Castillo Pools designed, manufactured and installed two bespoke 3m x 7m structurally self-supporting stainless steel infinity-edge spas, alongside a 1.4m x 1.4m deck-level stainless steel plunge pool. The three installations were designed specifically for the Serenity Spa, creating a cohesive hot and cold-water experience. The two infinity spas are positioned at different elevations allowing their full-length infinity edges to create the illusion of water flowing from one spa into the other.

This project deserves to win because it demonstrates how bespoke pool and spa engineering can transform a hospitality environment into a memorable guest experience, while delivering the quality, practicality and longevity expected from a premium commercial installation. The relationship between the three water features is central to the success of the project giving a sense of connection between the features and gives the installation a strong visual presence from across the spa.The project also demonstrates the value of bespoke manufacturing over a conventional off-the-shelf approach. Every aspect of the spas, from the dimensions and structural design to the seating, hydrotherapy jets and bubblers, was developed specifically for the site with maintenance in mind as well as for the guests using the facilities. Behind the visual impact is a considerable amount of precision engineering. Using recycled stainless steel within the one piece pools, all the laser cut 316L stainless steel is fully internally welded, and water tested at Castillo Pools' facility before delivery. This approach provided a high level of quality control while reducing the amount of work and potential complications on site.All features within the spa are de

The overall theme was inspired by Seaham Hall’s focus on luxury, tranquillity and wellbeing. Their different elevations and full-length infinity edges were carefully considered to create the illusion of water flowing from one spa into the other, making the water a central architectural feature of the space. The mirror-polished stainless-steel infinity edges were introduced to enhance this effect, reflecting the surrounding environment and adding a refined, luxurious finish. The client’s vision for the wall water feature flowing into the plunge pool inspired a unified design concept, with all three elements connected through the movement and flow of water. The internal layouts were developed around how guests would use the spas, incorporating tubular seating, bespoke bubblers and targeted hydrotherapy jets to maximise comfort and therapeutic benefit. At the same time, the design was developed with the hotel’s operational requirements in mind, incorporating concealed cover pit which can be accessed from above without the need to drain the pools. Maintenance access was carefully considered with dedicated space retained around the spas to provide easy access to pipework and equipment, making future servicing straightforward.

Paramount Pools / Marpiscine 316L stainless-steel fittings and jets were selected to complement the fully welded 316L stainless-steel construction of the spas. Stainless steel was considered the ideal material for this demanding commercial hospitality environment due to its durability, longevity, corrosion resistance and premium appearance. The plant room equipment was supplied separately by Chemsol Group. The hydrotherapy jets were carefully configured in a three-jet triangular arrangement, positioned to target key areas of the upper and lower back and shoulders. The jet height and positioning were coordinated with the tubular bench design to ensure an ergonomic and comfortable experience for guests of different heights. One of the main challenges was the delivery and installation of the spas, with difficult site access compounded by challenging weather conditions. The size and weight of the bespoke stainless-steel vessels required careful planning and coordination to ensure they could be safely delivered and positioned within the site constraints. The spas were manufactured in Castillo Pools' warehouse under controlled conditions and fully water tested before leaving the factory. This provided an additional level of quality control and gave the client greater confidence that the vessels were ready for installation upon arrival, reducing the risk of delays or remedial works on site. The spas were also designed with additional structural material to support the weight of a suspended floor, allowing the bespoke vessels to form part of the building's overall design rather than simply being installed as standalone units. The structurally self-supporting design also provides a significant long-term benefit to the client. By avoiding traditional backfilling and allowing access to pipework and equipment, future maintenance can be undertaken more easily and with less risk of disturbing the surrounding finished floor and minimising overall disruption to a commercial facility.

Castillo Pools