Urban design, legibility and the management of change in historic environments

Abstract

This thesis is concerned with the management of change in historic environments. Against a theoretical backdrop of the unresolved questions arising from UNESCO’s Historic Urban Landscape paradigm and its implicit acceptance of change/contemporary creativity (limits to change, relative importance of fabric vs spirit/values, intangible heritage), and the contention of an elitist ‘Authorised Heritage Discourse’ governing heritage, it assesses the utility of applying the Lynchian concept of legibility (how we read places) to regulating change to heritage designations. The underlying assumption is change affects how historic environments/heritage assets are perceived by their users, in addition to the criteria underpinning their aesthetic appreciation. The research demonstrates that quantification of such impacts is possible.

The methodology involves a photo survey with change to perception due to new development recorded using a semantic differential technique; including incremental percentage change to townscapes, differing typologies of extensions to historic assets, and ability to recognise the use of historic buildings viz-a-viz contemporary architectural forms. The research assesses impact of change on mental image formation replicating serial movement through places, quantifying impact on dominance of heritage landmarks through focal shift to new development in context, and factors involved in this. It assesses, through practitioner interviews, whether current regulatory practice is governed by an authorised heritage discourse.

The thesis concludes that, though absent from philosophical, theoretical and practice heritage discourses, assessing impact of new development on legibility would be of utility in management of change to historic environments, fundamentally challenging current regulatory practice operating against HE user’s preferences. Databases of perceptual impacts of various typologies of new development encountered in practice may be established assisting regulation through quantification of gradual change, extensions to historic buildings and the dominance effect of new development in their setting. Findings support the contention of elitist heritage governance that assessment of perceptual impact may counter, facilitating greater operational consistency.

Date of Award	Jun 2026
Original language	English
Supervisor	Linda McElduff (Supervisor), Ken Boston (Supervisor) & Neale Blair (Supervisor)