Artful replacement

London-based Associated Steel Window Services (ASWS) had to exhibit a degree of artfulness to ensure that a large composite replica window not only matched the original but could also facilitate safe cleaning. The window was fabricated as part of alterations to a prominent Grade II-listed building,

Continuing an established association with the leading firm of London architects, Barr Gazetas, ASWS undertook the work at the Royal Academy of Arts’ new Pace Gallery on behalf of John Sisk & Son; also a past client. The large composite bay, consisting of a pair of semi-headed frames with a separating fixed infill frames, measuring 2136mm wide by 2430mm high, dated from the late 19th century and were too badly corroded to repair. ASWS removed them with minimal damage to the stone reveals; and saved the ironmongery for reuse.

The company’s highly skilled craftsmen used W20 profiles to fabricate the new frames. Odd-leg sections and JB mullions were selected, to help maintain an authentic appearance. The team also created new steel cills to raise the level of the window slightly, and used Parliament hinges to enable the opening lights to clear the ornate stone columns, positioned just outside of the main building line.

Kris Bennell, ASWS’ contracts director, said: “Despite this being just one composite bay, there was an extensive design process – including our preparation of detailed drawings and even making a timber mock up of the frames – in order for permission to be gained. The original windows had not been made from standard steel sections, so matching them was challenging. In addition, the presence of the two very decorative columns outside made it difficult when it came to cleaning; we had to ensure we used the correct hinges to create sufficient space for window cleaners to reach out, safely.”

“The replacement windows were single-glazed with 6mm laminated glass, avoiding the slightly distorted reflections characteristic of double glazing. The frames were polyester powder coated in the factory, before being resprayed internally after fitting, to achieve the dual colour required inside and out. It has been a very successful, if protracted, process which has cemented our working relationships with both Sisk and Barr Gazetas.”

ASWS installed a mastic seal right around the new frames before handing the job back to the main contractor to complete the plastering and any masonry work. The installation was completed ahead of the Pace Gallery’s final fit out while, following the official opening, the space was used for several significant exhibitions of contemporary art.

The Royal Academy of Arts recently won a RIBA London Award. For further information about Associated Steel Window Services, visit or call 020 8665 5335.