Cold-applied liquid waterproofing specialists, Kemper System, has successfully completed the roof refurbishment of St. John the Baptist RC Church in Rochdale, Greater Manchester.

The Grade II listed landmark building - notable for its domed roof sections and iconic mosaic artwork inside - required a comprehensive overhaul of its roof to address issues with leaks, due to the existing roof materials being poorly installed.

Phased Works
Kemper System's Kempertherm Tapered Insulation solution was specified and installed for the first phase which saw the refurbishment of the west transept roof areas. The existing felt roof areas had been poorly installed to the upstand details resulting in longstanding issues with water ingress. The existing insulation was found to be wet during initial investigative works and was therefore removed as part of the works.

The second phase of the project involved the refurbishment of the east transept roofs which required the use of cut-to-falls and ‘lamella’ insulation boards to fit over the barrelled roof sections. Kemper System’s BBA Certified, Kemperol V210, a polyester resin-based fully bonded waterproofing system, was used for both these phases of the works; a cold liquid waterproofing system applied with a fleece reinforcement. This waterproofing solution adapts to the structure like a second skin and offers long-term protection down to the last detail, making sure all areas are integrated in the surface waterproofing - without any seams or joints.

The third and final phase of the project involved the refurbishment of the large, central dome roof. After localised repairs to the concrete substrate were completed and the area treated with the solvent free, epoxy based Kempertec EP5 penetrative primer, the Kemperol 1K-PUR cold liquid applied waterproofing system was applied. This fleece-reinforced, waterproofing system is based on polyurethane resin and can be applied straight from the container after mixing, without the addition of separate hardeners, making it the ideal choice when working section-by-section on a complex structure from a multitude of work platforms.

Challenges Overcome
The project presented a number of challenges for roofing contractors. The height of the building was a vital factor to consider during product specification for Kendal-based, Crosby Granger Architects. Large expanses of sheet material would not have been suitable or adhered to health and safety protocol because of the height of the church.

Meticulous planning for the logistics and access of the building was also required, as the church is located in a busy area of Rochdale with a train and tram station opposite, and the adjacent pedestrian walkways still in use.

The presence of the historic mosaic roof design inside the domed roof of the church, which was experiencing severe water ingress, meant that a quick and easy application of a robust and durable waterproofing solution was required.

Specification Considerations
Crosby Granger Architects undertook a detailed high-access examination of the dome and clerestory, and conducted a more holistic condition survey of the entire building prior to specification.

Speaking of the specification process, Andrew Bodenham from Crosby Granger Architects, said: “We have used Kemper System for projects in the past and know the company’s range of waterproofing solutions are versatile and durable for the requirements of this complex and time-sensitive project.

“Preserving the historic piece of mosaic art within the main dome roof area was of upmost importance, and we worked collaboratively with the team at Kemper System to develop a suitable solution for the refurbishment of this area, as well as the flat roof sections.”

The project was completed with up and over scaffolding over the domed area to ensure effective waterproofing of the roof, with contractors also repointing the brick work.

Continued Andrew: “We received superb support, technical assistance and communication from the team at Kemper System from day one, right up until post-installation and handover. The quick and easy application meant contractors were able to make the roof waterproof in a matter of days, which allowed them to continue the necessary concrete repairs to the rest of the building. It also limited additional costs for the building owners as the amount of scaffolding required for this project was vast – due to the size and height of the building. The amount of time and equipment was reduced, compared to if an alternative roofing solution was installed.”

Victoria Ramwell, commercial manager at Kemper System, added: "We are thrilled to have completed this important refurbishment project on the Church of St. John the Baptist. The building is a significant landmark in Rochdale and a testament to the skill and ingenuity of its architects and roofing contractors. We are proud to have been a part of this project and to have contributed to the ongoing preservation of this important historical site."