Amnesty International's necessary makeover of its Rosebery Avenue base gives the organisation a more public presence
The secretariat of Amnesty International occupies a deep block fronting on to Rosebery Avenue in central London, a couple of hundred metres down the road from Sadler's Wells Theatre. It is an undistinguished building with a three-storey, vaguely Edwardian facade along the main street.
On the side streets, there are four storeys of steel-framed strip windows plus brick spandrels, which could date from any time between the late 1930s and the mid '50s, and denote a semi-industrial original use.
At the north-east corner, the two elevations are patched together, or perhaps held apart, by a drab brick entrance tower, whose long window lights the stairway behind.
Amnesty is an utterly virtuous institution and part of its baggage is to eschew ostentation - including ostentatious accommodation. But because it was expanding its activities, its building had to be rethought and it called in City-based architect Artillery. Artillery's revised layout increases the organisation's conference area by more than three-quarters and provides new exhibition space, an eating area and the potential for a threefold increase in the size of its conference space. Security is an issue because of what Amnesty does, and because of the regular presence of so many distinguished figures who give their time to the organisation.
Taking the opportunity of the makeover to create a more public presence, the client asked for the entrance to be relocated from the corner to somewhere in the main Rosebery Avenue facade. The planners had made it clear that there could be no alterations to the upper two levels - but that the facade at ground-floor level, which had been messed around over the decades, could be changed.
Artillery's Karl Taylor says: 'Where we were coming from was to make an intervention in the facade that was faithful to the openings already there. The lower elevation was an interesting disjunction of later elements, which we quite liked because here was an interesting opportunity to articulate the ground-storey elevation - slightly out of kilter with the upper facade - but using the found openings.' Because these were all over the place, it was possible to use them only, as Taylor explains, 'as the generating size'. He adds: 'But then [the idea was] to shift it all slightly to create equal openings so you have a margin, a kind of negotiation between the given and the desired size. There was this metaphorical thing of Amnesty negotiating between two positions. And, quite by chance, there are six programmes in Amnesty's work - and six potential openings along the Rosebery Avenue facade.'
What Taylor has done is to continue down to the ground the main brick divisions between windows of the upper two levels, which you might call bays. These are not equal in width and one of them slants at an angle around the corner.At ground level, the bays are to be almost filled with storeyheight plate glass windows set back 346mm from the face of the brick facade. The deep reveals are in 6mm plate Cor-Ten. Because the windows are of equal width and the bays are not, there are solid panels of Cor-Ten of between 200mm and 1m widths, filling the spaces adjacent to the glass. Taylor says: 'We want it to be quite refined, so the Cor-Ten will be sandblasted before it is installed.'
Cor-Ten oxidises outdoors but not in, so the continuation of the reveal inside is a clear powder-coated bright steel.
One of the great urban legends about Cor-Ten concerns that man with a wheelbarrow who every week did the rounds of the Cor-Ten Cummings factory and swept up the rust. At Rosebery Avenue, along the bottom of each of the windows there is a grate over a little bucket containing an uplighter and a collection of stones. Taylor says: 'Over time the stones will turn orange and you can pop the Cor-Ten grate off to access surface drainage.'
Taylor took the view that 'the openings in the brickwork should look undisturbed'. He adds: 'It was important that it looked as though the glass and Cor-Ten had been pushed into the face of the building; an additional layer; a palimpsest of different ages. We didn't want to wreck what was there.' I put it to him that Palladio had done something similar at that basilica makeover in Vicenza - but he didn't take that bait.
Making an entrance
The new entrance is a weatherboarded cube with a projecting lid. It has doors at the front, which fold back and are contained in side pockets. It is to be seen at night as a timber box and during the day as a timber portal inside a Cor-Ten frame. The long window over the old corner entrance is to be adorned by the Amnesty logo of a candle and barbed wire, with a long trailing tail integrated with the right-hand jamb.
'All the way through the project we have been trying to use materials in a natural way, in a kind of untreated form, ' says Taylor. He notes the difficulty of doing this when, for example, the inner linings to the window are of steel plate, because Cor-Ten will not rust properly if it is inside. 'But, ' he adds, 'there was the aspiration to let steel be steel and timber be timber, without overegging the applied finishes.Cor-Ten seemed like the closest we were going to get to steel performing at its best, with the oxidation forming a natural protective finish.'
Persuading the contractor
In the pre-contract stage, Taylor's team was dissuaded by the quantity surveyor from pre-ordering the Cor-Ten. 'There's no difficulty getting Cor-Ten but there's not an abundance of contractors who have seemed happy and confident to use it, ' explains Taylor. But he wanted to have the fabrication completed and the rusting started. So, as a solution, Taylor says, 'one of the guys whose plant is close to a river recommended that the fabricated bits be stored on a windswept section of his site and blasted with water'.
Handle with care
As a material that goes rusty, many (wrongly) assume Cor-Ten does not have to be handled with great care. But welding, weld bloom, grinding and even crayon identification marks have to be kept to a minimum, and are better avoided altogether. Taylor says: 'We have detailed it in such a way that the welds are internal and, if face grinding should be required, we would anticipate that the grinding would cover the whole face of the element. Protection is important for the oxidation process, especially after arrival on site - even against fingering.'