Table 3 Minimum intervention level assessment factors for historical buildings

value assessment

protection level

legality

Laws and regulations related to this historical building, including international, national, and local ones

protection level

Protection level of historical buildings

artistic value

uniqueness

The uniqueness of historical background

decorative

The aesthetic features and cultural symbols of historical buildings displayed through external art forms such as carving, painting, patterns, and components

spatial expressiveness

The functional imagery and emotional experience created by historical buildings through spatial organization techniques such as axes, levels, and opening closing relationships

historic value

continuity

As tangible witnesses of the changing times, historical buildings carry the historical context and social development information from their construction to the present day

educational

Historical architecture conveys historical knowledge, cultural traditions, and values through intuitive material forms, becoming a living textbook for future generations to understand and reflect on the past

social value

cultural heritage

Historical buildings serve as cultural carriers, continuing regional traditional customs, techniques, and spiritual connotations

economic

Historical buildings are transformed into economic value through cultural and tourism development, cultural creativity, and other forms, driving regional development

urban memory

As a collective emotional symbol, historical buildings embody citizens’ sense of identity and belonging to the city

Scientific value

adaptability

The adaptability of historical buildings to the local natural and social environment

technical

Historical buildings contain the architectural technology of the time, showcasing the wisdom and engineering abilities of ancient people, and can provide reference and inspiration for modern architecture

diversity

Historical buildings have rich diversity in types, styles, regions, and other aspects

usability evaluation

visibility

layout

Refers to the visual order and rationality of the overall spatial planning and functional zoning of a building, reflecting the recognizability and logical use of spatial organization

facade

The external appearance of a building, consisting of walls, doors, windows, eaves, etc., reflecting the architectural style, historical features, and visual coordination with the surrounding environment

structure

Refers to the visible form of the load-bearing system of a building (such as beams, columns, walls, roofs, etc.), demonstrating the historical significance of construction techniques and the intuitive expression of mechanical logic

material

Refers to the visible texture, color, and weathering state of materials such as bricks, wood, metal, etc. used on the inner and outer surfaces of a building, conveying the age information and technological characteristics of the building

decoration

Refers to the visible artistic treatment of building components (such as carving, painting, patterns, etc.), reflecting historical and cultural connotations, aesthetic orientation, and craftsmanship level

night lighting

Refers to the nighttime visual presentation of building appearance and details through lighting design, emphasizing the recognizability of historical features at night and the creation of environmental atmosphere

spatial features

types of public spaces

The types of spaces available for public use inside and outside historical buildings (such as squares, courtyards, corridors, etc.) reflect the diversity of spatial functions and the adaptability of public participation

spatial recognition

The visual recognizability of various functional spaces in historical buildings (such as entrances, exhibition halls, traffic flow lines, etc.) presented through form, signage, or historical elements, ensuring that users can quickly understand the spatial attributes and orientation

spatial quality

The physical and visual effects of historical architectural spaces, such as lighting, ventilation, color matching, scale ratios, etc., need to balance the protection of historical features with the comfort of modern usage needs

integration of old and new spaces

Refers to the degree of coordination and unity in visual elements such as material, form, and scale between the original space of historical buildings and newly built/renovated spaces, reflecting the continuity of historical context and the compatibility of contemporary functions

integrity

complete historical architecture

The degree of integrity of the architectural entity (such as structure, components, decoration, site, etc.) of a historical building, ensuring that the core historical elements are not missing, tampered with, or excessively damaged

complete literature

The completeness and accuracy of archives, drawings, images, written records, and other documentary materials related to historical buildings, which should comprehensively and truthfully reflect the historical evolution, construction techniques, and cultural value of the buildings

functional evaluation

functionality

diverse functions

The richness of functional types that historical buildings can carry in the process of reuse (such as cultural exhibitions, commercial services, office and residential areas, etc.), while taking into account the adaptability of historical value protection and diverse social needs

flexible space

Refers to the dynamic adaptability of the internal space of a building to different usage scenarios (such as exhibitions, conferences, retail, etc.) through adjustable layout, modular design, or multifunctional furniture

modern facilities

Refers to the organic integration of historical style and contemporary usage needs by incorporating modern technologies (such as HVAC, fire protection, intelligent systems) and design language while preserving the core elements of historical buildings

barrier-free design

Refers to the elimination of physical barriers (such as ramps, elevators, braille signage, etc.) to ensure the convenience and safety of historical buildings for different groups of people (such as disabled and elderly), in line with modern inclusive design principles