Case Study: Lead Valley Replacement & Re-Slating in Dublin

• Location: Dublin (Residential Property)
• Project Type: Roof Valley Repair & Re-Slating
• Lead Contractor: Augustine Doherty & AD Roofing Team

Project Overview & Problem

A Dublin homeowner contacted AD Roofing Dublin after noticing persistent water ingress following heavy rainfall. During our physical on-site survey, Augustine traced the leak to an aged, severely degraded lead valley channel situated between two slate roof pitches.

Over decades of exposure to Dublin weather, the existing lead had suffered from thermal fatigue, thinning, and stress fractures along the central water line. Water was tracking beneath the deteriorated lead and bypassing the edges of the surrounding slates, risking damage to the underlying rafters and ceiling timbers.

Job Description

1. Stripping Adjacent Slates: Carefully lifted and removed multiple courses of slates along both flanks of the valley to expose the full channel without damaging sound tiles.
2. Substrate & Timber Prep: Inspected the timber valley boards for rot or moisture damage, renewed the waterproof underlay with breathable membrane, and secured new pressure-treated timber battens.
3. Installing New Lead Valley: Hand-formed and dressed heavy-duty Code 5 sheet lead down the length of the channel, fitting proper overlapping joints to allow for natural thermal expansion and contraction without splitting.
4. Re-Slating & Alignment: Cut and re-laid matched slates along both sides of the new valley, ensuring clean lines and a wide, unobstructed water run directly to the gutter.
5. Final Inspection & Clearance: Inspected all fixings, ensured a watertight seal across both roof slopes, and cleared away all debris.

Materials Used

• Code 5 Milled Sheet Lead: Sized and dressed to provide a durable, watertight channel designed to last over 50 years.
• Heavy-Duty Breathable Membrane: Installed beneath the valley lining to provide a secondary condensation and moisture barrier.
• Treated Timber Battens: Pressure-treated timber battens fitted to ensure long-term structural integrity.
• Matched Roofing Slates: Slates trimmed and nailed to match the existing pitch and profile.
• Copper Nails & Fixings: Non-corrosive roofing nails used to prevent future nail sickness and rust.