The timber carpentry renaissance in England

Edward Barnsley was one of a handful of furniture makers who, remarkably, maintained the living thread of the 19th century Arts and Crafts movement through the course of the twentieth century. He died in the 1980’s, but today the Edward Barnsley Trust continues this tradition with apprentices learning the skills of furniture making in the very workshop high above the Hampshire town of Petersfield, on a verdantly leafy outcrop of the Southdowns, that Barnsley occupied for so many years.

With his father Sidney, and uncle, Ernest, and their long time architect partner, Ernest Gimson, Barnsley is also known for another project which has stood the test of time down through years. In 1919, immediately after the First World War, all four worked on and built the beautiful timber frame structure known as the Gimson Memorial Library at the independent, one-time progressive educational movements’ school, Bedales. Eighty-five years on, stepping inside the brickclad library with its great oak timber frame, amply visible joists, beams and timber posts, still brings on a sense of peace and restfulness, made very evident by

Figures such as these almost disappeared towards the latter years of the twentieth century, but not quite; In the last twenty-five years the sensibility informing timber frame buildings such as the Gimson library has been making a recovery, and quietly and with the minimum of media attention there has been a remarkable re-emergence in Britain of timber frame construction. Houses, homes and non-domestic buildings have been built increasingly using oak and other indigenous wood such as chestnut and larch. At the same time, skills involved in this craft tradition, which stretches back over six hundred years, have been re-learnt by a small band of like-minded individuals from the generation who came of age in the nineteen seventies; re-generating the skills base which was near to extinction only a decade before. The story is a complex mixture of people searching out the old ways of timber-frame building, combined with other key elements in the timberbuild grid – including palpable leaps in applying both contemporary engineering and new technology to timber. This affiliated timber engineering movement has fused with timber or heavy wood carpentry along with a surge of interest and rediscovery in the public mind for actual timber-frame building. Together, all of this, has provided the work and experience for the found skills of this small group of carpenters to apply and passed on to an ever wider net of trainee carpenter crafts-people. And in a sense a significant part of the story leads back to Bedales and the immediate Petersfield region.

In 1995 the school decided to build a new theatre, which would be both a contemporary expression of a timber-frame low energy structure, and a counterpoint to the oak-framed library, turning this tradition around to face the approaching twenty first century. In so doing they turned to a young oak-frame carpentry company, Carpenter Oak and Woodland (acronymously COWCo for short) to build the frame, alongside the well known environmental architects Feilden Clegg, who had designed the building. Returned in fact because Carpenter Oaks founder, Charley Brentnall had been involved in an earlier building project – the Sotherington barn which Brentnall and a small if enthusiastic bunch of pupils moved from a site in Essex Selbourne and rebuilt within Bedales schools grounds in 1981.

This was just when Brentnall – who originally trained as a ceramicist – was getting Carpenter Oak & Woodland off the ground, Brentnall being among a handful of people who in the early seventies became immersed in the (nuts and bolts  I’d be the laughing stock of the trad framers if you used these words!!!!!! So perhaps you might use ….) intricacies of timber frame construction; and he learnt a fair amount of his skills from two his contemporaries; including John Winterbottom and Paul Russell. Russell had recently returned from France, where he had sought out a surviving French Guild or ‘Campagnons’ school of craftspeople to acquire still extant jointing techniques. These techniques had disappeared from Britain by the early nineteenth century, but not across the channel, and included ‘plumb and level’, and datums in timber – where the levels on timber are measured and cut with accuracy, however mishapen the wood. With Russell, techniques such as these were re-imported and transmitted back to some of the small group of incipient carpenters in Britain. At the time, Brentnall says, it was only a handful who started re-tracing and re-learning this lost knowledge; and although at first those involved were not aware of it, soon it was recognised there was a ground-swell of interested people, who “began popping out of their rabbit holes” and realising that they weren’t alone. Brentnall recalls it as “re-inventing the wheel”, re-creating the secrecy of Guild knowledge amongst the first wave of carpenters about their self-taught knowledge.

Brentnall went on to set up Carpenter Oak and Woodland, one of the most respected heavy wood carpentry companies in the country. Today they are based between Bath and Chippenham, down a woody lane in the middle of countryside. Much of the timber framing is done either on site or in their yard and sheds and transported to site. It is a reassuring experience to visit the yard with long stacks of timber sitting waiting to be used, open sheds with frames half completed, and master carpenters crafting sections of buildings for use in the near future. Carpenter Oak & Woodland have been involved in many of the most exciting of the current generation of timber buildings and structures; from the Bedales theatre, Henley Rowing Museum, and at Doncaster’s Earth Centre the spectacular Solar Canopy timber space-frame, to completing a balloon frame design for the latest Maggies’ Centres cancer care project in Inverness. Alongside these public buildings, Carpenter Oak & Woodland continue to be commissioned to construct private domestic homes, including a recent crucible shaped cruck frame structure in Scotland.

If the proximity and transmission of the architectural side of the Arts and Crafts movement embodied in two buildings from the two ends of the century’s hundred year spectrum isn’t enough, just down the road in Rake is Carpenter Oak’s Oak & Woodland’s  younger peer, the Green Oak Carpentry Company, making the area, either by synchronous or incidental design, a nodal epicentre for the emergence of timber build in the south of the country. Set up by Andrew Holloway – another ex-ceramicist – the company was, along with COWCo, among the first half dozen or so to develop in the early nineties. Their first project was a barn in South Harting built in 1991 again a few miles from Petersfield, followed by Orchard House, a four bedroom oak frame home in Winchester. In 1996 Green Oak were invited to join the engineering and architectural team on the celebrated Weald & Downland Museum Gridshell building – where the upper level is specifically for timber-frame teaching – which multiplied their confidence about the possibilities of timber build. And not only for Green Oak. The high profile Gridshell project – almost winning the 2001 Stirling Architecture prize – has given British timber engineering a sizeable boost, recalibrating professional curiosity among architects and engineers about what is achievable with new engineering and new technology and wood as a material. It has also shown continental Europe that the Brits can build and deliver striking new timber building structures. Although again, it is a fundamentally post-nineteenth century structure, its ‘strength’ being in its grid-based lightness, which is somewhat at odds with the traditional heavyweight approach of oak and timber framing, and it has been said there are considerable numbers of people in the traditional timber-framing world who do not care for this “sticks and string” building.

Overall, Andrew Holloway, feels that the timber-framing revival is apparent primarily in the southern half of the country, and he points to both the general public’s rebirth of interest in domestic timber build, which in turn has led architects into unexpected and hitherto unfamiliar terrain. Traditional timber frame buildings have been in demand for, for example pool barns, extensions, and garden rooms; a self-grown interest occurring over the last decade which seems undeniably linked both to the buoyancy of the economy during the period, and the fact that there is more money is located in the south. Architects – who, in Holloway’s view, are ‘as a breed’ generally interested in what is new – are becoming aware of the general public interest have been beginning to look into, address and learn about timber framing. Perhaps, to their surprise, they have generally found it interesting. At the same time it has to be said that there is a ‘retro’ element to the public’s desire, Holloway believes, that there is something brazenly English about the phenomena harking back to a lost England of another time, and relates the restored fortunes of timber frame building to the British being romantic, partial to historical revivalism. The building conservation movement is a point in case, and the increased interest in restoring and maintaining old historic timber frames has added to the building revival in significant measure. This in turn predated the arrival of the fully-fledged Heritage Culture, in which, as Holloway points out, the Brits have become world leaders.

Answering the question of why people are so attracted to timber frames and to wood , Holloway returns to the ideal. “There is a dream to live in a house which actually elevates your spirits and changes your consciousness. We’ve been so bludgeoned into accepting the box”, he believes, “that we no longer notice the difference.” But the timber frame dream is about “physically changing your state of being” closely akin to the dream of the natural home movement. “Building used to be the provenance of the very wealthy, now everybody wants to do it, and the vast majority of say, the British population can”. The public, he says, are unusally interested in timber buildings, “want a building which will elevate their senses, their sense of being. With galleys and open spaces, and with the beauty of construction as part of the building they are in.”

The sustainability dimension of this phenomena occurs almost by default. Overall, British forestry is in overproduction. On a year-by-year basis the degree of woodland covering the country increases annually, with the amount being cut for timber and smaller wood use comprising a smaller segment than the annual additional growth. This is another arrow in the quiver for those who contend that wood based building is the most consistently sustainable of forms, along with wood being a renewable material – as opposed to steel, concrete or glass – wood after all replenishes, growing again and again. Not only this but wood acts as a carbon sink – storing carbon and potentially lowering the releases of carbon dioxide into the atmosphere. Production of man-made materials does just the opposite. Ironically the vast majority of timber used in British building comes not from local indigenous woods, but from relatively distant, cheap sources, notably, historically from around the Baltic basin. Initiatives of varying kinds are being developed to encourage the further growth of local timber construction, for instance, the TimberBuild Network and, in East Sussex, the Flimwell Woodland Enterprise Centre. Together, helped by the Internet, they are working to connect wood suppliers to people wanting to build close to the supply, thus reducing another element in the ecological footprint: transportation of materials.

The immediately relevant element in this story however, is that a skill and physical knowledge that was on its knees has survived a protracted period of adversity and is bouncing back, almost flourishing. Almost, as there are still no professional courses apart from NVQ (“a joke” says Holloway) since its one-time educational stronghold, the City & Guilds courses, were abandoned to the progressive corporatisation of knowledge in the early years of Thatcherism. Often enough, on larger projects, carpenters have had to be recruited from as afar afield as Germany and Canada. This said, where other companies could be counted on one hand ten years ago, and a dozen companies five or six years ago, Andrew Holloway says there are probably a hundred operating today, many seeded from Carpenter Oak and Woodland and a fair few from Green Oak. “The way it should be”, he comments. The future for wood construction is brightening distinctively. Indeed, from one-off woodland projects such as Ben Law’s very popular Prickly Nutwood home – which struck such a sympathetic chord with the tele-viewing public through the Channel 4 programme Grand Designs – to Green Oak’s latest project, a new Gridshell twice the size of Weald & Downland in Windsor’s Great Park going up in the next two years, it may be that the timberbuild renaissance is only just beginning.

Hands-On learning revives a timber classic

Wynstones school Belfast Truss New Hall project

Gloucester’s Wynstones school ‘new hall’ project has reclaimed the Belfast truss, a former barrel vaulted wooden roof structure that disappeared after World War II.

This July, the Waldorf Steiner school, Wynstones, completed the second stage of its unique school building project, preparing and raising their new timber frame school hall. One of the UK’s older Steiner schools, seven miles from Gloucester, this second stage of the new hall project has been remarkable in showing just how participatory an initiative such as this can be. During the first week the whole school pitched in, while for the next three weeks a diverse band of volunteers cut, sawed and hammered it’s way to raising the timber frame amidst this years wet, wet, wet summer weather. All this was overseen, guided, and from time to time, cajoled along by a small team of carpenters who had converged on the school to lend their expertise to the enthusiastic though inexperienced crew. And not only was the level of hand’s on involvement unusual for schools in this country, but the timber frame structure they worked on and raised is a first, those running the project believe, for at least fifty years. The Belfast Truss was a popular timber structure system towards the end of the nineteenth century before disappearing in the aftermath of world war two.

It hadn’t always going to be this way. The school had for several years been planning a new hall on the edge of its playing fields. Originally the schools new hall steering committee, albeit with a certain heaviness of heart, had in 2002 directed an architect to prepare initial plans for a bog standard steel frame industrial shed. Fundraising had been ongoing for quite some time but funds thus far were not exactly over-brimming, and the committee – focused around parents, Charles Crittall and Richard Fox – although wanting a green building – saw this as the only way forward. Building a big metal box also grated with the Steiner school ethos, with its emphasis on the natural, organic and traditional craft which threads its way throughout the curriculum.

Before they got this far, though, chance – or design – intervened. Henry Russell, a carpenter of long experience, had been working for another school parent, who told him about the new hall project. Russell, it so turned out, had been at Bedales School, another node in the one time progressive schools network. Bedales, also, historically emphasised the hands as much as the head, and as a pupil kindled in Russell an enthusiasm for wood and buildings, including the re-construction of two timber frame farm barns on the schools grounds. After leaving he gravitated back into carpentry, and has since become something of a font of wood and carpentry knowledge, being one of the driving forces of the annual Frame timber-framing conference weekends. A part of his reservoir of wood knowledge he was aware of a cheap and elegant structure, the Belfast Truss barrel roofs. Also in 1995, during a seven year stint at Carpenter Oak & Woodland, Russell had returned to Bedales to do exactly what was now being proposed for Wynstones, getting the whole school involved in direct, hands-on building. That time, too, the building had been a new hall, FeildenClegg’s Olivier theatre, which once completed was applauded for its timber detailing and was a high water mark in the practices arts and crafts phase.

The fortuitous connection with the parent led to meetings with, first Crittall and from there, Richard Fox. Russell told Fox about Belfast Trusses, essentially a variation on the barrel vaulted roof. This included their extensive late nineteenth century use; how they were both comparatively cheap and simple to construct and could also cover wide spans, in Wynstones case 18.6 metres was required (which is and sounds impressive though paling in comparison to trusses capacity of up to 30 metres.) Henry also recalled the previous experience at Bedales. And only a few miles away, across the other side of the River Severn in the Forest of Dean he knew of a wood mill, which could provide very good quality, and well-priced Douglas fir and other timber for the job. Fox’s eyes were probably lighting up at this; not only was this so much closer to the heart of the Steiner educational ethos, but the economics were such that it was actually potentially realistic to go with.

Russell was excited because here was an opportunity to build a structure he’d long wanted to try his hand at; a host of timber carpentry experiments could be tested by the building. He thought very little steel would be needed. Crittall and Fox were excited because here was a way out of their steel box cul de sac; the economics stacked up – just about; and it could involve the whole school. So much more to the educational way of doing to which they wanted to adhere.

In the meantime Crittall and Fox had found another architect, a Hants CC with schools experience, although the changing brief was quickly passed on to a colleague, David Gregory. Gregory brought in Romsey based engineers Andrew Waring Associates with Nigel Chalice from their team getting involved.

Architect and particularly engineer, cautious at Russell’s all timber, steel free claims, revised the plan, in effect combining two designs; the modern steel frame with a more traditional timber truss structure. In so doing a significant amount of steelwork was added to the plan, partially, it seems as health & safety insurance. At each end extra steel bays were added, bookending the nine latticed trusses, separated by bays, each 3.6metres apart, while along each side of the building are further single floor 4 metre high floor post and beam aisles. Seeing the hall immediately after the frame had gone up, I was unprepared for the sheer scale of the building, reaching a height of 9.6 metres. Added into this is an intermediary mezzanine level will be built in at one end. Russell now acknowledges that the additional steelwork is quite an important part of the structure, ensuring the timber frame won’t (and can’t) wrack in either direction. Inevitably, he acknowledges, this makes for a much more stable building, particularly with a rigid steel lattice within the roof plane, running laterally, along the buildings spine. Still, the hall, covering around 2250 sq metres is a sizeable and ambitious project.
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When the time arrived to order the wood, sourcing the complete required amounts from his forest of Dean mill, Woodgate, was more complicated than anticipated. Woodgate eventually supplied between a third to a half of the buildings Douglas Fir and Larch. The remainder was supplied by Vasterns, British grown C16 graded Douglas Fir, which had been kiln dried. Ungraded timber was used on the larger sections and on the stud panels.

The early work was carried out by the whole school during the last week of term, with over 70 pupils, divided into teams, working on specific parts of the whole building. The first two trusses were completed in that first week and parts for most of the majority of the remaining trusses were started. Also during that first week the aisle walls post and beam frame was prepared and scarfed together. Other post and rails were prepared with 22 morticed and tenons, as well as many of the stud panels.

The next week the volunteers arrived, a mixture of parents, friends and others who had had about the project, through the schools grapevine, (including myself and my son) as well as a sizeable contingent of German Waldorf school teenagers. Both Russell and the school had invited specialist carpenter colleagues to lead the nine or ten teams, one by Russell’s old friend and Carpenter Oak and Woodland founder Charley Brentnall. Three weeks later the second stage was completed on time, despite much of time being wet and sodden. By week four, when I turned up, much of the work was completed, with the last trusses being finished off, the post and beams being manoeuvred into position ready for raising, before the heavens opened again and 24 hours later much of Gloucestershire being declared a flood emergency area. The main team, plus a reduced number of volunteers ploughed on, into the last week when the crane arrived and the whole build went up, still on time, and without too many mishaps.

Russell was particularly interested in how both this low tech and non-specialist truss construction process could provide a long span girder covering considerable areas, and that part of that process, the external top and bottom chords, in effect, carry out the trusses work. These trusses are 2.6 metres high at their ridges, with the web lattice section joined to their external frame – the upper and lower chords. He loved how both these top and bottom chords – using short panels of ungraded wood – could be simply nail laminated onto the lattice section, a piece of carpentry easily carried out by the unskilled volunteers. Similarly, the next step, of the upper chord being bent round a jig was straight-forward, bowing the chord into the barrel arch shape, introducing the compression element to the truss. Once completed the chords carry the trusses load, its weight extended to the trusses eaves, while the lattice web strengthens each of the trusses stability, in all a relatively uncomplicated process. Lengthwise the hall is about 120m metres, with the 7.3 metre 22 posts on each of the structures two sides sitting on galvanised steel shoes, within the concrete slab. At each end stands the extra steelwork added in by the engineer.

As each of the trusses were completed, with its different layers fixed together, the team literally lifted it off the jig with small dollies before starting the next one. With volunteers, the trusses were completed in a day and a half, through very low tech processes. Russell thought that professional carpenters using power tools, would bring this down to one day. Also, as it was, Russell believes, using a Belfast Truss reduced the amount of wood by about a third. He could also see that a comparable traditional timberframe building would use significantly more steel.

Once up, all those involved were very pleased with the result and Russell particularly believes, that the Belfast Truss could be an effective wide span timber frame exemplar to push today in the early 21st century. Noting how ubiquitous truss roofs are in the mass housing market, and their re-emergence in the larger buildings, he points out that durability remains a problem, something a structure such this, using the right wood, could effectively help.

Their history goes back to the mid 19th century when the lattice truss was first developed. The Belfast truss is an adaptation of two earlier structural systems; the lattice and bowstring trusses, this latter so called because of its arched form. Belfast trusses began to be built at the end of the century and continued to remain competitive because of their cheapness compared to steel, particularly during world war one, as steel was needed for the war effort. Over the next thirty years Belfast trusses were gradually eclipsed by increasingly economic steel girder construction and although a number were constructed up to the second world war – including a vast factory hall at Belfast’s Harland & Wolff’s ship building yards and in various other parts of Ireland – Russell doesn’t know of any that postdate those final mid-century examples. So not only is this an unique experiment in learning, the hall has reintroduced the Belfast Truss structure and technique after decades of languishing in obscurity.

It looks quite sophisticated, he says, compared to what the describes as the blobby bolted Frink truss, ‘which is not subtle.’ He talks momentarily of their being a renewed interest in large span buildings, and that such sorts of truss structures could be used for supermarket and industrial buildings, competing well against steel, if steel prices continue to spiral, which, as he says, seems ‘quite likely’. And if this happens timber built large span could come into their own.

No-one has done the sums to compare this timberbuild’s carbon footprint to that of the originally planned, steel building, even if the total timber bill was around £40 000. Perhaps such energy and carbon footprint calculations could be integrated some of the pupil’s lessons. As it is that much again was spent on the concrete slab, during the first year, and another £30 000 on the steel used within the building. Further environmental features include a ground heat pump, natural ventilation and rockwool insulation.  An aluminium roof membrane is to added soon, at about another £150, 000, a compromise of sorts, indicates organiser Crittall, the cost of working with such a small, constraining budget. Travelling hopefully, fundraising will now begin for stage three, to complete the hall. The budget ran originally to £500 000, though that has now probably risen to £750 000, also successfully raised, and the school is confident that the remaining funding can be found. Still, it’s a very economic build, about £560 sq metre. Compare this with a normal school hall and the cost would likely be in the millions. It will not have passed everyone’s attention reading this piece that I have written about another very different school hall in this issue of Green Buildings, which not only uses a very different hi tech timber system for its construction requirements, but embodies a completely different school building paradigm. I am not sure of the difference in floor space, but without wishing to make any particular judgements on the Kingsdale project, dRMM’s two halls were built to a budget of £3,4 million. The difference in cost is thought provoking.  Henry Russell, talking about what kind of influence Wynstones children will have received from this experience, suggests that for every single one, it’s likely they will remember it for the rest of their lives. And also, not all, though probably many, will have found it a real and enjoyable experience. It is also one where, through physical doing, the rudiments of building and of construction will have been experienced and learnt in the body.

Kingsdale offered many other possibilities, including various second level forms of participation. As it is participatory learning has become a focus of division across the state educational sector. Those of an educational turn of mind see the Government’s Building Schools for the Future (BSF) programme as a once in a life time opportunity to integrate learning through elements of participation into the programme. Set against this are the mainstream architectural and other building sector orthodoxies who may talk the participation talk, including the right words in their tendering bids, but once awarded contracts end up ignoring such principles and resist applying their participatory rhetoric from there on in. The Sorrell Foundations JoinedUpDesignforSchools initiative has attempted to bring change to this, spearheading participation, which is good as far as it goes, but it remains to be seen how much gets integrated into BSF over the coming years. Participation, however, is not active doing, in the sense of children being in on the making of a building. Wynstones, in this small, idealistic, though equally, fun project are way ahead of where joined up thinking in schools is heading. It’s nuts to suggest that participatory timberbuild could be integrated into every inner city schools project, say, but a project like this suggests that the difficulties inhibiting active doing can be navigated. Would that it could happen more often, beyond the fearful sway of health & safety ‘litigation’ culture. And would that those in the progressive educational architectural and building sector would support it, rather than concertedly falling into line behind an educational status quo that frames participation within the conventions of the SATS target obsessed national curriculum, might venture more daring forms of participation. Not only this, but consider the prospective savings to budgets! Will it happen within BSF? It’s nice to dream but if this was mainstream education, you, I am sure, can imagine the pained looks of disbelief were such a scheme brought before the local education bureaucrats.

The school build can be seen on the schools website www.wynstones.com and also at www.wynstones-school.co.uk

Notes: For a short, technical discussion of Belfast trusses see The Belfast roof truss, by M H Gould, et al, The Structural Engineer, vol 70, no 7, April 1992.

Timberbuild comes to the office

The structural use of timber in office, industrial and commercial building, as part of integrating ecologically sensitive sustainability into the work environment, could go a long way to humanising the work-spaces of the future. Here are three isolated examples in Britain, which begs the question as to why are there are so few precedents.

When do isolated instances of a building form turn into a trend? Not quite yet, it seems in the case of timberbuild office, commercial and administrative buildings in Britain at least. This despite the efforts of FeildenCleggBradley Architects to conjour renewed interest in this sector of the industry, a bread and butter staple to many mainstream practices. Did last years completion of two sizeable office and commercial projects – the National Trust Heelis HQ offices in Swindon, and Neals Yard Remedies, (a more fundamental timberbuild, brought about by the companies relocation of operations to Gillingham, Dorset, by the veteran sustainable architects) – signal possible winds of change or just as possible, business buildings as usual?

The Neals Yard Remedies building offers provocative food for thought for those drawn to the benefit and advantages of timber construction. Recently completed, it also underlines just how sparse construction of this building type in timber is, with few precedents to draw on. There are, potentially, a range of benefits. They can be divided into functional, or energy led; psychological and productivity led; or seen as the benefits to public image and identity that companies can derive from investing in such buildings.

A primary sustainable rationale is that timber structural systems are the most energy efficient construction technique in terms of embodied energy, compared to any other material. Whilst reluctant to rehearse the argument for Building for A Future readers, as most will be aware the amount of embodied energy which goes into producing timber for structural use is significantly less than steel, concrete or other materials. Steel and concrete are the failsafe competitors and comprise the standard structural materials in office buildings. Yet inescapably they make for much heavier energy and ecological footprints, which can be reduced by the introduction of timber construction.

A second argument dovetails with, or is subsumed within a wider and essentially psychological approach and is also closely linked to issues of well being. Well designed offices using natural materials, with natural lighting and heating – and space – feel good. Good, that is, compared to vast open plan air conditioned spaces filled to cramming with work-forces, often under fluorescent lighting, at times without natural light, an increasingly desktop technology-centred work environment, of in the main computers and phones. Now this isn’t primarily about structural use of timber as such, but repeatedly if anecdotally, the reports are of people liking being in a woody environment, being amidst wood, and this can include glue laminated beams. As Craig White from Bristol practice White-Design, says of his glulam build experience, no-one goes and strokes or feels steel columns. Feeling good affects  the productivity of work-forces; and more than one academic has made a career out of linking the quality of design and interior architecture to the efficiency and effectiveness of an organisation. And Sustainable buildings are much more likely to deliver on these counts. The title of Brian Edwards study of office buildings Green Buildings Pay1 tells its own story. Or consider the Guardian’s Jonathan Glancey in an article last year; ‘the state of your office tells you what your firm thinks of you,’ going on to add what the paradigm contemporary office design mimics above all, is the crammed call centre2.

A third timber-favourable argument is the showcase value of a considered sustainable building. This is the inverse of Glancey’s point, sending the message that the company does care. A point conveyed in the recent European overview of the field, Timber Construction for Trade, Industry and Administration by Wolfgang Ruske. Acknowledging that many industrial buildings are little more than ‘luridly coloured excrement’ the introduction explores how a small number of companies have taken a pro-active interest in using buildings as part of their identity; to convey both the company’s business philosophy and its overall identity, as well as drawing attention to the quality of its products3.  Within the books pages twenty three projects from all around the developed world are high-lighted, thirteen from the German speaking countries – Austria, Switzerland and Germany itself – though also North America and Japan, but dispiritingly, not Britain. This is prefaced by a brief discussion of various timber construction methods and discussion of the relative merits of differing materials. While not all the projects are by any means primarily sustainable, many are, and the thrust of the book is clear: timber constructed buildings make much more sustainable buildings than others.

A couple of months ago while being shown round the NT’s Heelis, my guide pointed out that any desk on its two floors was lit by natural sunlight. This came across as intelligent and smart design. Yet a few weeks later it was the Neals Yard Remedies site, an architecturally less ambitious build, but more adventurous overall project, which was feeding my imagination with all sorts of further ‘what ifs’.

As Ben Bamber reported in BFF Vol 15, no 3, Neals Yard Remedies are the complementary creams and health company, which started life in the hippy mini citadel of Neals Yard, Covent Garden some twenty-five years ago. Growing rapidly over the intervening period, encouraged by the boom in alternative medicinal and healthcare products, the need for a new centre of operations became pressing; and grabbing the nettle of relocation, the company decided to head to similarly fast growing Gillingham. FCB’s resulting design joins the administration to the storage buildings via a bridging canteen space. While visually understated what is of structural interest is that the whole of admin and canteen area is a timber construction – the first I can find in Britain in this building type for six years. The company wanted to convey its strong sustainable ethos, and what I found so potentially exciting in addition to the timber frame system was a sustainable building being integrated into the wider philosophy of the company: the adjoining land will grow some of the products as well as providing for other work needs. As project architect Alex Morris says, it’s a cross between an office and a farm.

First off though, a glulam post and beam system runs throughout the admin and refectory area. To supplement the application of wood, a sandwich construction system, using SIPS panels sits between the frame members, with insulation foam blown in before hardening, both reducing the number of frame members and bracing the frame. Neals Yard initially also wanted the much taller storage and manufacture building to be a timberframe construction. This would have involved 12 metre glulam columns and 1 metre deep beams. Technically do-able, such scale turned out to beyond the financial pockets of the company, who reverted to steel in the consequent cost cutting exercise. In a study, which he carried out while working on the building, Morris compared a variety of wood types with a variety of metals4. Tabulating these, Morris was able to quantify low, high and average kilowatt hours embodied energy and compare the building frame embodied energy in both steel and timber. For a glulam frame the low embodied energy was estimated between 82,000 kwh, and 360,000 kwh, while for a steel frame the low embodied energy was 353,000 kwh and the high 866,000 kwh. So in both cases the glulam used significantly lower embodied energy. Anenergy use estimation once the building was occupied, came in at 79 kwh per sq metre for heating and water. Extrapolating this to the buildings main energy uses, Morris concluded that 194,000 kwh, or between the first one and a half and two and a half years, of the buildings energy use had been sliced off through the reduced embodied energy footprint glulam allowed. This is with glulam imported from Germany, rather than timber sourced much closer to the building. While the mainstream architectural and engineering world’s main focus is on energy use reduction once buildings are up and running, such buildings and studies demonstrate the embodied energy advantages of using timber structurally.  This would also improve were the engineered timber industry to grow. At present, compared to steel the industry’s small size means it finds it difficult to offer competitive tender prices. As it is, the engineered timber companies vary in tender costs depending on how busy companies are. These and other factors do militate against timber breaking into the office building market, although this hasn’t stopped FCB pushing it as a building approach they would very much like to develop further.

If their new building is made primarily of wood, the core material to the whole Neals Yard Remedies business are plants, those smaller cousins to trees in the vegetable realm. Situated in field at the edge of Gillingham, the company are relocating their herb garden from nearby Fontnell Magna, part of the field is gradually being turned into an orchard. Not only this, but to the side of the building an employees vegetable garden is in the early stages of planting, with staff all offered garden time. Other features, including an avenue of Gingko trees line the entrance.

What Neals Yard Remedies appear to be doing, is a form of integrating timber construction with a variety of other parts of the plant world; linking the ecosystems, and helping to complete the circle as it were, rather than a timberbuild project isolated from the surrounding ecology. Not only this but a field of allotments, herb gardens and orchards is perhaps one pathway exemplar for how mainstream offices might be designed, even, in the near future. You can’t see it yet, full growth is a few seasons away, and at present elements of the three piece building can feel incongruous in the flat Dorset valley countryside. But it felt like a genuinely intriguing experiment, marrying timberbuild to the seasons. Only the interzone was missing: plants on the inside, either for growing: be it flowers, fruit or vegetables, or as additional quiet contributors to the workings of the building; spider plants, helping with ventilation for instance. The staff seemed to be wholly into their new environment. As I left near to the end of a working day, a girl was also leaving. “It’s a great space to work,” she said after enquiring what I was writing about.

The Neals Yard Remedies building is the latest in the somewhat woefully short list of office and commercial buildings in this country which apply timber structurally. The first recent example I can trace is in midlands Kettering. There, the young Bristol based White-Design practice was given an early break soon after setting up in 1998. Through a chance referral, Craig White was recommended as a low energy specialist architect to the Danish natural light and ventilation company, Velux. Velux wanted to build a demonstration showcase. The brief was fourfold. Use Velux products in the building, demonstrating use beyond domestic attics and lofts, while doubling as their UK headquarters and maintaining a pronounced Scandinavian aesthetic and identity. Which in effect meant wood. White-Design undertook a feasibility plan, thinking they were too inexperienced to get invited back. But they were, and after a series of further tendering hoops were offered the project.

The solution which won White and colleagues the tender, makes much of designing by section, rather than plan. White describes the build as in effect a contemporary barn. Held up by nine initially vertical glulam posts, before flying over and turning into near horizontal beams, which extend out above the far roof face. This face slopes down steeply to near ground level on the building’s far side. In the space between the two faces, skylight windows bathe the office within natural daylight. The glulam is left exposed both internally and externally, dividing the interior into eight discreet bays; while the final ninth beam stands outside fully visible, creating a dramatic shelter at the back end of the building, as well as providing the external fire escape space. Velux photovoltaic windows are used, and other various core sustainable elements are integrated including concrete thermal mass, as well as timber studwork walls.

White describes the building as Velux mark I, which encapsulates a whole approach. Economic at the time of Velux I – £1050 per cubic metres – in the years since the practice have developed this approach a further five iterations. These have included a redesigned version has been entered into competitions, including what looks from the competition drawings like a striking application for Sittingbourne, Kent, Civic Centre. More recently what is described as Velux mark II, has been developed as an office model template with contractors Willmott Dixon, one version which may see the light of day for European Velux centre, and another which is on course to be realised for a new building for Edinburgh based company, Ecosse Regeneration.

Another example, again a showcase, is the Eden Project’s Foundation Building completed in 2000. The 6 by 14 metre box has two floors, designed around a central staircase. Ten propped glulam Whitewood beams make up the lightweight column based post and beam timber frame adapted to the box build, with these beams exposed, except in parts of the ground floor. They are also bolted to concrete pads on a raised timber floor. A series of OSB and softwood Truss Joists sit between the posts, with 600mm centres. Although the softwood beam system was milled to slender dimensions for what Grimshaws call aesthetic reasons, something of the feel of a fully timber building has been lost with the building wrapped with an aluminium cladding system, even if these also support a timber-decked terrace to the front entrance side of the building. Again this building is naturally lit and ventilated.

Discussions with various professionals in the timber architecture, carpentry, engineering and marketing world didn’t produce any further examples; most referred to the Neals Yard building as the only office structure they knew of which fitted the office/industrial description. And in email correspondence with Jonathan Shanks, who recently researched the building type as an internal assessment for Buro Happold’s timber engineering department, Shanks was pretty categorical that he, similarly, had come across no other precedents for timber constructed office and commercial buildings in the country.

In Europe, and particularly timber producing areas of Germany, Austria and Switzerland the story is markedly different. One striking example in the Ruske’s Timber Construction book is a zero emissions factory in Brunswick, Germany by Banz and Riecks Architects5. Unsurprisingly, the firm, which manufactures solar energy systems, had a company interest in developing the factory. The timber construction covers production, storage and admin areas where glulam is used, with two wide 27.5 metre open span structures.

There are also examples across the Nordic countries, although these are not as prolific as might be expected, given the close identification of timber building with the forested north. In fact, in Finland, it was only in the last year that the first  timber built offices were completed. METLA, the Finnish Forest Research organisation, opened their showcase offices, which apply the increasingly popular solid wood techniques in Joensuu6, to the far east of the country. And in the summer 2005 Finnforest were to open its FMO Tapiola office where, as with the Velux building, the building acts as an advertisment for the occupiers’. In this case Finnforests products including modular prefabricated Kerto LVL columns and beams. Whether the prefabricated Kerto remains exposed in the buildings design doesn’t come across on the website6.

What do these examples tell us about the prospects of timber construction becoming more common-place in the office and commercial build environment? Given that in each instance the organisations who have stumped up the money for these buildings have a direct commercial interest in doing so, its wider application could well be quite far off. Craig White argues that encouraging the embodied energy agenda is the next stage in any more thorough going greening of mainstream sustainable architecture. The need for further exemplars, familiarity in the mainstream professions, as well as an engineered timber industry sizeable enough to compete with steel – including the regrowth of homegrown glulam producers – are also contributory preconditions to stimulate change. Putting aside the perspective of whether there ought to be any offices in the first place, triggered by utopian dreamings, a humanising of office space, through ecologically sensitive sustainability, feels to my mind the most hopeful option for the future of modern industrial, and commercial buildings. Whether and when this happens to any viable and visible degree is another matter.

2005 – Originally published in Building for a Future

The Savill Gardens Gridshell, Glen Howells Architects

In the late nineteen eighties the German engineer-architect, Frei Otto, visited Dorset in South West England. Otto had been invited by the furniture maker and entrepreneur, John Makepeace, to participate in a wood build experiment which aimed to revitalise the use of roundwood thinnings, or wastewood. The result was the main furniture and crafts workshop at Hooke Park, the forest-based teaching and learning addition to Makepeace’s Parnham House Furniture School, down the road in the small and picturesque village of Beaminster. It was, as it turned out, Otto’s only project in this country.

Back in Germany, Otto’s reputation remains formidable to this day. Some of this has to do with Munich’s 1972 Olympic stadium, which he designed and which is still, apparently, many a German citizen’s favourite piece of modern architecture. Among the wood architectural fraternity he is best known, however, for the Mannheim Multihall, an extraordinary organic labyrinth of curving timber lattices, combining a series of pod-like snake-skin walk-through entrances and exits, and encompassing two open space halls. The building was originally designed as a temporary structure for a flower festival.  The structural engineering technique Otto developed for Mannheim he called gridshells. Again, despite its success, Mannheim is the only gridshell Otto actually completed.

A major and, at the time, insurmountable problem to building further gridshells was  breakages among the laths, the long strips of wood which criss-crossed to comprise the double curvature gridshell skin. Back then, there seemed to be no way around this. Although the engineering for Mannheim was very advanced for the time, optimising the geometry to reduce breakages was very difficult, and reportedly the lath breakages for Mannheim were over 11, 000. Many of the mathematical calculations for Mannheim were done, in that pre-computer age, by some of the smartest engineering brains of the generation, including the English engineers, Ian Liddell and Ted Happold. The two had for many years worked at the international, though London centred, firm of engineers, Ove Arup. However, in 1972 they went independent and  set up the firm of Buro Happold, with Happold continuing as prime engineer at Otto’s court. Liddell and Happold worked on many Frei Otto projects together, including a variety of wood projects, of which Mannheim was but one,  though  the most ambitious.

It was Buro Happold who provided all the engineering for Otto’s, and the other subsequent, Hooke Park buildings designed in collaboration with Edward Cullinan Architects, and the experience of Mannheim stayed in their minds. The centrality of sustainability at Hooke Park has been disputed, but what Hooke Park did do is show that waste round wood could be used for building, and the buildings have remained an inspiration for each subsequent generation of timber-hued architects.

Happold, in fact, were keen to build a gridshell at Hooke Park, but this proved impracticable. Their chance to build a gridshell came soon enough, however, when Cullinan’s and Happold, were appointed to design the Weald and Downland Museum Gridshell in the later nineties. What had changed in the intervening years was the arrival of computer technology, including the ability to model the physics and geometry of shell-structures to minimise breakages. At the Weald and Downland build this added dimension reduced breakages radically, making the gridshell technique far more feasible to realise. The Weald and Downland Gridshell, as many will know, has been very successful, winning awards, and becoming something of an icon for one possible future to timberbuild. This is  not surprising;  it is a beautiful and resolved building. In the years since there has been a significant and definite undertow of fascination for the gridshell form among many in the architectural world, with a steady flow of plans for new gridshells emerging from computer screens and drawing boards around the country, but none, frustratingly, have as yet to be built.

This summer all that changed, with the opening of the first major gridshell since Weald and Downland five years ago. The Savill Building, the ticketing and visitor gateway to Savill Gardens in Great Windsor Park, redefines the gridshell, pulling its design far from its experimental beginnings and into the mainstream. And yet quite a bit of the ancestry of those previous buildings – from Mannheim through Hooke Park, to the Weald and Downland building – is very much part of this brand new, ambitious and thoroughly modern gridshell at Savill Gardens. Buro Happold are in there again, as are the Weald and Downland carpenters, – Green Oak Carpentry Company, – although this time they have teamed up with the Glenn Howells Practice.  Thirty years on, the Otto timberbuild spirit is in the air again.

Savill Gardens is part of the Royal Family’s land, managed by the Crown Estates, and set within Great Windsor Park. Although unlikely, given the Royals staid and conservative reputation, the Estate have plumped for a wholly avant-garde building, a kind of evidence that even the ultimate bastions of the establishment need to move with the times. The decision to build a gridshell by Crown Estates highlights the paradoxes of a defining conservative organisation finding iconic architecture mandatory for raising profile and profit. “We wanted, shall we say, a contemporary building” states the diplomatic Estates ranger, Derek Rogers, at the press launch in June, going on to detail how the limited competition for Savill Gardens stipulated both an eye-catching building, and timber as a core material harvested from Windsor Great Park’s own sustainably managed woodland.

Approaching the building from the Gardens car-park entrance, only the hint of the full gridshell is visible, behind an earth covered and landscaped entrance corridor. The curvature of the three valleyed larch grid deck is much flatter than either Mannheim or Weald and Downland, apparently the lowest curvature manageable, in order, says architect Glenn Howells, so as not to break the tree-line. From outside, the deck is just as organic as its forebears, but by comparison, a slim futuristic, leaf-like shape gives a slick contemporary feel. And at 90 by 25 metres the Savill Building is the first gridshell to compete with Mannheim scale-wise, and is twice the size of the Cullinan building. Once inside the canopy becomes clear – at least if you look up – with the criss-crossing larch laths coming into their own, playing perceptual tricks within the troughs and domes. Compared to the timber experimentalism of its predecessors, however, Glenn Howells have fused the deck with mainstream materials, including two tone brick along the interior wall of the entrances’ ticketing area; steel struts; a further steel rim edge tube holding the grid; and an  extensive curtain of window paneling for viewing the beginnings of the gardens.

There are other differences, as well. The actual gridded shell doesn’t make it to the ground. On the entrance side, the roof structure begins within the softly sloping, grass covered, earth wall, within which are a group of rooms, for ticketing, etc, before entering the restaurant and shop facilities which sit on oak flooring under the canopy. On the gardens’ entrance, or far side the steel pylon quadropod struts hold the long tubular steel edge beam, which then connects to the far edge of the grids’ roof. This edge beam holds much of the roof load, and the deck ends in an overhang, rather than dropping to the ground.  The quadropod steel struts, developed separately by the small engineering practice, Haskins, Robinson, and Waters, – (HRW) who also worked on the concrete building, – take most of the shells’ load. Much engineering effort went into designing the connectors between that edge beam and the lath system of latticed shell.

From inside, the view out is to the beginnings of the park.  Between the end of the gridshell  and the ground is the glazing system, the glass panels enclosing this visitor area with windows between 8.5 to 5 metres in height, providing a degree of protection along with a dramatic first view of the gardens’ entry paths  for those just arriving.

For Andrew Holloway, managing director of Green Oak Carpenters, the Savill Gardens building is a distinctive contrast to the Weald & Downland gridshell. “It’s a very different approach to the whole aesthetic of Cullinan’s gridshell. Cullinan’s approach was to use materials honestly and let the building speak for itself. In a sense that’s a “warts and all” approach to construction, where you make the detailing work as elegantly as you can and the buildings’ structural aspects become part of the story. In this it’s concealed; the architects are much more interested in clean, simple, elegant, uncluttered lines, so that the buildings’ working parts are hidden. That’s really okay.”

,In the evolution of the gridshell, Holloway believes the hybrid nature of the structure, with its edge beam steel legs, represents its most innovative element. “It is a very interesting further application and development of shell structures”, says Holloway. ‘The evolutionary process that this building represents moves shell structures into what is the most difficult structural form, which is roof only, shell only curvature retained by a perimeter beam which is propped off the ground. That is the significant achievement of the building in construction terms.”

Despite the palette of modernist materials, the semi-medieval practice of resorting to real trees in the building process couldn’t be avoided, with oak and larch sourced from Windsor Great Park. Green Oak advised on which trees were to be used, and means of  procurement though the wood needed to be cut some distance away as the Windsor Park sawmill had closed a decade earlier.  In addition, the timber, once cut, was sent to In Wood, the Sussex based company who have made a speciality out of preparing 6 m finger and scarf jointed laths. These were then returned to the site, where Green Oak had set up a poly-tunnel workshop where the sections were glue screwed into the long lath lengths for the roof. The diagonal laths are 46 metres in length, 12 metres longer than ones comparable for Weald & Downland, for whom this kind of work was first done.        Here, however, the wood is doubled using two laths to make up a length of almost 100 metres for the buildings’ length. Beginning with eight carpenters in February 2005, the number increased to eighteen at the busiest times. The building was also lowered with the same Peri scaffolding system used at Weald and Downland. What differed here was that the scaffolding’s lowering element was independent of the support scaffold, making adjustment much easier. Another fundamental difference was that at Weald and Downland all three of the shells’ layers were on before the lowering began, while here the lowering was done with only two layers; the first double layer of laths, followed by the second individual layer. This has meant that one of main design innovations at Weald and Downland, the node clamp systems, became unnecessary. The nodes have been replaced by bolts – bolted through layers separately, one through the upper, and one through the lower grid, assisted to by shear blocks, which, in effect join the two grids together, making them act as a beam.

Although the steel edge beam system has been used, a timber edge beam system was considered but would have been large and chunky, about 1.2 metres deep. Given the thin clean edges of the architectural concept such thick wooden legs felt intuitively alien, and were dropped. Also in the early design process, the intention was to make the building  a full shell structure running down to the ground. In this version the shell structure ended with legs down to the ground, which were to be formed from big glue-laminated timber legs landing on steel struts, in turn bolted to the substructure. Too complicated and too expensive, the steel props consequently became the key design solution.

The low angle of the buildings’ orientation is intended to make the most of solar gain, so that the building doesn’t require cooling. Heated by a lower energy gas fired system, the shell overhang on the Garden side’s window curtain also encourages natural ventilation. Although the gridshell canopy is its primary feature, followed by the locally sourced timber, as well as Kerto cladding, Savill Gardens ticks various other current low energy boxes. However, it would be hard to describe as a thorough-going example of a sustainable building, and indeed, this was never the main part of the brief.

Nonetheless, the Savill building pulls gridshells further into ‘ iconic building’ territory. Its mix of slick modernist design and modernist materials may well auger a rather different future for both design and technique, to the modern medieval dreamings generated by the line of buildings that came before it. As one sardonic wag noted, there’ll probably be gridshell kits in IKEA within a few years.  And, again, it does provide both an impressive exemplar of what contemporary timberbuild can deliver, along with a significant new pool of research, skill and knowledge as well as experience, which can  be called upon to develop further, more thoroughly and truly sustainable gridshell structures. Whether in Savill Gardens, making and building any perceived alternative identity the gridshell may have had, has been lost for good, is too early to tell for sure. The hope must be that this new timber showcase will inspire and motivate the design of a next generation of gridshells and other shell structure buildings over the coming years.

6th august 2006, Originally published in Building for a Future