Victoria Coach Station – Roof Canopy Works

 

Project: Victoria Coach Station – Roof Canopy Works

Client: LUL – SWIP

Works Value: £134,000

 

Our works at Victoria Coach Station were part of the refurbishment of the roof canopy over the Main Departure Terminal.  The scope included the refurbishment of the steel structure and the replacement of the glazing on the roof canopy.  D&D Rail Ltd were contracted carry out the following works:

  1. Profiled Roof Sheeting – replacement of existing profiled roof sheeting to the lower bay of the canopy.
  2. Patch repairs to damaged sections of the concrete eaves upstand beam.
  3. Removal and replacement of all the defective timber plates and fixing new & existing with suitable resin anchor fixings.
  4. Metal Sheeting Rib Filler Blocks – complete removal of all existing rib filler blocks and replace with new.
  5. Installation of new Roof Access Hatch and trimmer steels.
  6. Lead flashing around roof access hatch and vent ducts to match existing.
  7. Supply & fix Code 5 lead flashing to roof hip ridges and to head of roof sheets.
  8. Cut back existing hip ridge timber roll to allow flashing installation to all hips.

The existing profiled roof sheeting and glazing was removed sequentially by others prior to the commencement of our works.  As areas became available our specialist contractors initially attend site to install the lead flashing on the metal angle at the bottom of the glazing.  The lead was folded around the angle as per the existing flashing.  The profiled lead flashing was then folded back to allow the glaziers access to fit the glass roof panels.

Following the installation of new glazing in an agreed number of bays, our operatives carried out an assessment of the condition of the timber wall plates and concrete roof beam.  Where required we removed damaged lengths of the timber walls plates.  The profile of these timbers was cut at the required angle in our warehouse prior to delivery to site.  Following removal of the existing wall plates it was found that they were fixed in position via metal studs welded to the steel universal beam cast into the concrete roof beam.  Unfortunately, it was found that these studs had corroded meaning it was not possible to re-use them to fix down the replacement timbers.  Steel straps were therefore manufactured to fix the new timbers in place.  The steel straps were fixed to the new wall plates with coach screws and to the concrete roof beam with steel anchors and Hilti HY200A.

A joint assessment of the condition of the concrete roof beam was then made with the clients’ structural engineer.  As a result of this assessment, a methodology for the required repairs was agreed with the structural engineer.  Various Fosroc Renderoc cementitious products such as LA Repair concrete, Renderoc HB, ST & RP252 were used to repair the beam dependent on the depth and extent of the damage.  All exposed reinforcement bar and the universal beam were painted with Nitobond Primer prior to the application of the Renderoc, which was applied to damaged concrete in accordance with the manufacturer’s instructions and, where required, HAR Primer was applied to concrete prior to the application.

On completion of the replacement of the damaged timber wall plates and the concrete repairs the new profiled roof sheets were brought to site.  The new profiled roof sheets were laid out and fixed to the metal angle at the top and the timber wall plates at the bottom with steel tek screws.  Pilot holes were drilled in the steel angle with cobalt HSS drill bits prior to fixing to the steel angle.  The profiled roof sheets were lapped and pre-drilled with HSS bits and then joined with steel rivets.

Once the profiled roof sheets had been fixed in place our operatives installed the new rib filler blocks at the top of the sheets.  Our specialist lead workers then folded the flashing down over these sheets and dressed the lead.

Following the submission and approval of our CDS and fabrication drawings, steel trimmer beams were manufactured and delivered to site.  The trimmer beams were bolted to the steel angles at the top and the concrete beam at the bottom with the aid of brackets and steel plates.  The brackets at the bottom were fixed to the concrete beam with the aid of steel anchors and Hilti HY200A.  The new Roof Access Hatch was then carried to site and laid on the trimmer beams before being bolted into its final position.  Profiled roof sheets were cut to the required size/ shape and installed around the new hatch.  A sheet of chequer plate was cut to the required size and shape off site and the exposed edges chamfered with an angle grinder.  The chequer plate was delivered to the roof and positioned around the hatch on top of the profiled sheets.  It was fixed the steel angle at the top and the timber wall plates at the bottom with steel tek screws.

A new galvanised steel ladder was manufactured and brought to site following the submission and approval of a DCS and Risk Assessment.  The ladder was bolted to the trimmer beams at the top and through a second piece of chequer plate at the bottom used as a landing plate.  The edges of this plate were chamfered and painted yellow.

The existing roof Vent Ducts were incorporated into the new profiled roof sheets which were cut to the required size and shape prior to installation.  The skirts around the vents were reshaped/ profiled to the new sheets and drilled and fixed in place with the aid of large head rivets.

We also applied code 5 lead flashing along the length of the roof hips running up to the ridge.  Due to the associated wind loading this flashing was fixed to the hips with the aid of copper straps and shaped to the required profile.

 

 

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