Stack of all Trades

Workstack and speeding cars – photo Alex de Rijke

Workstack is the latest in dRMM’s portfolio of CLT buildings, and yet another which breaks the mould of conventional design thinking

East of that south-of-the-river oasis of bourgeois North London that is Greenwich, the cityscape turns rawer. Its gateway, the brave new twenty first century Millennium Dome and the generally less visible Greenwich Millennium Village, masks a creeping chaos of building sites and groundworks, even as the lattice of dual carriage feeder roads emanating out of the Millennium district ensure a further sprawl smattered with the signs of car-centric Non-Place: the out-of-town shopping malls and entertainment venues, the drive-by fast food joints and discount warehouses, and a sea of industrial sheds. Row upon rows of early twentieth century two-up, two-down housing gradually blur into suburban sprawl while the vast regeneration project that is Thamesmead grinds on like a permanent revolution.

It is into this bleak cartographic template of Super-Modernity that an intriguing example has been dropped, possibly way-signing a different industrial futurism. WorkStack, a five-storey Cross Laminated Timber (CLT) set of timber cassette boxes, each floor stacked upon its last, each cantilevering precipitously out a floor further over the entrance and projecting a further 6.2m out from the ground footprint.

Outside/inside – photos Alex de Rijke (also photo below)

dRMM are known for their pioneering CLT work in Britain and indeed building the first UK CLT project – Kingsdale school sports hall just a few miles south in Dulwich (Further, see Annular Archive feature here) – and the interior work units, internal corridors and additional admin and services rooms and facilities are well-suited to the rough and ready exposed CLT panel system that make up the walls, floor and ceiling surfaces of the workshop spaces. In all, the five storeys hold fourteen workspaces of differing sizes; the largest are on the top floor, at just under 6 x 20m, getting progressively smaller descending through the levels down to the ground floor, with the smallest units measuring 6 x 7.5m, while floor unit footprint sizes range between 117m2 and 46m2. All told, the fourteen units provide space for around sixty people. GEB have rented out the spaces to a mix of small businesses, including furniture makers, knitwear producers, workwear manufacturers and a bicycle/motorcycle workshop, rather conveying the impression of a PR aim to showcase greater Greenwich and Charlton as its own funky maker hipster coolsville, a piece of classic post-industrial regen strategy, with dRMM doing nothing to downplay this perception, unsurprising given they are avid media and image players.

Long in gestation, Workstack was conceived as a showcase for a different approach to out-of-town industrial work units. But it can also be read as a single piece of something larger, a step that works – or could potentially work – within a larger industrial ecology. Half part of its surroundings, half speculative stepping stone to a more comprehensive sustainability future.

First approached by Michael Finlay, head of the Greenwich Enterprise Board (GEB) in 2015, Alex de Rijke, dRMM’s co-founder and timber main-man, says Finlay was looking for a timber building to help project a forward-leaning agenda. Eight years later, with a significant Covid interruption, the completed Workstack sits on the Charlton Road, edging space-eating industrial sheds, quietly launched in late 2023, and has been filled by GEB-chosen small businesses.

Full frontal

Stacking up – this, and next two photos below – Oliver Lowenstein

de Rijke makes an intensification case for the building up on such a tight, limited footprint. Shed sprawl over large meterages of industrial land is an inefficient use, he believes of valuable urban space.  One analysis sets a figure of WorkStack attaining a 428-workspace density over a single hectare footprint. Rather than such redundancy, dRMM’s showpiece promotes going vertical – if to a modest low level – de Rijke says that he believes they’re fighting an eleventh-hour action to hold on to the rump of small-scale manufacturing which hasn’t already flown London. According to him, local markets remain one of the few places for workspaces. WorkStack is dRMM’s answer, differentiated from conventional workplaces.

Externally WorkStack doesn’t come across as any woodstack. As with their other CLT buildings, dRMM have skinned the CLT structure with a cladding façade of semi-translucent grey steel panels. Through its design journey, five years of studio work, there was a considerable amount of value engineering, including the height being reduced by a metre from 21 to 20m and the fire escape staircases moved from sitting externally on the rear of the building to inside at the back. “It reduced the overall size,” says de Rijke. With the change in external façade WorkStack moved from woody Rubrik cube to something more amorphous: the large sinusoidal corrugated panels.

The timber has disappeared out of the ground floor base of the building and been replaced by breezeblocks and steel bracing. “We were persuaded”, de Rijke notes, “not to do the ground floor in CLT, because the area is at river level, and could be flooded.” One section of the engineering where timber has been maintained is a wooden lift shaft. But other original elements, such as “huge open windows” in the polycarbonate rear façade, have gone. Much of the building features fully exposed structural timber, including walls and soffits, except on the ground floor where the timber soffits have been overclad.

Structurally, though, Workstack is a tightrope act. The relatively simple device of stacking a set of timber shoe boxes on top of each other has been complicated by dRMM and engineer and long-time collaborator Adrian Campbell (ex-Arup and now ChangeBuilding) appearing eager to take on the challenge of the structural gymnastics of front loading the floors in a series of progressive cantilevers, almost willing WorkStack to slip its moorings and topple over.

“dRMM don’t do normal buildings,” says Campbell down the phone line, a few weeks after my first visit – pleased, it seems, to talk about his association with dRMM as much as WorkStack. “I was really excited about the design. It was new, and I was pleased I’d be doing the detailing.”

The stack does a heft of work. The higher up the building the heavier the structural load being carried, gravity drawing the cantilevered building’s forces down to the ground. Cantilevering the CLT structure has pushed the engineering, with the stacked walls lateral forces pushed in a single direction, to the back of the building. The large CLT walls panels are especially stiff, helping strengthen the stability, Campbell notes, adding that the engineering is quite dependent on the floor and diaphragm. The largest panels are massive, 19m long, helping create that stiff diaphragm, while others range from 12 to 16m on some floors, and 3.5 to 10m on others. In all, there are 235 panels, primarily from Stora Enso. Inevitably, there’s no structural capacity in the jutting cantilevered boxes, while steel straps have been added to the rear wall, running down the back of the building. According to the carbon modelling carried out by Arup and B&K Structures, 343 carbon tonnes are locked into the CLT structure, about 21% less embodied carbon than LETI’s 2030 Design Target of 350 kg CO2 /m². Aiming to attain BREEAM excellent, the studio has made the most of highlighting Workstack’s biophilic properties, a part of dRMM’s broader strategic repositioning around regenerative design now that their value as CLT and engineered timber pioneers has become so diluted with timber’s increasingly pervasive mainstreaming.

Its origins were in some studio play experiments. “I was messing around with a plywood model in”, de Rijke stops and scrolls through his phone’s photo archive before coming upon the wooden model and adding, “November 2015.” Workstack’s antecedents lie in the Blackpool Tower of Love (pronounced ‘Lurve’), where dRMM explored the potential engineering of off-ground horizontal structures being held by the vertical structural system. It wasn’t the first experiment, however; the Milton Keynes tower came first.

“All of this stemmed from the Milton Keynes tower,” says de Rijke, who originally had seen what’s known as the MK40 tower project as a way to test a seven-storey housing block. “It was to be a landmark with a timber core, showing the structural performance, a fairly straight-forward structure,” helping move the then current engineering consensus away from needing concrete to accepting timber lift shafts. The Tower of Love features an 8m vertical cantilever. Now they’ve taken the idea an ambitious next step, and it’ll likely go further. There’s another reference as well though: Wick Lane in Hackney Wick, which Workstack’s project architect Steve Wallis acknowledges a connection to. The two projects involved a certain amount of “crosspollination of thinking around workplace provision.” Wick Lane is both brick and mixes workspace with residential, so together, says Wallis, Workstack and Wick Lane provide two very different ways to integrate workplace provision into growing cities. Though Wick Lane predated Workstack, Wallis believes the two designs developed pretty much in parallel.

Aside and away from the technical engineering issues the project advances, there’s the broader, industrial futures themes Workstack plays with. Since the launch, it has been sold around re-envisioning in-demand ground space. But there’s a potentially more expansive agenda. Long ago, de Rijke participated in Industry!, a 2006 Oslo, Norway exhibition emphasising systems design for buildings made from replicable and dismantlable parts. de Rijke contributed a short essay to the exhibition monograph which looked rather like it reworked ideas drawn from the 80s Industrial Ecology movement – though today de Rijke states he’s unfamiliar with them. Industrial Ecology and Industrial Ecology Parks never took off but showed tantalising promise regarding how industry and manufacturing could imitate ecological processes to optimise energy use and materials re-use in, speculatively at least, integrated industrial parks. Though the essay went on to make the case that industrial forestry, engineered timber and low- to no-carbon wood buildings were just such an ecology, WorksStack can be read as a lucid signpost adding to the greening of dRMM’s timber embrace as another in-parallel industrial ecology. It is not so great a leap of the imagination to envisaging multi-storey low-rise industrial parks, organised at a systems level, feeding and contributing materials and energy between its different parts, while working and contributing as an ecological whole.

Whether it’ll ever happen is another matter. Dreamers (such as myself) can wish and dream. In the real world of extortionately expensive land values ambitions of such sorts don’t get much of a hearing, and if they do are quickly put aside. In place, Workstack’s relatively modest ambition and pragmatism is what gets realised. Completing the relatively radical – yet entirely modest – spatial and land-use intensification agenda was likely hard enough and likely as good as it’ll get. ol

Further – for other dRMM features see Annular Archive here.

The Model Workstack – Alex de Rijke

Nice work – Alex de Rijke