The Property

Replacement of Lead Bay Window Coverings – York, North Yorkshire

This project involved the replacement of lead bay window coverings to a traditional detached 1950s property in York. The house featured multiple bay windows to the principal elevations, each forming an important visual feature to the front of the property.

From the images, the existing coverings had reached the point where replacement was more practical than localised repairs. Multiple bays required attention and all needed to match consistently in appearance and detailing.

Bay roofs are highly exposed elements. Although relatively small in size, they collect concentrated rainfall and often become vulnerable where movement has been restricted or older substrates begin to deteriorate.

Why the Original Leadwork Needed Replacing

The existing lead coverings had deteriorated with age and no longer represented a long-term solution. On bay windows, common defects include movement fatigue, worn joints, substrate failure and deterioration around eaves interfaces.

Rather than patch repairs, the decision was made to replace the coverings fully and rebuild the supporting structure beneath. This approach provides a more durable and technically correct outcome.

Leadwork Standards and Technical Approach

This project followed a standards-led approach focused on proper substrate construction, movement allowance and long-term performance.

• BS 6915 informed the installation and support requirements.
• BS EN 12588 governed the rolled lead sheet material specification.
• Lead Sheet Association guidance informed fixing methods, bay sizing and detailing principles.

Correct movement allowance remains essential. The lead must be restrained appropriately while still allowing natural expansion and contraction over time.

Specification of Works

Preparation and Removal

• Safe access established to all bay roof locations.
• Sections of eaves carefully removed to facilitate access.
• Existing lead coverings stripped and removed.
• Defective substrate materials removed where necessary.
• Bay areas prepared for reconstruction.

Substrate and Support

• New 18mm exterior plywood substrate installed.
• Additional insulation fitted within the bay void.
• Decking formed to create continuous support beneath the lead.
• Preparation completed for new lead detailing and flashings.

Leadwork Installation

• Three bay roofs covered using Code 5 rolled lead sheet.
• New lead coverings formed to suit each bay profile.
• Copper clips used to secure the lead correctly.
• Lead bossing and dressing carried out at corners and interfaces.
• Lead flashings integrated neatly into adjoining details.
• Fixings installed in accordance with good practice guidance.
• Perimeters formed to maintain movement allowance.
• All completed bays checked for weathering and drainage.

Finishing and Protection

• Patination oil applied to exposed lead.
• Surrounding areas cleaned and tidied.
• Completed works inspected before handover.

The Materials

• Code 5 lead
• 18mm exterior plywood
• Copper clips
• Patination oil
• Appropriate lead fixings