Materials (Concrete and Brick)
Materials
Concrete and Brick
In making materials selections, whether for a residential or a commercial project, the building materials utilised are ideally the most sustainable possible. In this article, we examine two common materials (concrete and brick) and how they perform as sustainable materials.
Concrete
While concrete has been a fundamental part of traditional and contemporary building techniques in architecture, there are many studies that highlight the negative impacts of cement-based material production within the construction industry.
For concrete (as well as stone and other ceramic materials) the biggest concern, in relation to sustainability, is the impact of the extraction of the raw materials. Extraction of the materials transforms the ground and thereby changing the surrounding landscapes and ecosystems. In addition, because of the heavy weight of the materials, transportation over long distances can also lead to high energy consumption.
However, there can be advantages to using concrete over other materials.
The strength and durability of concrete can ensure a long life for the material, often with very low maintenance requirements. Additionally, concrete is a material with good thermal mass performance; and used strategically can result in energy savings in terms of both air conditioning and heating.
Concrete also plays a role in resilient design decisions. As a material that does not burn, and one that retains its structural integrity in cases of flood, the use of concrete can lead to minimal wastage of materials in areas that are prone to fire or flood.
Concrete also performs well in comparison to other materials when looking at acoustic performance, durability, and robustness.
Recently, with the advent of new technologies, manufacturers have been using recycled concrete aggregates which helps to reduce landfill and carbon dioxide emissions. There have been some challenges with these sustainable alternatives in matching the strength and durability of traditional concrete but research continues to find solutions to these challenges.
Additionally, it is possible to recycle concrete at the end of a project life. Often the recycling process involves crushing the concrete into concrete rubble. Recycled concrete can be used in many ways including as gravel, paving materials and aggregates.
The case for using concrete as a building material when looking at sustainability is complex and often polarizing. In choosing concrete as a building material, it is imperative to consider the source of the concrete (local is best), the reason for using concrete (for example aiding in flood resilience) and whether using concrete can aid in minimising the use of other materials on the project.
Bricks
Like concrete, bricks are a fundamental material used in both traditional and contemporary buildings.
Made from organic minerals found in shale and clay, bricks are durable and generally require minimal maintenance across the building life span. Like any other building material, locally sourcing the bricks reduces the energy consumption. Choosing to use locally-sourced, recycled bricks makes the material choice better in terms of sustainability.
Bricks have a long life span but also are reusable. Where they are not being reused, bricks are recyclable thereby minimising end of building life environmental challenges.
Like concrete, brick does not burn making it a good choice for buildings in high fire-risk zones. Bricks do absorb water and cavity brick walls can potentially trap water and lead to subsequent mould problems. This is an important consideration when making materials choices in flood prone areas and it become very important that appropriate measures are taken to waterproof the bricks.
Blockwork
Blockwork (concrete blocks) are widely used in building projects.
Because of the cement in blockwork, it has a higher embodied energy than bricks. However, it is worth noting that because the concrete blockwork only needs to be cured in low temperature kilns unlike bricks.
Like bricks, blockwork is fire resistant making it a good choice for buildings in high fire risk zones. Like concrete itself, blockwork copes well in high moisture locations particularly where appropriate waterproofing measures are followed.
Unlike bricks, blockwork will typically be finished with a render or another applied finish for aesthetic reasons. The addition of the render or finish makes the materials choice less sustainable.
Conclusion
Choosing a building material is not always a simple choice. Factors such as design aesthetics, cost-effectiveness, longevity and environmental sustainability all form a part of the decision-making process. Understanding the purpose of the building material, the ease of building with the material and how the material performs as against the building life span become important factors in the material choice.
Resilience
Resilience
Recent natural disasters including the 2011 and 2022 Brisbane floods have reinforced the importance of resilience and adaptability as key components of sustainability strategies in architecture, the built environment and design.
Increasing pressures from climate change; environmental disasters including storms, bushfires and flooding have a direct impact on our communities and the built environment. Pressures from population growth and changing community demands add to the challenging conditions. An important element in architecture is a resilient design that can adapt to changing conditions and ideally is able to adapt and recover from adverse events. So, in terms of the built environment, what is meant by resilience and resilient design? What strategies can be applied in the design process?
Resilient Design
According to the Resilient Design Institute, “Resilience is the capacity to adapt to changing conditions and to maintain or regain functionality and vitality in the face of stress or disturbance. It is the capacity to bounce back after a disturbance or interruption”.
Resilient design then is the intentional and proactive design of buildings, landscapes, communities, and regions in response to these stresses and disturbances. The aim is to create a design that has an ability to adapt to known and unknown risks and vulnerabilities such a natural disasters or other major emergencies.
A resilient design incorporates sustainability considering environmental, social, and economic factors. From an architectural perspective, and as part of the process, it is important to consider the building as a whole, the products and materials used in the building and an acknowledgement of the surrounding environment and community demands. As always in the design process, it is important to balance costs of the project across the intended operational life of the project.
The design process continuously draws lessons from existing buildings and continues to evolve into even more refined designs. Importantly, resilient design draws on the expertise of a wide variety of specialists – from architects and engineers to town planners and local councils with the aim of creating strong and inclusive communities.
As we all know, the recent floods in Brisbane were devasting for many. However, flooding in Brisbane is not unprecedented. Whilst the 1974 and 2011 floods are woven into the story of the city, Brisbane has experienced many other flood events in our (short) recorded history. Indeed, for many Brisbane residents, living on a flood plane is a reality. For people in these suburbs and communities resilient design is incredibly important. It is about being aware of the risks and planning for them accordingly.
According to the Queensland Government, “Queensland is the most disaster impacted state in Australia, with flooding being the disaster event that happens most frequently. We can’t stop floods from occurring, but we can take steps to reduce their impact. Flood resilient design is one of the many ways Queenslanders can build their resilience to floods. It involves adapting the design, construction and materials incorporated into buildings to minimise damage caused by floodwaters”.
Case Study | Local Lessons - NA House
The design for NA House was undertaken for a family whose Fairfield home was severely damaged in the 2011 Queensland Floods. Rather than simply raising and restoring their existing home, the owners were open to exploring a design approach that would help their home become more resilient to flood risks.
Acknowledging the flood risks for their home and their suburb, the design incorporated a raised under-croft space. There were a number of benefits in taking this approach. In the first instance, the top storey was elevated above the anticipated level of any future flooding. Whilst this is not a guarantee of flood-proofing, it is an effective strategy for resilient design.
An important second part of the process was to recognise that there will be flooding that occurs around the house. Acknowledging that risk, the area of the house on the ground floor was designed with water ingress in mind. The materials used, including block masonry and concrete floors, were intended to permit floodwaters to permeate the area without causing significant damage. This design proved invaluable in the recent 2022 flood event. As expected, the suburb experienced flooding again. The resilient design strategy for NA House meant that the flood waters did not reach the upper storey. The ground floor did flood. However, the owners were able to wash the flood water away and the clean-up after the event was relatively simple.
Conclusion
It is simply not possible to create a design that can cope with every unpredictable event, however with good design, we help to make sure our buildings and cities are better able to cope with disruption and bounce back afterwards. Incorporating sustainability strategies, including the idea of resilience and adaptibility into the design process will help our community to react accordingly to climate change, resource destruction and depletion, and a host of other growing challenges.
Materials (Timber)
Materials (Timber)
In keeping with overall sustainability strategies, ideally the choices of building materials are the most sustainable possible. In this article, we examine timber (and the many timber product variations) and look at the way forward for this very fundamental building material.
An important starting point in any consideration of building product is the need to understand why the material (in this case, timber/timber product) is being used. For example, is there a way of creating the design so no material is needed in the first place? Can the timber be used for several purposes in the design? Can timber be used in lieu of a man-made material?
Another critical question to consider is where was the timber (or engineered timber product) sourced and manufactured? Ideally, priority should be given to locally sourced materials. Suppliers and manufacturers should be committed to sustainability and making ethical choices. In all building materials choices, it is important to consider the sustainability credentials of the manufacturer and/or supplier. For example, do they comply with local and national industry standards? Do they support their local community? Is the timber or engineered timber product’s transportation from origin to site energy efficient? Is the packaging of the material recyclable?
At the same time, it is also important to consider how using timber or timber products can add value to the project. Will the building owners enjoy long-term value from using timber in their project? In adding timber to the project has the designed been enhanced in ways that could not have bene achieved if timber wasn’t used?
There are a number of timber and timber product options available today for use in building design.
Traditional Timber
Timber has a lower carbon footprint compared to other traditional building materials and indeed is one of the few renewable materials that can contribute to the reduction of carbon emissions. Trees actively take carbon from the atmosphere while growing, and when they are cut down for use as building materials, the carbon is ‘trapped’ and unable to escape into the atmosphere as carbon emissions.
Timber also has several other environmental advantages:
- Particularly where it is locally sourced, timber uses relatively little energy to convert from the raw material to a building product in comparison to other structural materials such as steel and concrete.
- Because it is lightweight and versatile, timber is typically easy to handle and install. This facilitates a faster and less disruptive construction process with reduced construction costs and energy consumption.
- As a naturally insulating material, timber can create a barrier between hot and cold. In particular, where focus is given to energy efficiency, the use of lightweight timber can greatly contribute to maximising comfort and minimising non-renewable energy use.
- Even though it is combustible, timber is slow, predictable and measurable in the way that it burns which means, compared to other materials, it actually performs strongly in fire events given its natural fire performance capabilities.
Where the timber is sourced from is very important. Ideally when choosing it is best to prioritise timber as follows:
- Australian recycled timber (great for building walls, cabinetry, decks, floors, beams, panels and other structures)
- Australian Forest Stewardship Council (FSC) and chain of custody certified timber (trees are renewable but forests are not)
- Australian Australian Forestry Standard (AFS) and chain of custody certified timber
Responsible forestry and sourcing of timber and timber products is an essential part of the solution to reducing harmful carbon emissions. Accordingly new timber sourced from non-FSC or AFS accredited forests should be avoided.
In addition to the source of the timber being used, other elements to consider include choosing to use mechanical fixings, avoiding adhesives and finishes that might create unnecessary maintenance issues. These choices also make it easier to recycle the timber at the end of the building’s life. Timber which has been glue-fixed can be almost impossible to later recycle.
Engineered Timber
There are a wide variety of engineered timber products available to be used across building projects. Typically an “engineered timber” product has been created from different types of timber and derivatives of timber combined with some sort of binding agent (as opposed to solid pieces of timber from a single source). The intention is to create a stable and economical product. Common engineered timber products include plywood, MDF, particle board, laminated veneer and cross laminated timber (CLT).
Many of these products can be an efficient use of natural resources. The manufacturing process can utilise otherwise unusable smaller cuts or lower grade timber and produce a product that is stable and strong.
In choosing engineered timber products it is important to choose locally manufacturing products or manufacturers that hold carbon neutral certification.
As is the case for traditional timber, it is important to avoid engineered timber products that contain timber sourced from locations where responsible forestry cannot be guaranteed.
In many cases engineered timber products have excellent strength and stability and offer decent fire resistance. Typically, because the panels arrive on site prefabricated, there is less waste on building sites.
Engineered timber flooring
Engineered timber flooring is made by fusing a thin layer of hardwood and bonding it to several layers of high-quality plywood with extreme heat. The end product is a strong, durable flooring option. Because the top veneer is solid timber, the product still has the look and character of solid timber flooring. Depending on plank thickness, scuffs and scratches can be fixed through sanded and resanding.
There are additional energy resources required to manufacture some composite timber products. Re-processing composite timber products is possible, however, the glues and other adhesives in the composition and fixing of composite timbers can hinder recyclability.
Timber and Commercial Projects
Timber has traditionally been considered primarily as a building material for residential projects. However, advances in design and technology have seen an uptake in the use of timber and timber products in commercial projects. In particular, the advent of CLT (cross laminated timber) has resulted in an increasing number of commercial developments choosing timber as a viable building material.
CLT is created by layering planks of sawn, glued timber, where each layer is oriented perpendicular to the previous. Because of the perpendicular angles, structural rigidity for the panel is obtained in both directions, similar to plywood but with thicker components; giving the product tensile and compressive strength. It is this strength that means CLT can be used, in certain cases, as an alternative to concrete and steel for all or part of a building’s construction.
Current issue - Social sustainability
PEFC, the Programme for the Endorsement of Forest Certification, is an international non-profit, non-governmental organization, dedicated to promoting sustainable forest management through independent third-party certification.
As a direct response to the aggression against Ukraine, PEFC has declared that all timber originating from Russia and Belarus is ‘conflict timber’ and therefore cannot be used in PEFC-certified products. This also applies to all timber originating from occupied Ukrainian territory.
Energy
Energy
By adopting passive design principles, we can effectively reduce a building’s energy consumption. In Brisbane, we are fortunate to live in a near-perfect subtropical climate, where it is possible for a well-designed building to be comfortable almost all year without the need for air conditioning or artificial heating. Orientating a building effectively, maximizing the use of natural breezes and sunlight, effectively shading and insulating your building, and giving thoughtful consideration to building planning, can all work to reduce a building’s reliance on artificial systems and reduce your energy use.
Quantifying Energy Use
RESIDENTIAL A number of tools have been developed in an effort to quantify the energy efficiency of a building. For residential buildings, the Nationwide House Energy Rating Scheme (NatHERS) is used. Under this scheme, energy consultants use plans and building specifications to input data into a NatHERS accredited software tool, which will generate a rating out of 10. A 1-star rating means that the home is energy hungry – and extremely inefficient. A 10-star rated home is extremely energy efficient. In other words, the closer to 10 the rating is, the less energy is needed to heat and cool the home.
In Queensland, new houses and townhouses must achieve a minimum 6-star energy equivalence rating. However, a better performing home should look to achieve 7.5 stars or above.
To encourage Queenslanders to switch off their air-conditioners and take advantage of the natural environment, the energy rating scheme provides optional credits for homes that have a deck, veranda or balcony that complies with certain requirements (adding a code-compliant roof and a ceiling fan). The idea being that the more time home occupants spend time outside (and become acclimatized) the less they are inclined to use artificial cooling.
COMMERCIAL Commercial buildings must also meet certain energy efficiency standards. One of the leading measures used in Australia is the NABERS rating system (a 1-star to 6-star rating). The system provides a rating from one to six stars for buildings efficiency across energy, water, waste and indoor environment. The intention of the system is to provide a tool to understand a building’s performance across these elements compare to other similar buildings. Energy efficient buildings are generally rated above 4 Stars under the National Australian Built Environment Rating System (NABERS).
Why is this important?
Globally, the built environment accounts for over 40% of the world’s greenhouse gas emissions. Commercial buildings alone are responsible for around 25% of overall electricity use and 10% of total carbon emissions in Australia. The most recent IPCC report shows that we can mitigate climate catastrophe, but only through immediate and radical action. The Architect’s Declare movement in Australia is calling for all new buildings to be built to Net Zero emissions, which involves consideration of the entire building lifecycle, including its operational energy use.
Whether you are looking at a residential or commercial project, it can be prudent from a commercial perspective to seek to achieve building ratings that exceed today’s minimum standards. In addition to creating an energy-efficient building today, the building is likely to continue to be a “good performer” as rating standards increase over time. Reasons to be energy efficient:
Commercial buildings - owners
- Increase building value by reducing the costs to operate and maintain the building
- Helps to attract tenants and reduce tenant turnover
- Potentially achieve higher rents and increased property value
- Goes a long way to helping you be a good corporate citizen – meeting your goals for corporate, social and environmental responsibility
Commercial buildings - tenants
- Energy efficiency means saving money on your energy bills
- Enhancing your employee’s working environment Increases productivity
- Goes a long way to helping you be a good corporate citizen – meeting your goals for corporate, social and environmental responsibility
Residential homes
- Save money by reducing your energy bills
- Increase the comfort of your home
- Improve your health by living in a healthy building
- Play your part in helping reduce our carbon footprint
- Make a house that is more resilient to a changing climate
Increasing energy efficiency in existing buildings
Applying passive design principles to new building designs will help increase the energy efficiency of the project. But what if you are looking at renovating an existing building, what options are available to help increase energy efficiency?
Insulation, windows and draft proofing
A lack of insulation, poor draft proofing and aging windows can all contribute to excessive heat loss in winter and a building that gets too hot in summer. Addressing these elements – upgrading insulation, ensuring windows and doors are properly sealed and considering window glazing options can all contribute to a more energy efficient building.
Lighting
Lighting accounts for approximately 12% of total residential energy consumption in Australia and is a significant part of the energy usage by a building. Consider switching the building lighting to a more energy efficient options (eg LED lights) to have an immediate impact on energy usage. Retrofitting the building to enhance the use of natural light, through the installation of skylights or new additional windows, can also greatly reduce an existing building’s reliance on artificial lighting.
Appliances
Improving the energy efficiency of appliances and products has significant economic and environmental benefits, reducing running costs for households and businesses. The Energy Rating Label on appliances allows you to compare the energy efficiency and running costs of appliances before you buy.
Renewable Energy
Renewable energy from sources like wind, solar and hydro provide about 21% of Australia’s electricity supply. Today Australian businesses and householders have more options than ever to supply and manage energy for their buildings. Using a renewable source for your energy supply is a step towards a cleaner environment and responding to climate change.
Passive Design
Passive Design
A fundamental element of sustainability is the adoption of passive design principles. By responding to the climate and local conditions, free natural resources (sun, wind and shade) can be used to heat, cool and light spaces.
Passive design works with these natural resources, embracing the specific location and conditions of the site. Buildings are purposely oriented to respond to the movement of the sun and the wind. In addition, the building is designed to take advantage of the daylight and the change in seasons. Passive design seeks to ensure a building is naturally cooler in summer and warmer in winter, reducing reliance on artificial heating and cooling and improving a building’s energy efficiency.
Passive design strategies are important in helping to create sustainable building solutions. Key passive design principles include:
Orientation
The orientation of a building as well as its placement on the site plays a critical role in the passive design process. Managing the amount of sun a building receives (whether to achieve cooling or heating) as well as considering access to views and cooling breezes are all part of the process. Site location and orientation are factors that are considered at very beginning of the design process, to ensure that the building effectively responds to its unique site and context.
Ventilation
Designing to take advantage of passive ventilation, particularly in subtropical climates includes maximising the building’s exposure to cooling breezes and ensuring there a good air flow paths through the building. A key to encouraging and controlling natural ventilation is through the orientation and placement of doors and windows; using differences in air pressure to move air through the building. The combination of natural ventilation in conjunction with a fan running on renewable energy can help to move air and cool spaces on hot days.
Shading and Daylighting
Shading and ventilation strategies work to keep the building cool . Strategically shading windows and openings can help to control and minimise solar heat gain. Shading can be achieved with design elements such as awnings and eaves tailored for the path of the sun across the seasons or with landscape design elements such as deciduous trees. Overshadowing from neighbouring buildings and trees is also considered.
Thermal Mass and Insulation
The construction materials used directly impact the way heat is absorbed, stored and distributed within a building. Combined with properly insulated walls and ceilings, well chosen building materials will reduce the need for mechanical and electrical heating and cooling systems. For example, dense materials such as brick and concrete absorb heat. Thoughtful designing with thermal mass enables us to control how heat is stored and released; keeping the heat inside or outside as needed.
Building Size and Passive Design
When considering larger buildings (including larger homes) it is critical to ensure passive design is at the forefront of the design. Design elements including site orientation and building materials become critical. Incorporating shading and choosing insulation that does more than simply meeting minimum requirement is essential.
Further reading:
“That’s a crazy amount of floor area”’: Top architect on boom in big homes: Julie Power.
“Bigger apartments over the past year”: CommSec Annual Home Size Report
