Innovation built on experience

Cladding must be removed as a priority

Cladding must be removed as ‘a priority’, Grenfell fire expert says

Flammable cladding must be urgently removed from Melbourne’s skyscrapers, says the engineer the British government turned to in the wake of the deadly Grenfell blaze.

Dame Judith Hackitt spent a year investigating Britain’s building regulations and fire laws after 72 people died in the devastating fire at the public housing tower in London.

Grenfell was covered in the same sort of highly flammable cladding that has now caught fire at two Melbourne towers, and Dame Judith says action needs to be taken quickly.

“With regards to cladding specifically in Victoria, provided it is clear what can and cannot be used, replacement of existing non-compliant material should be pushed as a priority,” she said.

“The challenge will be who pays for the remediation.”

Dame Judith has found many similarities between the construction industries in Britain and Australia.

Last May, she told a House of Commons committee that there were extraordinary parallels. “They have exactly the same problems with the system; no enforcement, unclear standards and a race to the bottom,” she said.

Dame Judith, who was brought to Australia this week by RMIT’s School of Property, Construction and Project Management told The Age on Monday that in Britain she uncovered “a system that simply doesn’t work, that is broken in many different ways”.

Grenfell tower

The school’s head, Ron Wakefield, said the issues Britain was confronting post-Grenfell were identical to those Melbourne faced after the Lacrosse fire in Docklands in 2014 and this month’s Neo 200 cladding blaze in Spencer Street.

Many residents of the Neo 200 building, which caught fire on February 4, remain locked out of their apartments. Eight of the units will be unusable for up to a year while repairs are made.

Hundreds of other buildings across Victoria, including hospitals, remain covered in banned cladding materials that catch fire easily and burn ferociously. Few have immediate plans to tackle the problem.

Professor Wakefield said the scale of the flammable cladding problem meant the industry needed to change. “Part of us getting [Dame Judith] out was to try and build impetus and for the industry to take this seriously,” he said.

Dame Judith said builders and building designers in Britain took many shortcuts, and that “gaming of the system” was a constant. She said there appeared to be very similar problems in the Australian system where, like England, there was a focus on “box ticking” regulatory requirements, rather than a focus on building safety.

“Construction safety is too focused on the workforce, not those who will use the buildings,” she said.

Britain’s privatised system of building surveying and inspection is similar to Australia’s, and Dame Judith said this was not a problem if handled correctly.

“Inspectors in the private sector … have to be part of the regulatory side of the equation, not working for and in the pay of the construction industry,” she said. “That’s a clear conflict of interest.”

And she said, as in Australia, Britain’s enforcement of unsafe building practices was simply “not there – because it’s under-resourced”.

When things do go wrong on Australian building projects, it is often unclear precisely who should take responsibility.

In the tribunal hearing over 2014’s Lacrosse building fire, the developer, builder, architect, fire engineer and building surveyor have, in effect, all blamed each other.

Dame Judith said this was similar to the UK, and needed to change.

“There has to be, at every stage of a building’s life cycle, someone who is clearly identified for the safety of that building.”

She said the Grenfell fire had created a sense in Britain that “we have got to change, we cannot let this happen again. … The size of the tragedy that happened in London, that sense of shock and the need to improve, that needs to reflected around the world”.

“Some of the practices that go on in this sector, when you compare it to other industrial sectors, it’s literally back in the Dark Ages.

If [a] car manufacturer discovers a flaw with a car, they can trace where every component [came from]. If they can do that for cars and aeroplanes, why can’t we do that for buildings?”

By Clay Lucas The Age

Clay Lucas is a senior reporter for The Age. Clay has worked at The Age since 2005, covering urban affairs, transport, state politics, local government and workplace relations for The Age and Sunday Age

 Full Story @ The Age

Dame Judith Hackitt warns of Grenfell tragedy In Australia

Judith Hackitt warns of Grenfell tragedy in Australia

Dame Judith Hackitt, who led the UK government inquiry into Britain’s Grenfell Tower fire, said a similar tragedy was “entirely foreseeable” in Australia and criticised the “foolhardy” comments of politicians who said it could not happen here.

There was a “stark difference” between the urgency shown by authorities in Australia and by their UK counterparts, who had been stung to act by the cladding-related fire in June 2017 that killed 72 people, but Australian politicians could not assume their buildings were safe enough to prevent a similar occurrence, Dame Judith said.

“Although there is concern here about the problem, no one has died – yet,” the veteran engineer said in an interview on Tuesday.

“You need to see that as an opportunity to fix that before someone dies. Because knowing what we all know, such a tragedy is entirely foreseeable here.”

Her report into the Grenfell tragedy prompted the British government to, late last year, commit to all the recommendations she made to improve accountability and the quality of finished buildings. Even in the politically torn UK, there was bipartisan support for legislation due to be passed next year that will require building designs to meet demonstrable safety standards, and contractors to show they have constructed what was designed.

Dame Judith Hackitt

‘Not held to account’

In Australia, state and territory governments have committed to construction reforms proposed by academic Peter Shergold and lawyer Bronwyn Weir last year. They are due to reveal their progress this week.

The use of combustible cladding on residential buildings such as Melbourne’s Lacrosse and Neo200 towers, and the structural failure of newly built towers such as Opal Tower in Sydney, were consequences of a construction industry that was not held to account for what it built, Dame Judith said.

Some Australian politicians said a Grenfell-type fire would never happen in Australia because residential towers were fitted with mechanisms such as fire sprinklers, which Grenfell lacked.

This, however, was “pretty foolhardy behaviour”, Dame Judith said.

“You always look for a reason why it happened to them and couldn’t happen to you,” she said.

“This displacement that says ‘this couldn’t happen to us’ is pretty unhelpful. We simply do not know enough about the quality of our buildings.”

Judith Hackity warns of Grenfell tragedy in Australia

Author Michael Bleby

Finanical Review

2019 NCC has now previewed to become effective in May

The 2019 NCC has now previewed to become effective in May, with a huge swath of changes being made across all sections. In terms of the external wall envelope, these changes have the potential to bring about significant change in wall design and processes into the future.


For volume 1 of the BCA, the three main areas of change for the external envelope are fire resistance, condensation management and energy efficiency.


  • Sarking will not be required to be non-combustible, however, must be maximum 1mm in thickness with a flammability index not greater than 5.
  • A controversial new Fire Safety Verification Method CV4 has been previewed, which provides a list of fire scenarios to be considered by a fire safety engineer when developing a performance solution. The implementation of this has been deferred until May 2020.
  • The provision for Bonded Laminates has been retained. This had been proposed to be removed in the draft NCC, however at the time of the publication of the draft the ABCB stated that the removal was specifically to encourage public comment around the clause.


  • Condensation management is a new section in the BCA, requiring condensation not to present a risk to building occupants.
  • The verification method FV6 provides for the use of hydrothermal modelling (WIFI) to comply with the clause.
  • The Deemed-to-Satisfy clauses require either:
  • Pliable building membrane (i.e. Proctorwrap), that is vapour permeable in climate zones 6, 7 and 8 (this includes Melbourne, Canberra and non-coastal areas of Sydney)
  • A drained cavity separating the primary water control layer from water sensitive materials


  • Overall the requirements for energy efficiency have been lifted substantially, for both thermal performance of walls and additionally the building air-tightness.
  • External walls having the external cladding and internal lining fixed to the same metal frame now require thermal breaks between the cladding and the frame, as prescribed in J0.5


  1. Deemed-to-Satisfy will be the most common route to compliance for fire performance of external walls, as the membrane concession allows both fire performance and condensation to be addressed as DtS. If a performance solution was to be used to assess fire performance, the combustibility of a sarking membrane would need to be factored into this. Additionally, the Fire Safety Verification Method has not been popularly received in the industry.
  2. The increased focus around thermal performance and condensation is likely to create more interest in externally installed insulation and rainscreen systems, as seen more typically in Europe. These serve to move the condensation dew point outside the structure, and provide a better-insulated wall.
  3. In areas with higher wind loads or ventilated cavities, traditionally products such as galvanised sheeting have been used in lieu of sarking. The condensation requirements mean this system will no longer be compliant in many applications, and a breathable rigid air barrier or external sheathing board will be required.

Arup fire expert blames “Lack of Plan B” for Grenfell Tower disaster

Arup fire engineer Dr. Barbara Lane told the Grenfell Tower Inquiry that inadequate building regulations and the lack of a “Plan B” were largely to blame for the magnitude of the Grenfell Tower Fire.

According to Lane, compartmentation was the only strategy listed in the design, construction and building regulations for the tower.

The aim of compartmentation is to inhibit rapid fire spread throughout a building by reducing the fuel available in the initial stages of a fire, thus keeping it contained to one area. This can be achieved by using fireproof walls, floors and doors to restrict the fire.

This was the only strategy employed in Grenfell Tower, says Lane, and when this strategy failed there was no back-up plan. This was made worse by the building’s ‘stay put’ strategy, which required residents to stay in the building while firefighters attended to (what should have been) a fire in one individual unit.

According to Lane, the tower’s design did not allow firefighters to tackle an external fire, and the building was not fitted with a whole-building alarm system that would tell all residents to evacuate.

[Compartmentation] is the single safety condition provided for in the design of high-rise residential buildings in England,” says Lane.

“The statutory guidance makes no provision within the building for anything other than a stay put strategy.”

The situation was also made worse by ongoing gas pipe replacement works that had left a pipe running through multiple floors with “incomplete compartmentation works and incomplete ventilation works on the night of the fire,” says Lane.

 Lack of Plane B form Grenfell Tower disaster

Grenfell Tower Fire

Jason Jude Angello Rasquinha – Internship with Proctor Group Australia

Proctor Group Australia (PGA) and Dynamic Composite Technologies wanted to give a student at the audio and acoustics program at the University of Sydney the chance to help develop a sound proofing design for our passive ventilation system, ProctorVentient.  The University of Sydney School of Architecture, Design and Planning offer an excellent short term internship programme as part of the masters degree course.

We selected Jason Rasquinha a student pursuing a master’s degree at the university to work with us.  Under the mentorship of Arup’s Chris Field and the team members from PGA, Andy Russell and Alex George, Jason played a key role in researching the various acoustic treatment options for the Ventient system.

Starting with an identified set of acoustic materials previously researched at the University, the team collectively developed a series of prototype acoustic sleeves that could be incorporated into test modules. In order to quantitatively identify the performance of these sleeves, the team tested the transmission loss (TL) performance of many modules at the University of Sydney acoustics laboratory. The two stage testing and review process helped us to identify an acoustic sleeve with minimal compromise on air flow and also meet the needs for simple manufacturing and installation.

Through the development and testing process, the project helped Jason build on his learnings from the taught acoustics program. Jason showed great commitment to the internship and made a huge contribution to design and testing with a valuable theoretical grounding. Jason has a bright future ahead of him upon graduation we look forward to working with him in the future.  Thanks also Chris Field,  the Sydney School of Architecture, Design and Planning and the acoustics lab for making this experience possible for Jason & PGA.

Jason Jude Rasquinha
Acoustic Testing

Nationwide Condensation Survey

by Andy Russell

“Based on the nationwide condensation survey, more than 40% of new buildings have condensation and mould.”

The Australian Building Codes Board has finally published the findings of the October 2015 national condensation survey.

10 years ago, when I arrived in Australia I was told there was no condensation problem here other than indoor swimming pools and wine cellars. About 5 years ago the same people were dismissing this a just a Tasmania or Darwin problem. How I wish I have been wrong all this time, but the findings from the survey make for depressing reading wherever you are in Australia.

There are 80 pages to get through before hitting the conclusions but stick with it. As a spoiler alert, the solution is not to wait for global warming to fix it.

Andy Russell
By Andy Russell
Asia Pacific Manager

On a more positive note, the report maps out a solid 3-stage approach to address the problem and the solutions are neither revolutionary or expensive, particularly when compared to the significant benefits to building occupants, building owners and the broader community.

The report was completed in September 2016, so hopefully the ABCB have been busy over the past 14 months working out how to implement the recommendations. Only time will tell but I fear that many more lives will be significantly impacted before we get out the other side of this one.

Launch of AWS Ventient™ Integrated Trickle Ventilation System

by Andy Russell

For more details and information on how to specify the AWS Ventient system, please visit the AWS website   

For more information about Proctor Ventient click here    

Bulk Fill Versus Foil – Suspended floor insulation


Congratulations to va-Q-tec who have been named in the
2014 Global Cleantech 100 Company

va-Q-tec, the expert in energy saving thermal insulation solutions, was named in the 2014 Global Cleantech 100. Since 2009 the Global Cleantech 100 represents the most innovative and promising ideas in cleantech. Featuring companies that are best positioned to solve tomorrow’s clean technology challenges, Global Cleantech 100 is a comprehensive list of private companies with the highest potential to make the most significant market impact.

Collated by combining proprietary Cleantech Group research data, with over 11,000 nominations and specific input from an expert panel, these companies represent the most innovative and promising ideas in cleantech-the companies that are best positioned to solve tomorrow’s clean technology challenges.


By Wendy Wright
Marketing & Communications

The list Global Cleantech 100 represents 17 sectors, showing a diversity of interests and a continued focus on water & wastewater, advanced materials and other areas of sustainable innovation.

Roland Caps, CRO at va-Q-tec received the official Cleantech Certificate on October 9th 2014 in London.

Global Cleantech 100

Proctor Ventient – Natural Ventilation

Buildings are for people

Indoor Environmental Quality (IEQ)

With the focus on the environmental and economical sustainability of new buildings, it can be easy to forget that most buildings exist to provide a safe and comfortable environment for people to live and work in.

And it is not just the initial construction costs, operational and on-going maintenance expenses that need to be considered. Did you know that in a typical office building, the cost of the employees or “human capital” far outweighs that of the “building’s capital”?


By Wendy Wright
Marketing & Communications

Just as there are benefits for an appropriately designed building, there are negative costs for a poorly designed one. The introduction of a natural ventilation system can not only reduce running costs and carbon emissions, but also improve many of the key elements of good IEQ.

Natural (Passive) Ventilation

Natural ventilation has become regarded by many architects as the socially responsible alternative to mechanical ventilation in todays’ green buildings.

Natural or passive ventilation is considered a low cost energy solution, whilst providing an optimum level of thermal comfort and a healthier indoor environment by the use of a sustainable, natural resource… air!

By controlling air movement through natural ventilation, many risks associated with a poorly maintained HVAC system on occupant health, such as upper and lower respiratory ailments, eye and skin irritations, headaches and fatigue can be alleviated.


CPD Seminars

Condensation Conundrums
Where to put your insulation, vapour barriers and breather membranes

Understand and minimise the risk of condensation forming in your building projects. During this 1 hour presentation, Andy Russell from Proctor Group Australia will present topics on:-

  • Condensation principles
  • Moisture management and the building envelope
  • Consequences
  • Condensation risk
  • Addressing the risks

By Wendy Wright
Marketing & Communications

Proctor Group Australia would like to offer Australian architectural practices the opportunity to participate in a free CPD presentation at your premises. Click here to register your interest.


About the presenter

Andy Russell has worked in the field of condensation in Europe with UK based building envelope specialists A Proctor Group. Andy has also worked in Japan for 7 years including a spell on secondment to Daiwa House, a major prefabricated steel frame house manufacturer. He also conducted research into the performance of construction membranes at the Kyoto Institute of Technology. Andy has been in Australia since 2007 and was a member of the group writing the first edition of the “Condensation Handbook” published in 2011 by the Australian Building Codes Board and presented across Australia on the subject to several industry associations and as part of the 2011 Australian Institute of Architects Refuel National Seminar Series.

Andy Russell
By Andy Russell
Asia Pacific Manager

Could your home be giving you asthma?


When we think of this word images of that furry white patch that is growing from the month old pasta in the back of your fridge may come to mind, but that isn’t the only mould that could be found in your home and it isn’t the only one that could make you sick.

Being exposed to mould in your home, as a result of a condensation issue, has the potential to not only cause unsightly, fury growths or slimy patches throughout your house, it also has the potential to trigger life threatening reactions, like asthma for example.

Andy Russell
By Andy Russell
Asia Pacific Manager

In the article “Is your home harming you? Asthma, allergies and indoor mould” by John Burgess, CRE for Chronic Respiratory Disease at the University of Melbourne, you can see for yourself just how dangerous the side effects of indoor dampness can be.

As a way of addressing these issues that may lead to illness Burgess suggests, “It’s also important to address the causes of mould. This comes down to lessening indoor humidity and dampness by improving home ventilation and heating.”

So don’t wait until you’re wheezing up that flight of stairs or struggling to breathe as you lie in bed at night. Know the cause and find a fix before you health is put on the line.

Know how to identify mould growth in your home before it gets to this

Team UOW wins Solar Decathlon China 2013


Team UOW wins Solar Decathlon China 2013!
On the 11 August 2013, it was announced Team UOW as the winner of the Solar Decathlon China 2013 finals ahead of 19 other entries from around the globe.

Proctor Group Australia is very proud to have been a part of your journey.


By Wendy Wright
Marketing & Communications

Watch the video below to be part of the UOW journey.


PGA appoint CSR Bradford as the exclusive distributor of ProctorWrap

Proctor Group Australia and CSR Bradford have signed an agreement appointing CSR Bradford as the exclusive Australian and New Zealand distributor of ProctorWrap High Performance Vapour Permeable Construction Membranes.

CSR Bradford is dedicated to supplying a complete range of high performing, and technically based solutions that meet the increasing demands of energy efficient design and changing climatic conditions. Many years of research and development has gone into producing the Proctor Group Australia building membrane range and CSR Bradford will continue to be supported by Proctor’s local Technical team.


By Wendy Wright
Marketing & Communications

Products that are available in the Bradford Enviroseal ProctorWrap range include:

  • Enviroseal ProctorWrap Residential Wall (RW)
    an ideal light duty, vapour permeable wall wrap for residential properties
  • Enviroseal ProctorWrap Commercial Wall (CW)
    a light duty, higher strength vapour permeable wall wrap for commercial buildings
  • Enviroseal ProctorWrap HT-Roof (HT-R)
    a medium duty, vapour permeable roof sarking for use under tiled, slate and metal roof applications
  • Enviroseal ProctorWrap Black Label (BL)
    a sarking for use behind open joint facades to help form an air and water tight construction.

The addition of this product range further enhances the product offering available from CSR Bradford and brings together the technical knowledge of Proctor Group Australia.


Proctor Group Australia Sponsors Team UOW in International Solar Decathlon Competition

Proctor Group Australia sponsors Team UOW as they endeavour to build a net zero home for the international Solar Decathlon China competition.

Products including ProctorWrap vapour permeable membrane and DCT Tuff-R insulation were supplied to assist the team in achieving their sustainable retro-fit home.

The competition, run as a joint venture between the US Department of Energy and the China National Energy Administration, is the largest student-run competition in the world.

Held in Dantong, China it is estimated that over 500,000 people will attend the competition which spans over an area larger than that used in the Beijing Olympics.

The 30 student strong team, comprised of students from Wollongong TAFE and the University of Wollongong, aim to retro-fit an existing Australian fibro home with sustainable technologies making it the first of its kind ever entered into the competition.


By Wendy Wright
Marketing & Communications

Living Wall 1 Bligh Street Sydney and ProctorWrap Black Label

When visiting the CBD of Sydney of late I have been trying to take a detour past the recently complete office tower, 1 Bligh Street.

Designed by Architectus, in association with Ingenhoven Architects in Germany, the sustainable office tower achieved the 6 Star Green Star Office Design V2 Certified Rating from the Green Building Council of Australia and has won a series of awards recently including the 2011 UDIA NSW Awards for Excellence – Retail/Commercial Development.

Besides my interest in the double skin façade and other sustainable features, this is also one of the first projects in Australia to use the ProctorWrap Black Label – a recent addition to our range of vapour permeable sarking membranes. The membrane was used behind the green wall designed and installed by Fytogreen.

Andy Russell
By Andy Russell
Asia Pacific Manager

At 9.7m high and covering just 377m2 I was a bit surprised to discover that this is Australia’s largest green wall or vertical garden. This is a record I expect will be over overtaken in the near future if the growing interest in the media about 1 Bligh Street and green facades is anything to go by.

Plenty of positives from greens on the side, Sydney Morning Herald, David Adams, 19 Nov2011.

Erwin Taal, a landscape architect and spokesman for the Australian Institute of Landscape Architects, says wall gardens are growing in popularity.

He ascribes the demand to new products, the need to make the most of space and the environmental benefits, which can include improving air quality and filtering water runoff.

Proctor Black Label Construction Membrane

“People like the idea of a salad bar or a herb wall or something like that, rather than traditional pots or hanging gardens,” he says.

Vertical gardens can be as little as one or two square metres, or cover an entire wall or walls.


In addition to the green façade, some of the other features that led to 1 Bligh St receiving the six star accreditation are:

  • Full building height naturally ventilated glass atrium providing a flow of fresh air and a sense of openness on every floor.
  • First high-rise office tower in Australia to feature a double-skin, glass façade. The outer skin protects computer-controlled sun shades, shielding the double glazed curtain wall from the sun, whilst reflecting natural light into the building.
  • Hybrid variable air volume (VAV) with a chilled beam air conditioning system.
  • Tri-generation system that uses gas and solar energy to generate cooling, heating and electricity. The series of curved solar thermal collectors provide the energy to drive the cooling systems.
  • Black water recycling is used amongst other things, to irrigate the feature green wall, rooftop terrace and plantings throughout the building.

Also pictured here is a photo of one of my favourite green walls which I used to pass by on occasional Friday night on my way home from the Shinsaibashi district of Osaka, Japan. Not as blessed as Sydney with green spaces, the green here offers a much welcome break in the grey concrete landscape of Osaka.    


10 Critical points in rain screen details

Rain screens, while common in Europe and North America, have begun to emerge to a greater degree in discussions within the Australian architecture and design community. A rain screen system offers numerous benefits in moisture-management and energy-efficiency but when I dig deep into conversations over the past couple years with local architects, façade consultants, suppliers and installers there is a huge variety of perceptions on what “rain screen” actually means and what the key design components are.

I recently came across an excellent document jointly published by the Ontario Institute of Architects and available for free for download from the Canadian Mortgage and Housing Corporation.

Page 26 includes an excellent checklist of 10 critical points in rain screen details.

  1. Provision for water shedding at the outer cladding, away from joints, with drips under any projections to prevent water collecting at the building face.
  2. A cavity of appropriate width to allow pressure equalization across the cladding system and prevent capillary movement (allow for construction tolerances!).
  3. A continuous and effective (for example, airtight to a maximum air leakage of 0.1 L/s/m²) air barrier within the backup wall.
  4. Drainage of the cavity through continuous flashings and weep openings, and proper management of drained water.
  5. Adequate venting of the cavity provided through properly located openings in the cladding (appropriate ratio achieved between vent area and leakage of air barrier and seals).
  6. Additional provision for drainage at the backup wall (located on the “warm” side of the insulation to avoid condensation problems).
  7. Effective compartmentalization of the cavity at each building face with airtight seals, and additionally across the width of the façade as required (refer to calculations).
  8. Sufficient rigidity and/or structural support of the air barrier to resist wind loads and limit deflection.
  9. Sufficient rigidity of the cladding to limit deflection and resist wind loads as required.
  10. Special attention paid to water-resistance and drainage at building edges and parapets (areas subject to heaviest rain-wetting and wind pressure differences, where pressure equalization may not be achievable)

The National Association of Home Builders (NAHB) in the US outline the advantages of rain screen

  • It neutralizes physical forces inducing water intrusion.
  • It is a simple, forgiving system with built-in, multi-layered redundancy, and
  • It has integrated drainage and ventilation that accelerates cavity moisture removal.

Rain screens prevent or reduce moisture problems in exterior walls, including siding rot and peeling paint. Thermal shock, solar driven moisture effects, and pressure forces are diminished. In high moisture environments, the additional cost and complexity of Pressure Equalized Rain Screen construction may be cost effective over the long term.

Rain screen designs do not increase the cost of drainable EIFS and brick veneer wall systems. To install the air space behind the cladding in most assemblies, however, costs for furring or other spacer materials cause costs to increase. The few cents per square foot spent on a rain screen offer exceptional value to design professionals seeking liability protection, builders wanting to avoid call backs, and homeowners looking for comfort.

The Proctor range of vapour permeable membranes ProctorWrap High Tensile, Air Tight and Black Label can play an important part in meeting these requirements and provide a continuous air barrier. In particular the Black Label has been designed with high UV resistance for use in open joint rain screen applications.

One area of debate is if a flexible membrane can be relied upon as the air barrier in pressure equalized rain screen design without a rigid substrate. Point 8 above advises that a “sufficient rigidity and/or structural support of the air barrier to resist wind loads and limit deflection,” is required.

Studies by the Institute for Research and Construction in Canada report that the performance of the air barrier system affects the ability of the wall assembly to achieve pressure equalization across the rain screen, by reducing the flow of air through the wall assembly, and greatly contributing toward reducing the air pressure differential across the rain screen.

“Under dynamic-pressure conditions, recent IRC studies indicate that excessive flexibility of the air barrier system will result in fluctuations in the volume of the air chamber compartment. These fluctuations adversely affect the potential for rapid pressure equalization across the rainscreen.”

Chown, G.A., Poirier, G.F. and W.C. Brown, “Designing Exterior Walls According to the Rainscreen Principle”; Technology Update No. 17, Institute for Research in Construction, National Research Council of Canada, 1998.

It is clear that in order to attain the full benefits of rain screen then we need at the outset a clearer understanding of the function of the rains screen and what is required for the building envelop to function as such.

Download the full CMHC document here:

Andy Russell
By Andy Russell
Asia Pacific Manager

In over your head?

“One of the most difficult buildings to build is a building with a swimming pool because – wait for it –there is a swimming pool inside.”

Is it any wonder that heated indoor swimming pool roofs in Australia tend to have a very short life span and are a constant source of moisture and corrosion related headaches for facilities managers and local authorities that need to ensure their facilities remain open and provide a safe environment.
Next time you are at the local swimming pool take a look up the roof and keep an eye out for damp staining on suspended ceilings. If the foil faced insulation blanket is exposed, is it in good condition and continuous? At my local pool I was not surprised at what I saw.
(see images on the right of your screen)

The pool just down the road at Lane Cove has suffered corrosion, with the local council already down $1million in legal fees over the past 4 years as part of an action taken against the builders and architects.

In Victoria, closure for refurbishment of the Collingwood aquatic centre was brought forward as the council was forced to close twice in six months because of problems with a 30 year old “ageing roof structure.”

By Andy Russell
Asia Pacific Manager

In Canberra, the original Australian Institute of Sport Aquatic Centre is on its third roof since 1984 after requiring major structural work in 2010 to resolve corrosion issues resulting from condensation. This work had to be completed with the added complication of keeping the facility open.

Anyone involved in the design of indoor swimming pools or investigating condensation related issues with a swimming pool should read Joseph W. Lstiburek’s very accessible Building Science Insight which is an edited version of the insight that first appeared in the ASHRAE Journal.
“The problem is fundamentally pretty straightforward. We have a huge internal moisture load that, for once, you cannot blame on your mechanical engineer or HVAC contractor. There’s a pool filled with water in your building for Pete’s sake. You can’t dehumidify your way out of the problem; you can’t ventilate your way out of the problem. You can localize the problem by  depressurizing the pool area relative to adjacent spaces or by pressurizing a boundary space between the pool area and adjacent areas, but, in the pool area, you are pretty much toast.” 

“The problem is fundamentally pretty straightforward. We have a huge internal moisture load that, for once, you cannot blame on your mechanical engineer or HVAC contractor. There’s a pool filled with water in your building for Pete’s sake. You can’t dehumidify your way out of the problem; you can’t ventilate your way out of the problem. You can localize the problem by  depressurizing the pool area relative to adjacent spaces or by pressurizing a boundary space between the pool area and adjacent areas, but, in the pool area, you are pretty much toast.” 


“The problem is fundamentally pretty straightforward. We have a huge internal moisture load that, for once, you cannot blame on your mechanical engineer or HVAC contractor. There’s a pool filled with water in your building for Pete’s sake. You can’t dehumidify your way out of the problem; you can’t ventilate your way out of the problem. You can localize the problem by  depressurizing the pool area relative to adjacent spaces or by pressurizing a boundary space between the pool area and adjacent areas, but, in the pool area, you are pretty much toast.” 

“We need to be perfect. And the only wall that will work, of course, is “the perfect wall.” We have been here before. Put the water control layer, the air control layer, the vapor control layer and the thermal control layer on the outside of the structure.  Put everything else inside, especially the services. Same for the roof. Done.”

Got to wonder what has been going on up here?

“A few little tricks of the trade – think of cladding as a dehumidifier that sucks moisture out of the shaded stuff. That means the back of the cladding will get wet if there is a flaw in your wall. What are the odds of there being a flaw or less than perfect workmanship?  If  I  were  using wood cladding, I would not just back ventilate it, I would back-coat it with primer and paint. Just like the old guys used to. I do not want the wood to absorb water.  If it does, it can leach tannins and other water-soluble extractives. Ask me how I know?” 

“If it is cement siding, you had better coat it on the backside, as well as ventilate it. If you have brick, you had better ventilate the heck out of the space.”

“If it is metal, you had better think a lot about stainless steel and magic pookey to protect it, as well as good cladding ventilation. If there is a flaw and air gets out, the air is going to be carrying more than just water vapor: chlorine, bromine and other aggressive oxidizing (a.k.a. corrosive) agents. You ever see what they put into the water? It will eat your insides out and the insides of your wall assembly as well.”

This is all that stands between the vapour and the roof sheet
This is all that stands between the vapour and the roof sheet

The Tom Cruise Wall – High Risk Walls

Not in reference to Top Gun, but the1983 film “Risky Business,” building science guru Joseph Lstiburek in his own inimitable style has this month published his latest Building Science Insight entitled “Risky Business : High Risk Walls.”

For anyone designing buildings that incorporate tilt-up concrete walls, particularly in the colder and temperate climate zones of Australia, and plan to insulate on the inside of the panel, this very readable paper is well worth taking a look at.

Unfortunately we have seen first hand this winter, such walls going badly wrong and suspect there will be more out there. Below is an extract from the edited version of this insight which first appeared in the ASHRAE Journal.

By Andy Russell
Asia Pacific Manager
“As my friend Mac Pierce likes to point out: you could get a blindfolded drunk epileptic to cross Niagara Falls on a high wire without a net, but it wouldn’t be a good idea. There are some wall assemblies that are like that. One in particular irritates me. It has lead to a great deal of grief. It has problems that can easily be avoided. But simple analysis shows it works, and that is the rub. The simple analysis shows that it works, but the real world shows that it does not.

It gets better. More complicated analysis shows that it sometimes works, and truth be told, the real world shows that it also sometimes works. No moisture and exceptional workmanship can make it work. What are the odds? Clint Eastwood thermodynamics again: do you feel lucky punk? Well, do you?

So what does this wall look like? I am not sure what to call it. It has a face-sealed cladding (“perfect barrier”) that is impermeable to water vapor. It is insulated on the interior with air permeable insulation usually held in place between steel studs or impaled on pins protruding from the back of the cladding and covered by a vapor barrier. Let’s call it a “Tom Cruise Wall.”

The insulation is typically a fiberglass batt “smushed” between steel studs. Sometimes, it is rockwool or mineral wool pinned to the interior of the exterior cladding. The fiberglass batt sometimes comes with a foil facing – the “vapor barrier.” More often the whole kit and kaboodle is covered with sheet polyethylene that may, or may not, be called an “air-vapor barrier.” Yuck.

So what is the problem? Well, the cladding is easy to make almost perfectly airtight and the interior lining is almost impossible to make airtight. That’s it? Really? That simple? Yup. You’re kidding. Everyone knows you can’t seal plastic sheets on the inside of wall assemblies and make them airtight.”

The full paper is available from or directly by downloading here

 Tom Cruise Wall

The 'Tom Cruise' Wall High risk walls