Westburn Gardens

Description:

BriggsAmasco’s experience and expertise facilitated the design and installation of a single-ply system to meet the complex requirements of a multiple roof application that helped transform a dilapidated hospital site into a desirable new housing development. Such was the excellence of its all-round performance on the Westburn Gardens project, BriggsAmasco was acclaimed winner of the Single-ply Roofing category at the 2023 NFRC Scottish Roofing Contractor of the Year awards.

Popular with first-time buyers and conveniently located in the centre of Aberdeen, the new apartment complex of Westburn Gardens is built on the site of the old Royal Cornhill Hospital.

The hospital had stood derelict for many years and been subject to a series of fires. Hence, the site was in urgent need of intervention. As the only developer committed to renovating the area to prevent its total demolition, Barratt Homes was awarded the project.

The hospital site is a designated conservation area with several listed buildings. It added to the project’s complexity. Aside from the intricate renovations – five of the original 12 buildings were saved – the site’s new buildings had to be in keeping with the appearance of the original hospital and renovated buildings. Where possible, granite from the original structures would be used in the new apartment buildings, giving the apartments a distinct appearance that helped to preserve the history and significance of the site.

The requirement to keep the original character of the site also applied to the roof. Its colour needed to match the granite colouring of the building, and the shape had to reflect the appearance of the old hospital. The shape would include multiple roof areas at different levels, with several dormers a significant part of the design.

Originally a lead specification, BriggsAmasco advocated a Sika Sarnafil single-ply solution for one of the newly-built apartment blocks that would be visually suited to the project and cost-effective. A complex design and challenging details meant that highly-skilled, experienced operatives were vital, and careful planning for each section was essential.

The Sika Sarnafil build-up comprised Sarnavap 500E, Sikatherm PIR AL and Sika Sarnafil S327-12 EL in lead grey. The S327-12 EL membrane provided a roofing solution that would be quicker to install, while offering excellent longevity, durability and a pristine finish.

The main structure was secured and in place prior to BriggsAmasco’s team embarking on the roof’s installation. Following a roll out of Sarnavap air vapour control layer, the insulation boards and single-ply membrane were mechanically fixed.

The intricate installation involved multiple roofs on different levels. BriggsAmasco teams had several dormers to contend with, which further complicated the design. Working the membrane around dormers and adapting to details such as side slips was challenging, and each section had to be carefully considered. The BriggsAmasco team frequently worked in conjunction with a Sika Technical Site Support Engineer to ascertain how best to tackle certain details.

Typically, a flat roofing solution, the single-ply membrane needed to be applied to a sloped roof – making the project especially challenging. With tight angles, windows and several areas vulnerable to water ingress, application of the single-ply system required careful planning and expert workmanship. It was mechanically fixed using a Sarnafast system, with each overlapping seam hot air welded. This meticulous process was instrumental to the installation’s success. The system was applied to all 26 dormers and other areas of the roof, ensuring the structure would be protected.

BriggsAmasco teams needed to stay within the original lead specification’s parameters and adapt it to a single-ply roofing solution. The roof’s shape was constructed prior to the team’s involvement with the project – they successfully changed the specification to single-ply, mirroring the original plans.

Aided by the flexibility of the Sika single-ply membrane, BriggsAmasco applied the system to the roof without relying on any other roofing solution, which would have detracted from the roof’s uniform aesthetic. This was vital, as replicating the original appearance of the old Royal Cornhill Hospital was among the client’s key requirements.

Thanks to BriggsAmasco’s consummate workmanship and professionalism, the Westburn Gardens roof installation was completed on time to the client’s full satisfaction. The work’s quality was of such a high standard that BriggsAmasco not only triumphed at the NFRC Scottish Roofing Contractor of the Year awards, it was awarded phase 2 of the Westburn project. Work on this project phase began in May 2023.