Beautiful, sustainable, practical
Peter Smith, Senior Architect, AHMM was one of the first people involved in this project when it began in 2013. AHMM were invited to prepare a design for the fit out for the top half of the Pancras Square building with work due to commence in February 2015. However, two months before work was due to begin the whole scope of the project was dramatically altered when Google took the entire building, rather than just the top half, and now needed to redevelop it in its entirety including the eleventh floor which had previously been allocated to a French bank.
A scaffold was built full height into the atrium however the atrium itself was not strong enough to support the scaffold so the scaffold was proposed to be propped from the basement floor, two floors below the ground level. However Google acquired the basement during this planning stage and, now having taken the lease for the whole building, this was knocked out to create two recording studios, both two storeys high, to provide the London YouTube Space. This meant nowhere from which to prop the scaffolding.
ISG had to bring onto site 1200 – 1300 deep beams and create a platform from which to build the scaffolding which was an extensive undertaking in engineering for the temporary works.
Solving the construction puzzle
Sem Kyegombe is Project Director at ISG plc and directed the Google project.
The initial product selection was an extended process as the design brief was that the staircase had an industrial and honest look but this was countered by the fact that the building was not owned by Google. This meant that any additions to the building needed to be harmonious with the overall style. Sem says “Now time has passed the wax coating is developing a patina as it was intended to do and the exposed primary steel members contribute to the architectural honesty of the structure.”
The arrival at the eventual wax coating for the stainless steel was through a process of sampling and assessment involving close liaison with John Desmond, ISG and the project team. To create an integrated feel, the treads and risers needed to be seamless with the building’s floorplate and therefore had to be obtained from the same timber supplier despite the complexity of it being installed on site by three different contractors.
Another major challenge was how to build the staircase within the atrium. Initially it was considered to remove sections of the building to create access but the eventual solution was to build an internal scaffold gantry with the load being borne by the pile caps and avoiding any stress being placed on the floor slabs. The number of components was crucial as too many would create an unacceptable risk to the structure.
Access to the building was via Pancras Square which is famously busy most of the time. This meant that all materials had to be brought on site during night-time hours which was done using dollies and forklifts. An additional restriction was that the structural elements had to be brought into the building through the existing revolving doors and were therefore limited to 2.5 or 3m in length.
Because of the access and space restrictions the build methodology had to be minutely and intricately planned. Materials had to be brought on site in a highly specific sequence, firstly those for the scaffold gantry and then the stair superstructure, components and panels. To give an indication of the scale of the scaffold gantry, its steel members were larger than those used for the primary steelwork in the original building.
The stair panels fabricated by John Desmond were at the end of the delivery process and again, had to be brought in strictly according to the build sequence. John Desmond built entire stair superstructure sections off-site and fully clad these with the panels. These were then dis-assembled with the superstructures being sent on site whilst the panels were coloured and finished. This was carried out for each stair section and was project-managed to synchronise with the crucial delivery sequence.
Working with Google’s Biophilic Design philosophy
The Google approach to eco-friendly environments is more than a system, it is a philosophy. The purpose of it is to enable Googlers to feel energised, inspired and motivated through the use of natural materials and elements that occur in nature. Natural materials were specified for the stair finishes with the interior being of rough-sawn timber to accentuate its relationship to a tree, a very different statement to that of a highly polished wood.
Level 8 and level 11 are destination floors and provide balconies with views across London from the Olympic stadium in the East to Wembley in the West. By not having working desks on the floors with these views means all Googlers have equal access to the balconies and on fine days the facility of being outside. The sensations generated are emotional and in response to the natural world and elements – an outcome which is at the core of Biophilia.
The project team worked closely with several departments and individuals within Google. One important team was the Google E team, based in California, who are responsible for ensuring the best environmental and sustainability measures are implemented. The project had its own Carbon consultant who calculated the amounts of carbon that would be generated from the building’s use and recommended ways in which this could be reduced.
Google’s Healthy Materials Programme
Alicia Freire of Twin & Earth, an engineering and sustainability consultancy, was in charge of ensuring that John Desmond met the stringent Healthy Materials compliancy standards. The Healthy Materials standards go beyond those set by LEEDS and BREEAM and relate to a range of issues including recycled content, waste disposal and precise provenance of materials used. For John Desmond this meant tracking every piece of material used coming from any part of the world, to ensure compliancy. There are also strict criteria in relation to working on site with processes such as dust-generation being rigorously controlled.
Alicia says “The steel market is one in which it is historically very difficult to track materials however all suppliers were selected, and re-selected, on the basis that they could disclose the necessary data which would meet the high standards of the Healthy Materials policy.
John Desmond allocated two of their internal staff, Jenny and Joyce, to pursue all of the crucial information on steel, finishes and treatments. The huge on-going benefit from this Google exercise is that John Desmond are now operating comfortably within the most stringent and demanding sustainability standards in the construction industry”
The project served as a pilot scheme for Google’s in-house environmental assessment tool, Portico, also known as The Healthy Materials Tool. The tool assesses every single component of all materials proposed for use within the building to discover whether any harmful chemicals are present that could affect the health of people or the environment. This required a ninety-nine per cent disclosure by suppliers of the contents of their products including paints which famously have many, often secret, ingredients.
This rigorous process meant that many products were re-specified or replacement suppliers appointed to ensure compliance with Google’s standards. The target set by Google for the St Pancras building was between sixty and seventy per cent conformability but in actual fact, to everyone’s delight, the eventual score was one hundred per cent. Again, at the core of this success was collaboration. Information was shared between contractors and subcontractors so that products that had “passed” could be identified and used rather than adding more “new” products to be assessed and potentially rejected.
The staircase was designed for other useful purposes. The surrounding fascia glass of the atrium requires cleaning and also replacing when damaged. The points at the widest end of the U shape of the stair course allow for the width of a maintenance cradle to drop down between them.
Concealed by a flat disc in the base of the staircase flights is a “lifting eye”. This is a ring into which a hook can be connected thus converting the stair flight into a lifting beam from which replacement windows and materials can be hoisted up the atrium.
From the half-landings it is possible to look down onto the other levels.