How EIFS Cladding Can Enhance Building Envelope Performance 4

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Wednesday, April 6th, 2016
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The latest round of high-rise fire disasters involving sub-par cladding materials serve to highlight the potential sustainability and efficiency advantages brought by better quality systems for covering building exteriors.

While traditionally considered to be a cut-and-dry construction material whose sole purpose is to provide protection against the rigours of harsh weather, cladding can also serve a highly effective means of improving the sustainability and efficiency of buildings themselves.

This ability of cladding to play a greater role in enhancing the building envelope is perhaps highlighted by the recent safety failings of exterior wall installations in Australia and other parts of the world. Sub-par cladding has actually contributed to fire disasters in both Melbourne and Dubai in recent times, while it was recently revealed that Victoria’s tallest building is decked out in flammable product.

The dilemma of sub-par cladding would appear to be more widespread that previously anticipated, with a recent audit by the Victorian Building Authority uncovering a slew of non-compliant buildings in the heart of downtown Melbourne.

Instead of turning to sub-par material to cut down on short-term overhead, designers and developers could instead be availing themselves of higher quality cladding systems to shore up the safety, sustainability as well as aesthetic appeal of their building exteriors.

Some of the higher quality exterior insulation and finish systems (EIFS) serve as perhaps the best examples of cladding options currently available on the market which can serve to improve building performance across a broad range of areas.

EIFS are non-load bearing building cladding systems made from integrated composite materials. They generally consist of insulation boards made using materials such as expanded polystyrene, adhesive or mechanical fasteners that attach these boards to a substrate, as well as a reinforcing mesh to shore up resistance to fire or external impact.

Base coats are added to improve weather resistance and further secure the reinforcing mesh, while a finishing coat can be used to raise durability as well as impart aesthetically pleasing design qualities.

EIFS have been employed in North America since the 1960s, becoming a particularly sound option for wood-framed buildings toward the end of last century. Historic issues with water infiltration have led manufacturers to include drainage planes in the products, permitting the discharge of water to the rear of the cladding during heavy rainfall.

EIFS possess particularly strong insulating properties that can improve the efficiency performance of buildings.

The continuous insulation (CI) which is an intrinsic part of these cladding systems serves to reduce air leakages and eliminate thermal bridging almost completely, dramatically reducing heat flow between building interiors and the outside environment.

The continuous insulation provided by EIFS as a system external to the building structure stands in stark contrast to traditional insulation that is installed within wall cavities, the effectiveness of which can be significantly comrpomised by thermal bridging.

The enhanced insulating ability of EIFS can dramatically improve building efficiency when it comes to both the heating and cooling of interiors, thus reducing the burden on the HVAC systems which comprise a primary source of energy consumption by built environments.

The ability of EIFS to improve the energy efficiency of buildings has long been known by the North American construction sector, which was on the verge of making the cladding system a mainstay product in the wake of the 1970s oil crisis that left consumers with increasingly hefty energy bills.

In addition to the elimination of thermal bridging, EIFS can serve to improve the efficiency of the building envelope when it comes to mitigating other forms of interaction with the surrounding climate or outside environment.

EIFS can control the flow of water vapour, thus preventing problems caused by the accumulation of condensation within building interiors.

Moisture reduction is particularly important for building durability and long-term performance, given the damage that mould proliferation can cause following the buildup of condensation. The moisture prevention capabilities of EIFS can be improved via the addition of vapour control layers where required, while condensation potential is further reduced via isolation of the insulation from the stud-cavity wall construction.

The superior insulating properties of EIFS can also improve acoustic control and help cut down on noise pollution, thus improving the comfort of building interiors for occupants.

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4
  1. Leighton

    Very saddened to see this push for the use of EIFS. Yes, it has good thermal properties, but one would certainly not use it in a high wind area such as cyclonic Australia. I did several damage surveys with the AAWE and others organizations after hurricanes, like Andrew and later, events in the US (mainly Florida, Texas and Louisiana) and routinely EIFS was ripped off the sides of modest height commercial buildings. I sincerely hope this product does not make inroads into cyclonic locales in Australia; that would be huge error.

  2. Graeme Doreian

    Polystyrene you must be kidding, polystyrene, burns creating thick toxic smoke last time I burnt some.

    Can or does polystyrene have fire inhibitors in the finished product, and can the toxic smoke be eliminated?
    If not.
    Why are we allowing this product in building, again if it has no safeguards in its manufacturing.

    Even though there are further layers of material covering the polystyrene ON THE OUTSIDE, there only needs to be an open area and fire can move to the exposed back and cause the polystyrene to burn from behind towards the outer protective layer and spread rapidly depending on the ferocity of the fire making fire fighting almost impossible at times

    As polystyrene is widely used, the potential for fire spread, once the polystyrene is ignited is no better than the non complying cladding products that have the potential for a trillion dollar repair bill, that the Chinese Government should pay Mr Turnbull.

    No wonder Trade Minister Robb is retiring.

    Standards have rushed through a new fire test method for cladding. I would suggest unprotected edges of polystyrene cladding would fail the Standards fire test. untreated.

    Most of all concerning is the thick black toxic smoke caused when polystyrene burns. I notice no one has addressed that issue in any media release, or Government discussion. WHY?

    Remember once the outside of a building is on fire, smoke will somehow enter the building, and if toxic has the ability to cause serious harm.

    • Matt

      Sorry Graeme you don't know what you are talking about
      Polystyrene is relatively non-toxic. case in point, They make coffee cups out of it. Its 100% recyclable. Unfortunately it has a bad name due to issues around disposal of said cups. There have been several campaigns trying to ban polystyrene cups. Due to this polystyrene is seen as the toxic boogyman.

      When polystyrene burns it releases mainly carbon dioxide. So technically its toxic but its the same gas which comes out your mouth.

      Building grade polystyrene has flame retardants which stop it from burning. We have conducted fire tests and the product passes without a problem.

      You should be more concerned about the carpets curtains and other soft furnishing in your house. Virtually no controls on them.

      What about the house frame made from timber!!! no fire retardants there!

    • andrew

      Completely agree with Matt. Having conducted numerous fire tests on wall systems that included polystyrene and EIFS specifically, I can attest that its fire behavior is well documented and understood. Building codes in U.S., U. K. and most other developed countries have specific requirements for fire performance on building materials. Have also investigated many actual building fires and when properly installed, the actual fire behavior matches very closely to the lab tests. As far as toxicity, polystyrene is classified as "not more toxic than burning wood". As with any fire, carbon monoxide is given off, but burning of polystyrene does not increase the toxicity of the fire. There is smoke given off, which may be an issue for interior uses, but when used in exteriors it would not affect life safety.