Google KGX1 - Radmat Building Products Ltd

We undertook the full and complex roofing works, encompassing advanced waterproofing and insulation systems, to meet the project’s rigorous sustainability goals and architectural vision fitting for the world stage.

The standout feature of the building is the expansive roof, which spans approximately 300 meters, providing employees with an integrated outdoor space for relaxation, exercise, and work. The roof environment is not just a recreational area but plays a significant role in enhancing biodiversity, improving air quality, reducing the urban heat island effect, and managing stormwater runoff. It integrates seamlessly with the building’s indoor spaces, enhancing both the thermal performance of the building and its environmental footprint. This innovative design integrates cascading green terraces with outdoor pathways, blending natural elements with the architectural aesthetics of the workspace.

We were carefully selected to partner for this iconic project to provide the Radmat Permaquick bituminous hot melt system which served as the primary waterproofing featuring a seamless, monolithic fully bonded membrane, ensuring superior waterproofing performance. It was selected for its durability back by its 40-year guarantee and BBA Certification for the building’s design life. Throughout the roofing phase of KGX1, our operatives, the project manager, and the on-site contract management team maintained the quality of the hot melt roof installation by dovetailing our own process with Radmat’s product installation requirements vetting procedures in partnership with our extensive 70+ year experience in delivering roofing systems of this nature.

Alongside the PermaQuik waterproofing, Radmat’s ProTherm G XPS X 300 SL insulation was used to provide effective thermal performance, achieving a U-value of 0.25 W/m²K. The combination of these systems ensured that the rooftop garden, pathways, and various surfaces could endure foot traffic, weather exposure, and the weight of the planted gardens. The inherent risks attached to potential leaks to the spaces below meant that a business with demonstrable experience, expertise, quality control process and longevity was the obvious choice in this demanding market throughout the recent world changing events.

The roofing system included the installation of the Radmat PermaQuik PQ6100 hot melt waterproofing system, applied across various roof zones, including the main roof, BMU (Building Maintenance Unit) zone, and plenum areas. The main roof required 130mm of Radmat ProTherm G Ultra XPS insulation to ensure optimal thermal performance. Special waterproofing solutions were also applied to the North Sheds’ plant areas, which require weather resistance and durability due to their operational nature. MedO D40 Reservoir/Drainage Boards were installed for efficient water drainage, while the Geotextile Filter Fleece and Texsa Protection Sheet provided additional safeguards against water infiltration.

The bespoke BMU encapsulation grille posed intricate design challenges and demanded meticulous execution. The successful delivery underscored our commitment to innovative solutions and showcased our expertise in managing complex high-rise construction projects.

The BMU zone, which requires robust and durable systems due to its frequent maintenance use, also featured hot melt waterproofing, applied on sloped areas and staircases to ensure proper drainage. The BMU zone was further insulated with 160mm of insulation and covered with ballast and paving finishes. The green roof was integrated into this zone, adding to the building’s sustainability features while supporting the thermal and drainage systems.

In addition to the main roofing package. We also carried out expansive and operationally challenging roofing works that are cleverly hidden from sight but play a major part of the plant systems used to heat and cool the building within the confined plenum areas.

The plenum areas, crucial for the building’s ventilation and infrastructure, required a different approach due to their confined space and bespoke design requirements. These spaces included 150mm of FoamGlas T4+ insulation boards, applied with a three-layer built-up felt waterproofing system. The system was combined with EshaFlex 370 Reinforced Bitumen Firesafe Membranes and the ReadySeal Cold Liquid Applied Waterproofing Membrane was used to seal the huge steel-work interfaces and pipework joints.

The floors of the plenum were bonded to a Vapor Control Layer using PC58 adhesive. Pitched Precast concrete panels, 250mm thick (by others), were used for the plenum walls, where the three-layer felt system and finished with EshaFlex 370 FireSafe SBS Modified Bitumen to ensure fire safety was applied..
The importance of the roofing systems within these environments is not to be understated as these plenums are open to the elements are pose significant risk to the building should failure occur. Our technical expertise ensured that a robust solution was sought in the best interest of the overall project.
Additionally, structural framing systems (SFS) were used to support the plenum walls, while Trimo composite cladding panels were installed on both dividing and external walls to meet stringent fire safety standards whilst supporting the air flow requirements in providing the separation between the split plenum design. These were further complicated by the ductwork which was routed through the plenums as part of the build-up process, with particular attention to integration with the insulation, waterproofing, and cladding systems. These areas had every type of complication within a small space you could imagine, on top of the requirement for a world class quality finish, these area’s are the unsung hero’s as is often the case where functionality and performance when work hand in hand are supposed to go unnoticed and understated.

Throughout the installation process, the team encountered several challenges, particularly in relation to the confined space in the plenums. The bespoke nature of the cladding panels, custom measurements, and varying horizontal and vertical angles added complexity to the task. Precision was key, with each plenum requiring bespoke installation solutions to ensure proper functionality.The collaborative approach between ourselves, the professional team and the supply chain played a critical role in maintaining quality and ensuring that all systems worked together seamlessly.

Radmat’s Site Quality Technicians, fully trained and approved to work at height, visited the site regularly to inspect the works and provide a non-biased independent report. Working closely with Radmat over our extensive relationship allows for direct relationships and a desire to improve and fine tune the art of hot melt waterproofing. Radmat also interrogate the site set up, location of hot melt boilers and work hand in hand with our team to unlock and promote ideas for each project challenge. In this case, reviewing and commenting on lifting arrangements, positing of equipment, transport of hot melt material and quality control is fundamental in ensuring that the workmanship, warranties and guarantees are provided.

Quality assurance and legacy control was a priority due to the challenges in revisiting the work faces.
Our directly employed operatives who are specialist’s in the art of installing bituminous hot melt roofing was the clear route to providing consistency in the workforce and was crucial for maintaining quality, with the same operatives engaged throughout the build. All team members are suitably trained, holding a minimum of NVQ4 accreditation and mandatory health and safety certifications, including manual handling, fire warden, first aid at work, and working at height. The quality of installation was also monitored and maintained by adherence to robust, in-house quality procedures and regular visits to the site.

From the very start of the project, the philosophy of high quality, right first time and awareness of the challenges surrounding the scale of the building provided a central core focus throughout the design and delivery aspect of the project. We used these principals to drive the strategies needed to overcome the operational complexities along with upholding the highest standards of workmanship to ensure that the legacy of the building is maintained.

Our dedication to addressing challenges through innovative solutions, exemplified by this unique approach and played a significant role in the project’s success. Our collaborative partnership with Lendlease further strengthened our project management approach, placing a strong emphasis on effective communication and understanding challenges from a broader, project-level perspective. This informed our approach and allowed us to proactively address these challenges from an early stage.
In addition, we implemented on-need delivery practices, minimising storage requirements, mitigating issues, and maximising flexibility.
The revamped RAMS template in a pictorial format, catered to diverse linguistic backgrounds, facilitating better understanding and adherence to safety guidelines. Regular safety briefings, master communication schedules, and controls for residual health and safety risks, including occupational health surveillance, respiratory protective equipment, and HAVS monitoring, demonstrated our unwavering commitment to maintaining a safe working environment.

A cohesive project team, spanning design, commercial, senior management and site operatives played a pivotal role in ensuring seamless operations and delivery. Regular briefings and weekly directors’ meetings were instrumental in monitoring progress, addressing challenges promptly, and maintaining a proactive problem solving approach.
Flexibility in delivery schedules became crucial due to challenges arising from the crane’s regular wind-offs, necessitating reliance on on-site hoists and lifts. This adaptability ensured that project timelines were met despite logistical complexities.

Consistency in the workforce was crucial for maintaining quality, with the same operatives engaged throughout the build. All team members were CSCS trained, holding a minimum of NVQ4 accreditation and mandatory health and safety certifications, including manual handling, fire warden, first aid at work, and working at height. This consistent team undertook the weekly site inspections, being trained to work at height and install the full range of Radmat roofing systems. The Radmat Site Quality Technician completed inspection reports at each visit, utilising an iPad and a bespoke app to highlight works of excellence and address any issues. This record was consistently shared with the site team.

The logistical challenges were another significant hurdle. Given the project’s central urban location and adjacent rail networks, traffic management, delivery coordination, and contractor coordination were vital to maintaining the project requirements for such an iconic project where all eyes and scrutiny is at the highest level.. Special care was required to manage the site’s central locality to heavy foot traffic outside King Cross, with crane wind-offs being a regular occurrence, requiring adaptive techniques, co-ordination and a positive attitude to overcome the obstacles throughout the build.

Lastly, the project initially started prior to Covid and has had to endure and succeed regardless of the world economic challenges that have affected the construction industry. The complex design of the building has the highest level of scrutiny in every aspect of the design and delivery which has undergone a challenging design development process for a project of this scale and aspiration.
These challenges impacted every part of the project, affecting the availability and price of materials, labour, plant and equipment as well as cash flow, team fatigue and passion.

Despite these challenges, the project demonstrated operational excellence, showcasing our ability to handle complex, bespoke installations in confined and challenging spaces, the complex and adaptive roof environments as well as the integration of all the plant and equipment needed to maintain and manage the building use.
The project not only met the sustainability goals set out by the client but also demonstrated innovative solutions to overcoming the technical challenges presented by the unique building design. The team’s commitment to quality, sustainability, and operational excellence was crucial in delivering this world class iconic project of which we are extremely proud to have been selected as the trusted subcontractor of choice.