

Part 1: Principles and procedures

Part 1 sets the context for Part 2 in a series of introductory texts which explain the purpose of the guidance, how it should be used and the definitions of buildings to which this guidance applies. It also explains how traditional buildings are different in the way their materials and construction perform. Part 1 covers the wider context of building standards procedures and other related policy and legislation that practitioners should be aware of when working with traditional buildings.

Part 2: Application of the standards

Part 2 is called Application of the standards and looks at each standard in turn. It sets out the standards in the same order at the seven subject areas in the building regulations and Technical Handbooks. However, it only considers those standards that most commonly apply to projects for the conversion of buildings of traditional construction or which have protection by being listed or sited within a conservation area.

3.2 Layout of Part 2: Application of the standards

Part 2 is the main ‘working’ part of the document that is likely to become the principal source of reference for frequent users of the guidance. There are seven sections covering standards relating to Structure, Fire, Environment, Safety, Noise, Energy and Sustainability. Each section is set out as follows:

a) Introductory text

Each section has an introductory text which provides a context for the way in which the standards are considered and discussed. Typically, the introductions will highlight the main aims of the standards and any considerations that are important to their application within that subject area. The introductions may include a history of improving standards and regulation changes in their subject area. They also provide a summary of good practice within their subject areas, putting it into the context of a sensitive approach to traditional buildings. The principles summarised in the introductions are then revisited within the advice under each standard.

b) Mandatory standard

As with the Technical Handbooks, each standard is set out in white text within a coloured field at the head of the relevant page.

c) Application of standard to conversions

In line with the Technical Handbooks, each standard is then qualified in relation to conversions. It confirms whether the building as converted shall:

• meet the requirement of the standard, or
• meet the requirements of the standard in so far as is reasonably practicable, and in no case be worse than before the conversion.

d) Discussion for each standard

Each standard has four headings below it which are Commentary, Issues to be considered (within light green text box), Recommendations to meet the standard and Further reading. An outline of the purpose of these parts under each standard is as follows:

i. Commentary

In this part, the author has provided a general narrative setting out the key issues and principles that relate to the standard based on their experience in practice. This may include references to the Technical Handbooks and procedures (such as RdSAP) which were important to inform their thinking in writing the advice and recommendations that follow and should be borne in mind by users when reading the following advice.

ii. Issues to be considered

This part lists the typical risks which may have a negative impact on the performance and character of traditional buildings. The risks are set out in note form under the main heading risks to traditional buildings. These are contained within a light green text box to help with visual navigation through each section. These are the key points that are most likely to arise to help practitioners prepare for discussions with verifiers on how to meet a standard. The points are then considered in the following section.

iii. Recommendations to meet the standard

This part considers the issues and risks outlined in the table above. In line with the principal remit of the guide, this is often written in the form of discussion to stimulate problem-solving thinking that will inform discussion between parties with a view to reaching agreement.

iv. Further reading

Not all standards within the guidance have a list of further reading, but those documents that are listed typically include other relevant legislation, regulations and British Standards referred to in the text, other guidance by Building Standards Division and Historic Environment Scotland, Historic England and other Scottish and UK organisations, and documents relating to the history of safety standards in those subject areas.

3.3 Application of this guidance in practice

Part 2 of this guidance covers the application of the building standards to the conversion of traditional buildings. It is not intended to address every standard but will offer guidance on how best to satisfy the functional standards, likely to have the greatest impact on the character of these buildings.

Each traditional building is unique, or will at least contain unique features, which means that the use of model solutions to meet the requirements of the standards must be treated with caution. Each situation must be carefully assessed so that an appropriate solution to meet the standard is achieved without compromising the historic character of the building.

The guidance provided in this section is based on best practice for the situations described. It is designed to meet the requirements of the regulations and mandatory standards whilst also acknowledging how traditional buildings are designed and constructed to function and recognising the need to maintain the character of such buildings.

The examples of solutions offered have been agreed by the Building Standards Division and Historic Environment Scotland as suitable generic examples, illustrating how to satisfy the relevant functional standards. However, the guidance provided is applicable to only the described situations: they are not ‘deemed to satisfy’ specifications for general application.

The key remit of this guidance is to promote constructive dialogue between practitioners and verifiers. Because of the individual nature of traditional buildings, the examples given in this guidance are of a general nature that are intended to be interpreted within the specific circumstances presented by a building or conversion project. Therefore, where the construction or other features of a building do not follow the examples, the construction, materials and elements of the building, and the principles set out in this guidance must be thoroughly assessed before any of the recommendations are implemented.

Similarly, the drawings in this guidance are indicative illustrations and do not contain information such as dimensions, U-values or material specifications. As with the written guidance, the drawings should be interpreted according to the building and circumstances that are the subject of a scheme or discussion. Note that the drawings will often relate to one issue being considered under a certain standard and may not show other considerations within the same drawing (such as noise transmission, ventilation, insulation and fire protection).

Regulation 12 of the Building (Scotland) Regulations 2004 recognises that, in the conversion of an existing building, it may not always be reasonable to meet all of the mandatory standards in every situation. In schedule 6 to regulation 12 (refer to section 0.12 of the Technical Handbook), two classifications of standards are established for conversions – those that must be met and those that shall be met in so far as is reasonably practicable. The contents page of this guide provides a summary of the standards addressed. Only those standards most likely to have an impact on the fabric and character of traditional buildings have been included for detailed guidance.

In the case of standards that shall meet the requirements, there is typically no relaxation of the standard available. However, the flexibility inherent in the functional nature of the standards does mean that it may be possible to achieve the function by alternative means.

Where schedule 6 notes that a standard may be met as far as is ‘reasonably practicable’, this recognises that the designer will be working within a set of constraints imposed by the building construction and form. For traditional buildings, this includes considering solutions which are compatible with their form of construction and sensitive to their character. Interventions should be appropriate in that context. A more detailed explanation of the performance and characteristics of traditional buildings is set out in chapter 7 of Part 1: Understanding traditional buildings. While the requirement is to make every effort to achieve the relevant standard, the outcome achieved may have to be limited to what is feasible and appropriate in each specific circumstance. In all cases, a ‘do nothing’ approach will not be acceptable.

This document provides guidance applicable more widely than defined in the Act, to cover the range of traditional buildings defined in chapter 4 of Part 1 (Building definitions). The definition of a traditional building is necessary because the building regulations recognise that existing buildings being converted cannot always meet the full requirements.

While the sections in Part 2 of this guidance are set out to reflect the order and content of the individual standards, there will be many instances when the needs of one standard will impact upon another. The standards may also influence the way in which the fabric of the building reacts to the changes imposed upon it. Sometimes an attempt to satisfy a standard may cause a change in the fabric condition that is detrimental to the building. For example, sealing off ventilation pathways within the construction to satisfy the needs of improved building envelope insulation, fire safety and noise insulation can raise humidity levels in hidden voids to dangerous levels.

Consequently, it is most important that users of this guidance have a sound understanding of how traditional buildings are constructed and intended to function, so that any changes imposed on the building are fully understood. Each standard should not be addressed in isolation, and the solution or solutions adopted must be assessed to determine their impact on the performance of the building as a whole. A holistic approach to the application of the building standards to traditional buildings is therefore essential.

The conversion of a traditional building sets challenges to designers, certifiers of design and verifiers because each situation is unique. It will be essential to understand how the building performs in use and to conduct a full appraisal of the relevant features of the building, with testing where appropriate, to ensure compliance with the standard. It is likely to be beneficial for the designer and verifier to discuss proposed solutions for potentially contentious issues at an early stage in the process.

3.4 Further reading

• The Building (Scotland) Regulations 2004 (as amended)