Terracotta Craft Skills and Technology Combine to Restore Historic Church

St Catherine’s Parish Church in Horwich, near Bolton, is noted for its magnificent West window framed in terracotta and has been at the heart of the community for more than 100 years. Time had not been kind to the terracotta; the prevailing weather had eroded joints permitting water ingress resulting in secondary frost damage to the blocks. To restore these original features, more than 100 new blocks, manufactured by Darwen Terracotta Limted (DTL) in Blackburn have been installed by conservation and restoration contractors Lambert Walker Limited under the supervision of Buttress Architects in Manchester.

Initially built between 1897 and 1902 with a later phase added in 1932, St Catherine’s is predominantly Accrington brick with terracotta and sandstone decoration. “DTL director Jon Almond observed, “The level of craftsmanship in buildings of this period is exceptional, but time takes its toll and limitations of the technology of the time can open the fabric to attack. At the time the original blocks were made, firing would have been in coal fired kilns where temperatures would be uneven, causing the clay to vitrify to differing degrees. Some underfired pieces would have been softer, porous and liable to damage in the long term.”

In total over 100 blocks were identified that were damaged beyond repair including sills, mullions and window surrounds as well as wall copings and buttress units. “The new pieces will be more resilient than the originals since modern gas fired kilns have multiple burners and close temperature control for even firing so that all pieces are consistently vitrified.”

Quality control during manufacture ensures that the new blocks achieve a precision fit and are a close colour match to the adjoining pieces. This starts with careful measurement and photography of the damaged pieces following which new models were sculpted by DTL skilled crafts people permitting the creation of moulds for repetition manufacture. All new pieces were slightly oversized to take into account shrinkage in both the drying and firing phases. After casting each block was hand finished to ensure a good match on both colour and texture to surrounding terracotta. All components were 100 percent inspected before being shipped to site in protective packaging.

Darwen Terracotta are one of only a handful of architectural ceramics workshops left in the UK with the experience and skilled crafts people able to complete such work. The company produce both terracotta and faience, a glazed ceramic available in multiple colour and finish options. Craft skills are core to the business, but where modern technology such as computer aided design and scientific glaze formulation provide advantages the company is quick to deploy them. DTL provide a nationwide service enabling heritage buildings such as churches, schools, baths, theatres and municipal buildings to be fully restored to go on serving their communities.

More Information

Jon Wilson, Director Tel. +44 (0)1254 460 500
E-mail: jonwilson@darwenterracotta.com Web: www.darwenterracotta.com
Darwen Terracotta Ltd, Building O, Ribble House, Ribble Business Park, Challenge Way, Blackburn, Lancashire. BB1 5RB

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