Commercial office retrofit in practice: lessons from No.1 Poultry

Commercial office retrofit in practice: lessons from No.1 Poultry

The launch of UKGBC’s Innovation in Commercial Retrofit: A Live Project Demonstrator comes at a critical moment for the office sector.

The challenge is no longer identifying solutions. It’s delivering them, within live projects, under real constraints, at the scale required to meet both regulatory pressure and market demand.

Using No.1 Poultry as a live test case, the demonstrator moves the conversation forward. It shows what happens when innovation is treated as part of the core delivery model, not something added late in the process.

From ambition to delivery

Commercial office retrofit is under growing pressure from multiple directions:

• tenant expectations for higher-performing space
• regulatory requirements, including MEES
• rising operational costs
• and the need to address both operational and embodied carbon

UKGBC highlights that energy use in commercial buildings alone accounts for nearly a quarter of the built environment’s carbon footprint. 

Despite this, many retrofit projects still follow delivery models designed around new build - where solutions are introduced late and innovation is constrained by decisions already made.

The No.1 Poultry project demonstrates a different approach: starting with innovation early, and structuring the project around it.

Embedding innovation earlier 

A key shift in the demonstrator is timing.

Applying the UKGBC’s Innovation Map from RIBA Stage 0–1 enabled solutions at No.1 Poultry to be evaluated before key project decisions were fixed.

In practice, this enabled:

• early engagement with solution providers
• assessment of technical and commercial viability
• clearer ownership of decisions across the project team

This is consistent with a broader shift we are seeing across the retrofit of offices: the most effective projects are those that front-load decision-making, not defer it.

Designing as a system, not a set of components

Another defining feature of the project is how decisions were made.

The Innovation Map structures interventions across building systems - including energy, materials and building fabric - enabling teams to consider not just individual products, but how they work together. 

At No.1 Poultry, this translated into:

• aligning fabric upgrades with energy strategy
• linking airtightness improvements with system sizing
• considering material selection alongside circularity objectives

This reflects a key principle for office retrofit: performance is delivered through integration, not specification alone.

Façade and glazing: early decisions, wider impact

Within this system-led approach, façade and glazing decisions played a critical role - not in isolation, but as part of a wider building fabric strategy.

On this project, these decisions were shaped by:

• the constraints of a Grade II* listed building
• the need to improve thermal performance
• and the requirement to integrate new solutions with existing systems

Because of these factors, glazing could not be left to later stages. Early engagement allowed the team to test what was technically and commercially viable within the project constraints. 

The outcome was a combination of glass solutions, including:

• vacuum-insulated glazing for targeted applications
• lower-carbon glass solutions, such as ORAÉ®, where different performance and scale requirements applied
• and circular approaches to recovering and remanufacturing glass

Together, these decisions show how façade strategy sits within a broader set of interventions - influencing energy performance, embodied carbon and long-term building use. As a result, solutions were not just identified, but integrated into the design, supported by earlier engagement and clearer ownership across the project team.