Modern Heritage and Facade Improvements

Developing Intervention Strategies for post-war Facades



Photo of Uta Pottgiesser

Uta Pottgiesser

Chair of Heritage & Technology

TU Delft

Photo of Angel Ayón

Angel Ayón


AYON Studio Architecture and Preservation


Approximately 80% of our total building stock is from the 20th century. During the last decades, along with an increasing appreciation of modern architecture, there has also been a growing recognition of the need to address the adverse effects of climate change, particularly as related to existing buildings. Accomplishing this goal will require transforming the majority of the existing buildings from being highly energy-inefficient to having nearly net-zero energy use. Over the last years the environmental conditions have worsened and extreme weather events have increased, but the required carbon-reduction changes have not yet found their way into new regulations.

While the need to reduce energy consumption as a way to improve our carbon footprint has continued to gain acceptance worldwide, there have been discussions on the applicability of well-established historic preservation principles to the conservation of everyday’s modern architecture reflecting on authenticity, conservation of historic fabric and original design intent as part of intangible values. To that effect, little research has been conducted on technical issues exploring how to reconcile environmental performance and heritage preservation, or on the full range of options available to enhance the appearance of aging facades, improve their environmental performance and address safety and comfort concerns. Thus, there is an urgent need to outline evidence-based and applicable recommendations and set forth professional best practices to guide interventions on existing modern buildings.

The paper explores various options available for restoration, rehabilitation and replacement of Modern Movement facades depending on their cultural significance, current understanding of user and compliance with contemporary requirements for preservation, building performance and energy conservation. Based on the presented cases and research - by a combination of indepth research and documentation, experience-based critical analysis, and compelling and informative construction details - the ongoing research will also address the limits of current policies and regulations and argue for a more holistic and simplified preservation and renovation approach to ensure the safeguard of the listed and everyday’s modern heritage in different parts of the world.


Approximately 80% of our total building stock dates to the 20th century (Baxter, 2001). The use of new materials and construction assemblies such as extensive metal and glass facades permitted

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There have been discussions on the applicability of well-established historic preservation principles to the conservation of everyday’s modern architecture and other conceptual topics regarding authenticity, conservation of historic fabric and

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Developing An Intervention FRAMEWORK for MODERN POST-WAR Facades

The authors are aiming to develop an extended intervention framework for modern metal-framed post-war facades. Based on the existing approaches and categorization shown in table 1 they propose a more

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Conclusion, Recommendations and Future Work

In the US, building envelope practitioners and consultants are often the first professionals, architects and owners call upon to intervene on aging glazed assemblies. Preservation professionals have not yet developed

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This paper is based on a previous study performed thanks to a Mid-Career Preservation grant from the James Marston Fitch Charitable Foundation in 2015,further resulting in a book publication by the authors with Birkhäuser in 2019. The authors would also like to thank Docomomo International, APTi, and their members and for supporting this paper with content and practical input based on publications, symposia and site visits. Owners and caretakers of the properties included in the research, as well as some of the contractors that implemented the facade alterations, provided valuable information on past or current conditions or assisted with gaining access to the buildings to evaluate the existing and as-built conditions. All images by the author(s) unless noted otherwise

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