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Project Duration
This small lead bay window replacement was completed by our team in around 3 days.
Project Location
Leadwork Services
The Lead Lads provide specialist leadwork services for bay windows, flashings, valleys, gutters and traditional roof details.
Leadwork Project Details | The Lead Lads ®
The Property
Small Lead Bay Window Replacement – York, North Yorkshire
This project involved the replacement of the lead sheet roof covering to a small traditional Victorian bay window in York, North Yorkshire. The bay formed part of the principal elevation of the property, making the finish highly visible from the street and important to the overall appearance of the front façade.
The Lead Lads were engaged by GNR Roofing to complete the leadwork element of the project. The timber substrate was formed on our behalf, allowing our team to focus on the lead detailing, including the new bay covering, edge formation, dressing, clipping and integration with the surrounding window and masonry details.
Although this was a small bay roof, the work still required careful setting out. Traditional bay windows are exposed to concentrated rainfall, wind uplift at the leading edge and movement stress across the lead sheet. The finished covering therefore needed to be both visually sympathetic and technically correct.
Why the Original Leadwork Needed Replacing
The original lead bay roof covering had reached the point where replacement was the most suitable long-term option. Older bay roofs often fail because of age, tired fixings, poor substrate condition, restricted movement, inadequate edge detailing or splits forming at stressed corners and junctions.
On this type of Victorian bay, patch repairs can sometimes hide the underlying issue without resolving it. A proper replacement allows the substrate, insulation and lead sheet covering to be considered together, creating a cleaner and more durable roof detail.
Leadwork Standards and Technical Approach
This project was completed using a standards-led approach focused on correct lead sheet detailing, suitable support and neat integration with the existing bay window structure.
- 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, dressing, bossing, clipping and movement allowance.
The key principle on a small lead bay roof is that the covering must remain secure without being over-fixed. The lead needs freedom to expand and contract, while the front edge, corners and abutments must be formed carefully to provide proper weathering and reduce the risk of wind uplift.
Contact us about leadwork More leadwork resources and guides The leadwork LinkSpecification of Works
Preparation and Removal
- Bay window roof area inspected before replacement works began.
- Existing defective lead covering removed from the bay window roof.
- Surrounding masonry, glazing and decorative frontage details protected.
- Timber substrate works coordinated with GNR Roofing.
- Bay roof prepared for new underlay, rolls, clips and lead sheet installation.
Substrate and Support
- New 18mm exterior-grade plywood substrate formed to support the lead covering.
- Insulation provided within the bay roof void where required.
- Building paper underlay installed beneath the lead sheet covering.
- Wood core rolls formed to support the bay roof layout and joint detailing.
Leadwork Installation
- New bay roof covering formed using Code 5 rolled lead sheet suitable for the detail.
- Lead dressed neatly over the newly formed timber substrate.
- Wood core roll details used to divide and control the leadwork layout.
- Front edge formed to provide clean weathering and a neat finish to the bay.
- Copper clips used to secure the lead without restricting natural movement.
- Lead bossed and dressed around corners and tight junctions.
- Leadwork integrated with the surrounding window, masonry and roof details.
- Finished bay checked for falls, fixings, laps and weathering performance.
Finishing and Protection
- Patination oil applied to exposed lead where required.
- Surrounding surfaces cleaned down after installation.
- Completed bay inspected for finish, alignment and long-term performance.
The Materials
This project used a focused set of materials chosen to provide a sound substrate, clean lead finish and secure traditional bay roof detail.
- 18mm exterior-grade plywood
- Wood core rolls
- Building paper underlay
- Copper clips
- Code 5 rolled lead sheet
- 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.
The Lead & Materials Used By Us 🛒 Lead Weight Calculator
Skills Required
- joinery coordination
- lead flashing
- lead dressing
- lead bossing
- forming traditional bay details
What This Project Teaches About Small Lead Bay Roofs
Small lead bay roofs can be just as important as larger roof areas. They sit on the most visible part of the property, protect the window structure below and often receive concentrated rainwater from the elevation above. A poor detail can quickly lead to staining, movement damage or moisture ingress.
This project shows why the substrate, underlay, edge detailing and fixing method all matter. A neat lead finish is only successful when it is supported properly below and allowed to move naturally through changing temperatures.
Property Owner Takeaways
- Small bay roofs should not be treated as minor details.
- A sound plywood substrate is essential beneath a new lead covering.
- Copper clips and correct fixing help secure the lead without restricting movement.
- Traditional Victorian bay windows benefit from sympathetic leadwork that suits the original frontage.
Related Lead Lads Resources
- Lead roofing projects
- Leadwork standards hub
- Leadwork services
- Shoppable lead chart
- Lead roll
- Leadwork fixings
Frequently Asked Questions
Why do small lead bay roofs fail?
Common causes include age, poor substrate, over-fixing, weak edge details and lack of movement allowance.
Does a small bay roof need a proper substrate?
Yes. A sound plywood deck is essential to support the lead and help the finished covering perform correctly.
Why is building paper used under lead?
Building paper separates the lead from the deck and helps reduce abrasion as the lead expands and contracts.
What fixings are used for lead bay roofs?
Copper clips are commonly used because they secure the lead while remaining compatible with traditional leadwork.
Can lead be used on Victorian bay windows?
Yes. Lead is well suited to Victorian bay windows because it is durable, traditional and visually sympathetic.
Where can I buy lead bay roof materials?
You can explore lead roll, fixings, underlay and guides through the Lead Lads Shop.
