Being Carbon Neutral
The question is how many trees do I need to plant to be carbon neutral. Can I do this myself without paying a third party
to do this on my behalf? If I can do it myself how much land do I need?
Instantly I find out that the area of the house is
essential to working out your carbon impact. So building a smaller house per household member is important to keeping your carbon output low. The
house we are building for ourselves will have an area that is heated –
including general living areas, bathrooms, bedrooms. There will also be an area that doesn’t need
to be heated such as a garage space and a studio space. The studio space will
contain a ceiling fan for summer and a wood fireplace for winter. The wood
fireplace was purchased for our previous house but we decided it wasn’t
appropriate. We think it will suit our new studio space. This will require a
separate carbon offset compensation.
The area of the house that will need to be heated with a
form of mechanical heating (most likely air water heat pump hydronic heating)
is 194m2 – which is nominally less than 50m2 per person – this is under the
current 89m2 average size of building. The studio space is 26m2.
Doing this research there are a number of alternative
European systems that offer energy efficiency. There is the German Passive
House. There is also the French Effinergie and Swiss Minergie that are all
certifiable systems based on thermal tightness and passive solar design for low
energy consumption buildings. Passive House, Effinergie and Minergie rely on a
mechanical ventilation system for moving air around a building to push
naturally warm air into cold areas in winter and naturally cool air in warm
areas in summer.
In order to stop climate change the
maximum amount of CO2 produced by each person per annum is 0.600 tonne (600 kg
of CO2 per year) according to “My Climate” (Swiss). An Australian website
“Particle” says that in Australia we need to reduce our carbon to below 2 tonne (2000kg of CO2 per
year) (this seems a lot compared to the Swiss prediction).
Carbon Neutrality is the ability
to produce the same amount of carbon saving as carbon usage.
Therefore, the question is how
much carbon is captured with the planting of one tree? The question is complex
as the older the tree, the more carbon is captured. So in theory if your energy
use is static, then the trees that are planted will each year absorb more
carbon. The amount of trees that are then planted are then reduced until the
equilibrium for that household is achieved. If more trees are planted then in
theory you go into a climate positive position. An idea / theory then is to
produce a landscaping schedule that works out the carbon absorption of the
trees for that site, and the large trees are balanced with the smaller tress to
produce a climate positive property. This is a theory to understand in real terms
what it means to be climate positive, trees can keep being planted to greatly
Some various quotes from the
internet of interest:
Tree species that “grow quickly
and live long are ideal carbon sinks”
“A carbon planting is a deliberate
planting of vegetation for the purpose of sequestering carbon”
“A young tree is still small and
converts less, but as the tree grows bigger it
also absorbs more CO2. A young tree absorbs about 5900
gram CO2 per year, while a 10 year old tree absorbs almost
22.000 gram per year. By taking these numbers we can calculate the
average CO2 that is absorbed by a tree during his lifetime” www.carbonpirates.com
“We used carbonfootprint.com to find
how many tonnes of CO2 each trip would generate. Trees for Life
calculates 6 trees offset 1 tonne of CO2. So 1 Tree
= 0.16 tonnes CO2. We then divided carbon figure by 0.16 to
get the total number of trees.” www.shipit.co.uk
“A sweeping study of forests around the world
finds that the older the tree, the greater its
potential to store carbon and slow climate change. The 38 researchers from 15
countries found that 97 percent of trees from more than 400
species studied grew more quickly as they aged, thus absorbing
more carbon.” www.pacificforest.org
We are currently designing our own house. This process is
making us think deeply about the way we engage with buildings, and is making us
more aware, at this point in time, of the need that our expectations of housing
needs to be redefined. Housing is linked to our dreams and aspirations. Part of
those aspirations are dictated by social expectations and desire. What is
essential in creating a sustainable design practice is to maintain the ability
to reach those expectations and fulfil those desires for clients at the same
time as creating buildings that are more in line with current reduced energy usage
requirements. As our own clients we are looking
to achieve this as best practice, at the same time as working efficiently
within a budget, and with the expectations of architects building our own
Ultimately building sustainably isn’t that hard. The goals
are to reduce the operation impact of buildings, reduce the embodied energy of
buildings and most significantly reduce the scale of buildings. By reducing
scale both the operational impact and embodied energy can be simply reduced. Overly
large houses are a big problem in Australia (Australian House sizes are one of the
largest in the world), but with good design a building doesn’t need to be
overly large. We are currently renting a house in a housing estate. It has been
eye opening, as insiders rather than as onlookers. We are shocked by the
endless cookie cutter McMansions that are constructed to minimum construction standards.
Houses that don’t even include sisilation in the roof, which is of minimum
cost, but has impact on the overall energy efficiency and longevity of a house.
I wonder about the life cycle of these houses that are built in the estates, and
how in the future they will be renovated? Access to good housing is essential to
all, but offering very large, cheaply constructed and poorly designed houses is
an offence to the built environment but also a liability to the future. Saying that there are households and smaller building companies that are making an effort to reduce their energy impact, and they should be commended for not conforming.
Another issue we wish to deal with is reducing the embodied
energy of a building as this is a hidden major source of stored energy in a
house. Material choice is therefore essential in reducing the embodied energy
of a building. For example, reducing the amount of Portland Cement Concrete and
reducing the amount steelwork in a building will reduce embodied energy. Using sustainably
sourced timber or recycled materials will also reduce embodied energy.
In other jobs in the past, we have also looked at reducing manufactured
items within the house, and had the carpenters on site make items that can be
easily substituted, such as door handles, coat hooks, towel rails and other
metal fabricated items. This is a very
simple way of reducing embodied energy.
We always also try and specify local or Australian made products. Reducing the use
of imported products reduces material miles. We are always investigating where
materials are made, and there are many beautifully made products made locally.
We have found beautiful tapware and bathware made in Victoria, handmade fabrics
made locally, light fittings made in Australia. We are also investigating locally
made appliances (these are limited).
One of the biggest issues we need to contend with is window size,
location and quality. Quality windows that are air tight are essential to designing
houses that will use the outdoor climate to its advantage. Maximizing North
facing glass, minimizing South facing glass, and having the correct type
of external cover to East and West facing glass is essential to the way buildings
operate. We are also told that the colour of the window frame also effects the
energy efficiency of a dwelling. Balancing the correct window size to the floor
area with the beauty of visual access to the outside and the sky is a delicate
matter. We love big windows, and feel liberated inside when we have the visual
access to outside, but it will be a challenge to get that balance right.
Healthy natural materials also contribute to the health of
the environment. Chromed taps and the use of Hexavalent Chromium on Hot dip Galvanised
steel are to be avoided as these finishes are toxic to the environment and
human health. We have used many natural finishes including natural oils and
natural paints in the past, and we will endeavour to explore the use of these
in the construction of our home.
The next step is to explore net zero calculations and how
this achieved, investigating air tightness and the advantages of passive house and how this system is being adapted to our climate, waste reduction during construction and during a buildings life, and the active and smart use of low emissions technology.
We are starting a journal, so what we will write is what we
are currently thinking about and working through as an architectural practice
that is focussed on sustainable building practices. We will also discuss
current design ideas we have and ideas that we have heard about from different
The main question for us is how do we as a practice, operate
as sustainably as possible, and how do the buildings that we design also
operate as sustainably as possible. This is not only about designing building
that have a reduced energy expenditure, but also using the natural climatic conditions
around a building so that the occupants have the advantage and enjoyment of their
building working with the natural environment. For example, using natural
daylight, natural ventilation, passive heating and cooling. Understanding insulation,
building leaks and thermal mass. Having reduced
reliance on mechanical forms of heating and cooling so that the air we breathe
is clean and the climate we experience is seasonal. Other influences are making
buildings as healthy as possible so that we use a reduced number of
petrochemicals, and specifying natural products or raw materials that are long
wearing, and that age beautifully. Other ideas are building smaller, so that reduced materials are used, using recycled
or upcycled materials, or repairing building for reuse. Using local or hand
made products to reduce embodied energy. These are some of a number of strategies
that we employ to build sustainably.
We find that having these core values and beliefs not only invigorates
our design process but also informs a visual style that is nature based.
We are also beginning to design ourselves a new house and as
part of the process we will revisit a house we built for ourselves in Jan Juc.
This will happen in subsequent posts. We will also discuss the process of the
design of our new house at 13th Beach.
The ultimate goal is to be Carbon Neutral.
So, what is carbon neutral. What does this mean in real
terms – not just theory or paying someone else money to plant trees to
compensate for our carbon emissions. How do we reduce our carbon footprint enough
to plant trees ourselves and therefore take the responsibility (or even just
have the understanding) of our carbon usage?
The disadvantage of the whole sustainable movement is the
guilt associated with it, and the stress associated with thinking that our lives
impact the environment. By understanding our actions at a base level, it may
empower our actions. Living sustainably is almost like being on a life diet.
Where we feel that we can’t live freely without the impact of what we do. In
fact once the diet is understood, and rationalized, then maybe the diet doesn’t
feel so bad, it actually feels really good to be engaged with the environment,
and living within the environment, rather than being isolated from it.
Understanding how to go carbon neutral is something that we
have been exploring. We are told that we can provide information to a company
(or number of companies) who can take our office or home information break it
down and then charge us a fee for planting trees to offset our Carbon usage.
I am interested in understanding what this actually means.
What am I doing within my life and with our office business life that is
producing carbon? How can we reduce this, and then if we do what are we doing
that produces carbon, and what do I need to do to offset the carbon I am producing
by my daily tasks? I like the idea of actually understanding the base line of
my actions and then through my own activity – like planting trees – I can take
responsibility. It is also about the process of understanding what we do, what
is the effect, how can I slowly change my habits, and evolve to a more carbon neutral
On the side - one thing I heard today was that if you are
hot or cold you aren’t kitted out right – ie if it is cold put on a jumper and
wear warm footwear, if it is hot wear less. It is a bit of a simplistic view
but worth a thought.
More about being carbon neutral in our next post….
Sunrise Torquay Beach March 2021
Taking photos today at a house we recently finished. It is good to see owners take possession of their new homes.
The Mount Buffalo Cafe - a classic lodge building
Photos from our recent trip to Tasmania from Lake Pedder. The lodge is the original lodge built in the 1970’s, and still retains it’s original utilitarian features.
The landscape of Lake Pedder is a contrast of beauty and devastation.
We were specifying lights recently and thought that lighting manufacturers have adapted very quickly to the regulations requiring greater lighting efficiencies. A few years ago it was difficult to achieve wattage limitations, now it is straight forward.
For soft ambient lighting these handmade glass feature pendants are a favourite of ours.
A site is ideally viewed as a total integrated element inseparable from a building. In a codependant relationship a building and landscape can work as an entire space for habitation. Rather than viewing a site as a singular plane where a building, as an object, is placed, a site can be viewed as a series of ecosystems dependent on orientation, views, topographies, vegetation and external influences. A building ideally interacts with its landscape and engages with its aspects in such a way that responds to the natural breezes, sun angles, rainfall etc. Rather than breaking up the site in broad strokes such as street frontage, rear aspect, a landscape and building can be designed together as a series of spaces that co-exist, relate to and invigorate each other.
A landscape is constantly being reinterpreted independently by the elements. A building is constantly being reinterpreted through use, by its inhabitants. The garden is the place to experience the elements, and a building can be a place to experience and understand the elements in comfort and shelter
The garden is an independent space that changes with time. It can be re-interpreted and redefined, and with time has a life of its own. A building also changes with time from within - as the occupants grow and change and it’s use is re-interpreted and re-defined. Built form can be used to define and give character to the broader landscape, as much as a landscape can add meaning to a built form. Our buildings aim to explore the relationship with garden and the broader landscape and ultimately aim to invigorate and inspire the everyday experience.
Brunswick 04 House
Works to this Brunswick house are typical of many of the inner city houses in heritage zones that we design. Generally with heritage houses the existing original house is kept intact, thermally upgraded and renovated as required. Opportunity to open up the existing building to the outdoors is also explored, in order to obtain natural light, air and views that would not have been originally there, thus increasing the perceived size and livability of these existing spaces. Retaining, upgrading and adding to existing heritage houses allows for the opportunity to connect with the heritage of a place as well as create individual and unique spaces in a contemporary home. Original features and materials including floors can add character. In this instance we retained the existing Baltic pine floor and used a 100% natural oil finish which gives the timber a very soft natural feel.
With each house we work on, we like to address the sun, to maximize solar access for passive heating and natural daylighting. In this instance we connected a new building to the rear of the existing heritage building - which was to the south of the existing building. The new building was designed to zone the wet areas together and locate a new family area directly adjoining the back garden. In order to maximize solar access, a north facing clerestory window was added to allow to high levels of northern light into the main living space all day, maximize the outdoor space and maintain a closeness to the surrounding garden .
Materials and finishes were carefully chosen to achieve the sustainable outcomes that the client sought, including using a geo-polymer concrete slab for thermal mass and sustainably sourced timber cladding.
The new building is a light filled garden room that transforms an originally internally focused heritage house into a series of contemporary living spaces with alternative room types for varying functions that suit different times of the day.
Geo-polymer Concrete Slab
Brunswick House 04
This fly ash-based geopolymer concrete slab was poured on a job in Brunswick that is now complete. The slab is made from a cement free mix. Instead of cement, fly ash is used. Fly ash can consist of either a by-product of coal burning at a power station or as a by-product of steel production. As long as the fly ash is sustainably sourced using a fly ash based geopolymer concrete can reduce embodied energy of the concrete (ie the CO2 emissions) as well as have the advantage of absorbing recycled industrial waste. This type of material is still considered to be experimental, but once industry catches up to the science it will see a positive reduction in green house gas emissions.
Our clients in this instance were very keen to ensure their house was as sustainable as possible, and requested the use of this material. Our structural engineer approved the material prior to it being specified. The builder commented that the geopolymer mix was a bit stickier than normal concrete, and did take a bit more work to trowel finish. The initial material was quite green in colour, but once it dried it appeared just like a conventional concrete finish. In this instance we included hydronic coils in the slab, and the slab had a polished finish. The final slab was a bit softer than normal concrete, and a Hiperfloor finish wasn’t thought to be possible. We therefore researched the best applied finish for the slab, and with the concrete polisher’s advice chose a water based product. Overall the final polished concrete finish looked great, and our clients were satisfied that their home has achieved their sustainable objectives.
The thermal efficiencies of a house are essential to the physical workings of the house and to the comfort of the occupants. With correct orientation the outlook of a house can provide understanding of how the environment and seasons, specific to that site, work - where the sun rises and sets, where the breezes come from etc.
We have been working in the inner city of Melbourne, designing energy efficient, climate responsive houses since 2004.
Like many inner city families living ethically and sustainably can be difficult if the dwelling is an original heritage house. The owners of the Brunswick House approached us wanting to upgrade their house to current living standards, they wanted to create a vibrant dynamic space for their family to grow into. A house renovation like this comes out of a combination of the owners’ vision and willingness to have a house that can open up, close down, respond to breezes and sun, be thermally efficient and also be a reflection of the owners’ personal beliefs. We not only responded to the owners’ sustainable and environmental objectives, but also the owners’ life perspective, in this instance the playful use of colour and timber were core to the clients’ preferences.
Our approach with the Brunswick House was to keep as much of the original house that was usable and upgrade to current standards. This included cleaning out the existing roof space and installing new bulk insulation, and installing bulk insulation to any opened up accessible walls. The floors were patched, re-sanded and sealed. An internal wall and chimney was removed and a new internal wall added in order for the room sizes to suit their new function. Large robes were added to the new ground floor bedroom. An open bathroom with a Japanese soaker bath and walk in shower was included in this front private zone of the house. The bathroom receives soft dappled natural light and garden views. A European style laundry and large linen cupboard allow for a compact service area with plenty of storage. Efficient storage is essential to living in smaller urban sites and allows for more space to be allocated to the living areas zones.
A central pivot space between the old house and new house separate the two buildings. This central circulation space goes beyond its function by lining the walls with bookshelves, pin boards and allowing space for an upright piano. A small slot window to the north allows for light and ventilation. The owners had a reclaimed pair of lead light windows, which were restored and then double glazed. The lead lights were integrated into a new window that has become a feature of this area. This space, which would essentially be just a corridor, is redefined as a central hub to the house providing a lively space for family activities and expression and a dense amount of storage for books, games, display of photos and family memorabilia.
Adjoining this threshold space is a central courtyard / secondary entry. This space was designed to suit the owners’ brief of creating a cooler courtyard space for outdoor relaxation in the warmer months, a summer outdoor retreat. A timber shade structure defines this space and allows for an ornamental grapevine to adorn it and create a shaded space in the warmer months.
Once entering the back room much of the owners’ vision to create a personalized space is evident. They specifically asked us to use cool colours and “lots of timber”. Dappled light from the north and south exterior vines gives life to the interior which is almost forest like. Concrete floors were used for thermal mass and a one off special mix was designed to create a figured lighter tone at the request of the owner. A double brick boundary wall which was used for added thermal mass, is roughly bagged - this also adds texture to this space.
The owner is an avid gardener with the need for rain water storage and a desire to maximize the size of the garden, a hidden underground tank was installed beneath the garden. Tight urban sites don’t need to be restrictive in terms of how much garden or access to outdoor space a family can enjoy. In fact the under-utilized in-between spaces can add to the vitality of the internal spaces offering solar access, possibilities for ventilation and alternative garden views. The east boundary green tunnel could be a banal side access way and bike storage area, but with the owners use of plants the side access is transformed into a beautiful transition space. External timbers and unfinished steel are used for undercover bike storage and climbing plants add dappled filtered light.
As the architects we found the collaborative approach invigorating and helped us push our design in directions we may not otherwise have investigated. This resulted in a house that not only we believe represents our core philosophies but also the owners.
Upper Plenty House
We designed this reverse brick veneer house around 10 years ago. This photo gives a good idea of how reverse brick veneer construction works and how the bricks, which are located on the inside of the building, add to the thermal mass of the interior, and therefore increasing the thermal efficiency of the building.
In this instance a series of steel structural frames were constructed over a concrete slab. Steel infill framing was then used to create the external cladding frame. Bricks were then laid with a 50mm cavity to the inside skin of the building. Once the bricks were laid there was a significant amount of heat retained even within the unfinished building. External bulk insulation and sarking was then installed. The bulk insulation helps to isolate the thermal mass from the exterior to slow down the cooling or heating up of the bricks from the outside. Finally a hardy low maintenance colorbond corrugated sheet was used as the waterproof skin.
We maximized the north facing glazing to provide ample solar access into the house during the cooler months to warm the polished concrete slab and internal brick veneer walls. The eave overhang provides shading during the warmer months to ensure the interior remains cool.
In summary reverse brick veneer construction is considered to be a sound environmentally sustainable construction practice. As the bricks are located internally they add thermal mass to the building interior which acts to stabilize the indoor air temperature. The bricks can be bagged or rendered or left as face brick. This form of construction works remarkably well to retain warmth in winter and coolth in summer
We completed this alterations and additions project to an existing house in Glen Iris a few years ago. The existing house already had good orientation to the living spaces. We designed a new building containing the sleeping zones with its long orientation to the west. Conscious of having the major orientation to the west we designed a green screen across the face of this wall. A simple galvanized steel and timber structure was fixed to this west facing brick wall to allow greenery to grow up the wall and protect the building from solar radiation and heat penetration in summer. Green walls don’t need to be complex structures that are cost prohibitive. A simple structure can provide the framework for plant growth that is thermally effective and also visually pleasing.
The main sustainable advantage of building a green wall is that it will provide insulation and shading to that wall in summer. In this instance using a green wall along a west facing wall provided some insulation against the low hot western sun in summer. The insulation is provided not only by the physical barrier of the plants, but also by the air gap between the plants and the building. Therefore holding the plants off the building is preferred. We fixed a sustainably sourced Australian species cypress battens to the wall. A galvanised steel mesh was then fixed the battens. Cypress is a class 1 durability timber (above ground) so it is a good timber to use externally as it will have a longer lifespan than just ordinary hardwoods. We typically specify sustainably sourced Australian cypress for some inground and above ground use.
By strategically locating a green wall on a building, it can be used to help insulate and shade a building and act to reduce the heat load on a building. This is a passive sustainable design strategy.
Shoot day at one of our Brunswick Houses.
There is always anticipation and surprise in what the photographer sees.
Great to see our Hawthorn East House feature in new The Rug Collection photos.
Luxico also features our Hawthorn East House as a luxury rental property. Here are some of the photos that appear on their website.
Northcote House 01
The urban produce garden at our Northcote house is set up to produce fruit and vegetables all year round.
Ceres Eco House
A photo from the archives. The Ceres Eco House which we renovated in 2009. We also added a new airlock that opened onto this existing carport with its integrated solar panels and electric car charging facility. It’s great that Ceres Environment Park exists to educate about sustainable living.
Brunswick House 02
This Corten Steel box is a locked storage space for a Cargo Bike
Brunswick House 02:
The living space in this inner city house opens up onto a beautiful garden full of urban produce. The garden is watered via a 6500 litre underground rainwater tank that is hidden beneath the garden.
Brunswick House 02:
This south facing central courtyard was designed to be a shaded and cool outdoor space within this inner city house. It also acts as secondary entry from the side boundary bike storage area.