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Example of Slate Re-roof Manchester

Commercial Office Slate Roof

Extensive Victorian office building in Manchester city centre given a refurbishment.

• Commercial roof refurbishment contract with Adam Jeffries Property Management Company
• City Center Manchester, Lloyd St. off Albert Square.
• Total Roof Area: 1230 metres squared.

Roofing contractor required to:

• Remove existing roofing materials.
• Reslate the multiple roof structures using reclaimed slate tiles.
• Replace existing defective leadwork including flat roof areas.
• Apply lead cladding to glazed frames.

City Centre Works Preparation

• Obtain all permits for Manchester City Centre
• Provide full scaffolding

Roof Exposure

The original roof slates had over numerous years, been covered in many layers of bituminous felt in attempts to cheaply re-waterproof the building.

The roof slates were thus 'tarred' and unsuitable for reapplication.

The layers of felt and slate had to be carefully stripped back and lowered to the ground for disposal.

Timber Inspection Report

Once the roof structure was exposed, roof timber were assessed on their structural integrity, in particular checking for any sign of wet or dry rot that could compromise remedial work.

A full timber inspection report was supplied to the client.

Breathable Waterproof Membrane

A secondary roofing system - a waterproof breathable membrane - was positioned over the structural timbers. This creates an immediate seal against the weather and the new base layer of the roof covering.

The membrane is secured to the timbers using 25x50mm wooden battens, positioned horizontally and mechanically fixed in place, set out ready to take the course of reclaimed Welsh slates.

Re-Cladding Glazed Rooflight Panels

Each of the 4 pitched roof structures has external and internal facing pitched roof sides. The sides funnel down to a central area that contains a large, angled skylight window frame holding a total of 16 glazed window panes.

The skylights illuminate commercial offices below and need to be thoroughly and dependably waterproof.

Attached to the skylight panels are individual air conditioning units.

KK-Roofing contractors reclad each of the skylight and air conditioning units using sheet lead.

Code 6 lead cladding was installed to the base of the glazed areas. The cladding is inclusive of fully welded expansion joints which allow for the thermal movement as lead heats from solar radiation during the day.

The side cheeks of the dskylights were clad with code 5 lead - a lower specification lead - inclusive of fully welted joints.

Welted lead joints are suitable for this type of vertical join as they prevent water ingress and ponding.

The base lead cladding sheets are copper nailed at the top and then secured at the base with TCS at 300 centres.

Pre-fabricated window flashing pieces were installed to the gazed areas to provide full weather protection around the windows.

Code 4 lead was installed to all window flashing pieces.

Re-Slating of the Roof

Reclaimed slate tiles rather than new slates provided considerable cost savings.

Relatively cheap, high quality reclaimed Welsh slates were specifically acquired for the roof area of 1230 metes squared.

The slates were brought in from an individual project to ensure there wes minimum variation in colour/shade, grade, thickness and steps of slate.

The reslating task needed to be completed rapidly to both fully weatherproofing the building and ensuring completion within the allotted permit time. Our entire team of slaters and lead roofers worked together on the project.

All the slate and roofing materials were raised by a mobile crane.

Slates were graded then mechanically fixed to the roof battens. The smaller slates towards the top of the roof.

Code 4 lead was installed to all chimneys and roof valleys.

Blue Collared Slate Ridge Tiles

Blue collared slate ridge tiles were acquired and fully bedded in cement along the roof ridges.

The sides and collars were skimmed in cement to ensure a watertight hold.

Flat Roof Areas

The roof system contained small flat areas with lead covering which when inspected were found to have rotten timbers underneath.

The rot was caused by exposure to the excessive moisture from water leaks ingress that felt application had not sealed.

The rotten timbers were removed and disposed of.

New timbers were installed to marine ply specification.

All falls were formed to adhere to LDA regulations.

Code 6 lead was supplied and installed to the flat roof areas, inc of all rolled lead joints, upstands, flashing pieces and outlets.

Bespoke Vertical Lead Window Cladding

The front of the historic building contains sets of near vertical Velux windows. The existng window frames were rotten and required renovation.

All existing defective lead was stripped away and removed from site.

New timber glazing bars were fitted and all window glazing was renewed.

The new timber glazing bars were clad in code 5 lead to weather seal them.

Velux rooflights were fitted to the vertical upstands and leadwork was custom manufactured onsite and installed to provide full weather protection.