The refurbishment at 26 Belmont Terrace showcases the standout benefits of specifying the Polyroof Protec Warm Roof System for complex, live, and weather-challenging environments. By retaining the existing roof build-up and utilising Protec’s cold-applied, seamless waterproofing technology, the project delivered a fully compliant warm roof upgrade with minimal disruption, reduced waste, and enhanced sustainability. Protec’s RapidCure technology enabled dependable progress during tight weather windows, while its versatility excelled in tackling intricate details that traditional systems struggle to address. The result is a robust, thermally efficient, and visually unified roofing solution backed by a 25-year guarantee—demonstrating why Polyroof is the trusted choice for durable, future-proof flat roof refurbishment.
The Challenge
The refurbishment of the flat roof at 26 Belmont Terrace required the transformation of a deteriorating three-layer felt roof into a high-performance warm roof system capable of meeting modern thermal expectations and withstanding the demanding coastal climate of the Isle of Man. Core test samples confirmed an existing build-up comprising 100 mm insulation, an AVCL, and a structural metal deck, with only a small section requiring localised strip-out due to water ingress. The key challenge was to deliver a fully compliant warm roof upgrade while avoiding unnecessary demolition, waste, and disruption to an active commercial building.
The existing structure presented a variety of technical constraints. The roof featured numerous complex details—including parapets, mansard interfaces, chimneys, outlets, and multiple penetrations—where a traditional felt or single-ply system would have posed risks around jointing, detailing, and long-term reliability. The works also started during an exceptionally wet period, significantly restricting the availability of dry windows. Torch-on membranes or mechanically fixed sheet systems were impractical in these conditions, and health and safety considerations ruled out hot works. This was compounded by the roof operating as a live working environment, with mechanical plant and several trades requiring continuous access, as well as restricted crane access and limited material storage space. With various logistical constraints at play, including solar panel contractors travelling from off-island, a flexible and fast-curing roofing system was essential to executing a seamless programme of works.
The Solution
Polyroof’s Technical Team developed a solution that delivered the required thermal upgrade while preserving the integrity of the existing warm roof layers. Survey results confirmed that the felt could be retained, supporting vapour continuity and significantly reducing waste to landfill. A new layer of rigid insulation was installed above the existing build-up to enhance the thermal performance and achieve the target U-values, with adhesive bonding used across the field area and perimeter mechanical fixings introduced to meet wind-uplift requirements. The existing falls provided compliant drainage in line with BS 6229:2018, eliminating the need for tapered insulation and reducing both cost and programme time.
A Polyroof carrier layer was applied to create a stable, uniform surface ready to receive the liquid waterproofing membrane. The Polyroof Protec System was then installed across the roof, selected for its cold-applied nature, seamless coverage, and unique ability to deal with intricate detailing. Its RapidCure technology allowed installers to make significant progress in short, intermittent dry periods—an essential capability given the severity of the island’s weather during the works. The system’s fluid application made it possible to encapsulate upstands, corners, penetrations, and service interfaces without reliance on mechanical fixings or heat-based methods. This adaptability also supported phased installation around other trades and ensured coordinated progress with the solar panel installers, whose timings were particularly sensitive due to off-island travel requirements. To facilitate safe ongoing maintenance, a Polyroof ProGrip walkway in yellow was incorporated into the finished design.
The Result
The completed roof provides a high-performance warm roof system that meets modern thermal requirements, achieves a calculated U-value of 0.16 W/m²K, and delivers a durable, fully bonded waterproof finish. The Protec System forms a seamless, visually uniform surface that integrates effortlessly with the building’s architectural character and ensures long-term colour stability and UV resistance. Because the existing felt layers were retained, the refurbishment significantly reduced environmental impact, avoided intrusive demolition, and maintained vapour control continuity—a critical aspect of compliant warm-roof construction.
The liquid-applied specification ensured that even the most complex details were seamlessly encapsulated, providing robust long-term protection across previously high-risk junctions and interfaces. RapidCure technology enabled a dependable installation programme despite severe weather constraints and allowed the project to progress efficiently alongside other roof-level trades, including the installation of new solar panels. With the completed system supported by a 25-year Polyroof guarantee, the refurbishment now delivers a resilient, sustainable, and visually coherent roofing solution that enhances both the performance and aesthetic presence of this prominent coastal property.
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