Contemporary stone and brickwork design stands at the crossroads of craftsmanship and engineering, and also of invention and innovation
As craftsmanship, brickwork involves patiently calibrating textures, colours, shadows, lines and proportions. Brick modules seem open to unlimited invention. At one extreme, this involves aesthetic codes, sometimes from previous generations; at the other it begins to resemble art, with high levels of playfulness and innovation.
In engineering, brickwork is concerned with performance rather than culture or artistic quality. Whereas the Baths of Caracalla are great engineering feats, Jacobean gauged brickwork arches are outstanding craftsmanship. Brickwork as a structural material is a separate subject, and is also subject to height limits. Paradoxically, structural brickwork is more viable on smaller buildings, often those described as hand-crafted.
Recent projects in Africa show what can be achieved when traditional brickwork construction is used imaginatively. A primary school completed in 2013 in the Malinese village of Tanouan Ibi, designed by Amsterdam practice LEVS Architecten and constructed by members of the local community, uses locally produced hydraulic compressed earth blocks, suitable for intense sunlight and heavy rainfall.
Drawing on indigenous construction techniques, Berlin-based Kéré Architecture’s proposals for a school library in the village of Gando, Burkina Faso (AR September 2009), involves a roof constructed from a lively array of locally produced earthenware pots, hand-built by women from the village. Pots are sawn in half and then cast into the ceiling, providing natural light and passive ventilation, with air drawn upwards, assisted by a corrugated-iron roof which shelters the ceiling structure.
Case study: Tanouan Ibi school, dogon plain, Mali by LEVS architecten
Constructed by members of the local community, this primary school uses locally produced hydraulic compressed earth blocks, suitable for intense sunlight and heavy rainfall. Porches with gently stepped soffits and integral benches flank and also buttress a central barrel vault over the classrooms running the length of the school. The roof is covered with 20-30mm of red soil mixed with cement to resist water ingress, assisted by earthenware gargoyles. The interior is also vented and naturally illuminated by a firmament of ceramic tubes in the roof, which are sealed during the rainy season.
The brickwork for the Women’s Opportunity Centre in Kayonza, Rwanda (AR December 2013), was designed by New York practice Sharon Davis Design, who wanted to work with local technology but develop it in unique ways and aimed at high quality in handmade brickwork. The perforated brickwork walls, inspired by the all but lost tradition of Rwandan woven-reed palace residences, aim to combine natural ventilation with minimal distraction of building users.
Such concerns with craftsmanship - the elusive quality of proportion, texture, rhythm and shadow - are the essence of architecture, but contemporary brickwork engineering, the cross-traffic, is a lively area. On the subject of engineering challenges in brickwork design, three recent projects stand out: O’Donnell + Tuomey’s Saw Swee Hock Centre for LSE in London (AR February 2014), Aedes Studio’s Ivan Vazov Apartment Building in Sofia - also known as the Red Apple, which has an elaborate facade of Wienerberger perforated and facing brickwork on multiple storeys - and Gehry’s Dr Chau Chak Wing Building, for the University of Technology, Sydney.
As for craftsmanship in contemporary brickwork, architects, contractors and tradesmen have achieved high standards of aesthetic control working with brick manufacturer Petersen Tegl. Petersen excels at doing a few things really well, most notably using a randomising coal-firing process to manufacture water-struck bricks. These bricks are in varying degrees light and dark, subject to their quantity and position in the firing oven and, as at Lundgaard & Tranberg’s Louiselund care centre and housing for the elderly in Hørsholm near Copenhagen, 2013, wall surface patterns can be adjusted by rotating bricks around their long axes.
The bricks are water-struck, giving them a distinctive, comparatively smooth, sand-free finish. This process uses water as an agent to release the bricks from the mould. Ida Præstegaard, editor of the biannual Petersen magazine, characterises the Danish manufacturer’s bricks as consistently inconsistent, the outcome of a process involving high levels of quality control, before and after firing, hand craftsmanship and selective mechanisation rather than heavy industrialisation. Bricks are meticulously sorted to ensure that every palette is almost identical, helping bricklayers to avoid transitions and Friesian surface patches. Without this level of control, Virumgaard Arkitekter’s Bytoften housing development in Gladsaxe, near Copenhagen, completed last year, could never have been achieved.
Petersen bricks are also characterised by their size. 528 x 108 x 37mm is the standard module for its Kolumba range, developed with Peter Zumthor for his eponymous museum in Cologne. Along with texture and colour, these sizes can be customised: Dutch architect Geert Bosch requested three 920mm long Kolumba bricks for a villa near Utrecht because he wanted qualities characteristic of natural stone. Piercy&Company’s Turnmills office development in London’s Clerkenwell has 27 special brick types and three unique colours. Petersen bricks have high compressive strength and can also be laid without pronounced vertical movement joints, although careful attention to specification of components such as mortar and brickwork ties is essential.
Like the notes of a musical scale, brickwork modules seem to be open to unlimited invention in the way they are arranged and combined, for example in the shallow relieving panels at Louiselund with their thin shadows, or the use of soldier-coursed Kolumba modules in the brick plinth at Tegnestuen Mejeriet’s Henne Kirkeby Inn in Denmark (see p29). Celsing Arkitektkontor’s New Crematorium at Stockholm’s Woodland Cemetery uses red-brown Kolumba stretched bricks to add emphasis to its horizontal proportions and subtly underlines this with slightly recessed bed joints. Kolumba bricks with the same colour and texture are used on the roof and external flooring, where modules are subtly orientated according to the degree of exposure. Like Bytoften, this is an architecture of brick volumes uncompromised by the construction of its roofs or their drainage. Kolumba is also used for the internal floors, soffits and brick walls, except in the small waiting room, which has white glazed hollow modules.
York Handmade Brick also manufactures Continental format bricks. The company is known for the roughness of its products, but can supply many types of brick involving open texture, creases, smiles, bench-made specials, half-modules, reticulated formats and stains.
Craftsmanship and engineering are not watertight compartments, and there are different types of engineering. A proprietary facade system, for example, could be described as engineered. Petersen’s range of Cover tiles - added to its range in 2013 after prototyping with Dutch practice Min2 Architects for a villa in Bergen aan Zee and further developed by Lundgaard & Tranberg at the Sorø Art Museum - are not marketed as a system: their support structure, which might be steel or timber, is supplied by others. It nevertheless involves a certain tectonic strategy comprising a screen of tiles which can, in the old-fashioned way, be simply hung off a support framework with two or more fixing holes. Cover tiles have the handmade qualities of Kolumba, with a delicious chunkiness and, in their standard format, with 37mm thick symmetrical lips, they cast nervous dark shadows as though drawn with a 6B graphite stick, as seen at Mangor & Nagel’s Sydbyen housing development in Slagelse, Denmark, to be completed in spring 2016. As a possible sustainability asset, and also defying the ideology of brickwork as a permanent form of construction, Cover can be demounted.
Case Study: Henne Kirkeby Inn, Denmark by Tegnestuen Mejeriet
The new four-winged Jægerhuset (hunter’s lodge) extension to this historic Danish inn is clad in Kolumba bricks by Petersen (see p27). The plinth of this seven-room guesthouse is formed of vertically laid K47 bricks, while hard-fired, water-brushed Petersen D48 bricks are used for the exterior and interior paving of the original and new addition. The original buildings date from 1790 and are built from traditional West Jutland local bricks, historically made from mud trampled by livestock and pressed into wooden moulds, before being fired with peat in makeshift ovens limited to 1,000 brick batches.
Austrian manufacturer Wienerberger has launched Corium, a fully tested and approved facing brick cladding system with steel backing sections, galvanised above ground and stainless below. This system, designed to last for 60 years, also offers the benefits of fast erection and availability of a wide range of facing brick colours, textures and modules.
Stone is essentially a craftsman’s material, often valued for its scarcity or virtuoso workmanship. Although, like brick, it is good at carrying vertical loads, it has limited structural potential: the great Gothic cathedrals were built in spite of their principal raw materials and many collapsed. Unlike most brickwork, natural stone is not an engineered material. Nevertheless, engineering has a role in designing and calculating support structures for stonework as well as in stoneworking. The precision of Renzo Piano Building Workshop’s Valletta City Gate project ( AR September 2014), constructed in collaboration with stonework specialist CFF Filiberti, relies on the latest numerically controlled laser-cutting technology, sculpting large blocks of stone to high tolerance levels. The Medieval Museum in Waterford is faced in Dundry stones. The project’s designer, Waterford City Council Architects, devised curved bands of stonework which are offset at different levels. Each stone is unique, as required by the setting out. Nicholas Hare Architects specified Fletcher Bank sandstone cladding and masonry for the St Paul’s School Science Building in London. This replaces the school’s 1960s prefabricated CLASP system building. The stone has a random buff to grey colour and was able to be worked to high levels of precision that complements interfacing brise-soleil, roof canopies, windows and doors. These three high-profile works demonstrate moderate inventiveness in contemporary architectural stonework design rather than innovation, which is a rare commodity and one more readily available in current brickwork projects.
The design of cladding or load-bearing panels faced with brickwork or stone is highly topical, especially with the cost premiums on the speed of high-rise construction lining congested highways in current markets. The viability of hand-set brickwork and masonry as well as achievable levels of on-site quality is inversely proportional to building height, with an effective cut-off point. This topic will be revisited in next month’s Skill feature on cladding.
Case Study: Dr Chau Chak Wing Building, Sydney, Australia by Gehry Partners
Using 380,000 bricks clipped to a custom-made groove and bolt steel frame, this business school has a complex triple-curved surface, with melting chocolate folds of brickwork. Specials included a Centre Rebate brick, K Brick, Offset Rebate and L Brick, all made by Australian manufacturer Bowral Bricks. The specially engineered wall tie keys into the rebate and anchors the bricks to the inner steel wall, restraining the brickwork until the mortar hardens. The complexity of the curving facade slowed the bricklaying considerably: while a bricklayer usually lays 500 bricks a day, on this building they were laying 70 or 80 per day. The M-section special bricks’ K-shape on plan is inventive: where they kick out from the face of the brickwork they resemble foamy wave-tips on a choppy sea. But the specials, with a continuous M-shaped vertical section which you could mistakenly read as frogged bricks if you didn’t realise they are simple extrusions, are incredibly useful.
First, they enable adjustable restraining brackets to hook over their vertical faces and, second, they enable rods to run through the rebates in their upper surfaces into which they are embedded as long threads: the brickwork and steel members work together in sophisticated ways. These refinements enabled the facade to be precisely constructed with inclinations leaning inwards and outwards of up to 27 degrees from the vertical, using the watertight backing structure rather than string lines as an aid to setting out. As further refinements, perpends in consecutive courses are offset to avoid the visual distraction of vertical alignment. Also, individual bricks were cut vertically to achieve consistent perpend widths. Because the facade has a snaky plan form and corbels in and out, the tops, bottoms and sides of bricks, as well as their faces, had to be manufactured with presentable finishes.