The Property

Lead Bay Roof Replacement – Harrogate, North Yorkshire

12 Granby Road in Harrogate is a substantial Victorian stone villa built in the traditional architectural style associated with the town’s 19th-century growth as a prosperous spa destination. Constructed from dressed Yorkshire stone, the property features large curved bay windows, deep overhanging eaves, classical entrance detailing and symmetrical proportions typical of high-status Victorian residential buildings. Its slate roof, formal frontage and refined stonework reflect the elegant character commonly seen in Harrogate’s historic villas overlooking The Stray. Today, the building retains strong period character while also being well suited to professional or commercial use due to its scale and prominent appearance.

The property features a lead-covered curved bay roof formed over a projecting bay window on a traditional stone property. It has been installed using Code 5 lead sheet with raised wood roll joints, welted perimeter edges and stepped lead flashings chased into the masonry above. Details like this are commonly found on Victorian properties and are designed to provide a durable, weatherproof covering while allowing the lead to expand and contract naturally.

Why the Original Leadwork Needed Replacing

The original lead bay roof appears to have suffered from age-related fatigue, failed thermal movement detailing and deterioration of the flashings and joints. The stained and weathered appearance of the lead suggests long-term exposure, while restricted expansion or over-fixing may have caused splits and stress fractures around the roll joints, corners and wall abutments. There may also have been movement or decay within the timber substrate beneath the covering, creating uneven areas and additional stress on the lead sheet. Typical symptoms would likely have included water ingress into the bay window below, internal damp staining, lifting or cracking to the lead edges, failed flashings and areas of standing water across the roof surface.

On bay roofs, the most common long-term problems are usually linked to a combination of age, poor movement allowance, inadequate drips, weak corners, failing decks or ineffective abutment detailing beneath the window and against the masonry reveals. That is why a proper replacement needs to address the whole bay detail rather than only the visible outer skin.

Leadwork Standards and Technical Approach

This project was completed using a standards-led approach focused on proper lead detailing, correct material selection and durable support beneath the finished covering.

• BS 6915 informed the design and installation of the fully supported lead sheet covering.
• BS EN 12588 governed the rolled lead sheet material specification.
• Lead Sheet Association guidance informed bay sizing, fixing principles, bossing, welting, corner formation and general good practice.

The replacement of this lead bay roof would follow a standards-led approach in accordance with BS 6915, BS EN 12588 and Lead Sheet Association guidance. The existing covering and defective substrate would be removed and replaced with new exterior-grade plywood decking to provide a stable fully supported base. New Code 5 lead sheet would then be installed using correctly sized bays, raised wood roll joints and stepped flashings chased into the masonry, allowing the lead to expand and contract naturally while providing a durable and weatherproof finish.

Specification of Works

Preparation and Removal

• Erect safe scaffold access to both bay window roofs.
• Inspect and record the condition of the existing leadwork and substrate.
• Protect surrounding stonework, joinery and glazing during the works.
• Carefully remove existing lead coverings, flashings and fixings.
• Strip out defective timber decking and clear all waste materials.

Substrate and Support

• Repair and level the existing bay roof structure where required.
• Fit new exterior-grade plywood decking to provide a fully supported substrate.
• Install building paper underlay between the timber deck and lead sheet.
• Form timber roll details and edge supports in accordance with LSA guidance.

Leadwork Installation

• Set out the lead bays in accordance with BS 6915 and LSA recommended sizes.
• Install new Code 5 lead sheet coverings to both curved bay roofs.
• Form raised wood roll joints to accommodate thermal movement.
• Dress and boss the lead carefully to follow the curved bay roof profiles.
• Form welted perimeter edges to provide a secure weathered finish.
• Fit stepped lead flashings chased into the masonry abutments.
• Secure the lead using copper fixings and non-ferrous clips.
• Dress and finish all joints, corners and details to achieve a watertight installation.

Finishing and Protection

• Apply patination oil to all newly installed lead surfaces.
• Check all joints, flashings and fixings to ensure a watertight finish.
• Remove debris and clean down the work area on completion.

The Materials

This project used a straightforward but important group of materials, each chosen for a clear purpose within the bay roof build-up.

• Code 5 lead
• Copper ringshank nails
• Exterior-grade 18mm plywood decking
• Building paper / lead underlay
• Lead sealant
• Patination oil

If you are trying to understand which code of lead is right for a similar detail, our shoppable lead chart is a useful starting point. For broader product learning, see The Lead Handbook and our lead roofing guides.