Many London skyscrapers have a dull name and a nickname. The Leadenhall Building is dull-ly titled because it's on Leadenhall Street, but is better known as the Cheesegrater because of its distinctive wedge-like shape. Here it is in Lego, in case you need reminding.
The Cheesegrater is the second tallest building in the City of London (or the tallest if you think the Heron Tower's 92ft mast is a cheat). It's the shape it is to protect views of St Paul's Cathedral from Fleet Street - the upper storeys taper back to keep out of the way of Wren's dome. Its planning application was approved in 2005, but construction was held back by the economic downturn and so final completion took place only two years ago. It's unusual in that the building's spine is at the rear, with a 'cassette' of liftshafts and utilities bolted onto the back, allowing the floors to cantilever forwards in open plan style for maximum office flexibility. 48 floors, 225 metres high, if you're counting.
The architects were Rogers Stirk Harbour + Partners, better known as "the agency Richard Rogers started", but since renamed to reflect new talent rising up through the ranks. Although it was never intended, the company needed new premises a couple of years ago and the 14th floor of the Leadenhall Building was available, so they now run their international practice from a building they designed. They were also the ones providing guides for the Open House tours, which meant visitors were particularly well informed.
The Cheesegrater squeezes a significant amount of public space into its small footprint because there's a gap where the ground and first floors ought to be. Bring your table tennis bat and you can even have a game of ping pong underneath the overhang in this outdoor atrium. Two sets of escalators swoop up through the void, on weekdays delivering a suited insurance salesforce to the main lobby on the second floor. Head through the security barriers and, surprise, you're already pretty much at the back of the building. Three sets of glass lifts shoot up from a lofty corridor fringed in geometric yellow, with (whoa!) an all round view if you stand at the rear.
What does a top-rank architectural practice have just inside its entrance? Security, obviously, and then a long rack of scale models of some of the more famous buildings they've designed. Lloyd's of London (1978-86) is there in wood at 1:500, while the Pompidou Centre (1971-77) is a colourful burst of perspex at 1:1000. Several far flung global landmarks are included - the practice has a particular penchant for airport terminals - but the Cheesegrater itself doesn't fit on the shelf and gets to stand elsewhere. Some modern clients now prefer to see a digital blueprint, but all the physical models are still cut, carved and stuck together in a glass-fronted workshop located in the room behind.
This being expensive real estate the RHSP workforce are tightly packed in, but there are also meeting spaces and a cafe area, plus breakout tables with a rather distracting view. The dome of St Paul's is clearly seen to the west, while other buildings the practice has designed are picked out by stickers on the glass. It doesn't take a sticker to identify the Lloyd's Building, whose metallic Grade I bulk rises immediately opposite, extruded service shafts and all. It must help for getting work done that this is only the 14th floor, not up in the forties, although the amount of floor space does get considerably narrower up there.
The guide for our group had worked on designing the unsexy part of the building - the basement - rather than the cheaper visible stuff in the sky. He therefore knew his stuff, in considerable depth, without cramming a few key facts the night before or having to read the salient points off a cribsheet. Maybe that's why he also ended up apologising for talking too much at each of the stopping-off points and making our tour much longer than everyone else's. When you're up a special skyscraper for a one-off visit, hell yes, these are the kind of guides you want. [7 photos]
Not every Open House building with a lofty view is a pre-book. Some are turn-up-and-walk-in, capacious enough to cope without a queue, and offering a perspective only employees normally see. This year Watermark House was one such venue, the employee base for a Japanese bank previously sited out in Docklands and now tucked in by the Thames adjacent to Cannon Street station. Their office block is built partly on the site of a Roman wharf and partly on the site of a key medieval trading post, which sounds dreadfully destructive except that several centuries of later development had already destroyed what was previously here, and all Nomura's tenancy replaced was a 1970s telephone exchange.
For Open House, all visitors got to see was the lobby and the 6th floor, but the 6th floor is home to the City of London's largest roof terrace, so that's all good. Open decking surrounds various bits of garden, some shrubby, some floral and one raised section used to grow vegetables. With a beehive or two, a row of deckchairs and a reflective pool, it all feels appropriately zen. The lack of pigeons is also a bonus, which is thanks to the two year-old Harris Hawk which handler Laura wields on site two days a week. Bumping into a falconry display in an elevated Japanese garden is one of the delights which helps keep Open House fresh.
I don't know how many of the employees bring their coffee or lunch out from the cafe inside, but what a great resource, and what splendid views. The twin brick towers of Cannon Street station dominate, but one's eye will more likely turn to the thread of the Thames. Immediately opposite lie Pickfords Wharf and the Golden Hind, while the Shard is unmissable further downstream, and then an unobstructed view of Tower Bridge. Pick your City employer carefully and every day can have a scenic interlude to balance out the hours of slog. [6 photos]