SIG Design & Technology played a vital role in the material choice in the restoring Our Lady Help of Christians Catholic Church, in Birmingham, a Grade II listed building, back to its former glory.
Along with its distinctive obelisk roof, which has an existing copper membrane finish, other features of the Our Lady Help of Christians Church include its striking concrete building envelope.
However, despite the previous resurfacing of its copper roof in 2000, the structure of this renowned church had deteriorated in recent years and reached the end of its useful working design life. Now, approximately 50 years after the original congregation first took their seats to worship at Our Lady Help of Christians, a project to sympathetically restore the roofing membrane to resemble its original glory has been completed.
The biggest challenge on the project was finding a material to re-roof the building with, as the original covering (a copper foil faced bitumen sheet) is no longer manufactured.
The existing roof presented a number of challenges; it curves in two directions and goes from flat to vertical, meaning the use of sheet metals would not work. Its location (near the end of Birmingham Airport’s runway) meant that the roof was subject to deterioration from aviation fuel, and the shape of the roof created strong uplift forces on its covering. The existing bitumen covering had also bonded with the concrete below, making it impossible to remove without damaging the concrete.
SIG Design & Technology played a vital role in the material choice. Due to the church’s architectural status, Historic England took an interest in the restoration and specified that the roofing finish should match the colour and texture of the original copper membrane of the 1960s in appearance.
It was concluded that a liquid solution was the best answer. There were two prerequisites to the choice of membrane; identical colour matching to the original finish and longevity through the choice of a long lasting, resilient liquid waterproofing. To recreate the tint of the copper roof at its 1968 peak appearance, a number of colour options were tried, and SIG consulted a painting of the church which is believed to have been created by a parishioner at ‘Our Lady’.
The perfect colour match was achieved by providing Repoma’s manufacturer with an original colour sample. A spectrometer determined the precise pigment ratio required and the top coat was supplied mixed ready for application.
With its unique “PUMA” technology, Repoma combines the flexibility and crack bridging qualities
of PU liquids and the key renovation benefits of MMA resins. Well suited for the repair of roofs, Repoma can waterproof almost any roof surface without removal. The membrane and fabric combine to offer a highlyflow text elastomeric system which lasts for up to 30 years, even at -30°C or at very high temperatures.
Cold applied, Repoma can adhere to any form of detailing and requires no priming. It is very fast curing, dries in 30 minutes at 15°C and is ready for foot traffic in an hour.
In preparation, the existing roof needed to be power washed, the copper system solvent wiped to remove all dirt and to provide a suitable key. Adhesion testing had been carried out to confirm compatibility of the existing roof and new Repoma System.