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Derwent London

SkA rating Assessment & Consulting

Project Specs


23,000 Sq Ft












Architects: Piercy & Company

MEP/BREEAM Assessor: Hilson Moran

Contractor: Knight Harwood

Lighting design: Pritchard Themis

Thermal modeling: Inkling LLP

Pre-refurbishment survey: Sustainable

Construction Solutions Ltd

Furniture supplier: SCP

Furniture recycling contractor: Premier Sustain


We were invited to advise on and assess Derwent London’s HQ project under the SKA rating for Offices v1.2 environmental assessment scheme. The refurbishment was to reflect a ‘Derwent designed space’ and perform on a day-to-day basis as a contemporary workplace, reflecting the company’s culture. The high quality, design oriented interior was also to reflect the high-end specifications expected in London’s West End.

This formed one of the biggest challenges for this project from an environmental perspective, as it meant working with non-mainstream teams, suppliers, crafts and materials.

From the outset, Derwent London set the requirement to achieve a Gold SKA rating.


This project was in the early days of the design process, when we came on board in September 2015, which immediately set the project on the right footing. We worked fluidly and intently with the client team, architect, specialist consultants and engineers, providing SKA and wider sustainability guidance in individual meetings or workshops, offering solutions on sustainable design thinking, products and material options, recommending further specialists to deliver specialised solutions.

Workshops were arranged to help the teams understand the project assessment and offer an early open platform for discussion around which measures should be set as targets, which progressively became reviews for detailed specifications. During the early stages, we guided strategic conversations on where the overall targets and achievements should be set and why, nudging the targets and client requirements to the most sustainable approach possible, within the capability of the team and the longer than average life-cycle expectation for the space.

The BREEAM assessment undertaken on the main building meant that in some cases issues were linked and affected. We had an early coordination exercise between the BREEAM and SKA assessments, reviewing targets and criteria for each, to ensure there were no conflicts and that efforts made by the project team benefited the targets and outcomes of both assessments where there were overlaps.

We initially identified 90 measures in the project’s scope, out of which 80 were targeted. We continuously monitored and managed the scope as the design evolved and changed through many design iterations, aiming for the perfect design aesthetic that is so core to Derwent London’s brand. Derwent London was committed to the sustainable target and ensured we were able to provide on-going advice to the supply chain which extended from direct suppliers for furniture all the way to finishes sub-contractors and fit-out product suppliers.

While on-site, a fast and informed response was critical to ensure targets were not lost in the transition to detailed specifications or when issues arose during installation. To support the delivery stage, we were separately appointed by the main contractor, Knight Harwood, to support their team and introduce a number of SKA compliant processes. Our role ensured they aligned all internal delivery processes to remove risk, change certain activities on site setup and procurement to meet with both SKA and BREEAM requirements.

The Soft Landings framework was followed throughout the process with the required mix of occupant involvement, facilities and building management consultations, numerous staff testing and briefing sessions, and commissioning; all this ensured a smooth and well integrated design process flowed throughout and into occupation.

Our involvement on the project ensured the high-end design quality required by Derwent London achieved a Gold SKA rating.


Economic Value

Efficient energy HVAC system design, refined through energy and thermal modelling of in-use scenarios with building manager. Monitoring systems installed throughout the building and demise floors, providing per floor and per use consumptions, enabling insights on technological and behaviour adjustments through on-going use. Effective investment thinking with longer than normal life-cycle ROI in the selection and specification of materials and their design detailing.


The contractor achieved very high site management and wellbeing levels, including introducing visits by a health consultant and having mindfulness exercises available in the site canteen. Air quality monitoring was innovatively undertaken during delivery, with wearable sensors planned around specific works and worker areas for maximum insights. Strong focus on contractor and sub-contractor to have training/ apprentice programs and work towards diversity for all skills on site. Up-skilled supply chain and numerous sub-contractors through on-site support and workshops. Staff and visitor facilities were designed to support comfort, productivity and an active life-style around the workplace. Occupant wellbeing was also considered through a number of design and system details that will support air quality and circadian rhythms. A Soft Landings framework was followed with very high occupant, building management and supplier engagement. Good quality existing furniture was donated to local charities.


100% of waste was diverted from landfill. 95% of waste was re-used or recycled. A pre-refurbishment survey was undertaken to identify potential reusable materials during early design stages. Strong focus was given on reduction of waste through packaging methods. High furniture re-use was achieved and new items were procured according to the SKA rating criteria. Long life-cycle materials and design for disassembly at the end of life were major considerations during the design process. The project targeted and achieved a Gold rating with 78% of measures in scope achieved. All furniture was SKA compliant with a high proportion of them re-used and refurbished. High use of natural recyclable and re-usable materials were included in the new material specifications.


“Elina and her team joined us for a challenging Derwent London project: refurbishing our HQ at 25 Savile Row. They swiftly aligned with our design and sustainability focus, facilitating our ambitious SKA Gold and BREEAM Excellent goals. Their proactive approach and support for the design team and contractor have been extremely valuable, making them a trusted choice for future projects.”

John Davies Head of Sustainability DERWENT LONDON
John Davies Head of Sustainability DERWENT LONDON