Replacing 160 windows in a school that never closes

Managing a live building, a listed building, and a tight budget all at once

Local authorities across the country are sitting on ageing public buildings that cost too much to heat, don’t meet modern energy standards, and need substantial investment to bring up to scratch. The challenge is rarely whether the work needs doing. It’s how to get it done when the building can’t close, the budget is fixed, and the procurement has to stand up to scrutiny.

Colville Primary School in Notting Hill is a good example of what that looks like in practice. Built in 1879, it’s a late-Victorian building with large sash windows that were designed to flood classrooms with natural light in an era before electric lighting. By the time the Royal Borough of Kensington and Chelsea came to address them, those windows had degraded badly. Heat was escaping through 160 failing window units and external doors, pushing up energy bills and making classrooms uncomfortable for children and staff through both winter and summer.

The school serves 480 pupils. It uses its limited outdoor space for staggered breaks and lunchtimes, runs clubs through the holidays, and is occupied almost every day of the year. There was no convenient empty period to hand the building over to a contractor. On top of that, the school is Grade II listed, which meant any replacement windows had to respect the building’s historic character while delivering modern thermal performance, all within the requirements of listed building consent and the local conservation area.

RBKC needed to find an experienced contractor, get them appointed through a compliant procurement route, and deliver a 35-week programme of works around a school full of children, within a budget of £1.64 million.

Getting to the right contractor without losing months to procurement

For a local authority managing public money, the procurement route matters as much as the contractor you end up with. Every decision needs to be defensible, auditable, and compliant. But running a full bespoke tender for a programme like this would have added months to the timeline, consumed procurement resources the council couldn’t spare, and pushed the start date well past the summer window that was critical for getting the most disruptive early works done before term began.

Instead, RBKC used an established planned works framework that gave them direct access to contractors already vetted for this type of building fabric work. McConnell Group was appointed through this route, with the compliance and governance built into the procurement from the outset. Because the framework suppliers had already been assessed for capability, financial standing and delivery track record, the council could move quickly without cutting corners on the due diligence that a project in a live school environment demands.

That’s one of the practical benefits of framework procurement that’s easy to overlook. It doesn’t just save time on the tender process. It gives the client confidence that the supplier they’re appointing has already been through a level of scrutiny that a standalone procurement would have had to build from scratch.

Phasing the works around 480 children

The programme ran from August 2025 to April 2026. Starting during the summer holidays gave McConnell a window to mobilise, set up site logistics and complete the most disruptive works while the building was quieter. Once pupils returned for the autumn term, the work continued carefully through the school year, with specific zones closed off and reopened in sequence as each phase completed.

Making this work required genuine collaboration between RBKC, the school and the contractor. McConnell held regular coordination meetings with school leadership to plan around lessons, assemblies, PE sessions and the staggered use of outdoor space. The phasing adapted as the school’s needs changed, and children’s safety was the non-negotiable that everything else worked around.

Partway through the programme, the team discovered failing brickwork that hadn’t been part of the original scope. Rather than flagging it for a separate project later, they carried out the repairs while the scaffolding was already in place. That kind of responsive, practical decision-making avoided the cost of a separate mobilisation, protected the original programme timeline, and dealt with deterioration before it became a more expensive problem. It’s a straightforward example of what active contract management delivers in practice: the confidence to make sensible decisions on site because the relationship between client and contractor supports it.

The project finished on time and within its £1.64 million budget.

Social value designed around the people living with the building works

Social value commitments in public sector contracts can sometimes sit in a tender document and never really connect with the community the contract is supposed to benefit. This project took a different approach, designing the social value delivery around the school community that was living alongside the building works every day.

McConnell’s team ran a construction safety assembly to help children understand the risks of a live building site, including a spot-the-hazard competition and a demonstration of site safety clothing. Rather than a dry health and safety briefing, it was designed to get children actively engaged with what was happening to their school. Pupils designed their own safety posters, and the winning designs were printed as signage and displayed on the site hoarding around the building, giving children a visible stake in the project.

Two classes took part in McConnell’s Raising Aspirations programme, where children formed their own mock construction companies and took on roles including architect, quantity surveyor, buyer, safety manager and site manager. For primary school children in central London, that kind of hands-on exposure to construction careers and the breadth of roles involved in a building project has a value that goes well beyond the contract period.

The contractor also turned used hard hats into planted hanging baskets donated to the school, and supplied and fitted new kitchen units for the school’s daycare facility, contributing nearly £2,000 in labour and materials. These weren’t merely grand gestures but practical contributions to a school community that had been patient through months of scaffolding and noise, and they left something tangible behind.

What the project tells us about procuring complex works in live public buildings

More than 160 new double-glazed sash windows and external doors, alongside façade repairs and drainage works, improving the building’s thermal performance, reducing running costs and helping the school’s existing low-carbon heating system work more efficiently. A programme delivered on time and on budget. And a school community that was genuinely part of the project rather than inconvenienced by it.

For local authorities and public sector organisations managing similar challenges across their estate, whether that’s schools, healthcare facilities, civic buildings or other operational properties, this project illustrates a few things worth holding onto. A compliant framework route can get you to a capable contractor quickly without sacrificing governance. Early planning around building users, done properly with regular dialogue rather than a one-off logistics meeting, is what makes delivery in a live environment work. And social value that’s designed around the community experiencing the works, rather than reported as a percentage in a contract review, creates outcomes people can actually see and feel.