The Property

Lead Bay Installation

This project involved the installation of a new lead bay roof to a traditional stone property. The bay sits below upper-level windows and forms an important weathering detail where the main elevation meets the projecting bay structure below.

Lead bays are highly exposed and technically important. They must protect the structure beneath, direct rainwater away from the wall, and integrate neatly with masonry, window details, flashings and rainwater goods.

The completed detail included a new lead bay covering, raised perimeter upstands, clipped flashings, welded details and a formed outlet arrangement discharging into the adjoining rainwater goods.

Why Correct Lead Bay Installation Matters

Lead bay roofs are exposed to concentrated rainfall, thermal movement and several vulnerable junctions. If the installation is poorly detailed, water can track behind the lead, collect at the wall junction, stain masonry or enter the building fabric below.

This project required accurate setting out and careful workmanship because the bay included perimeter upstands, abutment flashings, clipped edges, welded corners and a bespoke drainage outlet. Each element needed to work together as a complete weathering system.

Leadwork Standards and Technical Approach

From the outset, the focus was on movement, durability, neatness and long-term weathering performance.

• 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, welding, clipping, flashings and outlet formation.

In practice, that meant selecting the correct lead code, allowing for expansion and contraction, forming clean joints, and building reliable flashing and outlet details into the bay. Good leadwork must look right and work properly.

Specification of Works

Preparation and Removal

• Carefully prepared the bay roof area for new leadwork installation.
• Protected surrounding stonework, window details, scaffolding and rainwater goods.
• Checked abutments, outlet position and surrounding masonry before installation began.
• Prepared the supporting structure and surrounding details to receive the new lead bay covering.

Substrate and Support

• Prepared the supporting base to suit the new lead bay installation.
• Checked the bay for suitable falls and drainage performance.
• Formed perimeter upstands and weathering edges to suit the bay geometry.
• Prepared the outlet position to discharge into the existing rainwater goods.

Leadwork Installation

• Installed new Code 5 lead bay covering.
• Formed raised perimeter upstands to control water and protect the edge details.
• Fitted lead flashings to the stone abutment and secured them with suitable clips.
• Created dressed and welded corner details to suit the bay shape.
• Formed a bespoke lead outlet to discharge into the adjoining hopper or rainwater pipe.
• Used lead bossing and welding to shape the junctions neatly and accurately.

Finishing and Protection

• Applied patination oil to all newly completed leadwork.
• Checked the finished details for continuity, movement allowance and water run-off.
• Cleaned down the bay so the finished work sat neatly against the stone elevation.

The Materials

For this project, we selected traditional leadwork materials suited to bay roof detailing, drainage control and long-term weathering performance.

• Code 5 lead
• Copper clips and fixings
• Lead flashings
• Lead outlet details
• Lead-compatible sealant
• Patination oil

If you are comparing materials for a similar lead bay detail, our shoppable lead chart is a helpful place to start. In addition, you can explore broader product guidance through The Lead Handbook and our lead roofing guides.