Heavy weight

Photo: Iwan Baan

With each of its 670 pre-fabricated earth elements weighing between four and six tonnes, the Ricola Herb Center designed by Swiss starchitect’s, Herzog & de Meuron, in conjunction with Rauch’s LehmTonErde, is set to become a game changer for Europe’s rammed earth scene

High up in the Swiss hills I am being shown a small Alpine orchard and pasture covered in lush clover and summer grasses. There are apple trees, and round the orchard a small fence marking the orchard’s end and the neighbouring farms’ beginnings. Bees are busy seeking out nectar, and the world seems far away for a few minutes amidst this idyllic scene.

It is from these kinds of Alpine vistas that one of Switzerland’s most successful natural – and sugar-free - sweet producers, Ricola AG, source their herbal ingredients; Or at least that is the story my afternoon host, the Australian PR person from Ricola, would like me to take away from this brief upland visit. Not long after, with both point and connection made, we zigzag down the hillside to the valley below and another new, almost equally, if rather different, rural landscape. 

What hits me here, on the edge of Laufen, the town where Ricola began life and continues to operate from, is how is it that the air is filled with such a sweet aroma? The answer being that on other side of the field, is the company’s main herbal lozenge production factory; and the steam billowing from its chimneys unlike the grime of coal, or the bitter after tang of beer hops in the air, make for the sweetest smells.

Laufen, a small Swiss town about a dozen kilometres from Basel, is Ricola country; and over the last thirty years, has played a surprising and singular role in recent Swiss architectural history. In addition, over the past months Laufen has also arrived on the radar of Europe’s rammed earth community and networks.

In the late 1970’s, Alfred Richterich, one of the directors of family owned Ricola and grandson of founder Emil Richterich, convened a gathering of artists and architects in the town. Amongst those present, was twenty something Jacques Herzog, then one half of the young Basel unknowns, Herzog & de Meuron, who had formed their partnership in 1978. A professional friendship was struck up between Richterich and the architects, the first result of which was a redesign of Alfred Richterich’s private Laufen home. The relationship continued, and today, it is notable how instrumental the company has been in the fortunes of HdM’s early years. Witness the remodelling of the Ricola town bakery, followed by the commissioning of one of HdM’s initial key projects, a high rack steel clad warehouse, servicing a new phase in the automation of Ricola’s production process. The finished industrial building - the warehouse was soon referenced an early example of a new architectural materiality of the period; a variant on a metal box, stripped down grey panelled cladding fusing industrial atmospherics with sculptural minimalism. In due course, this building was to become one of the Basel studio’s early well known works, helping to propel the practice onto the European architectural stage.

Ricola Farming.
Photo: Ricola
HdM's first domestic refurbishment
in Laufen. Photo: Ricola
Light reflective interior of the Mulhouse warehouse
Photo: Margherita Spiluttini

In the years since the steel warehouse opened in 1987, Ricola have continued to populate Laufen with further HdM buildngs. Over time, the town has become a small time architectural destination for those enthused by the country’s best-known architects. A further four buildings appeared gradually, including the main marketing and admin office block (1998.) Further afield, another relatively high profile packing and distribution centre was completed over the French border in near-by Mulhouse-Brunstatt (1993). This building was precipitated by the need for a distribution hub inside a European Union member country, after the Swiss referendum vote against joining. Over these years Ricola have become the largest herb sweet producer in the world, sending out around 5 billion of their  sweets to around fifty countries.  

Photo: Simone Bossi
Now, nearly thirty years after their first project, HdM have added a seventh building to their Laufen list*. Like the eighties building, the Kräuterzentrum,or Herb Center, it is also a warehouse, bringing the Ricola HdM connection full circle. Not only this, but the new Herb Centre, which opened in summer 2014, may be Ricola’s most ambitious building yet. At which juncture, enter rammed earth and Martin Rauch.

The new warehouse introduces a fresh element to the Ricola-HdM collaboration: an unalloyed sustainability pitch and, specifically focused on rammed earth. All those involved, describe it as the largest contemporary loam or rammed earth building in Europe, the result of Rauch and Lehmtonerde’s involvement from the early days of the project.

What does large mean? Well, the Herb Centre is 111 m long, 28.9 m wide and 10.8 m high, which makes for almost 3000 sq metres of warehouse space. The façade has been constructed from 670 rammed earth elements, each weighing 4-6 metres, produced at a temporary factory for the duration of the build, in Zwingen just outside Laufen. Size matters in the building industry, and the scale is impressive, even if the publicity’s claim for the Herb Centre being the largest earth building in Europe, is likely tempered when it’s realised that the loam is for façade, rather than structural use; structurally, concrete and steel are the unsurprising fall backs. Nevertheless, the Rauch-HdM collaboration has produced, in various senses, a rammed earth heavy weight building for the mainstream to sit up and attend to.

Compared to London’s Tate Modern, the Beijing Bird’s Eye Olympics Stadium  or the current HdM showstopper the ElbPhilharmonie Hall in Hamburg, the rammed earth warehouse isn’t the sort of project which receives sizeable column inches in the international architectural press. Yet its influence across the European earth building world, will very likely be considerable; pushing the natural building materials and technologies agenda forward several sizeable steps. While size isn’t everything, by scaling up rammed earth, and placing the natural building material at the heart of the mainstream, the project sends a significant signal.  There again it must be a costly project, and it is noticeable there are no references to the cost on any Ricola, HdM or LehmTonErde’s websites or publicity. If the budget was really exorbitant, despite the argument that the building has emerged from the very ground it stands on, detractors may well point to the Herb Centre as something of a brown elephant.   Even so it remains arguably the most significant in Rauch’s wave of Swiss rammed earth buildings; and almost certainly augers interesting developments for the next chapter in European rammed earth culture over the coming decade.

New HdM starchitecture - the ElbPhilharmonie
under construction in Hamberg
Photo: Wikipedia – Open Source
Abandoned precedent - Schaulager museum
Photo: Wikipedia – Open Source

Freighted with history, Rauch’s collaboration with the architects, dates back over more than a decade to HdM’s design for the Schaulager museum  or ‘art depot’; a hanger-like art storage archive and research hub instituted by the Laurenz Foundation in Basel’s outskirts, eventually completed in 2004. The art collection housed there, required particularly sensitive temperature control; and HdM proposed rammed earth to stabilise temperatures, bringing in Rauch and his team until - due to technical and also bureaucratic difficulties - it became too complex to continue.  Nonetheless, the museum was eventually realised by a combination of clay, gravel, pebbles and concrete dug up from the site itself; contributing a high thermal inertia to the structural envelope. This is the heavy weight precedent, which has been reprised in Laufen. Not that Rauch disappeared out of HdM’s orbit completely. Far from it. Maintaining contact with the Basel practise, included another thermally sensitive (and private) commission – namely refitting Pierre de Meuron’s personal wine cellar with rammed earth walls in the mid-2000’s!

The site's clay pit Photo: LehmTonErde
Photo: Simone Bossi
Sited at Laufen’’s South Western edge and countryside proper, a stone’s throw from the production factory, this part of the town is filled with lovely sweet smelling steam curling upwards from across the way. In the adjoining field, the Herb Centre is the new heart of Ricola’s herb processing. The entire production – the drying, cutting, blending and storing of around 1.4 million kilograms of herbs arriving annually, taking place in highly automated fashion under the rammed earth building’s roof.

The original design apparently resembled a large, timber barn with a gable roof. The present low-rise factory however, features a concrete load-bearing structure and a flat roof, developed to take account of functional and hygienic constraints. Essentially a shell, the rammed earth weight adds stability to the concrete frame, maintaining a stable 40 to 60 degree humidity level for the herbs storage. Where before its opening, herbs were stored and dried on the hundred organic farms Ricola source from, now these are brought to the warehouse. Deliveries  (and distribution) centre largely underground lorry park, apart from local products brought in by tractor. According to the company, the thirteen principal Ricola herbs used are all grown in the higher hillside reaches across the Swiss countryside, in orchards like the one I’d visited earlier.

HdM, Rauch and Ricola have chosen to emphasise loam as the façade material in part, because of its historical associations with the Laufen valley. Clay is a geological feature of the landscape and has been exploited for centuries as a building material. The new factory is thus an industrialised agricultural plant, springing – like the herbs themselves – from the very soil the building sits on.  A mix of loam, marl and other material, excavated from the actual site before being mixed with earth from quarries and mines, all from within ten kilometres of the warehouse. What was first attempted with the Schaulager art archive, has now been achieved in the Laufen countryside.

The Zwingen Factory earth element production A
Photo: Ricola
Photo: Markus Bühler-Rasom/Derek Li Wan Po

Photo: Daniel Luthi/Ricola

Rauch’s LehmTonErde, set themselves up in a disused factory in near-by Zwingen three kilometre’s from the site, for the earth element production. This was the first large-scale application of the relatively new pre-fabrication approach by the Rauch team, and marks a significant threshold both in scale and method to the production of earth building materials. The first use of pre-fabricated elements, was an internal wall in the Hermann Kaufmann designed 1997 Haus R; followed through 1998/1999 by
Photo: LehmTonErde
Photo: Daniel Luthi  
the larger scale walls for the Gugler Printer’s office. Investment in ‘working inside’ the weather protected warehouse, combined with a series of technical innovations, have helped to quicken the rate at which heavy earth could be produced. And enabling production to proceed through the sixteen winter months of the build schedule, the Ricola Herb Centre represents a step change. At 4 to 6 tonnes (and measurement wise 3.40 meters long, 1.30 meters high by 0.45 meters thick) the earth elements are not exactly small bricks. Machinery developed by LehmTonErde, was introduced at the factory to speed up and simplify production, mechanically dropping prepared loam along a production line bed - in effect the formwork case for the elements, before automatically beginning the earth ramming and compacting process.  Rauch’s earthworkers then completed the process, refining and preparing each of the 670 earth elements, prior to transportation to the site. Despite these early steps in the mechanisation of the process, there is still much to rammed earth construction which can only be done by physical work and learnt through this doing; in other words, knowledge known in the body, a point Rauch (and others) always emphasise. Getting the consistency and mix of earth, marl, and gravels right, is a gradual process learnt by experience and actually working on projects, including Ricola. (Over half the twenty-five strong team signed up specifically to gain first hand physical knowledge of rammed earth building). Such transmission of oral craft knowledge, ‘learning by doing,’ is underlined by the fact that there are next to no dedicated academic rammed earth courses or, for that matter, commercial infrastructure for the material; since rammed earth is available anywhere, earth products and related industries don’t, so to speak, exist at all. A source of both strength and weakness.

Once arrived on site, the earth elements are lifted up by cranes, with each one swung individually into position. Lowered onto a clay mortar, once dried, horizontal joints and connections are sealed with trass lime before the complete facade of the element wall is cleaned and integrated; so that the join lines disappear from sight, the wall taking on a consistent single monolithic texture. Experiencing the walls, unfinished when I visited, and looking at photographs since opening, the self-supporting earth elements once in place, exude a consistency of feel and fineness of texture, part of LehmTonErde’s skilled dedication to rammed earth construction.

Photo: Ricola
Photo: Ricola
Photo: Simone Bossi

Photos: Daniel Luthi          

The large-scale walls also speak their weighted, quasi-archaic uniformity. Broken by four equally large 5.8 metre round ‘moongate’ windows, their spherical circular qualities adding a certain strangeness to the heavy earth building sitting amidst the agricultural fields. They are also a novel way of integrating openings into the earth walls, a key challenge of rammed earth buildings and structures. The window’s round form is supported by a surrounding arch effectively distributing forces equally, while also contributing natural lighting to some of the centre’s internal rooms. Rauch himself, is at the heart of communicating his new adaptation of very old knowledge through projects such as Ricola; and also through workshops, research and books - including the just published, beautifully produced Martin Rauch refined earth construction & design with rammed earth The book includes a lot of information, which, if not technically advanced, is extremely useful to those coming new to earth building. For instance, he describes something known as Calculated Erosion, a technique evolved to help slow down erosion brought on by wind and rain. Rauch uses examples like this and other personally developed techniques, throughout his work; and as with other projects, at Ricola for example, at regular intervals - in the Herb Centre’s case, every eighth layer - the compacted earth is lined with ancient trass mortar, made from mixing volcanic Tuff (trass) with lime - into the formwork. Rauch uses many such techniques throughout the majority of his work, including the new pre-fabricated approach on all the larger scale projects. Indeed, with other projects, including the Swiss Ornithology Centre and the Basel Ozeanium, coming on stream, LehmTonErde were hoping that the Zwingen production line would become a permanent fixture in Switzerland. But this wasn’t to be; and although it supplied the Ornithology Centre with its earth elements, LehmTonErde closed it once the Ricola work had been completed.

Photo: Daniel Luthi
The warehouse is a real presence in its loam-heavy agricultural Laufen valley setting; however, the blunt fact that the rammed earth is a façade, rather than structural material - the building’s shell, detracts from the sustainability narrative which all parties involved, underline and emphasise. The earth elements comprise an essentially separate façade to an all concrete structural frame. If there’s a clear connection between the plants which grow from the earth, and the earth itself, made physical by the earth elements helping control the buildings humidity some may feel the ‘natural’ building materials sensibility that the rammed earth building promotes, is something of a sleight of hand, echoing another Ricola ‘natural’ promotional ploy, their sweets being from ‘100% natural herbs’ - while remaining quiet about chemical additives, including aspartame, among many of their product’s ingredients. Nevertheless, a list of other sustainability features aims to support this building’s credentials. An energy-friendly heating system (hardly radical these days), complements the rammed earth elements supporting the stable internal temperature of the warehouse, and serves to maintain consistent humidity levels. Both lessen the need for air conditioning, which, along with photovoltaic modules on the roof, and waste heat from the near-by production factory, reduce energy use. All these features however, don’t really add up to a technically low carbon or low energy building, and the absence of any - Minergie, for instance - sustainability certification, feels telling.

You can’t really argue that in general, HdM has shown particular concern towards highlighting sustainability in their buildings over the decades. Theirs has been a concrete, steel and glass architecture of the mainstream; apocryphally the Birds Nest used up the majority of the steel available in the years leading up to the 2008 Olympics. The same can’t be said for Rauch and his outfit though; there’s an explicit sustainable agenda informing the whole LehmTonErde operation. Through the Ricola Herb Centre collaboration, a definite and striking statement is being made about what is, and what could be possible with earth.

The Herb Centre warehouse is the offspring of HdM’s first key building, the mid-eighties Ricola warehouse. If the former was a minimalist statement reflecting the late twentieth century, the coming full circle represented by the new Herb Centre warehouse, re-fashions that moment in sustainable guise for the early twenty first century. The sheer heavy-weight scale and ambition of the Herb Centre will, across the larger continental landscape, surely act as a game changer? Away from the iconic spotlight of their star spangled trajectory, Herzog & de Meuron have helped catapult Rauch’s rammed earth mission into a different league of building culture.

Photo: LehmTonErde
Photo: Simone Bossi
Photo: Simone Bossi

* Seven Buildings 1983-2014 a book on the relationship between Ricola and Herzog & de Meuron, with interviews and an essay by Gerhard Mack is available through the Swiss Architectural Museum

For a lovely series of photographs highlighting the building of the Herb Centre, one of the young earthworkers involved, look at architect Timur Ersen's website, where his and colleague Daniel Luthi’s photographic work tell the story well.