The Most Leaky Roof in the UK?

Asking whether this is the most leaky roof in the UK, occupants were soaked as the parliamentary building’s roof this week sprang another leak.

PORTCULLIS HOUSE, which connects the Houses of Parliament in London with 213 offices for politicians and their staff, was opened in 2001.

Since then, the £235m building’s roof has never been free for long from cracks and water ingress. The atrium roof has needed constant repairs and refurbishments costing hundreds of thousands of pounds.

Most Leaky Roof

Just this week, the roof developed a cricket ball-sized hole at the edge of one of the glass panels which allowed torrents of rainwater to gush down on the politicians below.

Parliamentarians, aides and visitors were sent dashing for cover during their lunchtime breaks on Tuesday 11 July when rain collected between the triple-glazed roofing panels before gushing out onto the unsuspecting diners on the floor below.

It is far from the first time Portcullis House’s roof has caused shock and alarm to the building’s occupants.

Designed by architects, Michael Hopkins and structural engineers from Arup, the atrium roof had a series of snagging issues in its first 12 months. A total of 7,500 defects were recorded, according to a National Audit Office report in 2002. Further problems were then reported in 2005, 2008, 2010, 2011, 2013 and 2014.

In 2016, a study found that small movements in the roof were causing cracks in the glazing panels.

In 2018, MPS debated the problematic roof, which Vince Cable MP dubbed “scandalous”. MPs rejected plans to spend the then estimated £100million it would cost to re-roof the building.

A parliamentary estate spokesperson said this week the cause of the latest leak was once again being investigated. The area underneath the middle of the roof had been cordoned off.

“Teams are currently attending to an issue with the atrium roof in Portcullis House,’ the spokesperson said. “Committee meetings are still scheduled to take place, with amended access routes. Catering facilities remain open.”

Portcullis House Atrium Roof

Portcullis House is designed around a central courtyard over which the atrium roof spans. The roof is constructed from a domed diagrid of straight timber members with stainless steel joints. The frameless glass skin of the roof is supported on a delicate secondary web of steel struts and 6264 tension rods which are laced across the timber framework.

Underneath the roof is a courtyard café and meeting area with sofas and chairs. Until last year the ground floor area was shaded by full-size trees, but these were removed as they had become pot bound. The building is notorious for overheating, with the atrium roof creating a greenhouse effect.

The recurring problems which have included the glass panels shattering onto the ground below, as well as many leaks, are thought to be due to the tolerances between the roof’s metal, wood, glass and supporting structures being too tight.

When outside temperatures fluctuate, movement is created in the various element of the roof’s framework putting pressure on the glazing. This has resulted in almost 10% of the panels cracking and numerous leaks across the entire roof span.

Shatter-proof film has been fitted to the glazing to stop it fracturing into shards onto people below. At other times nets have also been installed. Areas have had to be repeatedly cordoned off on the ground and buckets placed to catch leaks, embarrassing MPs who meet important visitors in the area and pass through it to access parliamentary committee rooms. This week, Bank of England board members were in the building when the water poured on to the occupants below.

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