Precision Liquid Waterproofing Delivers Heritage Roof Refurbishment

As one of the UK’s most iconic and historically significant structures, Tower Bridge is a Grade I listed site that demands the highest standards in conservation, safety and technical delivery.

As part of a planned heritage maintenance programme, three independent external ticket office roofs at the north and south approaches were identified as having reached the end of their serviceable life. The original asphalt waterproofing, installed in the 1960s, had deteriorated and required replacement to ensure continued weatherproofing.

The project required a carefully considered solution that would respect the bridge’s protected status, retain the visual character of the existing roofs, and be installed without disrupting operations. Working in a live public environment with significant pedestrian footfall added further complexity, as did the requirement to avoid hot works and maintain the original light grey reflective finish.

Garland UK was appointed as system designer and material supplier, with Technical Manager Jack Costello overseeing the specification, detailing and technical support throughout the works. Installation was delivered by Garland UK Approved Contractor, JAW Roofing.

Complex Heritage Constraints

While the roof areas were modest in size, the technical and logistical constraints created a highly sensitive working environment. The roofs form part of a functioning ticket office within a conservation area, requiring a non-invasive solution that would preserve the underlying structure and original appearance.

A key design constraint was that no changes could be made to existing parapet heights, thresholds or detailing. As a result, the new waterproofing system had to terminate precisely at existing interfaces, with no tolerance for additional build-up. Given the high traffic at Tower Bridge, hot works were strictly prohibited, and installation had to be carefully coordinated to avoid disrupting daily operations.

The winter programme introduced further challenges. Low ambient temperatures and variable conditions required careful control of catalyst quantities and curing times to maintain consistency of finish and performance. Attention to sequencing and interface detailing was central to maintaining compliance with both conservation and operational requirements.

Cold-Applied Dura-Coat System

Garland UK specified the Dura-Coat liquid waterproofing system, a polyurethane-modified methyl methacrylate (PMMA) solution designed to provide durable waterproofing over existing substrates, including aged asphalt. This approach enabled retention of the existing structure in line with conservation requirements.

Its flame-free, cold-applied application eliminated the need for hot works within the live public setting. Dura-Coat’s rapid curing properties supported installation during lower temperatures, with catalyst levels adjusted daily to suit site conditions. The system build-up allowed for direct application to the prepared asphalt substrate without altering thresholds or parapet levels.

The specification included primer, an embedment coat with reinforcement fleece, and a colour-matched light grey topcoat to replicate the original solar-reflective finish. All materials were fully compatible with the existing asphalt and designed to provide long-term waterproofing performance.

Quality assurance inspections were undertaken throughout the programme, with particular focus on terminations, drainage details, and junction interfaces to ensure the precision of the finish.

Precision Without Operational Impact

The project was delivered safely and without disruption to Tower Bridge’s daily operations. The refurbished roofs now provide high-performance waterproofing while preserving the heritage appearance and physical integrity of the original structures.

Completion was achieved without altering existing thresholds or structural elements, maintaining compliance with conservation requirements, with the finished result replicating the original light grey coating, ensuring continuity with the bridge’s architectural character.

The scheme stands as a measured example of how sensitive refurbishment work on nationally significant assets can be undertaken with technical precision and minimal operational impact, reinforcing the importance of disciplined installation and accurate detailing when working within strict heritage constraints.

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