Technical Envelope

obliquely from the outside, at certain angles you see deep chamfers, but at other angles all you see is window. The concept started as a planning game, but became a key concept in the design.” All windows are Schüco modifi ed

profi les, specifi cally extruded for this project. The biggest, a curved corner window that is about 4.5m in height and 800kg in weight, is one of the largest of its type in Europe.

Right: The elevation of the building was thought to be too horizontal for Clerkenwell, so an atrium was inserted to give the impression of two separate structures

Below right: The fi nished article, showing the effect of the variably chamfered windows

> atrium and entrance lobby. “During the early design we identifi ed this elevation as unusually long for Clerkenwell, which is characterised by warehouses with a vertical emphasis. To avoid a battle with planners we introduced the atrium so that the building reads as two separate structures,” says Piercy’s Humphreys. The design was also informed by the

Clerkenwell warehouse building with its generous fl oor-to-ceiling heights and full- height windows. However, modifi cations were required by planners, such as reducing the height by one storey and lightening the colour of the bricks.

The chamfer factor The Turnmill's windows are industrial in scale, and have deep reveals, designed to emphasise the building’s solidity. The reveals on the west and north elevations are chamfered on one side at a range of angles, as Humphrey explains: “The angles were created by drawing radial lines out from two points at the centre of fl oorplates on either side of the atrium. There are points you can stand in the

offi ces where the deep reveals peel away creating unobstructed views across the railway. And when looking at the facade

Hand-made bricks Petersen Tegl makes bricks the traditional way, using local clay hand-pressed into wooden moulds, then dried and fi red under varying temperatures to create a mixture of textures and shades. The Kolumba brick is hard wearing, has

low water absorption and is designed to undergo a degree of weathering after installation. The standard brick on this project measured 528 x 37 x 108mm, however the use of wooden moulds allowed the fl exibility to create the range of “specials”– something that would have been problematic with factory production.

32 | JANUARY 2015 | CONSTRUCTION MANAGER