21 Dartmouth Street

21 Dartmouth Street

21 Dartmouth Street was built c.1915. We worked with Ben Adams Architects to refurbish its nine storeys of office space, reception, central courtyard and showers, and to add dedicated cycle storage at lower ground and a communal roof terrace. 

We were appointed to provide M&E and acoustic design to bring the space up to modern commercial standards and a Category A office finish. During the construction we assisted the contractor to complete the design and monitored progress on site on behalf of the client.

The site is surrounded by conservation areas with Victorian and Georgian buildings and 21 Dartmouth Street itself is recognised as an ‘unlisted building of merit’ by Historic England. Prior to the refurbishment the building was a functioning office but was full of dark corners, stuffy rooms and twisting corridors, with services that had seen far better days. The existing structure of the building steps inward at each level to provide external terraces.

A key focus of the project was achieving simplicity in the design and to provide a minimal, hard-working system that would meet the requirements of any future occupants. We worked within the constraints of the existing building, coordinating the new services in order to provide the maximum useable space within the unusually shaped building and ensure a high quality environment throughout. This involved engaging closely with building measured surveys and making visits to site to fully understand the challenges and opportunities presented by the building geometry and existing services. As part of this work the two existing lifts were refurbished and a new lift was added to provide ease of travel throughout the building.

All spaces within the building are mechanically ventilated by central Air Handling Units, with heating and cooling delivered by fan coil units served by central VRF condensers. The ventilation is controlled by Variable Air Volume dampers to maintain the air quality at each level. Lighting is controlled by presence detection with daylight dimming and the controls are fully adaptable for adoption by the tenant.

Exposed services are neatly detailed to coordinate with the architecture and allow the space to achieve a higher ceiling height and feeling of spaciousness. Our acoustics team ensured the noise from the exposed equipment would be kept to appropriate levels to create a quiet environment suitable for work.

The entire building was leased to the House of Commons within a month of it achieving Practical Completion in January 2019.


Ben Adams Architects






Quadrum Global

Nicholas Worley Info
21 Dartmouth Street comprises nine storeys of office space, a reception, central courtyard, showers and cycle storage at lower ground, and a communal roof terrace.
Nicholas Worley Info
The reception is spacious and contains breakout spaces and a coffee point. The access control system means staff can securely enter the building out-of-hours.
Nicholas Worley Info
The exposed services on the office floors were carefully detailed and coordinated with Ben Adams Architects, resulting in sleek, minimal aesthetics.
Nicholas Worley Info
The lights have daylight dimming sensors, meaning that they only operate when there is not enough daylight. The ventilation is demand-controlled to each zone of the building and ramps up and down in order to maintain the air quality.
Nicholas Worley Info
The building is heated and cooled by Air Source Heat Pumps located within a roof plant enclosure. The enclosure is ventilated via acoustic louvres to allow the heat pumps to run quietly and effectively.