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More problems found with Portcullis House roof

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More problems have been found with the roof at the Hopkins-designed Portcullis House in Westminster, with yet another panel set to be replaced

The glass atrium has been plagued by issues since the £235 million building, which contains offices for MPs and their staff, opened in 2001.

In 2016 a 12-month technical study commissioned by the House of Commons’ Strategic Estates team into the causes of cracks in the roof panels, concluded that, despite ongoing problems, the roof would last its 30-year lifespan.

The £210,000 study looked at movements in the roof over a year-long cycle and confirmed that it was structurally stable and posed no safety risk.

But yesterday (July 19) a House of Commons spokesperson confirmed there had since been a further problem with the roof, which has caused part of the atrium to be closed off.

‘We are aware of an issue with one of the panels on the Portcullis House roof. The area is cordoned off and does not represent a danger to users of the building,’ they said.

‘Scaffolding is in place, and netting will be suspended underneath in preparation for the replacement of the panel, which will be undertaken once a temporary replacement panel has been manufactured (within the next three weeks).’

Last year’s study, based on computer modelling and more than 350 measuring points across the glazing, confirmed that the cracking in the glazing panels had been caused by small movements in the roof which were transmitting the loads into the glass units.

The report said that seasonal variations and settlement in the building’s roof structure could also have been a factor as the fixings designed to accommodate any movements may have been taken to the edge of their tolerances, causing the glazing units to fail.

It concluded that most of the settlement in the 16-year-old building’s structure had now probably already happened, and instances of breakages would reduce over time.

However the study warned that up to £200,000 would have to be spent on the roof during the next 12 to 18 months, with the possibility of a further £1.5 million over the remainder of its life when all the glass panels would be replaced. 

The strategy

The technical study recommended the following strategy for managing the maintenance of the roof: 

Immediate works (within 12 months)

  • Pack gaps that have opened up between some glazing support members, retighten glazing support rods and repair failed weather seals. 

    Cost up to £200,000

Medium term works (within five years) 

  • If further glass panels crack, install bracing or ties to limit movement
  • Replace polycarbonate panels with glass if there is noticeable discolouration in the replacement panels
  • Replace all seals between glazing panels if there is noticeable misting within the glazing units

    Cost up to £1.5 million 

In the building’s first year alone, 7,500 defects were reported in the office block, including loose door handles and cracked glass, according to a National Audit Office report in 2002, which examined its spiralling costs.

In 2005 a specialist crane was needed to replace four glass panels at a cost of £100,000, with a further £34,000 spent replacing panels since 2009.

Before this report was commissioned there had been a number of attempts at fixing the roof’s problems but many were abandoned due to cost issues.

In 2008 a glazing consultant made recommendations to solve the problem, however the roof was not deemed to be a hazard, so no action was taken.

Since then a number of panels have shattered, with a glass panel found hanging from the frame and glass shards falling to the floor in one incident in 2014.

A special ‘anti-shatter film’ was then installed on the underside of each panel to stop pieces of glass falling to the floor, while panels that cracked have been replaced with polycarbonate.

Although MP considered launching legal action against the design and construction team last year, no proceedings were ever brought forward.

  • 1 Comment

Readers' comments (1)

  • 30 year lifespan for a roof on a £235m office??
    What wonderful sustainability......

    Unsuitable or offensive? Report this comment

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