Between December 2020 and June 2023, HDR had the privilege of delivering a full design fit-out for the 181-bedroom five-star 1 Hotel Mayfair, the internationally renowned eco-conscious brand's first location within the U.K. This exciting development was part of a larger refurbishment of a mixed-use scheme originally built in the 1970s, located in London's world-famous Mayfair district, home to nearly 700 listed properties.

Our holistic building engineering services strategy for 1 Hotel Mayfair included the following: mechanical, electrical and public health; plumbing and hydraulics; fire and life safety; back-of-house lighting; control systems, including building management system and sustainability.

The most complex challenge of this refurbishment project was the creation of an industry–leading five-star guest experience whilst retaining the 50–year-old existing structure; further exacerbated by the fact that the previous tenant of the space was a three-star hotel.

HDR collaborated with an external point cloud survey company that scanned the entire building to create an accurate Revit 3D model to inform the service design. In some sections we utilized both 3D and 2D to have absolute confidence that holes were cut in the right locations. We stacked services to accommodate the fact that substantial volume of the original structure’s cement could not be altered. In the words of HDR's Jim Mulvihill, the project manager for 1 Hotel, “Coordination was the most challenging aspect of this project, due to the many services that feed into a hotel guest room.’’

The hotel was extended from seven to eight stories. Utilizing the Revit model, we located a natural transfer zone within the existing structure at level seven. We used that void, together with existing holes, to access the rooms on the newly built level.

Overcoming Challenges

Prior to the commencement of the larger works, HDR delivered two fully working on-site mock-ups for King Penthouse and Standard rooms, including fan coil units, sprinklers and diffusers. This was carried out in order to evidence the resiliency of the proposed engineering design as well as to test different finishing options. One of the two mock-ups, the King Penthouse, was not dismantled and eventually became an actual bookable room.

Another issue that exacerbates the challenges of an effective hotel refurbishment is room layout. Retaining the existing structure resulted in 22 different room sizes, far more than modern five-star hospitality requirements; typically, a new build hotel would only have two or three room layouts. To fulfil the brief, HDR created 22 different engineering services design solutions to help create an exemplary guest experience, deploying a variety of creative design decisions such as utilizing underfloor ventilation on level seven. 

HDR redeveloped the basement of the building, originally a car park, into a full-spec main kitchen for 1 Hotel. In a recycling and energy conservation effort, we used the car park's existing large drainage runs under the slab as pathways for the ductwork for smoke extraction. 

High ceilings are often synonymous with a premium guest experience. This highly desirable aesthetic applies to all spaces within the building, including rooms, corridors, open show kitchen in the restaurant and public areas such as the lobby bar. HDR planned the services by utilizing the space, for example by designing high pressure mist sprinklers with smaller pipe work for flexibility and height. Every potential gain, even as small as 0.2 inches (5 millimeters), was meticulously explored and pursued.

Maximizing Space

The designs for the building engineering services were diligently tested by HDR and other stakeholders, including operational personnel. A chef was trialing the basement kitchen while maintenance staff were test running air conditioning units. In the guest rooms, all above ceiling services requiring maintenance were grouped to allow all access panels to be hidden away in the bathrooms, designed according to the architect's aesthetic vision.

HDR’s exemplar engineering effort is perfectly summed up by Jim Mulvihill: 

“The true innovation of the project, and its most extraordinary feature, is that we used every millimeter of this building to secure five stars.”

It is important to highlight that each decision to retain existing structure is also a decision directly impacting the building's sustainability statement by way of embodied carbon savings. To put this into context, data suggests that cement, iron, steel and aluminum constitute 15% of the world's annual carbon emissions.

Innovative Sustainability

Preserving the environment for future generations is one of the pillars of 1 Hotels brand, and HDR’s reflected this enlightened approach in a variety of sustainable design choices and cutting-edge innovations.

By installing energy meters, we helped to equip every room with an energy-saving room management system. Linked to the larger building management system, this smart solution monitors which rooms are booked and for what time and adjusts service usage accordingly. As such, it is an energy management tool that only uses resources when necessary, with heating, ventilation and air conditioning systems operating based on occupancy. 

This system is also integrated into an app, allowing guests to specify their check-in and occupancy times and personalize the room's ambience, for example temperature. Additionally, the Room Management System supports operations and maintenance.

HDR installed variable flow chilled and low temperature heating water distribution systems; with all heating and cooling in the rooms designed as a variable volume, so only the required amount of water is run, with no wastage. Every room was also equipped with a separate drinking water fountain, utilizing a central filtration station, in order to minimize resource cost of bottled water transportation. 

All our work was compliant with targeted BREEAAM Excellent and energy performance certificate requirements. As part of the client brief, we sourced sustainable mechanical and engineering materials. 

A variety of fireplace options for the penthouses were explored. HDR conducted a study proving that an open fire with no glass front in the rooms was not a sustainable option; with the requirement of an open-air shaft and the cost of ventilation and heating the space, there was an effective 90% loss of energy. We recommended and successfully implemented the sustainable option of a gel type open fire that does not require fresh air, delivering a resource-efficient premium experience.

Health and well-being are key concerns for both the client and HDR. Every room is user-adjustable via a keypad on the wall and the Room Management System app; we designed and delivered the technology that integrates into smart features, including the infrared sensors that detect movement as well as heat. We provided expertise on the fitness and wellness center, including treatment rooms and a gym.

Biophilic Design

Additionally, we worked to fulfil various elements of 1 Hotels’ biophilic design principles, inspired by the natural environment and aiming to create a seamless transition from the outside to the inside. The biophilic features enabled by HDR include: ambience shift in the reception space with all engineering services for two trickling water features; inclusion of plants through water maintenance and irrigation systems to interior sculptural moss wall and external green wall, as well as retractable winch for the plant chandelier for maintenance purposes; and an outdoor live fireplace, a centerpiece of the hotel's restaurant and garden terrace run by Tom Sellers, a Two Michelin Star chef.

The site required an advanced fire strategy as the core was shared between the hotel and adjacent offices and retail spaces; there was the added complexity of the hotel itself providing guests with an option to connect different rooms. HDR developed appropriate bespoke fire and life safety measures, so that additional stairs were not introduced into the structure.

Since launch, the project has garnered universal acclaim across a plethora of prestigious industry award events and recognition, such as the International Hotel & Property Awards, design et al Elite Awards, AHEAD Awards Europe and Michelin Key.

HDR’s engineering approach for the 1 Hotel Mayfair project is an industry-leading exemplar of the practical application of circular economy principles in collaboration with an enlightened Client, and a testament to how construction innovation and sustainability profile complement each other at every step of a refurbishment undertaken with sympathetic consideration. As custodians of the built environment, we can help reduce embodied carbon whilst adapting existing building stock to meet modern sensibilities and market demands. It is our collective responsibility to coalesce so that the industry has the momentum and commitment to achieve the Drive to Net Zero by providing exemplary building engineering services to make a meaningful difference to the performance of all buildings, irrespective of typology.

Photos courtesy of © Mikkel Vang 2023