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  • Clio Domenech

Weatherproofing and the Party Wall Act: Lead Flashing

As a homeowner, it’s crucial to understand your rights and responsibilities when it comes to undertaking building works that involve party walls. One common scenario where homeowners may encounter the Party Wall etc. Act 1996 is during weatherproofing upgrades or installations alongside an extension/ conversion project. Today we will go over typical weatherproofing installations, particularly lead flashing installations into a party wall.

The Party Wall Act 1996 was established to provide a framework for preventing and resolving disputes between neighbours regarding party walls, boundary walls, and excavations near neighbouring buildings. A party wall is a shared wall between two adjoining properties, and any work that affects it requires adherence to the regulations outlined in the Act.

When it comes to weatherproofing, installing lead flashing is a common practice to prevent water penetration through joints and gaps in the structure, particularly in areas where roofs meet walls. So, how does installing lead flashing impact the party wall, and what do homeowners need to know?

Under the Party Wall Act, installing lead flashing into the party wall is considered "notifiable work," meaning you are required to notify your neighbour if the work will affect the party wall. This involves serving them with a Party Wall Notice, detailing the nature of the work to be carried out. This notifiable work falls under Section 2(2)(j) of the Party Wall Act. If you're unsure how to write a Party Wall Notice, consider consulting a party wall surveyor for assistance. Your neighbour (Adjoining Owner) has the right to consent or dissent to the proposed work. If they dissent, a Party Wall Award must be created outlining how the work will proceed and any necessary measures to safeguard their property. More information on all the ways an Adjoining Owner can reply to a Party Wall Notice is detailed here.

The Party Wall Act requires that any work done should not compromise the structural integrity of the party wall or cause unnecessary inconvenience to adjoining property owners. Party wall surveyors can assess the proposed work, ensure compliance with the Party Wall Act, and provide expert advice on any necessary precautions or modifications.

Common Projects Requiring Lead Flashing

  1. Loft Conversions: Loft conversions, especially full-width dormers, often require lead flashing installations. When the original roof is removed to prepare for the rear dormer addition, the party wall becomes temporarily exposed and must be adequately weatherproofed during the build. Temporary solutions like tin hat scaffolding is often used alongside permanent weatherproofing measures.

  2. Older Buildings: In older buildings, chimney stacks or parapet party walls above roof levels may lack a damp proof course (DPC), necessitating new protective lead sheeting or flashings fitted into the masonry.

  3. Narrow Gaps Between Extensions: When rear extensions are built closely together, creating a narrow, inaccessible gap, a party wall surveyor may request that the roofs of the two extensions be sealed with a bridging weatherproofing sheet. This prevents moisture collection in the gap, thus avoiding damp formation.

Lead flashing installed along a dormer cheek and at the base of a chimney stack
Lead Flashing Installed along a Dormer Cheek and at the Base of a Chimney Stack

While installing lead flashing into a party wall is a common practice for weatherproofing, it’s essential for homeowners to understand their obligations under the Party Wall Act 1996. By following the proper procedures, obtaining consent from neighbours, and ensuring compliance with relevant regulations, homeowners can carry out their weatherproofing upgrades while maintaining good relations with their neighbours and safeguarding the integrity of the party wall.

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