Council on Tall Buildings and Urban Habitat
 London Conference News: Day 3
June 10, Pre-conference June 11, Day 1
June 12, Day 2 June 13, Day 3

Technical Tours

The Leadenhall Building Tour
By Robert Lau
The Leadenhall Building Technical Tour was kindly supported/organized by: Laing O’Rourke.
Developed by British Land and Oxford Properties, The Leadenhall Building is an exceptionally complex, 52-story engineering project undergoing construction in the heart of the City of London. The project team of Laing O’Rourke, Arup and Rogers Stirk Harbour + Partners explained how they have overcome extraordinary technical challenges through the implementation of innovative design and construction methods, driven by focusing on offsite manufacturing of building components. While there were several engineering challenges, the manufacturing and installation processes proved to be the highlights of the tour.
The site is quite constrictive, as are most sites in London. Ground for staging of materials was nonexistent. Street width and access controls determined the size and timing of delivering manufactured components, from steel sections to HVAC equipment. The longest steel section was 28 meters and the heaviest was 42 tons. However, the project team determined that factory-manufactured finished components were superior in quality to site-constructed components. As a result, the majority of installed items have been trucked from distant factories to this site with just-in-time delivery methods.

The vision of this office tower is to preserve the view corridor to St. Paul’s along Leadenhall St. As a result, the tower slopes away from this view corridor, toward the north. The north elevation forms the backbone of the tower by providing all services, elevator access, and structural stability. Complete sections of this megaframe were manufactured in factories, including the steel, HVAC equipment and precast concrete floor slabs. All steel was custom-fabricated, and fire-coated with intumescent paint at the factory. The sub-assembled modular components were lifted into place to form the 52-story structural megaframe, including 192 K-braces. The megaframe was intentionally installed out of plumb to resist the sloping lateral thrust of the south elevation as it rises along Leadenhall St.
The Leadenhall Building was nearly topped out
All steel columns and beams were custom-manufactured. The sloping exoskeleton is braced by the north megaframe, while six interior vertical columns support the office floors. Some nodes weigh as much as 21 tons. All field connections are bolted. The 3m x 4.5m precast floor planks are then dropped into position, and fixed into place on the steel beams via grouted rebar. Only required six installers were required per floor to place these planks, replacing the typical concrete crew that would be used to install a cast-in-place floor slab.
Delegates learn about the precast floor planks Tour attendees gather for a group photo
The building is double-skinned, using unitized cladding for the exterior rain screen and a double-glazed interior. The seven-story cavities are naturally ventilated to control the thermal expansion of the exoskeleton steel members. The unitized cladding was installed at the rate of 22 units per day. 

From an environmental viewpoint, the Leadenhall exemplifies a well-sited urban tall building. It contains few car parks, and many more bicycle and motor scooter spaces. There is also excellent public transportation available immediately nearby.

City of London Tour Report
By Daniel Safarik
To truly gain an understanding of how to reconcile “Height and Heritage,” the theme of this year’s CTBUH International Conference, one of the best options was to accompany the man whose job it is to do just exactly that. Peter Wynne Rees has been the chief planner for the City of London for 28 years. If one has the privilege of joining him for a few brief hours, his experience comes rolling out in a regalia of inside stories, one-liners and minutiae that solidify the visitor’s understanding of the richness of the Square Mile, and the challenges that come with guiding new construction in a lucrative, yet charming place.
City of London skyline with The Leadenhall Building (center) and 20 Fenchurch (right) under construction

On a blustery June morning, Rees took his charges through several hundred years of London history, through alleys and pubs frequented by Dickens, and through the remnants of Roman gladiatorial amphitheaters, illustrating the critical role that the coordinated chaos of the streets plays in a city’s vitality, all the while underscoring why tall buildings must succeed at street level in order to reinforce that vitality.

Echoing a theme he had hit upon in his address to the Conference, Rees defined the prime product of the City – the possibility of chance occurrences and shared gossip that could lead to vital business insights – which under his guidance, is to remain inviolate, regardless of how tall or dense development becomes.

“The City, being right in the heart of London, has the opportunity to be both the party and the workplace,” he said. “We are both the ‘compost’ and the ‘beehive’ here, and the honey is the gossip: the result of the bees rubbing up against things accidentally.”

In Rees’ telling, this means that even nominally excellent pieces of architecture can fail urbanistically.

“Buildings are almost irrelevant; people will find a place to work if they want to be in a place badly enough,” Rees said. “If there are places to gossip and bump into each other, then you will find an office nearby to do your business.” He noted the impending move of media outlets such as Bloomberg and advertising firm Saatchi & Saatchi into the City as examples of gossip’s magnetism.

Even though Richard Rogers’ Lloyd’s of London building is now a Grade I-listed historic building, and justifiably so, Rees finds fault with the way the building “floats in space” above the ground and creates awkward spaces around itself, he said.

“This building really broke the mold, and I think it’s a wonderful piece of architecture,” Rees said. “But as a planner, I have problems with it. It doesn’t meet the ground. You have these horrible spaces underneath the building. I do like a building that looks at its site, and somehow talks to the place where it is built.”
Lloyd's Building
Yet, he pointed out, this being the City, an urbanistically hostile Grade I-listed building from the 20th century does not crush the vitality, so long as it is directly adjoined by a Grade II-listed public market from the 19th century, Leadenhall Market, where conviviality can carry on.
Leadenhall Market, Photo by DAVID ILIFF
Rees’ operating theory is that monocultures in cities– most relevantly, in business and design – are as destructive to an ecosystem’s vitality as they are in nature and agriculture.
The planner’s antipathy toward the banking industry -- or at least the idea that the City was in recent decades becoming a monoculture thereof -- was on raw display during the tour. Rees chronicled his experience with Barclays Bank, which built a 19-story, postmodern, barrel-vaulted complex just yards from St. Michael’s church. Rees felt the project was overscaled for the site. Barclays had threatened to leave the City for Canary Wharf if it did not get its way, so Rees’ recommendation against project approval was overruled by the councilors in office at the time. Barclays moved into its building in 1992, and slowly decamped for Canary Wharf anyway, department by department, over the next few decades.

“So we got the building, and we haven’t got Barclays Bank,” Rees said. “I am pleased that we haven’t got Barclays Bank, but I am not pleased we do have the building.”
Former Barclays Bank Building
If Barclays got his heaviest criticism, Rees’ highest praise was reserved for a strikingly contemporary, if not particularly tall office building, Grimshaw’s 25 Gresham Street (Lloyd’s Banking Group), which sits back from the street behind a medieval church yard. The trees of the yard were retained and appear to be growing up into the building, which has two cantilevered leaves on either side of an atrium. Though its curving profile looks nothing like the stone livery halls that dominate the area, it does look as if it belongs there - which is exactly the point.

“Now that is building in its context,” Rees said. “That is a building that understands its site. That is what I am trying to achieve. I am not trying to tell an architect what material to use or what style to work in. I am saying, ‘Make this building work with its site, in your way.’ And when that happens, it’s magic. That’s what gives me pleasure.”
25 Gresham Street, Photo by Steve Cadman
Rees maintained that he does not have a favorite building, and whether he “likes” a building, as a planner, is beside the point. The question that must be resolved is: Does the building work from the perspective of urbanity?

In good planning, skepticism pays off. Rees is skeptical that a city can rise like a Phoenix, instantaneously, without a solid foundation of commercial culture and civic life beneath. Building a menagerie of towers does not a city make, no matter how exciting the architecture is, Rees said. He likened good architecture to “the icing on the cake…but first you must have the cake.”
Peter Rees (middle) finishes the tour with a view of St. Paul's Cathedral
Wending through the City for three hours confirms this argument, though it also confirms the uniqueness of the district.

“If you are going to have a vibrant place, why not also have good architecture to bolt on as well?” Rees said. “The fact that we now have tourists who come to London to photograph modern office towers tells you we have been doing something right for the past 25 years.”

Thames Boat Tour
Featuring: “The good, the bad and the ugly,” Commentary by Peter Rees
By Caroline Stephens
The Thames Boat Tour Hosted by Peter Rees was kindly supported/organized by: Hilson Moran
The Thames Boat Tour started at Westminster Pier which lies below Westminster Palace and opposite County Hall and the London Eye. On boarding, delegates were handed mini branded binoculars by Hilson Moran and offered a glass of fizz.
Vince Ugarow of Hilson Moran welcomes delegates aboard the William B

The grey skies gave way to sunshine as the boat made its way west, up the river to Vauxhall, where the boat turned around. Peter Wynne Rees, head planner for the City of London, started his commentary with an urban myth: apparently the Russian word for “railway” is vokzal. The Russian parliamentary delegation visited the UK in the 19th century to visit the famed new railway station at Vauxhall, and when they asked what it was (meaning the building), they were told, “Vauxhall.”

When passing the Millbank Tower (the 118-metre/387 ft high skyscraper in the City of Westminster), Rees mused that it would be interesting to find out why tall buildings are constructed in isolation.

Millbank Tower (left) and the London Eye (right)
As the boat passed under Lambeth Bridge, delegates were advised that the pineapple sculptures on its plinth represent the time when pineapples first brought into UK!

Approaching Blackfriars Bridge, Rees enthused that it is a brilliant example of engineering, and the fact that it remained an operational train station over a heavily trafficked  and busy river whilst the bridge and station expansion is underway, is certainly commendable.
Blackfriars Bridge
We cruised past Arts Ark Downings Roads Moorings which is one of the oldest surviving river moorings in London. The group of historic trading vessels supports a community of artists who organize arts and crafts events.
City of London with some of London's most famous skyscrapers including 20 Fenchurch (left), Leadenhall Building (center), and 30 St. Mary Axe (right)
Further east, the boat crossed the plane of the Thames Tunnel, designed by Marc Isambard Brunel and built between 1825 and 1843. It was the first subterranean crossing of the Thames, one of the first submarine tunnels anywhere, and the first use of the tunnelling shield invented by Brunel. It began life as a pedestrian tunnel, but by 1869 it supported railway use, as it continues to do so today. The Thames Tunnel Mill in Rotherhithe is a listed mid 19th-century former mill building and warehouse. It is one of the earliest warehouse residential conversions in the Docklands.
Thames Tunnel Mill
The Prospect pub, also in this area, is one of London’s oldest. Upon approach to Canary Wharf, Rees remarked on the steady development of the group of buildings since its initiation in the late 1980s: “It looks like something is going on there, rather than standing alone.”
Canary Wharf with One Canada Square (center), the former tallest building in the United Kingdom
Rees pointed out a 1970s tower block, which had 6 stories added to generate more money, which was then spent on more housing. “The river is a great piece of public space,” he said, remarking on the Thames’ role as a “front yard” for vast and varied sections of London.

20 Fenchurch (Walkie-Talkie)
View from the top of the Walkie Talkie building.
By Alan Cronin
The 20 Fenchurch Technical Tour was kindly supported/organized by: Canary Wharf Contractors.

Set to complete in 2014, 20 Fenchurch Street is already a feature of the London skyline. The 38-story, 177-meter tower has been nicknamed “The Walkie Talkie” because of its distinctive shape and stood proudly in front of the tour group as it arrived at the marketing suite directly opposite the site to begin the technical tour.

The tour started amidst the models in the marketing suite, where Kiran Pawar of Land Securities and Andrew Heath-Richardson of Canary Wharf Group described how the two companies had joined forces to develop 20 Fenchurch Street. The 16 tour members were then talked through the architectural aspects of the project by Marcos Blanes of Rafael Viñoly Architects and Andrew Ashfield of Hilson Moran, the Engineering and Sustainability consultant, who presented the overall services strategy for the building.

The group donned its Personal Protective Equipment (PPE) and transferred to the Project Meeting Room on-site, where a presentation on the project began. What became most evident, was how important 4D BIM technology had been to the Project Team, which had used it at concept through to detail design, and now into construction, showing how using technology enabled lettable space to be maximzed, and the building designed to a density of occupation of one person per eight square meters throughout. 

Level 32, south facade

This has resulted in tenants being able to occupy 20 percent less space, while accommodating the same number of people. BIM and 3D Revit modelling had enabled the design team to optimize the space to incorporate all of the services into the most efficient area possible, without compromising on performance. It was clear that the digital technology had not only influenced design but also construction even to the point of planning road closures and site logistics with the City of London authorities. This collaborative approach has been key to the success of the project.

The delegates then went on-site to the basements, where the benefits of integrated design approach were clear to see, as large areas of plant sat neatly in place with services distribution seemingly planned to the millimeter. The group then passed the eventual location of the 300 kilowatt fuel cell.

View of Tower 42, the under-construction Leadenhall Building and the Gherkin.
The tour continued onto level 11 to observe one of the typical, smaller office floors. Uninterrupted views across the river Thames opened up upon leaving the goods lift.

Although the roof structure, an extension of the the fins that hug the curves of the tower, are still being put in place, it didn’t take much imagination to see why the strap line on the site hoarding of the building ‘with more on top’ was adopted.

The location of 20 Fenchurch Street on the southern edge of the cluster of towers in the City of London provides 360-degree views over the City of London with the Gherkin, the under-construction Cheesegrater and Heron Tower in close proximity. Over the Thames, the Shard stood proud on South Bank. The Walkie-Talkie’s sky garden will also include a restaurant and provide three levels of public space.

The group then returned to level 32, and headed back via the goods lift, through the main lobby and back to the marketing suite.
Delegates got to explore the still under construction 32nd floor
The tour allowed delegates from the CTBUH Conference to closely examine a building they had already heard so much about during the event, with presentations on nearly every aspect of the project, from joint venture developers Land Securities & Canary Wharf Group, Canary Wharf Contractors, Rafael Viñoly Architects and engineer Hilson Moran.

A simple hand poll on the completion of the tour suggested that, in-line with the discussions at the CTBUH conference of the last two days, that 20 Fenchurch Street is already on its way to qualification as an iconic building in the City of London.
Facts and figures:
Commencement date First Qtr – 2011
Project Completion Date First Qtr – 2014
Total office 31 floors

Total floors of basement 2
7 Double Deck Low Rise Lifts  @ 4.0m/s
7 Double Deck High Rise Lifts @ 6.0m/s
2 Goods lifts at 3000kg
2 Fire-fighters lifts
2 Lorry Lifts at 20,000kg
Along with bicycle and passenger lifts within the Annex building
Total concrete 28,000m³
Total concrete used for core – 12,823m³
Total concrete used for raft -8000m ³
Structural Steel 8000 tonnes
Total reinforcement steel 5000 tonnes
 Metal Decking 69,000m²
Glass 32,727m²
Height of building 160m
NLA – 684,458 square feet
GIA – 1,112,356 square feet

30 St. Mary Axe
30 St. Mary Axe is one of the most recognizable buildings on the London skyline Photo by: Toby Philips
By Robert Lau
The 30 St. Mary Axe Technical Tour was kindly supported/organized by: 30 St. Mary Axe, Evans Randall, and IVG.
Since its completion in 2004, 30 St. Mary Axe has become a firm favorite, referred to by Londoners as “The Gherkin.” Incorporating multiple green features, including operable windows and multi-story atriums, it set a new standard for high-rise design in London and beyond.

The significance of the Gherkin is that it was the first in a high-rise district within London. Many others have now followed in its path. At 40 stories, it is not a significantly tall building globally, but is very much so in London. The old Baltic Exchange covered the entire site (street to street) before it was demolished in an IRA bombing in 1992. An initial desire was to open the grade to a pedestrian plaza instead of building over the entire site. As a result, the ground floor has an inviting pedestrian experience.

The twisting, cylindrical form is a result of the desire to provide natural ventilation, which produces a positive stack effect from any wind angle. The insertion of slots into the floor plates comes from a desire to introduce natural lighting into the deeper office areas. The final result is a series of five-degree twisting atria of six floors each. The entire building is sprinklered, and each atrium contains smoke curtains at the top floors to control any smoke produced.

Delegates gathered in the lobby © Dario Trabucco
The structure of the tower is in the diagrid perimeter. This has been designed for gravity loads, but the innovative structure, acting almost like a shell, is also stable in wind. The perimeter was custom-fabricated but the interior skeleton of the structure is comprised of standard steel components. This created a 30% custom-to-70% standard steel fabrication ratio, for economy.
One of the six floor atria of 30 St. Mary Axe
The double skin provides natural ventilation for many times of the year, adding to energy savings. Shades between each layer of the façade control the sun's glare. The atria act as buffers to limit extremes in temperature and to provide sufficient ventilation flow.

The Class A offices continue to provide exceptional space. The raised floor and suspended ceiling offices are physically separated, but viewable from the atria. Even though newer office projects have developed around the Gherkin, it continues to be a premium address.
Delegates gather for a group photo during the tour
The most spectacular spaces in the building are the 39th floor restaurant and 40th floor bar. The restaurant has 180-degree views of London. The bar has a breathtaking 360-degree complete view of all of London and beyond. No columns or mechanical equipment obstruct the view. The glazing has been carefully engineered to provide views out without letting admitting harmful UV rays. This feature makes the building particularly well-suited to its environs, despite its initial controversy over shape. One delegate stated, “London without clouds is Paris!” Day or night, this is the best spot in London to view the city.

Broadgate Tower Tour
By Richard Witt and Daniel Safarik
The Broadgate Tower Technical Tour was kindly supported/organized by Broadgate Estates, British Land and Blackstone. Additional touring was kindly provided by SOM.
The Broadgate Tower, developed by British Land and Blackstone as part of their highly successful City office estate, was designed by Skidmore, Owings & Merrill (SOM) and was the first tower building in the City designed specifically for the speculative market.
At 161m (529 ft) tall, it provides stunning views of London and elegant, wonderfully light offices over 30 floors. The Broadgate Tower is one of a small number of new buildings that redefine the City skyline, creating a corporate presence and identity. It now anchors the northern cluster of towers that rise near the financial heart of London.

The Broadgate Tower is the location for world-class businesses such as Reed Smith LLP, Itochu, Greenlight, William Blair, Dickson Minto WS, Regus, Gill Jennings & Every LLP, Liquidnet, Hill Dickinson LLP and Itau BBA.

Since launch, The Broadgate Tower has received numerous awards for its innovative architecture and design, including a New City Architecture Award, as well as being named the Best Tall Building in Europe by the Council on Tall Buildings and Urban Habitat.
Broadgate Tower as seen from below
The Broadgate Tower represents the resolution of an architectural and structural challenge, because it was originally designed in the 1990s as a 14-story financial services office building with large trading floors of up to 80,000 square feet. The preparations for that structure involved building a 2.5 meter-deep steel raft over 14 active railway tracks leading into Liverpool Street Station, which could not be taken out of service for any period of time.
Delegates take in the view of London from one of the office floors
“Over time, towers became more acceptable,” said Kent Jackson, director at SOM’s London office. “The raft was already in, but there was now an opportunity to go tall. We had to retrofit the structural solution that was already in place.”

Because no columns could be sunk into the railway trench, the majority of the tower’s weight is carried through a network of 2- to 3-m diameter piles with 7-8-m diameter underreams on the west side of the trench, and through massive angled struts that span the width of the trench and channel forces down from the east side of the tower. These struts connect to a steel exoskeleton that gives the building its distinctive appearance. This constraint, combined with the need to maintain view corridors from Richmond Park and Westminster Pier, accounts for the building’s unusual shape, Jackson said.
The entrace lobby with the escalators to the second floor elevator lobby
So little of the site is on solid ground at street level, that there is no room for elevator pits. Tenants take escalators up to the second floor, through a large glass atrium connected to the pedestrian passage between the 35-story west building (the Tower) and the 201 Bishopsgate, the 14-story east building. Bishopsgate now contains more modest trading floors than originally planned in the 1990s, at 40,000 square feet each; the Tower’s floor plates measure about 13,000 square feet. Again, the constraints of the tower’s shape forced another design choice that makes the building distinctive: Broadgate Tower is the world’s first to use destination-controlled, double-decker elevators, Jackson said.

Canary Wharf Tour
By Daniel Safarik
The One Canada Square Technical Tour was kindly supported/organized by: Canary Wharf Group PLC.
A tour of Canary Wharf is an object lesson in the kind of place-making that can stem from the exploitation of an increasing rarity and developer’s delight: a 100-acre (40-ha) blank space in a major metropolitan area. Before the City’s cluster of towers emerged at the beginning of the last decade, Canary Wharf was where large businesses – Citigroup, HSBC, JP Morgan, Reuters – went to secure the largest possible floor plates in the region, up to 80,000 SF. When they arrived, they found a unique build-to-suit developer / contractor / manager in Canary Wharf Group PLC. In the late 1980s, the earliest pioneers did not find much else, although a critical link in the Docklands Light Railway (DLR) had wisely been extended into the abandoned wharves and jetties on the Thames’ North Bank.
Canary Wharf as seen from the River Thames
The cluster of towers that now houses more than 15 million square feet of office space, 700,000 SF of retail, and 100,000 workers did not spring up all at once, but gradually grew outward from the center point.
This point is where the perfunctory DLR station was adjoined by Cesar Pelli’s One Canada Square, a 50-story Class A office building with a pyramidal crown. At the time, Britain’s financial services were deregulating in the “Big Bang,” and this was London’s bid to capture global financial institutions before they looked elsewhere. Less a “stake” in the ground than a beefy axis mundi, the 1.5 million-SF One Canada Square epitomized the confidence its developers were intending to project.

It was a big risk that paid off immensely. The building remains the tallest in the development, and new buildings step down away from it in succession, providing a sense of order and composition that its City compatriots have a much harder time achieving, as they swerve out of the way of heritage view corridors on their irregular plots.
One Canada Square is the center of Canary Wharf
Canary Wharf Group’s aim-to-please, one-stop-shop approach, combined with its laser focus on optimizing transit connections, largely accounts for the development’s success, said Tony Jordan, vice president of development for Canary Wharf Group.

“When we first started, there were about 800,000 working people within one hour’s commute of Canary Wharf,” Jordan said. “With the improvements that have taken place in public transportation over the last 25 years, that figure is now 2.5 million.”

The developers have a history of tweaking planned urban infrastructure to their own purposes, yet have provided many public benefits in the process. They built a canopy over the DLR platforms that reads like a postmodern version of the many Victorian trainsheds of Central London, which encourages travelers to dwell a bit longer in the attached subterranean mall, Cabot Place.
DLR platforms Canary Wharf Jubilee Line Underground station
When London Underground built the Canary Wharf Jubilee Line station in 1999, Canary Wharf Group worked with architect Foster + Partners to add an additional three entrances to accommodate an expected 33,000 people per hour at peak times.

And when Crossrail, the east-west express train service set to commence in 2018, reaches Canary Wharf, access for an additional 36,000 people per hour will be through an elaborate multi-level station submerged in a canal and the soil beneath. Cunningly, every transfer passenger between these modes will also be a Canary Wharf visitor – and potential shopper. The developers invested money and design input into the Crossrail station, so as to limit the impact of construction works on occupiers, but also to force-channel transferees through acres of underground retail.

“There was talk at one time of driving a very deep tunnel from Crossrail to the Jubilee line platform. We did not encourage that idea,” Jordan said. “We’d much prefer passengers to come through our retail.”
Typical office floor in One Canada Square
Everything onsite is optimized to provide the highest level of service, comfort and neighborhood amenities for the population who come here each day, Jordan said. The redundant utilities substations and cabling, stable of 32 lifts capable of speeds of 4 m/s, and core design in excess of fire code that characterize One Canada Square have set a high bar. Canary Wharf Group has seen fit to replicate or better these features in each new building on the estate, said Paul Mutti, director of building services at One Canada Square.
The inside of the pyramid on the roof of One Canada Square provides space for mechanical equipment
“In terms of the design standards for engineering services, we typically put twice the plant that you’d get in a typical building in London,” Mutti said.  “We are trying to avoid single points of failure inside as well as outside. Our service allowances in terms of cooling and power are generally better than standard.”
Delegates enjoy the view from the roof of One Canada Square
After touring an empty office floor, rooftop mechanical plant, mid-rise electrical substation, and the Building Management System control room, visitors to One Canada Square were taken on a brisk walk around the estate’s shopping malls and public squares. Geraldine Ryan, Corporate Liaison Manager for Canary Wharf Group, noted the public art, jazz clubs, and 30 acres of parkland for those who would mistake the place for a mere office park or shopping center.

The investment in the public realm has proven convincing. Between 20,000 and 30,000 people now live within a 10-minute walk of One Canada Square, she said. More mixed-use development is planned on the eastern fringes of the complex at Wood Wharf, where at least six more buildings are envisioned. In the meantime, Wood Wharf is a pop-up park. A room-sized 3-D model showed many future buildings in clear Perspex; unfortunately photography was not allowed.

While the City now epitomizes the tensions between “Height and Heritage,” Canary Wharf is now a place that has its own heritage to contend with. It’s beginning to take on the auspices of a city in its own right, though one psychologically still more at a remove from the City than the two-mile, 15-minute train ride from the Bank of England would imply.

Jubilee Park

Centre Point Tour
By Carissa Devereux
The Centre Point Technical Tour was kindly supported/organized by: Almacantar.
The historic Centre Point tower is an exceptional example of architecture completed in 1967. Originally built as a speculative office building, it now stands as a historically significant building that has been designated a Grade II listed building in the English Heritage Archive. Currently undergoing a retrofit, and a change from office to residential space, this tour allowed access behind the scenes of the building.
The presentations provided a glimpse into the team’s vision of engaging with the public space with a “heritage-led approach” to the retrofit, and illustrate how Centre Point has the “potential to really anchor this section of Oxford Street,” and “engage with the city at large in a unique way,” said Gavin Miller, Partner for Rick Mather Architects.

After presentations, delegates were led on a tour of the mezzanine and the link bridge to see where the future square around Centre Point will come to life once the building’s retrofit is complete. The proposed square will connect with the growing tube station, and really provide a strong relationship between building and space.
Delegates got to view the city from the top of Centre Point

Heron Tower
By Simon Lay
The Heron Tower Technical Tour was kindly supported and organized by: Heron.
Heron Tower is a world-class office building at the heart of London’s financial district. Stretching 230 meters into the London skyline, the 46-story building, which was completed in 2011, is the tallest in the City of London. It provides 36 stories of exceptional office space, with bars and restaurants on the ground and uppermost floors.

It's hard not to be impressed by Heron Tower. The £3.5M fish tank features lavish attention to detail, from the imported brilliant white stone and the careful selection of precisely the right thickness and patterned stainless steel cladding. The building stands as a testament to the business environment in 2004, when the scheme was amended to make it taller and more impressive than even the original planning permission the site had achieved.

But in a post-2008 era, does the exquisite building stack up? Will Heron rue the decision to spend money beefing up the structure to add 3 floors of lettable space, rather than making it possible to infill the atria that define the North facade?

Photo of Heron Tower
“The ‘village effect’ will really come to life when you have lettings that span floors,” explains Paul Simovic, director responsible for the project at KPF. However, even without that physical connectivity, the light penetration into the open span office spaces is remarkable, creating a sense of perimeter and tradition that was found in early sky-scrapers in the US, which articulated their facades to bring in light and fresh air.

Sadly, to date, tenants at the tower are not opting to take up the option of fresh air via the mixed-mode design that was incorporated in the scheme. Undeniably, offering tenants the option of a fully-sealed box against natural ventilation in a mixed-mode design was essential in a city where operable windows are far from the norm. However, one can't help feel that in operation, the tower is not fulfilling its maximum sustainable potential.

Like the Leadenhall "Cheesegrater," the Heron tower adopts a side-loaded core design, and it may perhaps initially seem wrong that the core is on the side of the tower that arguably has the best views. But as Simovic explains, views into the high rise cluster are fleeting, and both the Pinnacle and 100 Bishopsgate projects will impact on sight-lines to the south. More important to the scheme was the idea of using the core to shade the southern elevation. This single decision contributed to more than half of the energy savings achieved in the design.

The asymmetrical core introduced specific construction challenges, explained Jonathan Inman of Skanska. Lateral movement during construction as building mass is added plays a significant role in a side-loaded core design, and a 40-story "pre-camber" had to be calculated and incorporated into the construction.

Resolving the construction challenges of a tight, historic site, whilst seeking to shave months off the build schedule helped Skanska win this project, explained Inman. A complex and highly ambitious top-down approach used 3m-wide caissons to enable the piles to be driven through the ground, before the excavation of the soil around the access shafts to create the basement box commenced. This was, quite rightly, recognized with plaudits and awards.

Delegates tour Heron Tower with views of The Gherkin

Overlapping construction elements of the project, which are normally separated, took over 6 months off the schedule. Constructing the superstructure whilst the basement was being dug out, and enabling archaeological investigations whilst demolitions took place were critical to the accelerated schedle. Further time and cost savings came from the adoption of digital design methods and BIM, rationalizing the structural connections so as to reduce their number by a third.

It's questionable whether a building of the same quality as Heron Tower will be built in the foreseeable future in London. The push for smaller floor plates and shareholder revolts at opulent HQ locations will surely shape the next tranche of towers.  It's also not clear whether the construction improvements achieved by Skanska on this scheme will be repeated, as many of the pioneering advances they executed on this scheme have become the new norms.

Perhaps the great leaps forward have been made, and future improvements will be more incremental, unless of course the tenant demand really shifts towards the more utilitarian, clearing the way for the the fully modularized, off site approach emerging from China to find a place in London.

Lloyds of London Tour
By Dario Trabucco
The Lloyd's Building Technical Tour was kindly supported/organized by: Paragon.
The Lloyd’s Building received strong opposition after its completion, and almost 30 years later, it still remains a very recognizable building in London, and all Londoners have a clear opinion on it: either they love it or they hate it. There are four trading floors, and the building was designed to allow expansions.

The building is still controversial but it still works very well, with 2,500 traders and an additional 3,000 employees working here every day. Desks in the trading floors are owned by syndicates that are highly specialized insurance companies. Brokers receive orders from all around the world, and they travel to the tables to get offers for a specific project. The firm is known for choosing well, a notable exception being the choice to insure the Titanic.
The Lloyd's Building atrium is maximized by moving most mechanical systems to the outside of the building.
The building can be easily transformed to add two extra floors. The buffer space for expansions is now rented to law firms, but Lloyd's can promptly free the space and expand the building.

The building still uses a good deal of the original equipment, such as generators. The whole assembly of the building is designed to be reversible and expandable. Patterned after Rogers' previous seminal building, the Beaubourg Museum / Centre Pompidou, in collaboration with Renzo Piano, the Lloyd’s building also appears to be “inside-out.” All of the mechanical equipment is on the exterior of the building, and the interior completely free of obstructions to maximization for tenant use.

St Paul’s Cathedral – The Grandfather of Tall in London
By Patti Thurmond
The St. Paul’s Cathedral Technical Tour is kindly supported/organized by: Surveyor to the Fabric of St Paul’s Cathedral, by kind permission of the Cathedral Chapter.
A fortunate few Conference delegates were able to fully embrace “Height and Heritage” in the technical tour of St Paul’s Cathedral. Led by architect and Cathedral Surveyor Oliver Caroe, this tour provided a unique look not only at the history and structure of St Paul’s, but at how the cityscape of London is still being affected today by this historic icon.
St. Paul's Cathedral, photo by: Mark Fosh
The tour began with a brisk walk up to the Whispering Gallery, where in years past commoners could stand to view services, overlooking the nave of today’s St Paul’s. The first St Paul’s Cathedral was founded in 604 AD. As Caroe explained, the spiritual, educational, and civic life of Londoners all took place here. The last St Paul’s was the largest building in medieval England, longer, taller and wider than today’s.
Whispering Gallery
Clive Cornwell, City of London Corporation, joined in leading the tour. He shared the story of how protected views of today’s St. Paul’s have come about, with the non-negotiable St Paul’s Heights grid (1938) and the eight protected long distance Strategic Views (1991). In the Trophy Room, Mr. Caroe presented the Christopher Wren design of the Cathedral. At age 23, Wren had argued his plans to restore St Paul’s, when just 7 days later, it was all but destroyed by fire. Wren’s great vision and talent were available just when England needed it most. Shortly after being granted the design, Wren commissioned the Great Model, a working pattern, a structural model, and a fund raising tool.
The Great Model, a working pattern, a structural model, and a fund raising tool
In 1694, Wren used the exact same piece of paper from his early work in 1675, to start to draw the dome over the building, trying to work out where the dome’s structural load was going to go. It is an excellent example of Wren’s “bottom-up” design.
The building was completed in fragments, but this single-floor plan of the whole cathedral gives a good view of the overall plan. The Cathedral was intended to give a ceremonial access linked into the streets of London. Delegates enjoy this unique, cantilevered Geometric Stair, as featured in many movies, which brings people into the house of worship from the southwest tower entrance.
The perfect Georgian Library has hardly changed at all since constructed. Completed in 1709, due partly to the additional funding and patronage of Queen Anne, the books in this room were part of the original gift to restore the intellectual heart and spiritual knowledge that was lost in the fire. The group was shown an extraordinary drawing by Wren in 1706, showing the continuing construction of the cathedral. This is the moment when Wren drew the final section of the dome that he actually builds. And in a final thought, he tacked on an extra piece of paper and raised the height of the cupola to 530 feet. The essence of Wren’s genius is that he was able to make very late design decisions and carry them through. This drawing and story are available online.
Wren's drawing in 1706 of the construction of the cathedral
Caroe took the group of delegates to the upper chambers to explain the Cathedral’s structural system, pointing out the brick, stone, wood and iron all used in the construction of the Cathedral. It’s believed that the Great Model may have shown the need for relieving arches, which Caroe pointed out in the floor – two great relieving arches, curved the “wrong” way to help spread the load. Caroe explained how the saucer domes were constructed, as well as the choice of these 56’ oak beams from the Duke of Northumberland.
Relieving arches
Moving up to the Stone Gallery, one can easily observe what the results of careful planning look like in London. Cornwell pointed out the deep wedge of tall building construction in the cityscape where no height limitation is in place, as well as the much lower height development in other parts. A disadvantage is clearly seen as developers build flat tops in order to maximize the development potential of their site, forgoing Victorian gables, finials and crests.
View of London from St. Paul's Cathedral
Many thanks to architect and Surveyor Oliver Caroe, City of London Corporation’s Clive Cromwell, and Laura Chilton of St Paul’s Cathedral for planning and leading such an informative and insightful tour into one of the nation’s greatest treasures. The CTBUH Heights and Heritage Conference delegates were able to move about freely throughout the remainder of the Cathedral to further explore.

Tower 42 Tour
By Daniel Safarik and Tansri Muliani
The Tower 42 Technical Tour was kindly supported/organized by: Tower42.
The tallest building in the United Kingdom from the time of its completion in 1980 until 1991 and the first major skyscraper in the City of London, Tower 42 encapsulates the theme of the conference: “Height and Heritage.” It overcame many planning obstacles, including opposition to its unprecedented height, to get built.
Delegates learn about the building's history before the tour
Tower 42 also featured some new innovations at the time, such as double-decked elevators and sky lobbies, which had never been built in the UK before. Despite advanced fire-safety features such as pressurized stairwells, smoke venting and fire retardant floor barriers, the building did not originally have sprinklers. A fire during its 1996 renovation resulted in the introduction of a sprinkler requirement by the Greater London Council. This closely followed an IRA truck bombing in 1993 that required an external recladding, at a cost of GBP 75 million. Demolition was briefly considered, but dismissed as being too expensive an option.

After the refurbishment, NatWest chose to leave the building and sold it. It now is a multi-tenant building, and a two-level atrium entrance space has been added, improving the street presence and overall attractiveness of the building.
During the tour delegates got the chance to explore the roof of England's former tallest building
While it had a rough road coming up, Tower 42 has emerged from its awkward adolescence as legitimate London icon. An LED lighting system on floors 39 through 45 featured the Olympic Rings during the 2012 Games.

Delegates were shown through Tower 42 by Barry Rushmer, General Manager; Daniel Harris, Technical Services Manager; and Rob Coupar, Façade Access Director.

Willis Building Tour
By Steven Henry
The Willis Building Technical Tour was kindly supported/organized by: Willis.
The tour of 51 Lime Street, also known as Willis Building, started with a trip straight to the top floor. The host, Carmine Bilardello, Senior Vice President at Willis Group, was quick to impress the delegates with a first stop at the 23rd floor’s expansive balcony. Delegates took their time absorbing the breathtaking, sweeping views of the City of London, with the sounds of the busy street life below making their way up to the open-air terrace.
Delegates visit the 23rd floor balcony to start the tour
Presentations followed in the executive board room, where Ian Whitby of Foster + Partners gave some insights into the architecture of the building. The tower had to strike a careful balance within the existing historic context. The design took several steps to respect the relationship to the 1986 Lloyd’s Building directly across Lime Street. Willis’ form concaves away from, and steps down toward Lloyd’s. The impact of the the building on the skyline behind Lloyd’s was also carefully considered, so as not to distract from its neighbor, yet still hold its own presence.
Ian Whitby of Foster + Partners presents on the architecture of the building
Andy Highton at Stanhope presented on the development and construction of the building. He described how the distinctive saw-tooth façade developed as a solution to mitigate solar heat gain, without having to use any sort of external louvers or shading. Bilardello’s argument against allowing external louvers back in design development was, “how the heck will we clean them?” The session concluded with Andrew Dellow presenting briefly on the interiors of the building.
The 15th floor staff cafeteria
The tour then took delegates to the rooftop mechanical floor, which houses several massive backup generators to keep the building functional in the event of a power outage. The 15th floor houses a large staff cafeteria, which connects by stairs up to the 16th floor open-air balcony. Delegates toured the 14th floor to see how a typical open office plan was laid out. The 3rd floor of the building was converted into “Willis House,” a 17-room hotel accommodation for visiting Willis staff. The Basement level houses a large auditorium space, fitness center for Willis employees, and a car park, which is increasingly transitioning spaces into bicycle parking.
June 10, Pre-conference
June 11, Day 1
June 12, Day 2
June 13, Day 3