Background:
St Peter’s Church, built in 1903 and the largest designed by Peter Paul Pugin, is a substantial Gothic basilican-plan church made of rock-faced red sandstone with ashlar dressings. Its Aberfoyle green slate roof and Dumfriesshire red sandstone define its character.
The church has a nave, side aisles over nine bays, a canted eastern apse, a gabled northeast sacristy, and a two-storey presbytery connected by a corridor. The building features grey slate roofs, including a large steep-pitched roof, hood mouldings above the Gothic windows, cornices, and cast-iron rainwater goods.
Over 120 years old by 2024, the main roof was at the end of its life with slate fatigue, slip fixings, and water ingress. John Fulton Plumbing and Roofing were appointed to replace the roof covering on the nave, side aisles, sacristy, and presbytery.
Product Choice:
- SIGA 150 Vermont Green Slate (random diminishing courses)
- Reclaimed Aberfoyle green slate (presbytery only)
- Copper nails and stainless‑steel fixings
- Lead flashings, valleys and abutments
- Clay ridge tiles rebedded and pointed
- Refurbished cast‑iron gutters and downpipes
- Treated timber repairs to rafters
- Breathable underlay
As a Grade II listed building, all materials had to be chosen to preserve the building’s character and meet conservation requirements while offering a long-life roofing system.
The original roof was covered in Aberfoyle Scottish slate. As the quarries no longer produce the slate, a matching alternative slate was required.
Roofing contractors John Fulton Plumbing and Roofing worked with Accuroof, part of SIG Roofing, to source an alternative solution. SIGA 150 Vermont Green was selected because it provided the closest match to Aberfoyle slate in colour and texture and, as a new slate could hang and stay put on the steep pitch. Its availability in random diminishing courses also allowed the team to replicate the original Pugin roof design.
The product was supplied by the SIG Roofing branch in Linwood and is covered by the SIG Roofing One Warranty scheme, offering long-term assurance to the client.
Leadwork was renewed using LSA‑compliant detailing, as required in the roof plan, which specifies the renewal of hip flashings and leadwork around buttresses and chimneys. Clay ridge tiles were rebedded and pointed over copper rod.
Installation:
The roofing contractors started work on the principal nave roof by removing the existing slate. They then prepared the area by rolling out a breathable underlay across the rafters. The slates were fixed back to the existing sarking and substrate with the largest installed at the eaves fixing a double course. A diminishing course for the slates was then installed with each slate fixed with two copper nails.
Eaves and top courses were double‑lapped, and perimeter slates were cut and dressed by hand. At the end of the nave, the alter section is split into four slate sections with a double rolled lead between each section. Verges, hips, and valleys were formed using leadwork. Refurbished cast‑iron gutters were reinstalled with minor adjustments to improve capacity.
The original Aberfoil slates from the nave roof were hammer tested and graded to see which could be reused on the presbytery roof. Once these had been sorted and re-holed the roofing contractors installed the roof to match the original diminishing course.
All the lead work was renewed, the cast gutters were also taken off, refurbished and put back on again. There was a lead damp proof course (DPC) installed underneath the gutters and then all the leadwork to the hips.
The project also included refurbishment of the cast‑iron rainwater goods, extensive stone repairs, and the restoration of the leaded lights. All works were carried out while the church remained fully operational, requiring JR Scaffold to dismantle and re‑erect internal towers every weekend.
Challenges:
One of the biggest challenges working on the principal nave roof was that it was landlocked by the south and north aisle roofs, with only one entry and exit point. The nave roof also had a steep pitch, with the ridge-to-gutter length at about 12½ metres, which made the installation process much more difficult. The scaffold was also based on the wall and then transferred down onto the church, which meant that no materials could be stored during the works. As the team were uninstalling and reinstalling the roof, they had to hoist everything up and then immediately lay the slate.
St Peter’s is an active parish church, with multiple weekly services, funerals, weddings and community events. Maintaining uninterrupted access was essential. Noise, dust and vibration had to be tightly controlled. The church remained open for pastoral care, so safe segregation routes were required daily. Deliveries had to be timed around school traffic and parish activities. The landlocked site left no laydown space, requiring just‑in‑time delivery of slate and lead.
These challenges were overcome through close co-ordination between the architect, contractor, scaffolding company and the SIG Roofing branch at Linwood, which delivered in small batches to avoid congestion.
Summary
John Fulton Plumbing and Roofing have sympathetically restored this unique building, and the local community can now enjoy many more years of service. The project has been warmly received by the parish.
