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Coming up roses – Timber mullion solution to secondary glazing of rose window

Category:

Treat Of The Month

Tags:

acoustic secondary glazing, refurbishment and conservation, retrofit

Selectaglaze was tasked with designing an acoustic secondary glazing treatment for Trinity Methodist church, Clacton. One of the most challenging windows proved to be the rose window. Each of the eight petals making up the rose is glazed with stained glass displaying colourful stylised shapes, whilst each segment contributes to an overall concentric ring design. Viewed from ground level the combined design makes the rose appear to burst with light. Trinity Methodist between 1881 and 2019 Both protecting and enriching the church’s interior for one and a half centuries, the rose window has been fighting a losing battle with 21st-century sound. Since its creation the world outside has moved on apace, now cars, buses and lorries race past on three sides of the church, subjecting it to a cacophony of traffic sound. Spanning over 3 metres, this beautiful rose window required a combination of engineering acumen and ingenuity. With no true angles or symmetry, a strong adaptable method of fixing was required for any secondary glazing treatment. A timber mullioned cartwheel frame was devised which proved the ideal solution. The challenge was to create a treatment which would provide sufficient stability to securely hold the secondary glazing. The solution was found in building the timber subframes in segments, such that each mullion was split to be screwed together within the window opening. Each element of the rose window was initially created in CAD format by the in-house Development Engineer from precise laser measurements. From these, scaled trace sheets were produced to provide both the timber shop and factory with the exact dimensions for each element. The ‘annular sector’ (petal) mullion section was carefully crafted in the timber shop. These sections would form the cartwheel timber frame. Eight bespoke Series 46 Fixed Light (petal) segments were made and glazed with 4mm toughened K-glass incorporating white gaskets. With scaffolding in place, the rose-shaped secondary glazing treatment was painstakingly assembled in situ. Each element of the timber mullioned cartwheel received its respective section; all radiating out from the central fixed light core. Peace has returned to this special space thanks to an effective secondary glazing treatment. Whilst the low visual impact secondary glazing treatment rests securely within its ingeniously malleable frame.