Sustainable Building Guide - Christchurch City Council

Cover photo credits: Roger Buck & Associates Architects
Allan Green - UnderFloor Heating Specialists

Introduction
The aim of this guide is to promote environmentally sustainable development and to
encourage people to design new residential buildings so that they interact positively with
the various elements of their local environment. The result should be buildings that use
less energy and have less damaging environmental impacts over their whole life than
equivalent buildings designed without regard to these factors.
Buildings can be designed so as to respond intelligently to the existing topography and
climate. For maximum effect and economy the aim should be for integration of appropriate
design and technology into the overall building form and not simply to apply technology
as an afterthought or a ‘clip-on’. This may cost more initially but the long term running
costs should be lower, leading to overall cost savings.
A climatically responsive approach to building design will eventually help to generate a
genuine local or regional architecture rather than a style of building imported from another
place or time. However, this is not a building form or style guide, but is intended to be a
selection of medium to long term potential energy and resource saving ideas that can be
easily integrated into the design of a new building in the early stages at little or no extra
cost. For guidance on how to integrate the building, visually and otherwise, into the
surrounding urban or suburban context see the appropriate area or zone guide available
from the council such as ‘New Housing in Living 4 Zones. A Design Guide’.
Right: Pruszinski House, Adelaide, South Australia 2002. A house that responds to the
local climate and topography.

Site Design
There are many legal planning requirements and good urban design practices to consider
such as conforming to appropriate road boundary setbacks, complying with recession
planes, responding to the physical and/or historical context, including shading and
landscape, etc. Together with these, try to include suitable orientation for passive solar
heating potential and consider roof orientation for active solar devices, for example water
heating or preheating. See also topography below for site design guidance.
Sill
Outside
High angle summer sun
excluded by external shades
Plan through alternative
window openings
Double
glazing
Inside
Thermal break within frame to prevent heat
loss by conduction through frames
Section through frame of double glazed window
Passive Solar Heating
One of the simplest ways to improve environmental performance is to orientate the building
towards the sun. The basic elements of a passive solar system consist of a solar collector
and a heat storage device (typically a material of high thermal mass such as concrete).
The solar collector can simply be the windows and glazed doors of the building carefully
positioned for maximum sunlight penetration when it is needed most, on winter days.
Small scale design features such as splayed edges to any recessed windows will increase
the sunlight entering the building (see diagram opposite). Once the sun’s rays are within
the building they are absorbed by objects which are heated up and these in turn heat the
air within the space. The heat will be lost through the building perimeter unless this is
prevented through thermal insulation and tight ventilation control. Double glazing has an
insulating layer of air or inert gas (eg argon) in between the panes of glass to reduce heat
loss. Thermal breaks in the frames of double glazing enhance its performance and reduce
condensation and mould growth on the interior face of the frame (see diagram).
With residential passive solar heating schemes there is the desire to utilise surplus heat
gained by the collector during sunny periods of the day for heating during the night-time
and cloudy weather. To do this there is the need for some form of storage medium to hold
the heat energy until it is required. The storage of surplus heat will also limit and control
the potential for the building to overheat during periods of intense sunlight and to cool
down excessively at night. In well thought out designs the storage medium takes the form
of thermal mass already incorporated in the structure of the building, for example in
concrete floors and walls. By utilising the structure in this way there is minimal additional
cost for the thermal mass.
Low angle winter
sunshine admitted
to interior

Even with large amounts of thermal mass, spring, autumn and summer over heating is a
potential problem and must be prevented. This can be achieved through the use of
appropriately sized and angled solar shades, preferably external for increased effectiveness.
Ventilation is also essential; at high level, to allow rising warm air to escape and at low level
to allow cooler fresh external air to enter.
To insure against low levels of solar gain during long periods of adverse weather conditions,
you should include a renewable energy source as a supplementary and back up source
of heating. Recently designed wood burners, operated correctly, have low particulate
emissions and use a renewable, local fuel source.
Active Solar
In contrast to passive solar design ‘active’ solar devices are usually separate pieces of
technology with a single function such as to utilise solar radiation to produce hot water.
They can be bought as separate items and can also be retrofitted to an existing building.
They may require an electricity supply to power pumps, valves and other controlling
mechanisms. The orientation of the roof to the sun will need to be considered if these
items are to be easily roof mounted to gain maximum sunlight exposure.
Insulation and Energy Use
Insist on high levels of thermal insulation in all walls, ceilings and under floors. Thermally
line curtains and draught strip around door and window openings. This will allow you to
achieve controlled ventilation through purposefully designed vents. Avoid using clothes
dryers and other high power usage appliances wherever possible. Select new appliances
based on the star energy rating system, the higher the rating the more efficient the product.
Use low energy compact fluorescent light fittings and switch off all electrical appliances
when not in use.
North facing
glazing as collector
Thermal mass for heat storage insulated from ground below
Fan to assist heat dispersal
Thermal insulation to
retain heat (e.g. thermally
lined curtains)

Warm air out
Materials
Try to use materials that have a low embodied energy content in their manufacture.
Embodied energy includes all the energy consumed during initial quarrying of the raw
materials right through to their final packaging and transportation to the site. For this reason
use local materials where possible. Architecturally, this will reinforce regional identity, sense
of place and uniqueness.
Cool air in
Specify materials from a renewable source where possible. Care must be taken with timber
in particular to ensure it is not coming from very rare old growth temperate forests or
tropical rain forests but is instead certified from plantations.
Ventilation for summer cooling
Roof mounted
solar water heater
Consider using materials that are recycled or reused and recyclable and flexible enough
to be reused. Use bolted and screw fixed connections rather than adhesives, staples,
rivets and nails. Although slightly more expensive these will facilitate dismantling and reuse
with minimal damage to the material and the structure that it has been attached to.
Specify for low toxicity both in manufacture and in use. Most types of plywood and
chipboard, for example, contain urea formaldehyde resin that the United States Environmental
Protection Agency (EPA) classes as a probable carcinogen. Dangerous heavy metals other
than lead such as mercury, tin and arsenic are still present in many paints as are toxic
solvents. Many insulation materials can trigger allergies and fine fibres may prove to be
dangerous when inhaled. Try to use natural products such as wool insulation. There are
alternatives to the industry standard materials but these generally are harder to find and
must be clearly specified.
Design and specify for long life and for low maintenance. Replacement, repair and cleaning
of building shells can be difficult, dangerous and expensive. Materials that may cost less
initially can have high hidden long term costs.
Hot
water
cylinder
Use self-finishing materials such as timber or stone where appropriate as opposed to
those requiring an applied finish such as paint or varnish. This should help to speed up
the construction process and keep labour costs down. Consider natural oil and wax
finishes or if paints are to be used specify water based, solvent free paints.
Domestic Hot Water Supply

Topography
On sloping sites, design the building so as to minimize earth works. Try to design to fit the
slope, this way less energy and resources will need to be expended to dig out, remove
and dump the excavated material as well as support the remaining ground. Retaining walls
are generally very expensive in both design and construction and should be avoided where
possible. Designing with the slope helps prevent the loss of soil and mature vegetation.
It also makes undermining of adjacent structures, land and trees less likely. ‘Touch the
earth lightly’ is an expression used by the award winning Australian architect Glen Murcutt
to describe his approach to the design of buildings.
Hydrology
Try to design for water storage on site so as much winter and spring rainfall as possible
can be used during summer and autumn droughts. Design for appropriate water discharge
from the site to avoid soil erosion, ponding (stagnant water for mosquitoes and other
noxious insects) and flooding. Prevent pollution of ground water by catching oil and other
chemical spills from workshops and vehicle parking areas with oil and silt traps Where
some pollution is inevitable, grade the slope to collect pollutants in a single place. This
limits contamination of a site to a smaller area that can be more easily dealt with later on
when the site is redeveloped.
Use low consumption taps and shower fittings and specify low water usage washing
machines.These same fittings will also reduce energy consumption and costs.
Recycling and Reuse of Buildings
If at all possible, reuse entire existing buildings, this will result in the least total amount of
energy being expended. This approach has the added benefits of the retention of the
existing historical context and character, and the retention of craftsmanship, detailing and
materials that may be no longer readily available (for example, native timbers or rare exotic
timbers). Try and avoid the need to demolish, remove and dispose of materials. This is
often a dangerous activity or generates potentially dangerous substances such as dust,
noise, falling materials and may disturb dangerous materials, for example, asbestos. This
activity may also result in the undermining of adjacent structures and the disturbance of
the streetscape. However, earthquake strengthening and the upgrading of fire ratings are
not achieved easily in existing buildings and particularly in older masonry structures. The
costs can be high and there are issues to be addressed such as how to retain the character
and integrity of the existing building while adding structural bracing, insulation, lighting and
other services. Advice on appropriate design and strengthening may be needed from
architects and structural engineers.
Right; Former Biscuit Factory converted to apartments and cafe, Fremantle, Western Australia.

Design for Change
Try to design so that the building is flexible for change of use in the long term. Use design
devices such as demountable walls; movable partitions; retractable fixtures and fittings
(bolts & screws rather than nails etc); recyclable materials (notation and labelling generally
greatly helps later reuse); easy access to services, and space provision for future additions.
Ensure as a building owner that you are provided with thorough ‘as built’ records from
all of your consultants. Being able to alter or extend an existing building to make it meet
new requirements is much more efficient than demolition, disposal and then construction
of a new building.
Ensure efficient use of materials by using industry standard material sizes to reduce wasteful
off-cuts. Design internal spaces to be airtight through draught sealing around openings
in the building envelope and through the envelope itself. Controlled ventilation is essential
to minimise heat losses but at the same time to maintain fresh air requirements and to
prevent moisture build up and consequent condensation and mould growth.
Inevitably some degree of compromise will be needed in any design. Glazing has a high
thermal conductivity and so allows a relatively large amount of heat to be lost at night; but
during the day it facilitates solar gain and negates the need for artificial lighting as well as
helping to create a pleasant and varied internal environment. Double glazing would help
and external insulating shutters would further reduce the heat loss but would either have
to be powered or manually put in place each evening. A workable solution is required and
this may require some training on how to operate the new structure. An ‘Operators Manual’
may be called for just like a new car or washing machine to advise on the systems present
in the building and how to get the most out of them for the least inputs.
Lessons can be learnt and inspiration gained from the design of and materials used in
older buildings which have had a successful relationship with their surrounding environment.
There is however no desire for slavish replication of the existing built environment. The
building design dilemmas we face now are distinctly different from previous problems and
the available solutions are much more varied and complex with new technology and ideas
playing major roles.

Landscape
Landscaping can contribute significantly to household efficiency and environmental
sustainability. Energy use can be reduced considerably, water use can be minimised and
the unpleasant effects of climate, such as wind and hot sun, can be controlled. A low
maintenance, self sustaining landscape can be achieved while enhancing the environment.
In the same way that materials are chosen for the house, that is, they have low embodied
energy, are recycled, reused or renewable, have a long life and are low maintenance, they
should be chosen for the garden.
There are a range of energy saving landscape methods. Using paving in the right place
can help heat the house, more effectively dry clothes and extend the growing season for
vegetables and cold sensitive plants. Paving such as masonry, ceramic tiles, bricks, concrete
blocks and pavers, all have the capacity to absorb and store heat. Heat is then radiated
from the paving.The paving does not need to be solid to achieve this effect but may be
broken bits of concrete slab, river stones and such like.
Controlling climate through appropriate landscaping can also be very effective in reducing
energy consumption. Well sited trees and shrubs can provide shade in summer and shelter
from wind where needed. Planting immediately adjacent to the house, particularly on the
south side or in response to prevailing winds, can be an effective form of insulation, reducing
drafts and preventing heat from escaping internally.
Water use can be minimised in several ways. One way is to select plants that are appropriate
to the climate, for example using drought tolerant plants in dry areas. Often plants which
are native to the area will grow the most successfully as they have become well adapted
to the conditions. Another method to conserve water is to plant to give a layered effect,
for example from groundcover to shrubs with trees above. This can help create a more
self sufficient planting system, forming and retaining moisture, reducing the need for
irrigation.
Retain water from your roof or direct water from paved areas for watering the garden.
Water can be stored in tanks or distributed directly into the garden via soakage channels.
Small retention ponds or hollows can be used for the storage of water which will gradually
soak into the ground. These may simply be depressions in the lawn or garden area. Water
used this way will be appreciated by thirsty wildlife too. A further method for saving water
is to mulch around your plants. Mulching helps retain ground moisture as well as discouraging
weed growth. Ideally mulch, most commonly bark chip, should be at least 75mm thick
and may be laid on old newspapers for added effect.

Summer shadows
In areas with high water tables or that are prone to surface flooding, plants can act as pumps
to help dry the ground. The use of permeable paving also assists drainage and helps purify
the water as it soaks through the ground. Some plants also have the capacity to decontaminate
water and soil.
Water tank
for irrigation
Winter light
Storm water
retention pond
The use of harmful chemicals in gardens to eradicate pests can be avoided by selecting
pest resistant plants or by companion planting. Garlic for example has the ability to discourage
pests such as aphids. Some species of geranium deter mosquitoes, making the garden a
more pleasant place to sit in on summer evenings. Another method of warding off pests
is to encourage ecosystems to develop. Again a layered planting approach is beneficial.
Insect predators such as birds, spiders and ladybirds should be nurtured. Leave abundant
leaf litter, which is good not only for the health of the plants but also encourages hedgehogs
to snuffle out snails and slugs. Leaving the leaf litter also encourages worms, which break
down the leaf mass, building up nutrients in the garden. Generally the more that the garden
looks like a wilderness, the healthier it is. A good sign of a healthy garden is an abundance
of birds and insects.
The need for additional nutrients can also be avoided, again by using companion planting,
but in a way that the plant species benefit each other. For example one plant may produce
large quantities of nitrogen while the adjacent plant needs large quantities of nitrogen to
grow well. Again, plants that are native to the area or that thrive in the conditions that prevail
in the garden will help reduce the need for fertiliser. Such conditions will relate to soil type
and soil pH, both of which can be tested. The local garden centre can normally give advice
on this.
The role of landscaping in creating a sustainable environment cannot be under-estimated.
In hillside areas and next to watercourses landscaping can prevent erosion. Tree planting
can reduce air pollution, provide habitat for birds and generally create a more pleasant
environment. Sustainable gardening is all about creating functional, pleasing places that
require the minimum of inputs for the maximum gain.
Contacts
This design guide was prepared in 2003 by Brendan Smyth & Josie Schröder in conjunction
with other members of the Urban Design & Heritage Team, Christchurch City Council.
Further advice and other design guides referred to in this document are obtainable by
contacting overleaf.
Text pages printed on recycled paper

Notes: