Archives

Screens

Australia’s climate calls for careful and in-depth thought towards the positioning of wall surfaces and, in particular, the location of openings in relation to the sun and breezes. Doing this not only improves comfort levels but also reduces reliance on artificial means of temperature control. External screens have long been acknowledged for their aesthetic value and ability to maintain cool interior conditions.

Many of CODA’s architectural projects have included screening devices, and many of our urban design projects have discussed their practical application. The MG/GT Administration Building located in Kununurra and the Building for Diversity project in Northbridge both use screens to manage sun orientation as well as to enhance the visual quality of the built form. CODA referenced the historical use and positive application of screens in Broome throughout the Housing Design Guidelines recently prepared for the town.

The Kimberley region of Western Australia is characterised by extreme wet and dry seasons and a pervading warm, humidity for much of the year. Here, comfort relies heavily on shading from the hot sun as well as the ability to draw cooling breezes into interior spaces. A number of studies have been conducted in Broome outlining the means by which buildings can be designed to sustainably respond to the Kimberley climate. Cultural and historical precedents reveal the key built elements that have stood the test of time as effective means to work with typically hot temperatures. To an extent the harshness of the sub-tropical conditions shaped the built environment long before air-conditioning was an easy solution for cooling our buildings. The pearling industry that founded Broome brought with it a strong Asian influence and Japanese craftsmen introduced many innovative building techniques. This influence, in combination with direct responses to the climate, resulted in a unique ‘Broome Style’, which began to develop from the late 1800s, and can still be seen through portions of the town.

Many of the design principles that define ‘Broome Style’ buildings influence contemporary, sustainable architecture in general, for instance, the use of lightweight materials, wide verandahs and permeable external screening devices. Shutters and screens made of penetrable linings such as cheesecloth, canvas and lattice were typical to the exteriors of buildings in Broome, as were the use of louvers. These devises were particularly useful in Broome where the hot afternoon sun and cooling breeze come from the west, resulting in a need for a double skin that allows for airflow to permeate the buildings whilst shading the interior from the force of the sun. Operable screens are particularly useful in humid climates as they allow for maximized air movement. CODA’s research into Broome’s prevailing historical building techniques has significantly enhanced our work for the Broome Housing Guidelines. These guidelines suggest design outcomes that reference Broome’s established character and architectural language. They encourage climate responsive designs that learn from the proven historical built dialogue.

The MG/GT Administration Building in Kununurra uses the idea of a permeable second skin as a means to effectively separate the building fabric from the harsh effects of the sun. This building, which functions as an administrative and community facility for the Miriuwung Gajerrong Corporation and the Gelganyem Trust, features a plan that is open to both the environment and the community. The vibrant green screen that wraps around the front façade is constructed from vertically aligned painted steel angles and provides visual cohesiveness to the two volumes of the building. Most significantly, the screen provides shading to the non air-conditioned spaces often used for meetings outside of the offices, establishing comfortable and useable external spaces throughout the day. An additional benefit of the screen is that it has worked in conjunction with careful interior planning to reduce the overall running costs of the building. The screen has also enhanced the civic presence of the building, allowing it to glow like a beacon within Kununurra, particularly when lit from behind during the night.

Much like MG/GT, the affordable housing project, Building for Diversity, responds to orientation and the desire for an environmentally responsive building through both its planning and exterior treatment. This project challenged existing height restrictions of the site, forming a tower that allows for maximum use of the space whilst providing access to northern sunlight in all habitable rooms. A perforated anodized steel screen wraps around the building to provide shade and reduce heat load in the interior, whilst instilling moments of delight internally through the play of light and shadow. The screens, designed in collaboration with artist Olga Cironis, dress the exterior of the building and act as a beautiful binding element throughout the building.

CODA’s use of screening devices is a genuine response to the factors of climate and environment. At the same time CODA incorporates screening elements into their urban and built work as a means to inject moments of playfulness, beauty and, in the case of Broome, attempt to instill cultural relevance within new builds. In highlighting the practical and visual qualities that screens provide and taking particular interest in the fact that climatically, these are elements that have successfully been used throughout history, today they stand as tools for a sustainable level of architecture that seeks to eliminate the reliance on artificial cooling devices in hot climates.

 

Fill and Substructure Study: East Port Hedland

The purpose of this report is to compare costs of alternative methods for raising the ground floor level of buildings on a low-lying area located within the flood plain of East Port Hedland. The site has been identified by LANDCORP as the most likely next stage of residential subdivision in Port Hedland.

Commonly, in Western Australia, a business as usual (BAU) approach is applied to raising site levels, wherein compacted sand fill is introduced to raise ground levels to the required minimum habitable floor level.

CODA’s role, in conjunction with CAPITAL HOUSE AUSTRALASIA Engineers and DAVIS LANGDON Quantity Surveyors, was to interrogate costs associated with alternative housing typologies and various substructure solutions. From this analysis, costs for a comprehensive range of building types, construction types and site-filling levels have been obtained.

The report considers lots being partially raised by filling to minimum ground levels dictated by 1:20 and 1:50 year flood events. Three common sub-structure types, used to elevate the buildings to the required higher 1:100 year habitable floor level, are examined.

A Cost Calculator and series of Comparative Foundation Studies have been prepared to assist in determining and comparing costs (for filling plus sub-structure only) associated with 135 permutations of House Typology, Building Construction Type, Development Building Footprint and depth of Fill.

Intuitively, break-even costs exist between filling and raising buildings via elevated substructures. The report demonstrates that cost optimization is predominately driven by the cost to supply and place fill material, and the total building footprint intensity (i.e. the sum plan area of all buildings as a percentage of the overall site area being filled).

The report provides an exhaustive basis for analysis of costs associated with raising site levels. Furthermore, the model established is suitable for similar interrogation exercises at any site needing to be raised.

During the course of the investigation an attempt to collate local market views on residential housing typologies and construction methods was made.

Research from established Pilbara Home Builders’ websites revealed that the use of suspended floors is not currently favored and that the preferred house types predominantly comprise of a standard steel roof and wall frame construction with a concrete slab on the ground.

The Queensland floods of 2011 generated an extensive review of the response of Architectural, Civil, Planning and Structural design in relation to development in flood plain areas. Our research has collated some of the findings and identified applicable strategies important for consideration when developing in a flood plain. These included appropriateness of building typology and material selection with regards to resilience to water damage and absorption.

For a full copy of the report please email us at studio@coda-studio.com 

Main Image: Flood prone areas around Port Hedland

Human Comfort in the Tropics

The vastness of Western Australia and the variances in its climatic conditions calls for a variety of responses to its developing built environment. What is considered a suitable and sustainable architectural design in Perth will undoubtedly be less effective in Broome or Port Hedland.

Western Australia displays a large diversity of climate zones, ranging from the temperate south to desert and tropical conditions in the north. CODA’s involvement in remote projects within Western Australia has resulted in a substantial body of research and knowledge as to the climatic conditions within these regions. The resultant research forms design guidelines that outline how best to approach new built works. Amongst social and cultural benefits these guidelines essentially promote sustainability through climate-responsive design. Design guidelines for projects in the Kimberly and Pilbara clearly articulate the most effective way to build for comfort, without necessarily having to rely on artificial cooling.

Human comfort is a specific thermal level that is considered universally comfortable. External temperature, air movement and the ability for the body to warm or cool itself to maintain a required 36.9oC work together to influence our perception of comfort[1]. Within tropical climates, such as Broome, an ever-present humidity has to be taken into account. High levels of humidity generally lead to a feeling of discomfort as the increased levels of moisture in the air impede the body’s ability to perspire and cool itself through evaporation. Unlike sunlight and temperature humidity is a factor that is much harder to design for in the built environment, it cannot be controlled through shade as we do the sun, or insulated against as we do for the heat and cold. Instead, ventilation becomes the essential design consideration in controlling the effects of humidity.

The tropical climate of the Kimberly region is characterised by a distinct wet and dry season and warm, humid conditions throughout most of the year. There is also a notably low diurnal range meaning that there is very little variation in temperature from day to night. The Design Guidelines put forward for Broome establish the most suitable built form for comfortable living in the Kimberley. Low mass construction, light coloured external skins to decrease the absorption of heat, reflective insulation and careful positioning of openings to maximise the effect of ventilation [2] are all important in this climate.

In comparison, in climates where there is a broad diurnal range (where temperatures significantly drop at night) thermal mass works effectively in re-radiating the absorbed heat throughout the night. Places with low diurnal ranges, such as Broome, rely heavily on evening breezes to ventilate and so we must design to allow this to happen efficiently. In essence lightweight construction works most effectively, it does not store heat throughout the day, thus eliminating the consequent ‘heat blanket’ as the heat is re-radiated. This ‘blanket’ of warm air around and within the building would impede the cooling effect of any breezes throughout the night. Lightweight construction in combination with the careful positioning of openings to allow for cross ventilation is the most efficient means to providing comfort within a humid climate.

With this in mind the physical orientation of the home is crucial in maximising the effect of breezes. As a guide it is considered that within Broome, for example, the most beneficial breezes are westerly followed by those from the north-west and south-west.  Primary openings should be positioned to capture these and allow them to move through the home with as little obstruction as possible in order to flush warm air from the interior spaces. Focusing the principal living areas with respect to the prevailing breezes will essentially help in reducing the need for air-conditioning within the home.

The tropics are a unique climate because of the humidity factor but, despite this, it should not automatically be presumed that air-conditioning be the only solution for internal cooling. It is most certainly a climate that requires comprehensive consideration and planning, particularly in relation to the materials chosen and their thermal performance. Essentially the key to passive urban design within a tropical environment is to minimise exposure to direct sunlight, and to design openings that ensure sufficient airflow can pass through the whole building.


[1] Queensland University of Technology 2009

[2] Broome North Design Guidelines, CODA/Landcorp

Broome Housing Guide

In 2009 Landcorp engaged coda to develop a design strategy for the delivery of affordable, sustainable, climatically and culturally suitable housing for the Broome North development. Coda’s role was to understand the local housing market, its conditions and constraints, and propose design guidelines and urban design strategies to enable the provision of suitable housing as identified in the shire of Broome, local housing strategy 2009 document.

This document sets out a housing design style as part of the vision for the new development of Broome north and in response to the local housing strategy for Broome. The strategy outlines three key issues that relate directly to house design:

  • Housing affordability
  • High land and building costs
  • Housing mix

Other items listed as matters to be addressed include:

  • Public housing
  • Heritage
  • The Broome climate
  • State government planning policies and the R-codes

Based on the latest developments in the theories of tropical urban design adapted to the particular nature of the Broome environment, the Housing Guide reveals an understanding of the site, the history, the culture and the natural environment in and around the Broome peninsula at both macro and micro scales. Numerous meetings were held in Broome with consultants, builders, planning departments, the Yawuru people and other local interested parties to provide invaluable contextual information and a deeper understanding and knowledge of the area, eventuating in a detailed set of strategies and approaches towards an urban design and a housing typology that can be implemented in the development plan for Broome North.

BROOME_NORTH_HDG6

For a full copy of the Broome Housing Guide please contact us at                       studio@coda-studio.com 

 

Karratha Solar Analysis

Karratha is a coastal town in the Pilbara region of Western Australia. The town experiences tropical weather conditions, with hot humid summers and warm winters. Temperatures are high for most of the year, with 232 days per year over 30C. From September until April, average temperatures rarely fall below 30C, and can reach up to 48C (21st Jan 2003).

March is generally the hottest month of the year in Karratha, and it is not unusual to experience up to 4 days over 40C during this time. July on the other hand, is the coolest month with an average maximum temperature of 26.2C.

Due to these extreme temperatures, building design in Karratha requires additional design measures so as to not allow unwanted heat build-up or ingress into the house. The most effective of these is shade. Simply put, direct solar heat gain will occur to buildings and their surrounds unless adequate shading is provided.

In addition to shading windows and walls, it is beneficial in climates such as this to provide shade to any areas of thermal mass at ground level, such as paving and/or concrete (driveways and paths). Materials such as these, with thermal mass, have the capacity to absorb and store large amounts of heat energy over a period of time and re-release that stored heat once the heat source is removed. The re-radiated heat can then ‘blanket’ the house long after the sun has set.

Our Design Guidelines for Baynton West require an 800mm eave to all external walls on new residential properties. This requirement delivers additional shade to all walls and windows compared to standard (450mm or 600mm) eave lengths, and allows shade to surrounding ground surfaces to prevent heat build-up.

To demonstrate the benefits of an 800mm eave, CODA have conducted a solar study of the effect of an 800mm eave compared to a 100mm eave on a house with an eave height of 2700mm. For the purpose of the study, a lot size of 525sqm (15m x 35m) has been modelled, with a 265sqm (11.5m x 23m) rectangular house built on it. Note, the modelled house does not represent a form which is compliant with either the R-Codes or Design Guidelines with regards to setbacks etc, but simply demonstrates the shade provided by a 100m or 800m eave on each of the elevations. The solar study was conducted with a north-south house orientation and an east-west orientation.

 

Our findings are as follows:

1. A North-South orientated house (long-axis running from north to south) with an 800mm eave, is provided:

Summer Solstice: 100% shade to northern and southern elevations all day, with morning solar exposure to the eastern elevation and afternoon solar exposure to the western elevation. Full shade to house at midday.

Winter Solstice: 15-30% shade to northern elevation for most part of day, with 100% shade to southern elevation all day. Morning solar exposure to the eastern elevation and afternoon solar exposure to the western elevation.

Spring and Autumn Equinox: Both northern and southern elevations in full (90% or above) shade all day, including ground shade to the southern side of the house. Morning solar exposure to the eastern elevation, and afternoon solar exposure to the western elevation with both eastern and western elevations in full shade at midday.

 

2. A North-South orientated house (long axis running from north to south) with a 100m eave, is provided:

Summer solstice: 100% shade to northern elevations all day. Varying shade to Southern Elevation throughout the day, peaking at 80% shade at mid-day. Significant morning solar exposure to the eastern elevation and extreme afternoon solar exposure to the western elevation from early afternoon (15% shade at 3pm).

Winter Solstice: Little to no shade (max 5%) to northern elevation all day, 100% shade to southern elevation, including ground shade all day. Morning solar exposure to the eastern elevation and afternoon solar exposure to the western elevation.

Spring and Autumn Equinox: Southern elevations in full shade all day, including ground shade to the southern side of the house. Northern elevation shaded no more than 15% until late evening. Significant morning solar exposure to the eastern elevation lasting until early afternoon, and afternoon solar exposure to the western elevation from mid-day onwards.

 
3. An East-West oriented house (long axis running from east to west) with an 800mm eave, is provided:
Summer Solstice: 100% shade to northern and southern elevations all day, with morning solar exposure to the eastern elevation and afternoon solar exposure to the western elevation. Full shade to house at midday.
Winter Solstice: 15-30% shade to northern elevation for most part of day, with 100% shade to southern elevation all day. Morning solar exposure to the eastern elevation and afternoon solar exposure to the western elevation.
Spring and Autumn Equinox: Both northern and southern elevations in full (90% or above) shade all day, including ground shade to the southern side of the house. Morning solar exposure to the eastern elevation, and afternoon solar exposure to the western elevation with both eastern and western elevations in full shade at midday.

 
4. An East-West oriented house (long axis running from east to west) with a 100mm eave, is provided:
Summer Solstice: 100% shade to northern elevations all day. Varying shade to Southern Elevation throughout the day, peaking at 80% shade at mid-day. Significant morning solar exposure to the eastern elevation and extreme afternoon solar exposure to the western elevation from early afternoon (15% shade at 3pm).
Winter Solstice: Little to no shade (max 5%) to northern elevation all day, 100% shade to southern elevation, including ground shade all day. Morning solar exposure to the eastern elevation and afternoon solar exposure to the western elevation.
Spring and Autumn Equinox: Southern elevations in full shade all day, including ground shade to the southern side of the house. Northern elevation shaded no more than 15% until late evening. Significant morning solar exposure to the eastern elevation lasting until early afternoon, and afternoon solar exposure to the western elevation from mid-day onwards.

 
Conclusion:
While a 100mm eave will provide similar shade to an 800mm eave at midday on December 21st (summer solstice), the additional shade provided by an 800mm eave in the hours prior to and following mid-day is significant: 10% increase in shade to eastern walls at 9am and 35% increase in shade to western walls at 3pm.
An 800mm eave also provides superior solar protection during the spring, autumn and winter months, when the sun is much lower in the sky. Most significantly, a 75% increase in solar protection to northern walls in March, when the temperatures are often the hottest (up to 450C)and the sun is much lower in the sky.
An 800mm eave also provides significantly more ground shade year round, preventing heat build up and re-radiation from external thermal mass surfaces.

Broome North: Weather Stations

Designing for climate is one of the most important aspects for any construction and development project and is fundamental to the success of the final outcome. In order to achieve this we needed to understand the existing conditions on the site so that we can work with and not against the natural environment conditions in and around the Broome North site.

LandCorp commissioned CODA and ENGAWA Architects to install, monitor and report on findings of local micro-climate using carefully calibrated weather stations. This unique and detailed research component to the project will enable the design team to understand the micro-climate patterns across the whole site, and the implications of designs of street networks and on houses on the prevailing breeze paths. Careful consideration of local temperature, humidity and wind speed and direction are being recorded.

Following initial investigations into availability of climatic data on the site we undertook to obtain more detailed site-specific data that was not available from the local meteorological stations in order to track breezes and gather in depth temperature and humidity information. The data so far has revealed key differences in wind direction and temperature on our site from the published data. The data will be recorded for a period of one year after which the findings will be fed into the design development process.

We are interested in this data as a way of refining the project design to ensure that all residents of Broome North have the best possible chance to respond to the climate throughout the development.

The accompanying photograph sets out the location of the weather stations.