1. feature Commercial scale hemp construction
facility to reduce energy consumption. The key areas for
consideration were airtightness, thermal mass and high
levels of insulation.
Construction
The architects first became aware of Tradical Hemcrete at
the concept design stage, while researching alternatives to
the initial suggestions of either in situ or precast concrete
as the primary walling element. Hemcrete is manufactured
from locally grown hemp shiv - the woody core of the
plant - which is mixed with a lime-based binder to form
a composite material which is carbon negative and has a
high thermal inertia, giving it excellent thermal and acoustic
properties, but the suitability of the product for a large
scale commercial project was untested .
Hemp spraying had been used extensively on domestic
projects but not before on a building the size of the Wine
Society's warehouse project, where calculations had
suggested that to accommodate the required volume of
wine (about 3,500,000 bottles) within the 3,250m 2 floor
area , the building would have to be up to 21 m high.
A visit to the recently completed Adnams brewery
warehouse in Southwold confirmed the benefits of hemp
in terms of thermal performance and carbon emissions,
but did not resolve the design team's concerns that this
product, which had previously been used in a domestic
capacity, had no track record as part of a large scale
co mmercial development
T'he Wine Society is a non profit making wine organisation
Winner oftwo awards, and recently short-listed for
owned by its members. It was established in 1874 for the Top, far left: the outside of the finished building. Here can be seen the
the national RICS Sustainability Award, The Wine purpose of sourcing, importing, storing and distributing final cladding over the hemcrete panels and also the external aspect
of the Kalwall insulated walling system.
Society Warehouse, Stevenage, is a fine example wine to its members, all of whom are shareholders .
Above : the Kalwall wall insulating glazing system allows light to enter
of a simple green industrial building. It uses a the building and thus help to save on artificial lighting.
Most of its operations are located in Steven age,
Left and insets: The hemcrete panels being constructed, distributed
combination of insulating external envelope and Hertfordshire, from where it provides over seven million and installed.
interior thermal mass - the wine - to achieve an bottles of wine a year to its 100,000 members across the
country.
impressively low energy consumption, avoiding all Nevertheless, the unique properties of Hemcrete ­
forms of bolt-on bling. Olwyn Pritchard and Geoff Vincent and Gorbing has been actively involved in thermal mass, carbon negative, air permeability. etc - made
sustainable architecture since 1999 when the practice's it the first choice for the external envelope. Vincent and
Yeates report ...
first passively ventilated office building, the headquarters Gorbing and the design team developed the idea of using
of an expanding housing association, was commissioned . the sprayed form of Hemcrete in large pre-fabricated
In 2007, the Wine Society realised it needed a fourth Once completed, the newly occupied office building became wooden cassettes, measuring 2.4m high, 3.6m wide and
wine warehouse at its main Stevenage site and appointed the focus of a long-term exercise in modelling the diurnal 300mm thick.
local arcllitects and town planners Vincent and Gorbing and nocturnal airflows in naturally ventilated buildings which
Associates to lead their selected design team which was carried out by the Cambridge University-based BP The cassettes were framed up using standard TJI
included MLM Consultants as both structural and services Institute for Multiphase Flow. Building on this experience, joists. with the backing made from Samox board, which
engineers, and project managers Millbridge. With ever-in­ the practice has put sustainability at the core of its design is both breathable and vapour permeable. like Hemcrete,
creasing energy costs a major concern , the society was philosophy for all new projects. and which forms the visible inside face of the external
keen to limit. as far as possible, the additional burden that a wall construction. The cassettes were then transported
new building would impose on the site 's running costs and The initial design team meetings with The Wine Society to a disused airfield in Suffolk where they were sprayed
the g rowing need for an energy efficient building became a involved discussions about sustainability and the need to and cured before delivery to the site in Stevenage. Here
fJr ll'T1ary feature of the design brief. retain a steady-state envir onment within the new storage they were stacked up and tied back to a structural steel
frame for both support and stability. Between the walling
Green Building • 16 . Winter 2010 Green Building 17 . Winter 2010

2. Feature Commercial scale hemp construction
cassettes and the external cladding (a composite metal Fro m an ea rl y stage in the monitoring process , it was I omm ented, "Our priority is providing mem bers wit h hig h Adapt to a Chang ing Climate. Judges we re impressed at the
panelling system) is a void. quite literally a 'breath ing space'. clea r that the building was demonstrating remarkable ( IIJa lity wines and service s, so we have to take a practical use of innovative technologies, such as Hemcrete, within
whic h p rovides natural ventilation for th e Hemcrete. temperature stability with very little use of the M&E Ipproach; projects must make sense commerc ially as well its construction . They sa id ''The Wine Society Warehou se
insta llations, notwithstanding sig nificant daily external <1$ environ mentall y. Temperatu r e contro l is important in the points the way forward for bu ildings t hat are, traditi o nally,
Exten sive discussio ns followed with the structural temperature variation s and extended periods of sub-zero long term storage of wine, so clearly good insulation helped unsustainable and vulnerable to a changing c limate ".
engineers to see if the Hemc rete cassette system could be temperatures during the winter of 2009/ 20 10. The table <lchieve both goals. We used an 'alternative material called Geoff Yeates and Olwyn Pritchard
adapted for the roof constructio n. Unfortunately, structural below indicates the actual rec ord ed end-of-year energy Hemc rete. Not only does thi s have exce llent insulation
limitations and cost constraints precluded the use of thi s usage figu res compared to th e projected f igu res from the properties but it is also carbon negative. Somewhat more
approac h and a mo re conventio nal roof co nstru ction was thermal model and the savings, both in terms o f kWh per xpen sive to construct perhaps, but it brought good The team
adopted . ann um and in term s of CO? per annum . ,avin gs in equipment and energy". Client: The Wine Society, Stevenage
- - ~
-~~ Architect: Vincent and Gorbing Associates
Fu rthermore, the energy reductions arise solely from
Structural engineer: MLM Consul ting Engineers
Proje ct ed energy usage 384,948kWh 358.961kWh Ihe design of the bu ild ing and wi ll be fully ach ievab le fo r
Buil d ing services engi neer: MLM Co nsulting Engineers
Recorded energy usage 52,628kWh 295,490kWh the whole life of th e building without further interventi o ns.
Project manag er: Millbridge
Sa ving 332,320kWh 63,471kWh
Keith Laid law. Project Technica l Director of co nsulting Cost co ns ultant : RLF, Stevenage
kWh - kg CO 2 conversion factors 0.192 0.422
engineers MLM, said, "Each project needs to be considered D&B co ntracto r : Morgan Ashurst (now Morgan Sindall)
Saving in CO 2 pa 63805kg (63.8 tonnes) 26784kg (26.78 tonnes)
on its own merits, but this pa rticu lar project has H em crete: Lime Te ch no logy Ltd
All flgures per annum. dem onstrated how, with an en vironmentally awa r e client Kalwall: Stoakes Systems Ltd (advert below)
an d an in novati ve design team, modern green technology
Another desig n innovation was th e use of a Ka lwa ll The se figures are some 65% better than expected can be integrated into buildings where their use would not
translucen l wa lling sys lem to the whole of the north from the thermal model . in effect quantifying the dynamic normally have bee n considered with dramatic effects on
Geoff Yeate s i6 a ch ar~rt: d arc hi t ect now work inlj
elevation of the wa rehouse. Kalwall has good thermal component of the Hemcrete, and translating into a ener gy usage and long term benefits t o the environment' part~ t imc a :!ll a con su ltant for Y"incent and Garbing .
insulation properties but also allows a high level of daylight significant reductio n in an nu al running costs of: hay ing f"e cent-Iy retired .j!!5 tt: director of the pra ct ice. In
h i.e ~ p.a r e t im e he m o nltorSo th e pf rfoman ce of t he Wine.
penetration. and its northerly aspect meant that there was Electricity at 7.3p /k Wh = £ 13,854 M ark Chan dler, Vincent and Gorbing's Project Director, Soc j ttl~ P1C1 W w~re hOu ge in formally by sampling it e
little or no risk of solar heat gain throughout th e year. Ga s at 27p/kWh = £8,972 sa id , 'We firmly believe that the design team 's principal idea COrlte nts on an o cca ~ i o n al bS!!5is .
G[OFF.nAT£S@VINCEI'IIIT-(iQR8INC; .COaUK
o f ca pturing Hemcrete in prefabricated walling units has
At th e time of its co nstruction, the internal ra ck ing Taking the two CO.; sa ving s. which total 90.5 tonnes o pe ned up a wo rld of new opportunities in the sustainable
system for the pa ll ets hold ing t he wine was, at 18m, the of CO ? per an num , the total carbon redu ction ove r the (Jesign and construct io n of large sca le industrial buildings.
highest insta ll ed anywhere in the world. In its own way, this projected 40-ye ar life of the bu ilding is over 3 ,600 tonnes Bein g able to ac hieve long t erm carbon reduc tions and
was q uite an ac hievement but the co mpact nature of t he of CO 2 , energy savings in such an innovative way makes this
w in e storage was t o be a significa nt part of the energ y !')ur most sig nifi can t con tributi on yet to th e con cept of
Olwyn Prltc hard is on ~l ine t!1C W!5 c.di tor for t he G reen
saving t hat w as a funda menta l briefi ng r eq uirement Wine Some 730m 3 of Hemcret e was used on t his development. ust ainability. " Bui ld ing Pres s , and £I regu la r contr ib utor to t,he
has a si m ilar density t o water, and a similar t herma l mass: As a ca r bon negative mat erial w it h an embodied carbo n m agazi n e. She hae a 1I.'l ri e a bZlckg ro und . I n c ludin~ 9 0me
the presence of over 2 ,500m 3 of wi ne wo uld both provide figure of 130kg/ COi m3 thi s equates to an additiona l Awards t i me :; pent exp er ie n c ing 50cial hou8 ing . comm un ity 1ill i"g .
low Impac t living and a lon g ~t il nd i ng intere9 t In green
th e t hermoI moss ond be an essential element in stabilising contribution of 94.9 tonnes of CO ~ .
, The awards wh ich the building has so far gained are first ieeue5.
OlW VH@ GREEH9UILDINGPIUS.CO.UK
the internal temperature, a key factor not only in energy prize in the susta inability category of the RICS 2010 East
effici ency but also in the storage of wine in its optimu m The existing warehouses on the site have been o f England Awards, in May this year. and in December 2009
condition. constructed to va rious different standard s and have Vin cent & Gorbing was awarded the Herfordshire based
different levels and ages of equipm ent. However, it is 'Building Futures Award' for Outstan d ing Commitment to
The building was comp leted b y M organ As hu rst. now interesting to make a com pariso n betwee n t he new and the
M organ Sindall . in the autumn of 2008 and over the old warehouses by comparing the ener gy usage in terms
following months the Wine Soc iety's staff began stocking of kWh used per m ' of warehouse space. Thi s exe rcise
the building and familiarising themselves wi th its operating indicated t hat the new ware house is operating in the ord er KALWALL®
requirements. Once thi s initial period was complete. the of 70% more efficiently than th e existing wa rehouses .
Energy saving Kalwall is green because it
project's services engineers, MLM Co nsulti ng Engineers. reduces dependence on artificial light
and th e Wine Soc iety monitored the internal and external Th ere is little dou bt th at this building is a success
temperatures for a full ye ar. along w ith the building 's story for th e Wi ne Society. Its design t eam 's innovative It diffuses calming restful light for the worker
consum ption of both gas f or heating and electricity for concept has been able t o exceed the society's dual 'g reen ' which increases productivity
lighting. aspirations for a highly sustainable building and radical For cladding and roofing, it creates a perfect
reductions in its energ y costs. as well as demonstrating ambience for all building types, including
Monitoring of energy use convincingly that sustai nable design techniques are now as this Wine Society warehouse (right)
M LM and Th e Wine Society closely monitored the energy applicable to co mmercial high ba y warehousing as the y are
costs against th e projections of a thermal model that M LM to smaller sca le developments. Stoakes Systems Ltd
Tel 0208 660 7667
had deve loped at the design stage t o ena ble eval uati ons of
www.stoakes.co.uk
alt ernate construction systems. Oliver Johnson, ch ief executi ve of th e Wine Society
G B
reen uilding • 18 . W 2010
inter Green Building • 19 . W 2010
inter