Gridshell Building

22 Building for a Future Winter 2002/03

Lothian gridshell

Gridshell is in vogue. BFF has featured at least two other gridshell projects over the last year. Previous projects have portrayed the method as a highly technical use of a low tech resource. This, however, need not be the case as we see with this project - the new home of the Life Science Centre Trust. Oliver Lowenstein reports...

Lothian Gridshell

Building for a Future Winter 2002/03 23

Today, two buildings rest within the Centres grounds. The rst,

a timber-frame barn off to the edge of the Trusts land. The

other is a craft centre near the entrance, with signs of continu-

ing workmanship everywhere around; unstacked timber, builders tools

and materials. The building is almost complete. It sits easily under the

pine bowers, log columns on each side, and grass roof and stone walls

providing a deeply organic, quasi-rustic feel to the building as bets

the work of its architect, the respected Christopher Day. But it is upon

hearing about the heart of the building - the craft room, that ears have

been perking up, for its roof is a ten metre span self-built gridshell,

constructed entirely by the craftsmanship of working hands. News

of the gridshell has already leaked out into at least one mainstream

architectural journal. The other gridshell Riba magazine announced

months ago, immediately setting off comparison to the recently opened

and widely praised Weald and Downland

Museum gridshell in Sussex. There are

comparisons to be made, both are, after all,

gridshells. But in reality both are completely

different buildings constructed from related

but different mindsets. The Weald and

Downland gridshell is a notable achievement,

but it has been completed with international

architectural and engineering practises and

equally international level funding resources.

If you happen to have a spare 1.8 million

you too can build a gridshell of the scale

and dynamism of Weald and Downland, but

it doesnt need this writer to reiterate that

most organisations dont have that kind of

depth to their pockets.

This means it is out of reach of many in

the community who might want to explore

such forms at an equally valid if far smaller

scale. Which is where the Pishwanton

building (although it is beginning to be

known as Lothian gridshell) comes in.

Through what appears as a mixture of forti-

tude, foolhardiness and staying power, the

Pishwanton building has been completed over four years in a stop-start,

almost hand-to-mouth fashion. It is testimony to those involved that

against the kind of odds where more mainstream professional opera-

tions would have not entertained being involved, the Life Science Trust

has seen the project to completion. And they have done so at a cost a

fraction of its giant cousin far to the south between 50 and 60,000

- considerably inside the grant released by the Heritage Commission just

to begin the Weald and Downland gridshell reseach.1

Pishwantons story began with the founder of the Life Science

Trust, Margaret Colquhoun. A committed Anthroposophist2, Colquhoun

had, for many, years nursed the vision of creating a centre dedicated

to developing the work of Goethian life science.3 In the run-up to

the Millennium with Lottery and other money suddenly available she

appears to have seen a way of making it happen, or at least begin-

Top left: internal view of nished grid Above: nished turfed roof of central space Left: modelling of grid

Photos by Tasker/Lowenstein


Lothian gridshell

ning on her dream. After some preliminary on site work

by a local architect, Richard Shorter, Colquhoun enrolled

Christopher Day, the best known of a small band of

Anthroposophical or Steiner architects in this country, and

a revered inuence in certain segments of the architectural

rmament. Colquhoun and Day had already begun working

together right from Pishwantons inception. Even before

the land was purchased the two would go to Pishwanton

to, as Colquhoun puts it, listen to the land, applying

the same intuitive approach which Goethian Science

uses to try and sense what the land wants, and indeed in

their view, whether it was actually the right place for the

Centre to grow from. Colquhoun points out that her and

Days approach are in fact inseparable. As it was listen-

ing to Pishwantons landscape, its genius loci, extended

to everyone involved, and worked through a number of

stages aimed at heightening the senses to the atmos-

pheres and moods of the place, which in time resulted

in becoming aware of where exactly and what forms the

buildings would, as it were, manifest. This communal and

apparently all-inclusive approach is what Day means by

Consensual Design, enabled by a process of opening to

the environment. In fact Day would not claim the build-

ings are his, rather he expresses what those participating,

in their sensing of the place as a living animate entity, say

is needed. Such an esoteric process-led approach mat

appear bizarre to even the environmental building sector,

or at least those who nd it difcult to give credence to a

living, vitalistic environment. So it was out of this intui-

tive precognition that the building projects at Pishwanton

grew, initially three buildings, but as various funding constraints began

to bite, the focus turned to the craft building.

Day began sketching out the architectural ideas in 1997, using local

engineers, although design continued throughout the rest of the year

and into 98. At the same time Colquhoun did the landscaping, based

on the same Goethian Science principles. Originally, the rst of these

was going to be, symbolically, the Seed building, out of which the

other buildings would grow. But the Seed building needed 900,000

to make it happen, and although there was funding of sorts it wasnt

on this scale.

The nance there was came in the form of National Lottery

funding, a three year start up, plus other donations, some in kind,

some in money. With nancial support, but not enough to begin the

Seed building, there was a sense that a beginning needed to be made

somewhere, so attention turned to the craft building. The rst work was

begun by Malcolm Lemmon, a local forester and builder in residence (as

well as sawmiller and joiner). The building is to provide both sheltered

facilities for Life Science Trust activities in bad weather, and for pottery

classes, wood carving and other woodland crafts.

Initially work went well, but in 1999 things began to become

muddled. Completing the building was nowhere in site. The local

engineers were proposing an apparently sophisticated but prohibitively

expensive truss system, which would apply beams and columns to

the central area. Although interesting, it would have needed a very

extensive, and costly amount of timber. It was at this point that David

Tasker, a structural engineer well known both in and outside the Steiner

movement, who had already been involved was brought in to reassess

the situation. And Tasker, upon seeing the column planned, thought

this wants to be a gridshell.

The resulting plan envisaged three pod-like gridshells resting on an


irregular hexagon, nine metres in diameter. Today on each side of the

completed hexagon room, are two wings, one for storage the other

comprised of two smaller rooms.

There was limited structural analysis, which Tasker describes as

backyard engineering, mainly scaled modelling and basic shell

theory, but without the usual fancy software programmes; a full 3D

structural analysis wasnt applied both because of uncertainties over the

wood and the prohibitive cost. Tasker also acknowledges the jointing as

very basic - partially as a result of its computer independence. However,

for Tasker what has emerged is a unique organic building.

Apart from the wood used in the gridshell, beams and truss, the

building used primarily locally sourced limestone, sand, and wool. No

Portland cement was used at all; a Colquhoun stipulation. In its place

jura limecrete was imported for the foundations, and as mortar for the

stone walls. Given the commitment to being as ecologically benign

as possible, as well as its relative expense, bringing in this specialist

limestone from half-way across Switzerland may appear quixotic, but

within the lime community it is generally considered amongst the best

of limes, with a very low embodied energy. Recommended by Douglas

Johnson of Masons Mortar (a limesman extraordinaire quoth David

Tasker) its characteristics include its strength and quick rate of curing.

Also given that the Scottish have a predilection for using lime, its use

isnt a complete surprise. A second, St Astier lime, this time from France,

was applied to all the above ground walls. The walls were built up by

a contracted stonemason from local stone brought in from a farmers

old dry-stone wall a handful of miles along the hill ridge. The sand used

was from the local quarry. Mineral wool was used in the external walls

and cavity walls, whilst in the other openings sheep wool was used.

Marketed as Cosywool, it came from the Wool Marketing Board; being

made into tops on site, small long sausage shapes cut from 100 metres

of the material. The work took time having to repeatedly

fold the wool over, but was pleasant on the hands - unlike

many comparable glass and mineral wools.

At rst, admits Lemmon, he was sceptical about

gridshells. They didnt appear to follow the way the wood

wanted to go, rather, it seemed as if the form was ghting

against nature. But soon the challenge got the better of

him, and quite quickly the technical problems of realis-

ing the project, apart from delivering mighty headaches,

became fascinating issues with which to wrestle and nd

solutions to.

He found 40 tonnes of larch from a Steiner project in

Perthshire, which had oundered and was closing down.

Lemmon bought this after checking its sustainability

factors. The timber for the window frames was Highland

Douglas r - an increasingly popular, and durable,

tree crop in Scotland - manufactured into windows in

Edinburgh. The alternative, oak, was too costly to have

been considered within the spartan budget.

The work was carried out, evolving and creating, as the

team went along, fresh drawings and sketches frequently

arriving, so as to integrate new and added-on ideas. For

Lemmon, as for all those centrally involved, it was a steep

learning curve. What analysis there was happened on

site as the building progressed. Happily, once construc-

tion was underway the roof turned out to be not as

difcult as Lemmon had presumed it would be. Tasker

had prepared a small experiment with a miniature pine

dome model, and Lemmon used this to see how the wood

would respond. From this he realised that young green


Lothian gridshell

larch would work well; the saps elasticity ensuring the bending needed for the

curvature. From there, Lemmon went looking for the right potential larch, nding

it eventually in one of the Earl of Roseberys estates forests, a few miles south

of Edinburgh. Trained to be able to uncover woods from eye, he hand-picked the

larches, and took them away as part of a management thinning project with the

estate. These were prepared as laths around four metres long, and next, initially

by trial and error, Lemmon began constructing longer laths, scarf jointing three

together to make twelve metre lengths, until there were two sets of 20 laths, able

to cover twelve metres. These were made up in two layers of 35mm by 25mm by

600 cm squares, with the bits drilled in to form the nodes. These were checked

using pilot bolts, on the jig, to hold each square of the grid together.

Once it was ready, the grid was put together and bolted up in one day,

with nearly two dozen volunteers helping at the site, including many disabled

adults from a local Steiner Camphill community. It must have been quite a sight

watching Lemmon choreograph twenty or so people as they inched forward up

a specially constructed ramp. Two hours later the volunteers had manoeuvred

the grid into position as part of the roof, an inch too far and the fresh green

larch could all too easily break. In the event only two joints needed replacing.

Completely oppy, the gridshell was at this point both very supple and fragile

until the boards covering the laths were also put in place. After this further

boarding was applied, and the structural shape formed around a scaffolding

tower and temporary timber struts.

While the corners were held down by rope, the rst two layers of 100mm

boards were screwed into the lattice, the shell, according to Lemmon, becoming

more uniform, as it began to dry out. The board wood was found from a local

forest four miles away, an economic choice since this was small enough to be cut

into shape. In fact the whole gridshell cost was minimal, Lemmon believed the

fasteners for the roof came to 350, and the boards less than that. The whole

gridshell was in region of 2500, although as Lemmon points out that when you

add labour, his work and two intermittent paid helpers, it inevitably increases

the cost. As it was put into place, each layer of boarding soon reinforced the

emerging shape. Alternate layers were placed at 90 degrees to each other, to

reinforce the strength. With

three layers across the whole

dome, and four at the edges

this produced an effectively

extra-tough roof. An extra

complication was that the

shell was being placed onto

the hexagon. Domes have

been placed on square and

circular rooms, tting these

proportions easily, but they

have not been sat upon

hexagons. Not surprising,

perhaps, as they do not t so

readily. Lemmon pulled the

gridshell dome down upon

the two opposing sides of

the hexagon walls initially,

until they began to bend into

shape. Once the gridshell

dome and boarding was in

place it was covered with a

turf roof, and the Rubberfuse

membrane was sourced as

the best eco-friendly option

available. Insulation contin-

ued to be a problem and

cork was eventually applied

to the membrane. The cork,

another import, this time

from Portugal, compared well with polyutherene and other polyester insula-

tions. A cob wall was designed for the right hand side of the entrance, and this

late feature is currently on the verge of being passed by East Lothians building

and planning control ofces. At the same time the oor is suspended above

the ground, enabling the full ventilation system to work. The roof was nally

completed at the beginning of the year, being covered with horse and cow dung,

and presently sports a thick grass matting.

Before it went up, no-one knew whether the gridshell would actually work

and although Tasker felt condent there wouldnt be any real structural problems,

there were quite a few nerve-wracking days wondering what they were going

>>>>


Lothian gridshell

to say to the funders if it didnt. Unsurprisingly, the load testing was

unconventional. Rather than computer analysis, the building group

hand calculated 700 bags of sand which when massed equalled 13.4

tonnes of sand, so that the deection on the roof could be carefully

measured it came in at 25 millimetres, equalling the worst snow cover

scenario.

Work out it did, however, and in the summer of 2002 it began to be

used, even if it needs some nishing off. As such it represents a success

story for the small-scale and self-build, and it also demonstrates some-

thing of the tenacity of a small team. One can easily speculate that

were local building contractors let loose on such an unknown quality

as a gridshell, given so few have any experience of the form, let alone

have worked on one, they would price the risk

into budget oblivion. Since only one or two

companies have the relevant experience, this

must be one of the main constraints on its

growth in use, with specication and design

generally so expensive. The Pishwanton

gridshell demonstrates that with resolve and

patience people can construct for themselves.

All those involved state there were a variety

of things learnt, and could improve on it if it

was being constructed again. What would

be helpful is a further step by the team to

make available the step-by-step approach

for anyone interested. This would show

possible contractors some of the pitfalls and

begin to bring the prospective price into the

realm where anyone could, in theory, build

a gridshell. Certainly such smaller-scale

applications seem obvious. Gridshell pod

roofs could be used for 10 m classrooms both

in, and outside, the Steiner-Waldorf context.

Their further uses in a variety of contexts are

also easy to imagine.

One real surprise is that gridshells were

new to Day. Even if there are very few,

they suit his Spirit and Place aesthetic,

as expressed in his book4, very well. He

believes the double-curved parabolic form

contains considerable strength, and describes

the internal space as a very gracious and

harmonious gesture. All of which helps make

the form so satisfying, in Days words, at

a preconscious level. Tasker himself came

across gridshells in the seventies, when he

was a student at the Bartlett with the German

Architect, Florian Beigel, who today runs the

Architectural Research Unit at North London

University School of Architecture5. It is a

footnote of architectural history that Beigel

was instrumental in bringing gridshells to Britain. He came to Britain

from working with Frei Otto on another of the renowned Germans

gridshells, the Munich tent structure. This was a cable grid structure,

in contrast to Mannheims compression structure. Originally, Otto had

uncovered the possibilities of gridshellls by observing the biological

structure of double-curved coral, a textbook example of nature as a

strategy for design. When he came to Britain in nineteen seventy, Beigel

brought the gridshell concept with him. In 1974, along with his students,

he constructed a series of four gridshell structures on Highbury Fields

as experimental exercises. From there he tried to get funding support

from Arups and then Happolds to continue the research, just when

the two big engineering companies were rst beginning to research


tension structures, but to no avail. The Highbury Fields gridshells are

documented in one of the Stuttgart Institute for Lightweight Structures

booklets6, although Tasker recalls coming upon the form through a

brochure that Beigel published. Tasker found what he was looking at

very refreshing. Similarly Beigel in conversation, although not directly

involved in gridshell design for a number of years, to this day remains

absorbed by its simple elegance. Despite being double-curvature forms,

the use of laths makes for a very simple element. Usually such double-

curvature is difcult and the manufacturing expensive. I still nd the

elegance of the idea very fascinating, Beigel says. With wood there

was, for the rst time, a way of making the square of the form into a

parallelogram. He is also, as with Day, attracted to the gentleness of

the structures form, with its soft curves, compared to the tent gridshell,

with their lofty peaks. Given these curves Beigel feels certain of a

connection to the human body. It is very much a bodily relationship

he believes. His last direct involvement in the form was in 1992 when

he was centrally involved in plans for a gridshell theatre and arts centre

in Brentwood, Essex, it never got any further however. Were it to have,

the beginnings of this gridshell movement might have been earlier

off the starting block. By this time, the inuence of the Mannheim

building on the two Teds, Cullinan and Happold, was already water

under the bridge, an inuence Beigel helped along. He also notes that

Mannheims project engineer, Ian Liddell, was actually British. Today,

he points out the Weald and Downland gridshell is exactly the same

shape as the structures he and his students were playing around with

on the playing elds near-on thirty years ago. The difculty remains

with the decking, with its borrowed boat-building technique, and impli-

cation of hours and hours of craft input. As he says the actual structure

is straightforward and easy.

It is the spores of Beigels journey to Britain with the gridshell

fresh in his imagination and the subsequent exploration on Highbury

Fields, which is a primary inspiration for all three gridshells, which

have emerged during this millennium time. Last summer, the Weald

and Downland gridshell opened, and at a celebratory conference in July,

Time for Timber, it again reminded one what a remarkable building

it is. It did, however, also remind one of its exceptional showcase

nature. Whilst one cant but hope there will be further opportuni-

ties for such grand schemes, Tasker and Days smaller relative, way

up north, suggests that gridshells can also come in many varieties,

small and perfectly formed, as well as large-scale. At the Time for

Timber conference the word optimism close to the word wood was

on many peoples lips. The sense that the resurgence of wood is on

the cusp of a new growth, was underlined there, and that the Weald

and Downland gridshell constituted a springboard, so to speak, from

which this resurgence could develop. In fact it forms a midpoint in a

short triadic necklace of related buildings; Frei Ottos 90s Hooke Park

Workshop to the west in Dorset, and to the east, the smaller adapted

Flimwell Woodland Centre Chestnut gridshell. Even if Hooke Park is not

a gridshell, it belongs to the same family. One might also mention that

Gensler designed a four-double gridshell building, for a Home Counties

nancial services trading extension, but in reality this in a different

category, sharing neither the rural context, nor the ecological or craft

concerns of the other buildings. There is much that could grow from

this belt of projects, potentially stimulating a further generation of

such buildings over the coming years. And with the Pishwanton Lothian

project complete, a fourth family member brings another, accessibly

small-scale dimension to the growing band of buildings, which are

pulling this genuinely exciting, elegantly ecological and twenty-rst

century form into material existence.

Oliver Lowenstein

Refs:

1 Putting this in some context, this budget would hardly have paid for

all, or even much of the worktime of the complete team, if this had

been at the heart of the matter. At Weald and Downland, much of

this initial research budget apparently went on prototyping and timber

testing.

2 Anthroposophy is a spiritual philosophy founded by the twentieth

century thinker and mystic, Rudolf Steiner. Best known as founder

of Waldorf or Steiner schools, Steiners philosophy extends to many

aspects of life, including a specic approach to architecture. There are

anthroposophical architects throughout many parts of world, although

the majority are found in Europe, with a small number working in

Britain, the best known being Christopher Day.

3 The Goethian approach is one element at the heart of holistic

science, and is based around the qualities of the observation of the

onlooker on the subject of study, invariably, though not inevitably, the

processes of nature. Although contemporary Goethian science has a

variety of strands, if it is immediately related to any twentieth century

movement, it is that of the Anthroposophy of Rudolf Steiner, founder

of Waldorf or Steiner schools, and scientist of the invisible, whose

spiritual philosophy has been described as a resurrection of Goethes

scientic impulse, although Goethe is better known as the father of

German romantic poetry and literature.

4 Spirit and Place, Christopher Day, Architecture Press 2002

5 See www.aru.unl.ac.uk

6 IL13. Institute of Lightweight Structures, Stuttgart, Germany

Oliver Lowenstein runs the green cultural magazine, Fourth Door Review, www.fourthdoor.co.uk [email protected]

Gridshell Building

Documents

lothian gridshell building

gridshell projects

downland museum gridshell

downland gridshell reseach

pishwanton building

selfbuilt gridshell

gridshell riba magazine

life science trust