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Overview
Cannon Bridge House is a prominent commercial building located in central London. Like many buildings constructed during the 1990s, its façade and glazing systems had begun to show signs of ageing, both in terms of visual appearance and performance.
Over time, façade materials degrade due to exposure to weather, pollution, and daily environmental stress. In this case, the original façade system was no longer delivering the level of transparency, light transmission, and visual quality expected of a modern commercial workplace.
Structura was appointed to deliver specialist façade refurbishment works aimed at improving the building envelope and transforming the internal atrium environment. The project focused on upgrading the glazing system and installing a new atrium roof to increase natural daylight within the building.
The refurbishment also included restoration of existing aluminium façade components through specialist finishing and servicing processes.
The completed works significantly improved light transmittance, thermal performance, and the overall architectural appearance of the building, demonstrating how targeted façade upgrades can modernise existing structures without requiring full redevelopment.
Details
Client:
Blackstone Group
Location:
Dowgate Hill, Cannon Street, London
Architect:
Stiff + Trevillion
Project Metrics
Project type: Commercial façade refurbishment
Scope of works: Glazing replacement, atrium roof installation, aluminium façade restoration
Glazing system: Low-iron glass for improved transparency and daylight transmission
Atrium roof: Bespoke design incorporating high-performance acoustic glazing
Key performance improvements achieved through the project included:
- Increased natural daylight penetration
- Improved thermal performance
- Enhanced acoustic performance within the atrium
- Modernised façade appearance
These improvements demonstrate how strategic façade refurbishment can significantly enhance both the performance and visual quality of existing commercial buildings.
The Challenge
Buildings constructed in the 1990s often face a number of façade performance challenges as materials age and building standards evolve. For Cannon Bridge House, the main challenges centred around three key issues: façade deterioration, insufficient natural light, and the need to improve the overall architectural appearance of the building.
Ageing Façade System
The existing façade had reached a stage where visual deterioration and declining performance were becoming increasingly noticeable. Over time, façade systems can experience reduced glass clarity, surface degradation, diminished thermal efficiency, and outdated aesthetic appearance. The existing glazing system at Cannon Bridge House no longer reflected the standard expected for a modern commercial building in central London. Replacing or upgrading façade components therefore became necessary to improve both performance and visual quality.
Limited Natural Daylight in the Atrium
Atrium spaces are often designed to provide a central area of natural light within large buildings. However, older glazing systems or poorly performing roof structures can restrict daylight penetration. At Cannon Bridge House, the existing atrium roof limited the amount of natural light entering the building. This reduced the brightness and overall atmosphere of the internal space. Improving daylight penetration became one of the primary goals of the refurbishment project. Increasing natural light not only improves visual comfort but can also contribute to improved wellbeing for building occupants and reduced reliance on artificial lighting.
Maintaining Existing Building Structure
While upgrading the façade and glazing systems, the project needed to work within the constraints of the existing building structure. Full façade replacement was not required. Instead, the project focused on upgrading key elements while maintaining the underlying façade framework. This approach required careful coordination between glazing replacement works and restoration of the existing aluminium surfaces. The challenge was therefore to deliver a modernised façade while preserving the existing structural elements of the building.
Structura’s Solution
Structura delivered a targeted façade refurbishment strategy that addressed the key performance and architectural challenges of the building. The project included three main components including replacement glazing using low-iron glass, installation of a bespoke atrium roof with acoustic glazing, and restoration and refinishing of existing aluminium façade elements. Each component played an important role in improving the building’s overall performance and appearance.
Replacement Low-Iron Glass
A major part of the project involved replacing the existing glazing with low-iron glass. Low-iron glass is designed to deliver improved transparency compared to standard architectural glass. By reducing the iron content within the glass, the material allows more natural light to pass through and reduces the slight green tint that can appear in conventional glazing.
Installing low-iron glass provided several key advantages for the building including increased natural light transmission, improved visual clarity, a brighter interior environment, and a cleaner and more modern external appearance. The improved transparency of the glazing significantly enhanced the visual quality of both the exterior façade and the internal spaces of the building.
Bespoke Atrium Roof Installation
To further improve natural daylight within the building, Structura designed and installed a bespoke atrium roof. The atrium roof incorporated high-performance acoustic glazing designed to optimise both light transmission and sound performance. Atrium roof structures must be carefully engineered to perform under a range of environmental conditions, including wind loads, temperature changes, and rainfall. The bespoke glazing system installed at Cannon Bridge House was designed to ensure:
- Maximum daylight penetration into the atrium
- Long-term durability of the roof structure
- Effective acoustic performance within the building
- Reliable weather protection
The new roof structure transformed the internal atrium environment by allowing significantly more natural light to enter the building.
Restoration of Existing Aluminium Surfaces
In addition to glazing upgrades, the project also involved restoring the existing aluminium façade elements. Rather than replacing these components entirely, Structura undertook specialist restoration works including paint spraying of aluminium surfaces, servicing of existing façade elements, and re-finishing to improve durability and appearance. This approach allowed the project to retain the original façade framework while significantly improving its visual finish.
Refinishing aluminium components is often a highly effective refurbishment strategy, allowing buildings to be modernised without the cost and disruption of full façade replacement. The restored aluminium surfaces now complement the upgraded glazing systems and contribute to the refreshed architectural appearance of the building.
Project Results
The façade refurbishment works at Cannon Bridge House delivered a number of significant improvements to both the building’s performance and its architectural character. By combining glazing upgrades, atrium roof installation, and façade restoration, the project successfully transformed the building envelope while preserving the existing structure.
Increased Natural Daylight
One of the most noticeable improvements following the project was the increase in natural daylight within the building. The combination of low-iron glass and the new atrium roof significantly enhanced the amount of daylight entering the internal atrium space. This created a brighter, more welcoming interior environment for building occupants. Improved daylight penetration also helps reduce the need for artificial lighting during daytime hours, contributing to improved energy efficiency.
Improved Thermal & Acoustic Performance
The upgraded glazing systems also improved the building’s environmental performance. High-performance glazing contributes to improved insulation and more stable internal temperatures throughout the year. In addition, the acoustic glazing used within the atrium roof helps control sound within the building, improving comfort for occupants. These improvements help ensure the building performs to modern workplace standards.
Modernised Building Appearance
The refurbishment significantly improved the external appearance of Cannon Bridge House. The clearer low-iron glass gives the façade a more contemporary visual quality, while the refinished aluminium surfaces provide a clean and consistent architectural finish. Together, these upgrades transform the building’s appearance, helping it remain competitive within London’s commercial property market.
Efficient Refurbishment Strategy
One of the key advantages of the project was the ability to deliver substantial improvements without requiring a complete façade replacement. By focusing on targeted upgrades, Structura was able to modernise the building envelope while working within the existing façade structure. This approach allowed the project to deliver strong performance improvements with reduced construction impact.