Guide to Conversion of Traditional Buildings

4.2 Access within buildings

Mandatory Standard

Standard 4.2

Every building must be designed and constructed in such a way that:

a) in non-domestic buildings, safe, unassisted and convenient means of access is provided throughout the building

b) in residential buildings, a proportion of the rooms intended to be used as bedrooms must be accessible to a wheelchair user

c) in domestic buildings, safe and convenient means of access is provided within common areas and to each dwelling

d) in dwellings, safe and convenient means of access is provided throughout the dwelling, and

e) in dwellings, unassisted means of access is provided to, and throughout, at least one level.

Limitation:

There is no requirement to provide access suitable for a wheelchair user:

a) in a non-domestic building not served by a lift, to a room, intended to be used as a bedroom, that is not on an entrance storey, or

b) in a domestic building not served by a lift, within common areas and to each dwelling, other than on an entrance storey.

4.2.1 Application of standard to conversions

In the case of conversions, as specified in regulation 4, the building as converted shall meet the requirements of the standard in so far as is reasonably practicable, and in no case be worse than before the conversion (regulation 12, schedule 6).

4.2.2 Commentary

Standard 4.2 is concerned with issues of accessibility within buildings, including accessible accommodation, vertical access between storeys, changes of level within a storey, the design of horizontal circulation routes, the design of doorways, accessible facilities and suitable floor surfaces.

The application of this standard to the conversion of historic and traditional buildings has the potential to cause significant disruption to the character and fabric of a building. Historic buildings and landscapes were not designed to be readily accessible to everyone and thus introduce complex contradictions when attempting to adapt them to allow safe, convenient and unassisted access throughout while preserving their architectural or historic character.

The methodology set out in the introduction to this chapter should be followed to allow issues and appropriate solutions to be developed that will give the building an accessible interior.

Achieving the following improvements are likely to present the greatest challenges to practitioners:

i. Corridors of sufficiently unobstructed width (refer to technical guidance for specific dimensions to be met, both for accessibility and fire escape) may be impracticable. Even when these minimum widths are available, there is the potential for damage to historic fabric as occupants pass through narrow spaces.

ii. Internal doors of sufficient clear opening width (refer to technical guidance for specific dimensions to be met, both for accessibility and fire escape).

iii. Unassisted access at changes in level. Many historic buildings have been extended over the years with floors between various parts having differences in level. Accommodating unassisted access between changes in level may be difficult or even impossible.

iv. Access to storeys above and below the main entrance level, usually through the provision of a lift. Accommodating a passenger lift within many historic building conversions may be difficult to achieve without causing serious disruption to character and fabric.

As noted in the introduction, it is outside the scope of this guide to identify and discuss all the potential issues arising from an access audit, as this will cover issues that are unlikely to impinge directly on the requirements of this standard. For further information, reference should be made to BS 8300-2: 2018 ‘Design of an accessible and inclusive built environment; Part 2 – Buildings - Code of Practice’.

Experience suggests that most buildings can be successfully and effectively altered as part of the conversion process, but this does require a good knowledge and understanding of both historic building conservation and the needs of persons with diverse disabilities. The extent to which a historic interior can be modified depends on the cultural significance of the building. This includes features such as its materials, doors, finishes (panelling, decorative plasterwork and the like), and the importance of spaces and their arrangement. Principal rooms and spaces (such as entrance halls) may be more difficult to alter without affecting their character. Less significant rooms and spaces may provide scope for interventions without affecting the important characteristics of the wider building.

Every effort should be made to preserve the architectural or historic features that contribute to a building’s cultural significance. Typically, these features include materials, the form and style of the property, major architectural features and significant spaces within the building. However, with careful analysis of the building and sympathetic design, it should be possible, in most conversions, to make the building (or sufficient parts of the building) accessible to all.

In some cases, a reversible addition which avoids the removal of historic fabric may be preferable, but this must be balanced with the visual intrusion that these more temporary solutions often have. However, when considering all of the options in the adaptation of an older building, there should be a presumption against thinking of an accessible environment as a temporary measure or condition which can be reversed in the future.

4.2.3 Issues to be considered

Typical risks in the conversion of historic/traditional buildings

1. Access between storeys

• The unsympathetic installation of lifts and accessible stairs can be destructive to historic fabric and visually intrusive within important spaces.
• Accommodation of lift cars and lift motors etc. and meeting the space requirements may require structural strengthening and alteration of the building, with associated damage to historic fabric.
• The implications of fire escape from upper levels need to be considered in conjunction with accessibility, particularly where refuge spaces are provided within existing fabric.

2. Vertical circulation in common areas of domestic buildings

• While a building of up to four storeys may be constructed without a lift, stairs in common access areas should be accessible to ambulant disabled people (designed to standard 4.3 – refer to the guidance in Section 4.3 of this chapter). Alteration of existing stairs to comply with this standard may have a significant impact on the architecture and historic fabric of a building and its spaces.

3. Internal doors

• The technical standard gives required minimum clear opening widths of doors, depending on their situation. Increasing the opening width of a historic door may require extensive alterations to the supporting structure, doorframe and door leaf.
• Where required, the provision of a 300mm unobstructed space on the side next to the leading edge of an internal door may not be possible without major alterations to rooms and other spaces.
• The requirement for a door across a corridor or passageway to have a clear glazed vision panel may have a damaging effect on the historic fabric and character of the door.
• Historic doors can be heavy and may not comply with the limits on force required to open them.

4. Horizontal routes in domestic common areas and non-domestic buildings

• In traditional buildings it may not be viable to alter corridor width or room layout where this would impact on the historic character of the spaces or the structure of the building.
• Traditional buildings often have areas of differing floor levels and the need to avoid certain stepped changes in level may require damaging changes to fabric, design and structure.

5. Accessibility within dwellings

• Each storey within a dwelling should be accessible to all, which has implications for corridor width and layout, and minimum door opening sizes. There should also be unassisted access to basic accommodation (kitchen, accessible sanitary accommodation) / an enhanced apartment in the principal level.
• Existing stairs may not be suitable for retrofitting with stair lifts.

6. Floor finishes

• Floor finishes on accessible routes and circulation areas should be uniform and give sufficient traction to minimise slips. Changes in materials should be level and clearly visible. If a building has floor finishes of particular significance, they may be negatively affected by this regulation.

7. Fixed counters (non-domestic only)

• Where historic counter or screen features are present, they are unlikely to meet the standards without alterations that may impact on their character.

4.2.4 Recommendations to meet the standard

The preparation of an access plan, which analyses the cultural significance of a building and its potential to be adapted to create a fully accessible environment, is critical. This will help to define the key challenges specific to a building as well as identify the ways in which it can be most easily adapted. It is usually the installation of accessible stairs, ramps and passenger lifts that creates the greatest challenge to designers working within traditional buildings. The staircase will often be the most prominent architectural feature of an interior which may also have high floor to floor dimensions and limited space within circulation areas.

a) Providing access to and between storeys: lifts

There will be many conversions of both domestic and non-domestic buildings where access to storeys will require the installation of a passenger lift. The viability of the conversion will frequently depend on such a provision. The positioning of the lift is a key decision in the earliest stage in the design process if an accessible building is to be achieved with the minimum disturbance to historic fabric. Clearly there can be no standard solution to this problem and each situation must be assessed on its individual circumstances. Ideally, a lift installation should be located within a secondary space, such as a store or office, and not in a primary space, although bespoke designs can be successfully integrated into key spaces such as entrance halls.

Modern lifts are available that avoid the need for a separate, costly machine room because the mechanism can fit on top of the shaft. The lift type should be chosen to minimize loads onto the existing structure of the building. Adapted platform lifts can also be used between storeys, dependent on required reach and size.

These cannot be used for fire evacuation purposes therefore this regulation also needs to be co-ordinated with Section 2 (Fire), in particular the provision of a suitable means of escape from upper storeys for people who use wheelchairs. A fire-fighting lift that is suitable for evacuation purposes is much larger. Its size has greater implications for structure and makes it more challenging to fit and construct within the constraints of an existing building. The creation of a suitable refuge space for wheelchair users at upper levels based within existing fabric is also likely to be problematic as the materials and details of existing construction cannot be guaranteed to provide sufficient fire protection to users.

Where it is not possible to install a lift within the existing envelope without serious disruption to historic spaces and fabric, it may be appropriate to accommodate a passenger lift within a sympathetically designed extension to the building.

b) Historic lifts

Some buildings may have existing historic passenger lifts that do not comply with the standard required because of their size (too small for a wheelchair, control height or type, etc.), operational features or detailing. Where these lifts are clearly part of the historic interest of the building, they should be retained provided their use does not compromise safety. It is usually possible to upgrade them to improve their accessibility. For example, control panels can be made more accessible and modern signaling systems installed.

c) Providing vertical access: existing stairs

New stairs in common areas need to be designed to be accessible by ambulant disabled people. Existing stairs often present insurmountable barriers to many people with disabilities and it may be difficult to modify their physical characteristics (see also Section 4.3). However, some relatively simple improvements can be made that will improve their accessibility, such as:

• adding handrails if none exist – ends of rails should return to the wall to avoid catching on clothing or bags (see also 4.3 - effective width),
• infilling of open risers,
• fitting colour contrasting, non-slip strips for people with visual impairments or at minimum –
• improving lighting to provide good visual contrast between risers,
• reinstating historic paint schemes which differentiate (in colour and tone) between elements can also be beneficial for people with visual impairments.

d) Stepped level changes

A moveable ramp may sometimes be employed to accommodate differences in level within a storey or dwelling. This is unlikely to be an acceptable long-term solution for historic buildings and a ‘permanent’ access solution will be required. The design of a ramp should respect the principle of reversibility and avoid the destruction of important historic features.

Where possible, historically important steps should be retained in situ and hidden within new work or used as part of a revised design for the entrance. Steps should be provided as well as a ramp to benefit as many users as possible.

As an alternative to a ramp, a wheelchair platform lift or a powered lifting platform may be appropriate for some situations where a stair cannot be altered. Provided space is available, such installations can often be accommodated without disruption to historic features. Inclined stairlifts, which carry a wheelchair on a platform up a flight of stairs, tend to be visually intrusive. They are, however, a reversible installation although users will often require assistance to operate them.

e) Internal doors – setting out, opening widths, glazed panels, controls

The minimum clear opening width for internal doors may not be achievable without major alteration to a historic door opening. In these cases, it may be possible to gain a few millimetres of width by reducing the depth of doorstops. As a rule, there should be a presumption in favour of retaining and adapting historic doors and their frames.

Many historic doors contain a glazed panel that will meet the requirements of the standard. Where historic panelled doors are accessible to disabled people in non-domestic buildings, it may be possible to insert a glazed panel or panels in place of existing panels, or glazed sections within the panels themselves. Each existing door in a conversion project should be individually assessed to determine if it needs to be upgraded for accessibility (and fire performance) rather than assuming all doors within the development will require the same treatment.

Where it is not possible to provide an unobstructed space of at least 300mm next to the leading edge of a door, the door should be fitted with an automatic opening or, where possible, a ‘hold open’ mechanism (connected to fire alarms where required), which can make single or double-leaf doors fully operational by disabled people.

In addition, historic doors can be heavy and challenging to open, especially if fitted with door closers. If this is the case, the use of automatic opening devices or ‘hold open’ mechanisms are likely to be beneficial to users.

f) Floor finishes

It is generally accepted that surviving historic floor finishes such as decorative encaustic clay tiles, marble slabs or flagstones, should be retained wherever possible. It may be possible to overlay these with non-slip material or coverings, but this should be done in a way which avoids damage to the surface of the existing finish. Alternatively, a limited section may need to be reset to avoid trip hazards.

g) Counter design

Where historic public counters or screens survive in non-domestic buildings, there is a presumption in favour of their retention if they clearly contribute to an appreciation of the architecture and history of the building. It may be possible to carefully adapt a limited part to provide a lowered section within the original design, or an adjacent space formed or provided to create a new counter that meets the standard.