No.3 Circle Square

The Project

The final piece of the Circle Square masterplan, No.3 Circle Square was announced the winner of Building of the Year 2025 by the Greater Manchester Chamber of Commerce in March 2026. Located on the city’s bustling Oxford Road Corridor and at the heart of Manchester’s vibrant innovation district, the new 15-storey building boasts 267,000 sq,ft of top-class office spaces, with ground floor retail and leisure areas, as well as a communal lounge, event space and a roof terrace. 

 In addition to offering premium open-plan offices designed to attract modern tech-led businesses, the scheme is aiming to be a prime example of sustainable development for the city, not just environmentally, but also socially, culturally, economically and visually. It is expected to achieve net zero embodied carbon during construction, BREEAM Excellent status, a NABERS 5 Star rating and an EPC A rating once operational. 

Design and specification 

Paying tribute to Manchester’s Victorian and Edwardian architecture, the building features a red brick, punched-opening external wall system which sits on large, vaulted bases to reference the local railway arches. 

To fulfil the passive fire protection requirements for the building envelope, brickwork contractors, Kinlan, chose to use EW Cavity Barrier and EW Firestop. To prevent water ingress through the inner leaf of the cavity wall, CT Cavity Tray was the moisture drainage product of choice following successful installations on other projects— such as Anchorage Gateway in Salford and Old Boddingtons Brewery site in Manchester's city centre.

Installation 

The large footprint project had to be delivered within a tight build schedule. Here, the one-piece design and the non-compression fit of the Siderise solutions helped to realise real time savings. 

EW Cavity Barrier and Firestop feature our engineered stone wool Lamella core which allows it to be friction fitted in the cavity without exerting excessive pressure on the external brick leaf with wet mortar, that could otherwise lead to distorted brickwork or a compromised wall structure. 

Additionally, EW Cavity Barrier has been tested with masonry support brackets fully penetrating the exposed face in multiple configurations. This enabled simpler detailing and slab edge design, helping to save costs by negating the need for concrete up stands/down stands, and bespoke masonry support systems as the fire barrier could be fixed around brackets. 

Meanwhile, CT Cavity Tray has been factory-engineered to streamline installation as compared to alternative labour and resource intensive site-fabricated solutions. Combining a flexible aluminium angled tray with an integral non-combustible stone wool insulation core, the Kinlan team was able to install this ready-to-fit lightweight cavity bridge component quickly and easily using a standard cutting knife with sealing tape for joining at details such as corners or windows.  

Milen Milchov, Project Manager, Kinlan Ltd explained: 

“Siderise's exceptional service and unwavering commitment to quality have been instrumental in delivering a project of this scale and complexity. Their innovative solutions and technical expertise have not only streamlined the construction process but also ensured compliance with the highest standards of safety, sustainability, and performance. 

 We have used their fire barriers and cavity trays, which are not only easy to install but can also be cut onsite to suit different cavities and situations, offering incredible flexibility. Their technical team has been outstanding, promptly resolving every technical query and challenge, and their reliable, on-time deliveries have made them a trusted partner throughout the project. ”