Portland House (Thirty High) Refurbishment

The refurbishment and extension of Portland House, renamed as Thirty High, aimed to revitalise the iconic London building into a sustainable, office-led destination.

Thirty High is a large 29-story office building in Victoria, London, built in 1962. Being 60 years old with increasingly inefficient systems, a severely weathered façade, Landsec were looking to refurbish and extend the building. BuroHappold were appointed a sustainability and embodied carbon leads for the development. Jon led the embodied carbon workflows.

The works, which are under construction, combine a façade treatment to revitalise the characteristic pre-cast concrete façade, the replacement of 1,800 windows with high-performance double glazing to improve thermal performance, the creation of a two-storey ground floor extension, internal refurbishment of the office floorplates, and the creation of a restaurant bar within the reconstructed crown level.

As a refurbishment, there is limited industry knowledge regarding appropriate embodied carbon targets for this scope of development. As such Jon led a team to develop a set of bespoke embodied carbon targets for the building. He did this by assessment multiple industry sources and well as historic Landsec and BuroHappold development’s Whole Life Carbon (WLC) findings. Targets were set and further developed with respective design disciples.

Jon worked to undertake WLC assessments at each RIBA stage. Communicating embodied carbon outcomes, working with design teams to limited embodied carbon in their design and provide practical options to further meet targets.

By retaining major elements of the original structure, including the concrete façade, Thirty High achieves a significant 60% reduction in embodied carbon compared to a standard new build. With a targeted embodied carbon level under 400 kgCO2/m2 at Stage 4—meeting LETI B standards for modules A1-A5—the scheme balances the retention of existing material with the requirements of Grade A office occupiers. The scheme is anticipated to achieve a 20% reduction in regulated energy use compared to existing in addition to achieving a NABERS 5.0-star rating.