In the heart of London’s historic St James’s, a major redevelopment is quietly rewriting the rules of commercial construction. Fifty Five Pall Mall—formerly Commonwealth House—is one of the most sophisticated mass timber projects to date. It comprises of a mixed-use office-led retail and commercial space built around a retained façade, blending heritage with high-performance sustainability realised by our trusted partners, Hybrid Structures.

Heritage meets high spec

Behind the carefully preserved façade, (which involved meticulous dismantling, cleaning, and reinstallation of façade sections) and the new structure rises and is set to open late 2025.

Ultra practical wood products

Delivering materials to a congested Westminster site is no small feat. Consideration was taken to renovate the existing building however all of the buildings suffered from disjointed floorplates, with differing floor levels, low ceiling heights and plentiful columns, together providing poor quality accommodation.

Enter Stora Enso’s Sylva CLT Floors—a precision-engineered solution that made light work of a logistically complex build. With narrow passageways of 1-4 Crown Passage and limited street parking access, and a conservation area to respect, the lightweight, prefabricated CLT Floors were craned into place with minimal disruption and maximum efficiency.

The packages of Sylva™ CLT Floors were delivered with a just-in-time delivery service of four stages over from 30.07.2024 to 01.11.2024 so there was no need for long-term on-site storage.

This project also leveraged Stora Enso's Sylva Services and preapplied temporary membranes in the mill and preinstalled lifting devices so when the elements arrive on-site, they are ready to install immediately.

Façade intact, future packed

The encapsulated Sylva CLT elements deliver more than just sustainability—it provides long-term durability and design flexibility. With terraces on the upper floors constructed using traditional joists and plywood, the building is tailored for modern occupiers seeking adaptable, future-proof workspaces.

Low carbon footprint

With upfront embodied carbon expected to stay below 550kg CO₂e/m², (meeting the LETI/GLA 2030 target of 600 CO₂e/m²), Fifty Five Pall Mall is a benchmark for low-impact urban development. Stora Enso’s contribution helped the project embrace circular economy principles while delivering a building that’s as elegant as it is efficient. (Source),

The Sylva CLT Floors only generated 34 tonnes of greenhouse gases (CO₂e) to manufacture and 42 tonnes of CO₂e to transport.

Compared to the 499 tonnes of carbon dioxide that the trees removed while growing and will store in Fifty Five Mall, this amount is a small fraction. Choosing Sylva CLT elements instead of non-renewables avoided 749 tonnes of greenhouse gases. 

Source: Stora Enso Carbon Calculator (using third-party verified environmental product declarations). 

A low level of operating energy is also targeted, along with:

-BREEAM Outstanding

-EPC A

-WiredScore Platinum ratings

-ESG credentials throughout

(Source).

Wood Origins

The Sylva™ elements were made with wood sourced from PEFC-certified forests ensuring that the timber used comes from sustainably managed forests. PEFC and FSC are two of the most trusted and widely recognised certifications for sustainable forest management.