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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 slates.
• 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

• All the original roof slates had over numerous years, been covered in multiple layers of bituminous felt in attempts to re-proof the building.
• The roof slates had thus been 'tarred' and were unsuitable for re-use.
• The layers of felt and slates had to be carefully stripped back and lowered to the ground then disposed off.

Timber Inspection Report

• Once the roof structure of the roof had been exposed, the structural integrity of the roofing timbers could be assessed.
• An inspection of all existing timbers was carried out, in particular checking for any sign of wet or dry rot within the timbers which 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.
• The membrane created an immediate seal against the weather and a new base layer of the roof covering.
• The membrane was secured to the timbers using 25x50mm wooden batons, positioned horizontally and mechanically fixed in place.
• The positioning of the battons was set out ready to take the course of reclaimed Welsh slates.

Re-Clad Glazed Rooflight Panels

• Each of the 4 pitched roof structures consists of external and internally facing pitched roof sides which funnel down to a central area.
• Each of the 4 central areas contains a large, angled skylight window frame that holds a total of 16 glazed window panes.
• The skylights illuminate the commercial offices below.
• Attached to the skylight panels are individual air conditioning units.
• K-Roofing contractors reclad each of the skylight and air conditioning units in 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 thermal movement as the lead heats from solar radiation during the daytime.
• The side cheeks of glazed areas 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 will prevent water ingress and will not pond.
• 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

The choice of reclaimed slates rather than new slates provided considerable cost savings.

• Reclaimed Welsh slates were specifically acquired for the roof area 1230 metes squared.
• The slates were brought in from an individual project to ensure that there were minimum variations in colour/shade, grade, thickness and steps of slate.
• The reslating work needed to be completed in as short a time period as possible both fully weatherproofing the building and ensuring completion within the allotted permit. The maximum number of slaters and roofers worked together on the project.
• Slates amd roofing materials were raised to the roof using a mobile crane.
• Slates were graded then mechanically fixed to the roof battons with 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 contains small flat areas of roof with lead covering.
• Upon inspection the flat roof areas were found to have rotten timbers underneath the lead.
• The rot was caused by exposure to the excessive moisture from water ingress that had not been corrected by the felt application.
• The existing rotten timbers were removed and disposed of.
• New timber was 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.

Vertical Lead Window Cladding

• The front of the historic building contains sets of near vertical windows. The existng window frames were rotten and required renovation.
• All existing defective lead was stripped and removed from site.
• New timber glazing bars were fitted and all window galzing was renewed.
• The new timber galzing bars were clad in code 5 lead to weather seal them.
• Velux rooflights were fitted to the vertical upstands and leadwork was manufactured onsite and installed to provide full weather protection.