Embrace the Elements. with Ventilated Facades.

Transcription

1 Embrace the Elements with Ventilated Facades

2 Introduction Australia is a country not known for being steeped in tradition and convention; but in our built environment, when it comes to project delivery, doing it the way we ve always done it can be the surest way to make clients feel comfortable with managing the budget. For building owners or tenants, they re invariably facing the same old challenges when it comes to insulation, keeping spaces warm, cool or moisture free, acoustically sound and sustainable. Long held beliefs in the specification of traditional products and construction methods often belie the opportunity to remedy recurring problems that happen as a result of persistently sticking with such ingrained norms. For nearly 100 years, Europeans have recognised the value of alternative methods when it comes to building facades. The changing use of buildings over many decades has meant reconfiguring the flow and layout of the build environment, where space is often at a premium; resulting in many of the problems associated with the ventilation of buildings we know today. One commonly used system in Europe has successfully addressed many of these challenges, while simultaneously lending flexible aesthetic appeal and a multitude of new design opportunities. The changing use of buildings over many decades has meant reconfiguring the flow and layout of the built environment Using the elements to make the building perform more effectively Good design will always make the most of position, space, light and the elements; so a system that can take advantage of elements like airflow and temperature to improve ventilation or natural acoustic insulation for example, should certainly feature highly on the list of any intelligent building design. 1 One such system, sourced correctly, is the ventilated façade. Often commonly known as rain-screens or double-skin facades, ventilated facades are a simple system that can make any building more energy efficient and sustainable through the systems longevity and low cost maintenance. Evolution in technological and manufacturing capabilities has meant that designers can now meet very high performance requirements of even the most demanding of building standards; matching code for fire-resistance, sustainability and structural strength that allow for contemporary creations to be both stylish and compliant. As a high performance solution for building envelopes, ventilated facades take advantage of mechanical anchoring elements, which have been used throughout Europe and the US over the last years. The connections between cladding material and the mechanical assembly, transfer loads back to the structural wall, providing a safe and secure façade. The advantages of the façade systems are wide ranging, separating materials that keep the building and insulation dry and mould-free, and anchored independently to the building regardless of the outside elements. This makes ventilated facades particularly viable in the typically harsh climates of Australia and New Zealand, where problems such as weeping walls occur; a consequence of cladding that has been directly attached and waterproofing is compromised. Worldwide testing has shown that ventilated facades thrive in extreme conditions, both across the globe and in Australia. Made form a wide range of material options, the architectural market is beginning to recognise the varying benefits of eco-friendly and fire resistant aluminium composite panels, 100% timber veneer panels, Terracotta tiles, non-combustible Rockwool cored sandwich panels and architectural glass façade systems.

3 What makes Ventilated Facades work so well? A ventilated gap between the support structure and the external cladding prevents moisture from entering the building. It does this by utilising natural wind exposure and stabilises the effects of varying temperature differences in order to create natural ventilation. Initially, ventilated facades were developed to protect buildings and outer walls from prolonged exposure to wind and rain. While these insulation advantages are evident in colder weather conditions, thermal insulation can also apply to hot and humid climates. Australia has some of the most unique and varied weather conditions in the world; materials and products must be employed to withstand whatever is thrown at them. Experiencing harsh, unpredictable and frequently destructive weather events, Australian buildings can be exposed to extreme temperatures exceeding 40 degrees and dropping below freezing within the space of a few months. Open-joint ventilated façade systems provide a number of advantages for these unique Australian conditions. One such advantage is their ability to reduce cooling loads. This is achieved by the buoyancy effect created by solar radiation within the cavity. Studies have proved that ventilated facades achieve better energy performance than traditional facades. Researchers recognised this when analysing thermal and fluid-dynamics, which demonstrate higher potential energy savings in climates with hot summers and cool winters. 2 During colder weather, thermal losses are minimised due to the uninterrupted insulation of the support structure, whether single or multi-layered, which prevents thermal bridges and eliminates heat loss from critical areas such as floor slabs and separating walls.

4 Protecting your asset Safety is always a key priority for building design; so the design and specification of quality product not only needs to look good and perform well, but should conform to current building codes. As part of the building envelope, the consequences of poorly specifying this element of the build can result in poor performance, inefficiency and higher maintenance. While obvious, the sourcing of properly certified material should never be underestimated; as highlighted in the Lacrosse Apartment fire incident in Recent research has revealed that 92 per cent of Australian building and construction companies utilise non-conforming products somewhere in the supply chain. 4 The Victorian Building Authority investigating the fire at Lacrosse is looking to take action on several fronts relating to the use of non-compliant material. 5 So sourcing a façade system from a trustworthy manufacturer and distributor is paramount. While most façade damage is the result of moisture entering the insulation and the support structure this is not the case with ventilated facades since the cladding deflects most of the rainwater, while the remaining evaporates as a result of the chimney effect created by the air circulation inside the ventilation gap. Any residual moisture still present after the construction phase, and the vapour generated by the occupants is removed. A key reason for how designers can realise conceptual visualizations into real structures is through the separate functional layers of the façade, which make for highly adaptable design, while also reinforcing structural integrity of the building. Durability is also a top consideration when façade maintenance is required. The light-weight, flexible design of ventilated facades means maintenance is much more accessible, so issues such as colour-fading can be addressed more promptly, removing the need for costly construction works. Facades can be installed quickly; further decreasing construction and maintenance time on site and, as a result, meet project schedules for both older buildings as well as retrofitting for newer energy-efficient structures.

5 Why Ventilated Facades are uniquely positioned to help overcome todays building challenges The ventilated gap, typically 20-30mm, enhances energy efficiency by retaining the heat inside the building and delaying its dissipation. While the outer cladding reflects most of the solar radiation, the cooler air circulation in the ventilated gap reduces the amount of heat which is absorbed by the building. Facades enable high adaptability with respect to the building s climate; ensuring that the insulation is kept dry to maintain effectiveness and energy performance over the long term. Condensation caused by thermal bridges or the steam impermeability in non-ventilated façade structures can have a deteriorating effect on its insulating performance. In ventilated facades, diffusion is not affected by any material layers, thus eliminating all risks regarding condensation and reduced insulation efficiency. Essentially, ventilated facades adapt to climatic conditions, where dry insulation reduces energy costs; the storage capacity of the air gap maintains a cool environment and overall air conditioning costs are lowered. Independent anchoring of the individual façade panels relieves bottom elements from the pressure of all top elements and addresses the problem of critical height. The weight of the structure not only diminishes the fundamental loading but also provides for increased rentable square feet. Cladding can dilate without restraint in spite of thermal expansion of sub-framing and panels; moreover the elasticity of the cladding system absorbs any movement of the support structure and maintains its functionality, even when tremors occur. The composition of separate layers means that facades can absorb a significant amount of noise, at least 10dB and over 20dB depending on the materials. This is extremely important in urban or industrial areas where noise can be a contributing factor. Noise reduction gives building owners more confidence in gaining tenants, higher rental returns and peace of mind. Ventilated facades have proved to be very cost effective over the long term when considering system longevity, structural separation of materials, energy efficiency and low cost maintenance. The cladding s independence of the support structure provides unlimited options for the architectural design of the façade, offering a wide selection of materials, shapes, dimensions, panels joins and colours. As a separate part of the building structure, ventilated facades can be modified or substituted over time, allowing the existing façade to be removed and recycled, thus lowering the carbon footprint of the building envelope. Ventilated facades adapt to climatic conditions Choosing the right system It is critical to engage with qualified consultants to optimize the façade performance of any building. With access to a wide range of materials in the Australian market, from eco-friendly aluminium, to timber, cement, composite, clay, glass and Rockwool, designers are increasingly turning to the product expertise of suppliers such as SGI Architectural, Australia s leading distributor of quality facades. SGI Architectural consultants can also assign various roles during the construction process: aiding designers with client expectations, as well as assisting builders with logistics and ordering, while keeping installers up to date with the latest delivery information. Capable of providing relevant tests and feasibility reporting, SGI Architectural can work to given timeframes and ensure quality installation and longevity of the product.

6 REFERENCES 1 The core concept of ventilated facades utilizes naturally occurring phenomena 2 Energy evaluation of an horizontal open joint facade 3 Docklands tower blaze exposes dirty secret of cheap cladding story-fniz9vg AIG - The quest for a level playing field The non-conforming building products dilemma Publications/Reports/2013/Report_NCP_FINAL.pdf 5 VBA Active on Cladding