APPENDIX 23
Memorandum from Zed Factory Ltd
1. Zero heating specification homes and
workspace can be built at no additional cost if economies of scale
of around 5,000 units/year can be achieved within a UK sourced
supply chain. BedZED cost more than standard construction because
it is a prototype. With 1,000 units/year extra cost is reduced
to around 15%. This figure is easily matched by the increased
sales value on private for sale units.
See section 1 in evidence submission—tender
showing 20% cost reduction over BedZED
2. Lightweight steel framed or timber framed
Modern methods of construction that do not incorporate high levels
of thermally massive storage will require carbon intensive air
conditioning within 30 to 50 years. The ZED building physics model
developed with Arups allows new homes to take advantage of passive
solar gain in winter meeting around 30% of winter space heating
requirements, and passive cooling storing night-time coolth in
the building fabric to compensate for the hot day temperatures.
There is an urgent need for the sustainable communities programme
to address climate change, recognising that the latest DEFRA and
DOE predictions for summer temperatures in London in 2080 are
likely to be similar to those found in Marseilles today.There
are no lightweight homes or offices built in Mediterranean climates.
Changes in the gulf stream that could produce colder winters are
likely to be 300 to 500 years away.
See section 2 in evidence submission—slides
from DEFRA/DOE climate change conf.
3. Renewable energy sources can only meet
national demand towards the end of this century if ZED standard
load reduction exercises are adopted in new construction. The
BRE Ecohomes excellent specification only offers a 35% carbon
reduction on the current building regulations legal minimum. The
maximum environmental performance specification recognised by
English Partnerships is EcoHomes excellent. It is hard to see
how the low standards embodied in this standard can deliver long
term government targets. Despite repeated requests to the BRE
to raise this standard to ensure zero heating specification fabric
is a minimum reqirement, no progress has been made. ZEDfactory
are now setting a new independent ZED standard, fully integrated
with environmental performance targets for every part of the supply
chain which will form the new industry standard—in much
the same way that the Soil Association has regulated and maintained
organic food standards. We would like to do this with government
support, rather than as a private initiative. The Supply chain
needed to build new ZED urban fabric can also be used to renovate
existing buildings.
See section 3 in evidence submission—the
A to ZED supply chain book supplied
4. ODPM sponsored urban design codes based
on traditional urban values as promoted by staff from the Princes
Foundation are preventing the application of low environmental
impact zero carbon development, as solar access is not given a
high enough priority weighting. It is important that different
aesthetics, building forms and building integrated renewable energy
systems are allowed to inform the development of urban coding.
It should be noted that BedZED breaks almost every urban code
system currently being used, and yet it is very popular with the
public and residents, has won a Civic Trust award, and shows how
a low impact lifestyle and workstyle creates new urban layouts.
There is considerable public demand for aspirational
ZED communities, and there is already a large waiting list despite
no advertising and no new communities being available to the public.
Now that one exists, the public know what to ask for.
See section 4 in evidence submission—examples
of urban coding compared with BedZED
5. Using innovative design to increase density
without sacrificing amenity, at the same time as providing good
solar access and a garden for every home. On sites where a traditional
approach has set a maximum density of around 45 homes/ha (typical
on English Partnership sites in Milton Keynes) it is possible
to achieve around 70 homes/ha using the ZED approach—with
the increased density compensating for the increased construction
costs of a zero heating specification—whilst providing exactly
the same number of affordable homes and the same site land value
that a conventional approach would achieve. No loss of private
gardens or public open space was achieved, whilst meeting the
2050 carbon targets.
See Section 5 in evidence submission—case
study of Broughton bid in Milton Keynes.
WHAT IS
THE "NEW
ORDINARY"?
Carbon complacency, Urban design, cash, and
modern methods of construction within the sustainable community's
programme—the need for joined up thinking and a holistic
industry "Vision".
At almost any point in the history the UK construction
industry there has been healthy debate between those proposing
reduced environmental impact, and the majority of the developers,
consultants and their supply chain who have just got used to the
previous change in minimum legislative standards—and want
to practice business as usual—undisturbed. This is only
natural as predicting out turn construction cost, minimising planning
risk and minimising sales risk is how a volume house builder can
guarantee profit on new developments. The truth that planners
and developers refuse to admit is that ordinary affordable housing
[whether private or public sector] cannot be specially designed
for each site. To cut costs and deliver to tight margins—it
is necessary to invest in a highly refined product with as much
standardisation as possible between different sites. Only cladding
materials and roof forms can really be changed from site to site,
producing a formula capable of convincing local planners, but
in reality achieving a mono culture of similar estates from Cheshire
to Wiltshire.
This has produced a volume house building industry
in the UK that works with a very limited number of standard house
types, carefully engineered to skim through the building regulations
legal minimum construction standards, with standardisation of
architectural form maximising the opportunities for supply chain
economies of scale, and with the final product honed by marketing
professionals to offend the least number of potential customers.
Flying over almost all of our major cities—it becomes obvious
that a very limited number of standard house types built in relatively
short periods of time over the last 150 years account for most
ordinary homes in the UK.
Each mass housing boom and its associated typologies
have been derived from the prevalent social, economic and technological
conditions of the period. The UK government is currently proposing
unprecedented expansion of our current housing stock—fuelled
by increasing house prices, and a lack of affordable homes, especially
for key workers. The current shortage of housing stock is generally
attributed to increased lifespan, marital breakdown, and immigration,
with little or no notable increase in the indigenous UK population.
So before setting on the next major housing boom and planning
to build around four million new homes by the early 2020s—it
is really important we anticipate the major resource challenges
awaiting UK society in the C21.
Accelerating climate change will mean summertime
temperatures in the South East will approximate to Marseille sometime
between 2050 and 2080. Affordable coolth will become a larger
issue than affordable warmth with many thousands already dying
from overheating in the urban heat islands of Paris and London
in summer 2003. Any lightweight building without high levels of
thermal storage will require carbon intensive air conditioning
to be habitable throughout a UK summer. Current government policy
promotes lightweight prefabricated modern methods of construction
with virtually no passive cooling qualities. There are no examples
of lightweight homes or workspace in Mediterranean climatic zones.
Almost all timber based lightweight construction
concepts have originated in Northern America, Scandinavia or northern
Europe—where overall average temperatures tend to be significantly
cooler and summer overheating is rarely a problem. It is important
that the UK construction industry plans for the worst case scenario
of the Scandinavian winter combined with the Mediterranean summer.
The long term scenario of climate change redirecting the Gulf
Stream away from our shores could still take place—however
experts predict this is likely to start affecting UK climate after
around 150 years of intense warming, with the effects beginning
to be felt over a 300 year period. (source DEFRA—climate
change conference—London March 2004) The challenge for UK
will to combine the construction and urban response suitable for
a Scandinavian winter with the searing heat of a Mediterranean
summer. Simply meeting one or the other will either produce cold
gloomy buildings in winter, or cause problematic overheating in
summer. Addressing such a new bioclimatic challenge will inevitably
lead to new a new urban language for much of the UK—with
summer shade and passive cooling strategies needing to be convincingly
reconciled with the need to capture low angle winter sun for passive
solar gain and maximise daylight in the gloomy winter months.
Perhaps the new government championed urban design codes will
champion the ordinary citizens right to be both cool in summer
and receive a third of their winter space heating needs from passive
solar gain?
Global agricultural production will be in crisis,
as climate change creates winners and losers with desertification
affecting areas of Southern Europe. The UK imports 70% of its
food today, so losing agricultural land to housing may not be
the most sensible strategy. With around 11% of the surface area
of the UK covered by urban sprawl, and with the average UK meal
having travelled over 2,000 miles from farm to dinner plate, it
may not be in the long term national interest to plan a large
percentage of the four million new homes required by 2020 on prime
agricultural land. We would certainly struggle to provide a subsistence
diet for the current UK population from food sourced within our
national boundaries, and with the human global population still
expanding exponentially—it is likely to be increasingly
difficult for the UK plc to find the resources to secure healthy
low cost food on the international markets. This may be one of
the most important reasons why the UK cannot contemplate a secure
future without almost total dependency on the European Union breadbasket.
The challenge here is to reconcile the densities found in the
centre of a typical UK market town (100 to 120 homes/ha) with
the amenity and private garden provision found in semi detached
1930s suburbia.
Meanwhile the UK Government has a duty to be
wise and farsighted (we hope) It has a public duty to the electorate
to consult the best experts and plan ahead. Whilst future predictions
about anything are notoriously fraught, just about the only thing
that both experts and public awareness co-incide on is climate
change and global warming. So achieving a democratic mandate to
plan for climate change and the phased withdrawal from our near
total addiction to carbon emitting fossil fuel—is unquestionably
realistic. It is this thinking that produced the latest White
Energy Paper, with it's startling statement that North Sea gas
will run out in 5 years and North Sea oil in ten, making UK PLC
totally dependant on fossil fuel imports from some of the most
politically unstable countries in the world.
Fortunately the UK Government has accepted the
connection atmospheric carbon emissions and climate change and
has signed up to an agenda that will deliver a 20% reduction in
Carbon emissions by 2020 and a 60% reduction by 2050. So even
if we found unlimited stocks of gas and oil, we couldn't really
burn it!
As collectively we have democratically reached
this conclusion it becomes very important to debate the best way
of deploying our limited natural resources to cope with an increasingly
uncertain future. The billions of pounds spent on military intervention
trying to secure political stability in the Middle Eastern oilfields
could have been spent on fast tracking the UK's snail like process
towards a low or zero carbon economy.
So complacency about reducing carbon emissions
is probably about the most anti—social, dangerous stance
to adopt at this point in our islands history. We have to regard
a low carbon diet as cultural priority or fight and be prepared
to die for our perceived right to contribute more than our fair
share of global warming.
So the critics will say—"don't be
ridiculous we could never afford this whole scale change of technology,
cultural priorities and social change!" So the Government
consults the construction industry, suggests sensible targets
for reducing environmental impact and always finds any chance
of progress hindered by the industry lobby. Our experience indicates
the following standard responses are encountered in most circumstances
when consulting the key industry stakeholders:
"Planners" say—we cannot move
away from our formulaic design codes—with our preference
for perimeter block layouts and courtyard parking. We find the
technical requirements of daylight, solar access, airflow, acoustics
and renewable energy integration within the urban fabric hard
to integrate within conventional urban design priorities. We know
what has worked in the past so please use our design codes for
masterplanning any new projects. In this case social stability
is perceived to come from continuity with our historic past. Most
people find comfort in urban form and architectural expression
derived from a rose tinted view of our heritage. The danger is
that this approach degenerates into sentimentality reconciled
to an orgy of material and resource consumption that rapes the
present without restraint or joy.
"Architects" say—we cannot innovate
easily, because there is no fee, time or client appetite for environmental
innovation without coercive legislation. If left to our own devices,
we really prefer maximising peer approval by building experimental
artworks for wealthy clients, and avoiding unrewarding, high constraint
social housing if at all possible. And anyway, how can we integrate
solar technologies if the master planner or urban designer has
ignored solar access?
"Volume house builders" say—"the
carbon emissions from new housing is relatively small—why
not look at improving the existing building stock before making
us change our product? Our standard house types have evolved from
market demand—please leave us alone to get on with the job
of increasing annual numbers of new stock". [Source Pierre
Williams—house builders federation spokesman ]
"Developers" say—Homes have
a different market from workspace. Please let us build office
parks near motorway junctions and keep housing on Greenfield sites
away from complex urban communities on problematic Brownfield
land.
"The supply chain" says—We can
only tool up and invest in new low environmental impact technologies
and products if we have sufficient demand. Go and buy from Germany
if you want this specification now! If all the industry wants
is the legal minimum specification that is all we can realistically
provide.
"The legislators say"—We cannot
persuade the market to embrace low environmental impact thinking
without waiting for legislation, which will be unpopular and slow
coming. We have to treat the industry like a child being given
some bad tasting medicine that though initially unpleasant will
provide a long term cure. Here are some nice, easy entry level
standards, that won't taste too bad, and will start the process
of removing the national addiction to fossil fuel. We cannot push
ahead with reducing environmental impact too fast without attracting
a vociferous industry lobby.
"The government says"—Our short
term target is to build more affordable homes as soon as possible.
Environmental innovation costs more. Let's just build as many
homes as possible to the minimum plausible ecohomes standards.
Speed and delivering the maximum number of affordable homes is
far more important than carbon, so lets promote lightweight modern
methods of construction to overcome perceived traditional skills
shortages, and lets adopt non controversial urban design codes
to accelerate the planning process. Building traditional looking
homes is always populist, even if they are really made in factories
using modern methods of construction.
"The public say"—We want as
many affordable homes as possible, whilst allowing the existing
housing stock to increase in value, and without losing any green
belt or agricultural land, and without creating higher density
communities anywhere near my home. Just about the only politically
expedient response to this challenge is building large numbers
of new homes on unpopulated flood zone, preferably in the Thames
Gateway. And if we must have new development, please make it look
like something we are familiar and comfortable with—preferably
Victorian or older.
"The inevitable conclusion"—changes
in the legal minimum standards regulating carbon emissions seem
to always meet the predictable lobby against change from diverse
organisations ranging from the Urban villages Forum to The House
builders Federation, and those that stand to lose most from their
physical or intellectual investment in the current status quo.
Radical proposals such as zero heating spec homes are deemed unpalatable
and before long we will be fighting our next war to ensure supplies
of fossil fuel from outside our national boundaries.
So if we know what the long term carbon emission
targets we have to meet are, and we also know roughly what its
costs us in military intervention outside our national boundaries
to ensure supplies of fossil fuel—it should be possible
to agree a phased programme of progressive legislative carbon
reduction legislation, and could be interpreted through a planned
tightening of building regulations minimum carbon emissions standards,
or through planning legislation such as PPS22 (where new buildings
have a minimum quota of their annual energy load met from building
integrated renewables). The proportion of renewable energy generated
on site will become very important, as almost all the capacity
provided by green tariff electricity will be required to support
our historic urban quarters—where the heritage culture lobby
requires preservation in the interests of historic continuity.
Renewable energy only makes sense if the demand has been reduced
by excellent passive design. It will simply not be possible to
run UK plc off renewable energy sourced within our national boundaries
without adopting zero heating specification building fabric—or
ZED standards. Once these national environmental performance targets
for any new urban fabric have been agreed to be in the national
interest, it becomes important to develop design codes that provide
the planning system with an impartial assessment procedure for
development control. Somehow environmental impact, ecological
footprint analysis and carbon footprint need to be introduced
to the governments current enthusiasm for design codes—currently
designed to speed up planning approvals in the attempt to maximise
the delivery of new affordable homes.
Publishing this long term strategy of ever increasing
carbon reductions would do wonders for the UK development industry.
The planning profession can familiarise itself with the new urban
morphologies and aesthetics created by a low or zero carbon cultural
agenda. The supply chain could make long term investments in tooling
for the new standards, research and development would flood back
into the industry—and the cost of this new planned innovation
would drop dramatically. Better still the government could recognise
that best practice demonstration projects are an essential part
of this continuous innovation programme. The carbon threshold
provided by minimum legal regulations can only be increased if
the government is sure that workable affordable upgrade solutions
can be delivered at reasonable cost. Projects like BedZED are
essential to show where the regulations and urban design codes
could go over a five to ten year period. Initially these pathfinder
projects attract higher "prototype" construction costs—just
as a prototype car costs far more than a production run model.
The building regs minimum pass specification will always provide
the cheapest out turn construction cost simply because 99% of
the industry builds to these standards—achieving massive
economies of scale. It is absurd for industry critics to point
to such projects—comment on the increased construction costs,
and then lobby against any upgrading of carbon reduction legislation,
or the introduction of meaningful solar access into urban design
codes. Providing that the same carbon saving legislation applies
to the entire industry, a "level playing field" is achieved—and
any associated increase in construction costs effectively reduces
land value, anticipating that no developer will accept a reduction
in profit. Only those industry players with large existing land
banks will object to this approach, but then they shouldn't be
hoarding such a precious resource anyway. An easy way to phase
in any renewable obligation under the planning system would be
to make the exact percentage of building integrated renewables
required on each site proportional to the rateable value or poll
tax band. This would prevent the renewables obligation becoming
a development tax making regeneration unviable in low value areas
of the country.
Understanding that small runs of zero heating
specification homes would always attract higher construction costs,
ZEDfactory have now value engineered the BedZED prototype to create
a range of standard house types and associated urban design codes
that could be tendered to achieve similar supply chain economies
of scale to that achieved by the volume house builders. This is
important, as it is virtually impossible to distinguish their
volume product by company or brand, resulting in spectacular rationalisation
of the house building industry. This approach does not mean that
all zero heating spec homes have to look like BedZED, but that
the integrated supply chain defined in the ZEDproducts range can
now be used to create a variety of different generic forms capable
of supporting a variety of different architectural palates. The
results of applying volume discounts to the ZED supply chain are
spectacular, with 100 homes/year costing about 30% above regs
minimum, 1000 homes/year costing around 15% above regs minimum,
and 5000 home/year providing no extra cost over regs minimum.
Once this volume throughput has been achieved, the omission of
the central heating system pays for the additional fabric investment
[superinsulation, triple glazing, heat recovery etc] Almost all
of the ZED supply chain can be used to upgrade existing buildings,
potentially increasing its carbon savings by application to our
existing stock of homes and offices. Perhaps large regeneration
projects could look at the potential of volume discounted supply
chains—ensuring a consistent standard of high performance
components and locally sourced building materials, but with a
number of different professional teams including urban designers
and architects to provide variety and different forms of architectural
expression.
So why not use the government's Sustainable
Communities Programme to pioneer some of these best practice demonstration
projects, and kick start the supply chain economies of scale?
If only 5,000 of the 160,000 new homes built in the UK each year
were built to ZED standards, there would be no additional premium
for meeting this carbon neutral specification for both homes and
workspace. Instead the best we can hope for is the BRE ecohomes
excellent pass specification—offering only 35% carbon reductions
over a building regulations minimum specification. This is the
maximum green specification that the government will countenance,
based on consulting the conservative volume house builders. Most
new homes will be built to Eco Homes "very good standard"—offering
an even lower carbon reduction performance. Equally worrying is
the official promotion for lightweight prefabricated construction
under the modern methods of construction banner. With increasingly
hot summers, it is likely that affordable coolth will become as
important as affordable warmth as contributors to fuel poverty
in under privileged households. The lack of internal radiant thermal
mass in both timber frame and steel frame solutions virtually
guarantees the need for air conditioning within a thirty year
period—again raising carbon emissions. And it is no use
relying on ground source heat pumps—the electricity consumption
still rises spectacularly, incurring carbon penalties far in excess
of proven passive cooling strategies. It could be proposed that
to build the sustainable communities programme to these mediocre
specifications ignoring climate change—would be an environmental
liability, especially when the concept of creating new households
without any increase in population is already a strategy virtually
guaranteed to increase national carbon emissions.
It appears that English Partnerships owns around
50% of the land proposed for the sustainable communities programme.
It seems that many of the sites in Milton Keynes are being marketed
with perimeter block master plans briefs requiring max densities
of around 45 homes/ha.
The ZEDinabox range of standard house types
achieves between 80 top 90 homes/ha, with integral live/work workspace
as required, and virtually every home having a private garden,
and all family homes an integral conservatory. It looks possible
to almost half the amount of agricultural land lost to new housing,
achieve more balanced mixed use communities that encourage home
working and shared facilities like car pools and still achieve
the same financial receipt from the land sale, at the same time
as building an aspirational carbon neutral community. Until the
necessary economies of scale are achieved, additional density
or planning gain is the best way of offsetting the additional
construction cost, and creating a level playing field for the
ZED developer. All that is required is a little vision. If the
5000 homes / year target was achieved over a three year plan,
then there would be no financial penalty for constructing to the
ZED specifications, and most volume house builders would automatically
adopt these standards without concern—as is beginning to
happen in other parts of Europe—particularly Austria. This
would achieve a step change reduction in carbon emissions without
any real investment. It is vital that we do not worry about the
solar urban design breaking the rigid and out dated design codes
currently being promoted by the neo conservatives from the Prince's
Foundation—a new set of design criteria is bound to generate
a fresh urban layout, a fresh aesthetic and a new ways of leading
a one planet lifestyle. The UK replaced its homes and workspaces
at around 1.5%/year over much of the C20, meaning national carbon
neutrality could be achieved through the urban regeneration process
alone—a target now possible before the start of the next
century.
So how does this potential reassignment
of our cultural priorities translate into new urban form with
carbon auditing and ecological footprint analysis beginning to
inform fresh environmentally accountable urban interventions?
The following examples show how the ZED supply chain and urban
design approach can deliver different development solutions to
match the urban and suburban context, without all the schemes
looking like BedZED. If this supply chain was adopted by English
Partnerships or some of the regional development agencies for
even a tiny percentage of their development programme—somewhere
between 2,000 and 5,000 homes a year will result in no additional
cost for this aspirational step change specification. ZEDfactory
wish to actively encourage other delivery teams to adopt this
supply chain, and would prefer to work with the govt to make these
standards accessible to the entire industry. It is important that
this initiative is formulated to be in the national interest rather
than to benefit any individual companies.
CASE STUDIES—WORKED
EXAMPLES
BedZED—the new English Garden City prototype
BedZED tries to show how we can reconcile density
with amenity—achieving a step change reduction in environmental
impact at the same time as increasing most residents' quality
of life.
With a typical UK families annual carbon emissions
being spent on a third for heating and powering the home, a third
for transport, commuting and private car use, and a third for
food miles—with the average UK meal having travelled over
2,000 miles from farm to dinner plate. There's just no point in
addressing any one of these issues without addressing the other—so
at BedZED we have tried to make it so easy and convenient to lead
a near carbon neutral lifestyle that most people simply default
into this way of living without conscious effort. Built to densities
that mean we could meet almost all the new homes required by 2,016
on existing stocks of Brownfield sites—without losing valuable
agricultural land and green belt to low density traditional development.
At the same time as providing most new homes with both a garden,
a south facing conservatory, and the opportunity to avoid commuting
by working on site. BedZED re introduces the Victorian back to
back, with housing facing south, and commercial space facing north.
This very deep plan format provides two active frontages—minimising
external wall surface area, and minimising the overall site area
required by the super insulated wall thickness. This creates single
aspect dwellings looking south over their own gardens, with high
daylight levels maintained in a deep plan by triple glazed roof
lights over stair voids. Wherever possible the housing ground
floor level is raised 1,200 mm above the pavement and workspace,
allowing residents to look down at workers and public passing
in the mews streets. Terraces are never longer than six units—allowing
the development to be porous to pedestrians and cyclists, whilst
parking is flung to the perimeter of the site using Homezone principles.
Environmentally benign innovation will cost
more, so we have enabled the developer to buy a site with outline
planning permission for a housing estate with a maximum permitted
density, and then add an office park without having to pay for
the land. We have placed gardens on the workspace roofs—which
allow virtually every home to have a garden, showing how density
can be increased at the same time as increasing amenity. The adjacent
mid 1980's Laing homes development over the fence has the same
residential density as BedZED, but without any private gardens
on three storey walk up flats. The money the developer would have
normally spent buying land for the office park is then re invested
in the ZED super green specification. We have set a national precedent
for this legally, by expanding a normal Section 106 planning gain
agreement with the local authority to officially include reduced
environmental impact targets. This is a real breakthrough, as
it allows carbon neutral new mixed use development to be built
without always requiring govt grants. Resale values at BedZED
are a minimum of 15% higher than exactly the same size unit immediately
over the fence, and often around 30% higher on larger flats and
townhouses. Over 1,000 members of the public have registered an
interest in moving to a ZED community.
Sky ZED Wandsworth
How do you replicate as many of the social and
environmental features of BedZED on a compact inner city site
? We found an unloved Wandsworth traffic island in public transport
tariff Zone 2, with excellent public transport nodes, right beside
an underused over ground railway station on the Waterloo line.
The site had never been considered for housing, and is currently
a pedestrian no go zone housing a large advertising hoarding.
Wandsworth Council is currently occupying many short lease dysfunctional
office buildings up the road, so we designed a four storey car
free office plinth for the local authority, capped with a communal
roof garden complete with creche and residents bar/café.
Above two 35 storey aerodynamic blades house around 300 affordable
key worker one and two bedroom shared ownership flats. The blades
are connected every six floors with communal enlarged lift lobbies
incorporating communal herb gardens and shared play space for
residents. The homes are placed high enough above the traffic
to dilute air pollution to normal London standards, and the super
insulated, thermally massive construction with triple glazing
and heat recovery ventilation not only reduces thermal requirements
to about one fifth of a normal home, but also provides excellent
acoustic isolation. Double glazed balconies with opening windows
are provided for every home. The building has been designed to
focus the prevailing wind onto building integrated wind turbines—providing
all the homes annual electrical requirements from renewable energy
generated within the sites boundaries. The same wind turbines
can already be found in urban areas outside petrol stations and
supermarkets in this part of London and make the same noise in
high winds as a car passing in the street.. The careful shape
of the building means that a SkyZED turbine in Wandsworth has
the electrical output of the same unit sited on a hillside in
Wales.
The existing underpass system is renovated and
a series of glazed courtyards created, making it safe and easy
to cross from the station to the new Wandsworth riverside quarter,
effectively healing the damage to the urban fabric done by traffic
engineering in the 70s. SkyZED provides over 300 homes with no
loss of open space in the borough at the same time as creating
a landmark green gateway as the urban focus to one of the most
important approaches.
ZEDquarter at Kings Cross
Developer Argent St George have commissioned
Bill Dunster architects to produce a feasibility study for a carbon
neutral ZEDquarter on disused railway land behind Kings Cross
station. We had to work within the constraints of the existing
tunnels, incorporate a listed Victorian potato market arcade—and
work within the rules set by the master planners. A two storey
commercial base containing office and retail space is top lit
by east/west axis central arcades feeding into the listed glazed
street. Above roof gardens are placed wherever storey heights
are restricted by underground tunnels, with south facing three
storey family and live work residential accommodation above more
solid load bearing zones. Reclaimed London stock brick will tie
the new mixed use development into the tough street scene and
existing historic railway buildings providing the urban context
in this part of town. We believe this project shows how higher
density solar urbanism can work in inner city areas with high
land values.
Broughton Parcel D
As climate change accelerates—it is increasingly
important to plan urban quarters around the physical properties
of the construction proposed. This is particularly important if
lightweight timber framed or steel framed systems are proposed.
Conventional lightweight construction places thermally massive
brickwork or rendered blockwork on the outside face of any habitable
space, effectively removing any potential for passive cooling
or solar thermal storage in winter. With this construction it
becomes important to use small windows to limit summer solar gain,
and if possible keep to east/west orientation.
Working within English partnerships design codes
requiring perimeter block layouts, ZEDfactory have proposed placing
thermally massive ZED standard housetypes on all terraces within
20 to 30 degrees of dues south, and conventional timber framed
housetypes from a volume housebuilders standard range on all other
orientations.
The east/west facing homes all have individual
gables maximising the surface area of south facing roof surface.
This allows future installation of large areas of solar electric
panels and the opportunity for every household to install solar
thermal panels for domestic hot water at some stage in the future.
By using the large areas of "green space
left over after planning" for installing small 15 kw ouput
windturbines (making more or less the same noise at 20 metres
per second wind speed as a car passing in the street) we found
it was possible to meet the government target of a 60% carbon
reduction by 2050 at the targeted completion date for the project—autumn
2005.
Thermal modelling by Arup of both timber frame
and ZED housetypes shows ZED units to require 25% less winter
space heating than exactly the same spec east/west facing unit.
By combining the benefits of passive solar gain and the mounting
opportunities for active solar collection, it is clearly beneficial
to maximise south facing domestic frontage. By placing live/work
and workspace units in the shade zone of the purely residential
accommodation on the ZED units—it was also possible to achieve
two active frontages, with parking courtyard homezones working
well as a more commercial zone. The big difference between these
ZED units and the original BedZED design is that all live/work
units have their own roof gardens, allowing the Flexibility to
move towards purely residential use if market conditions suggest
this may be more appropriate. The flexibility to use the north
facing units as community spaces, bars, café's, shops,
offices, live work units—as well as residential will ensure
that this community will adapt easily to a future suggesting far
lower levels of private transport. Significantly, the Broughton
masterplan proposed a density of 45 homes/ha. The ZEDfactory scheme
achieved around 70 homes/ha, with the majority of homes having
their own garden, and although requiring a higher overall construction
cost to meet the low carbon specification—the residual land
value still substantially exceeded that achieved by a more conventional
EcoHomes excellent rating built to the original planning brief
density. The target of 50% affordable was still met. Using this
worked example, we believe it is possible to demonstrate how the
government sustainable communities programme can be fitted on
less land, with higher numbers of affordable homes, and with significantly
lower overall carbon emissions.
June 2004
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