Jones Weatherproofing was appointed by main contractor Mace to deliver specialist weatherproofing to complex building penetrations at Panorama St Paul’s. The works included sealing around cable trays, steel beams and structural columns across multiple levels of the development, ensuring long-term protection against water ingress, while also supporting the thermal performance and overall aesthetic design intent of the building.
Panorama St Paul’s is an ambitious project, and one of the largest redevelopments ever to achieve planning in the City of London. The transformation of the former BT headquarters at 81 Newgate Street is valued at around £700m and is set to become HSBC’s new UK base in 2026. The 592,000 sq ft building will is a mixed-use development and will feature premium office space, landscaped terraces, wellness amenities, a retail arcade at street level and a rooftop terrace with a restaurant and public wildflower meadow.
Weatherproofing complex building penetrations in a cut-and-carve project
The redevelopment of Panorama St Paul’s involved retaining around 60% of the original structure, with about 40% being demolished. Four new cores have been added, along with three to four new storeys, depending on the elevation of the building.
For Mace, this meant managing numerous service penetrations through the building envelope and plant spaces. While fire stopping was being carried out on cable trays, the team realised there was still a risk of water ingress — so Jones Weatherproofing was brought in to provide our weatherproofing expertise.
Assistant site manager at Mace, Ali Karakoc, explains: “They’ve solved many problems… we were able to weatherproof around the cable trays, resulting in no water ingress going inside the building or the plant.”
Ali also emphasised the importance of planning for weatherproofing from the outset of a project: “When considering building service penetrations, one thing that often gets forgotten is the weathering around the penetration itself. In my view, that should be incorporated as early as possible during the design stage.”
With early consultation, Jones Weatherproofing can advise on the correct sequencing of installations, so components don’t need to be removed and re-fitted just to allow weatherproofing to take place. We can also flag potential problem areas before they arise, reducing disruption and cost later on.
“We brought in Jones Weatherproofing a bit later on in the project, meaning that we had to review our current site conditions, and we had to remove some cables and some cable trays to allow it to be weathered,” Ali explains.
His comments highlight a key lesson from Panorama St Paul’s: early consultation with a specialist like Jones Weatherproofing saves time, avoids costly rework and ensures penetrations are designed with robust weatherproofing in mind throughout every stage of a project – not just at the end.
Specialist building penetration weatherproofing from Jones Weatherproofing
Jones Weatherproofing deployed its specialist team across multiple areas of the building, working over a two-month period to weatherproof a wide variety of building penetrations. Works included:
- Basement – weatherproofing wall penetrations for cable trays.
- Upper floors – weatherproofing around ducts, steelwork and complex cable trays at levels 12 and 13.
- Roof – Bespoke waterproofing of exposed cable trays and building penetrations.
- External plant areas – Weatherproofing around HVAC equipment and other external plant to protect the equipment and the building structure.
By applying our specialist weatherproofing system for building penetrations, Jones Weatherproofing reduced the risk of water ingress and wind damage, helping to protect the building’s structural integrity, thermal performance and appearance.
Discreet building penetration weatherproofing with aesthetics in mind
Jones Weatherproofing ensured a watertight seal around each penetration, while also preserving the project’s aesthetics. This included using colour-matching technology to seamlessly blend the weatherproofing with the insulated panel system (INS) facade.
Commercial director Matthew Jones commented: “The core function of our product is the weatherproofing, and it stops water from entering the building. But when you work on projects as prestigious as Panorama St Paul’s, I think that’s where we really come into our own. It’s crucial to make sure that our weathering blends in and doesn’t distract from any finishes to the building.”
“Working with Jones Weatherproofing has been great over the last two months,” Ali added. “The Mace team are very pleased with the quality of their work and the professionalism they’ve shown throughout the project. One thing I’ve really appreciated is their ability to colour-match the weatherproofing to the INS panels. So you actually cannot tell where it has been weathered and cannot tell the difference.”
Weatherproofing expertise from Jones Weatherproofing
From early design to final detailing, building penetrations must be considered as critical elements of the building envelope. Panorama St Paul’s demonstrates how specialist skills and knowledge can help to overcome challenges and ensure a bespoke solution that meets the many requirements of complex, large-scale refurbishments.
Jones Weatherproofing has extensive experience working on high-profile projects, including 40 Leadenhall Street, also located in the City of London, and AstraZeneca’s headquarters in Cambridge. Our team is committed to delivering the highest level of service, providing weatherproofing solutions that protect building performance without compromising the design intent of these landmark structures.
Whether your project is in the commercial, healthcare, education or residential sector, Jones Weatherproofing can help to ensure that all building penetrations are sealed, and the building envelope is protected. To discuss how we can support your next project, please get in touch using the form on the right.
