The design of Hans Place - a collection of apartments on the corner of Hans Place and Herbert Crescent in Knightsbridge - draws inspiration from the richly detailed rose red brick buildings which line the garden square, and form the character of the conservation area. A particular feature of the Hans Town Conservation Area is intricate gauged brickwork, which was traditionally carved by skilled brick masons and seen as an external sign of wealth and taste.
Gauged brickwork was historically carved by hand using a rubbed brick soft enough to manipulate into intricate artworks. We wanted to introduce a bespoke element of brick craftsmanship to the new buildings which related to the use of sculpted brick in the area. It quickly became apparent that hand carving large areas of brick would be too expensive, so we began to devise a pattern system which had a limited number of different moulded brick types. The initial concept took inspiration from the cocoa bean – introduced to the UK from Jamaica by Hans Sloane – but the complex pattern required too many different elements to be practical.
The designs moved towards a simpler, more geometric aesthetic which was limited to two core elements, but when rotated gave a varied pattern on the feature chimney, spandrels and lintels. The practice’s Modelshop worked with the design team to create a polystyrene mould with a negative imprint of the geometric pattern, which we took to specialist brick manufacturers to discuss production methods.
We approached two specialist manufacturers with experience in gauged brickwork, and worked up designs with a fifth generation family business based in Sussex. Together we tested two options; firstly machine or hand cutting a standard brick shape to achieve the pattern, and secondly moulding the brick shape using a negative imprint. Machine cutting was problematic due to the dust created during the process, and hand finishing did not achieve the accuracy of finish required. The moulded option was also far from perfect due to the shrinking which occurred naturally during the firing process, meaning the bricks didn’t match up accurately.
Joint and mortar sizes
Originally working to a mortar joint size of 1mm, we discussed increasing this to 3mm and using a colour matched mortar to disguise any misalignment. However this mock up was disappointing as it lost the expression of individuals bricks, looking more like a pre-fabricated panel. It was clear that a small joint size needed to be achieved as well as a high degree of accuracy in the making of the bricks.
We investigated difficulties with the brickmaking process and how we might achieve the low tolerance and exact brick moulding we needed to meet our design expectations. It became clear that CNC (computer numerical control) cutting the bricks was the only way to achieve such exact dimensions, and that we also needed to find a highly skilled bricklayer to achieve the end result.
Working with a brick supplier and the Materials Council, we extensively researched companies who were prepared to undertake CNC cutting of bricks – something we had disregarded earlier in design development due to the difficulty the process. However we were finally able to locate a CNC cutting company who were interested in the project. The CNC process was technically difficult but the result was consistent and could be undertaken in large batches of 40-50 bricks in one session. It also became easier to create the bricks required for junctions and corners, as well as the two which form the basic pattern.
Final mock up
Our production team for the third mock up comprised a brick manufacturer, CNC stonemason, and a specialist brick mason. Each brick was numbered corresponding to the drawings, and hand set using a 1mm lime mortar putty in which each brick is dipped before being laid. The mock up was approved in autumn 2014, and is set to be applied on site in summer 2015.