Breaking mould #2: Why architects, engineers and builders need to come to the table on moisture management and building mould proof, sustainable energy efficient houses

As the mould epidemic continues to rage this winter, experts are calling on all industries in the built environment to come together for more meaningful solutions that don’t hide behind the backs of “consumer behaviour change”. For instance, critics say the National Construction Code needs to be amended for a variety of climate zones to deal with the issue.

According to a 2016 report by the Australian Building Codes Board, 40 per cent of new houses have mould growing in their home by their first winter.

This statistic is the first thing taught to those attending the Australian College of Environmental Studies’ mould testing certification course – the only one accredited by the government in Australia. Chief executive of the college and building biologist Nicole Bijlsma said that the certification was a key solution in an industry where mould testing and remediation is not legally regulated and had no formal training requirement.

“The [remediation] industry doesn’t have any formal training,” said Bijlsma. “We don’t teach them to become architects or designers, but we’re looking at what advice to give when you’re designing a home to prevent the mould – which is really important.”

“If they did it at the design stage, we wouldn’t have a [mould] industry.”

The National Building Code could be a lot better at mould prevention

Bijlsma became interested in building biology after spending many years as a health practitioner looking to help patients chase down the root causes of mould.

• Read more on Bijlsma’s story in part 1 of breaking mould.

“It’s a systemic failure across multiple industries,” said Bijlsma. But the root source was the National Construction Code.

“Builders are complying with the code, but the code isn’t adequate. The builders I’ve talked to often express that the people designing it should have this information. [It’s] the design that ultimately needs this information, and the code needs to be updated.

“There are condensation handbooks from the NCC (National Construction Code) and the code board, which is good, but they are not legally enforceable, so until things are legally enforceable, [things won’t get better].”

“You’ve got to realise that you cannot have volume builders build [according to] one plan across a whole range of different climate zones. It just doesn’t work.”

Bijlsma added that the building industry urgently needed education and to seek out knowledge about what is happening at the ground level.

“You’ve got all these technical committees on waterproofing manuals that are out there but [again] are not legally enforceable, so very few people read them.

“We need a discussion with key industry leaders to go ‘this is a really big problem, and we need to address this’ because it’s a systemic failure across multiple industries that are resulting in very unhealthy new home housing.”

Healthy homes versus energy efficient homes – why there is conflict

There is a misnomer, said Bijlsma, that an energy efficient home equals health. “It doesn’t.”

“I definitely have very specific views about sustainability clashing with healthy homes and what’s happening in the reality of 8 Star-rated homes [when it comes to] condensation and mould.”

She added that she had found it hard to attract architects to take the certification “The architecture industry seems to be fixed on making it good aesthetically and energy efficient.”

Bijlsma said she has seen the consequences of this over the past 15 years as energy efficiency ratings became increasingly popular amongst developers, but there were not adequate design considerations to prevent mould.

This had created an “explosion” of mould because construction was so tight, with inadequate water vapour management, resulting in what she said is 40 per cent of new builds affected by mould.

“I’m all for sustainability, but it shouldn’t be coming at the cost of people’s health, which it appears to be.”

The issues and why it’s not just about the homeowners

According to certified mould technician and founder of The Mould Lady, Jodie Green, when elevated humidity indoors is sustained at over 70 per cent, there can be issues with hygroscopic (moisture prone) building materials.

She previously told The Fifth Estate that a lack of knowledge among builders meant that occupants needed to spend often more money fixing and risk health issues caused by cheap and moisture-absorbing building materials.

She added that some of her clients may have houses or extensions built with timber framing that’s been left in the rain and not been allowed to properly dry out before use, which can introduce mould.

The rise of fast construction also meant less careful consideration, said Green, so one solution for renovators was to pay for a mould inspection and ask for advice on mould-resistant building materials and furnishing.

According to remediation business Mould Cleaning Australia, an average inspection fee could range between $150 to $350, with the average cost of mould removal in a small room shooting up somewhere between $500 to $2000. Many homeowners make the mistake of “a simple mop and bucket setup”, which would generally “cost more in the long term”, writes the company.

Green echoed Bijlsma’s thoughts, saying that the design process should incorporate condensation management.

However, things were different for developers, said Bijlsma. “Why not just get a building biologist involved? Depending on the size, it might only be 10 hours of work, and it makes a huge difference to the life of the building. It’s not much investment for the health of the occupants and potentially the life of the building.”

Builders, architects and engineers also need to come to the table on moisture management. Ashburner Francis mechanical engineer and environmentally sustainable design expert Lara Bailey said that it was especially important since moisture needs to be removed from interiors, ideally at the point of creation.

While natural ventilation and airconditioning can help, both can’t be run simultaneously, “if the airconditioning is running, the place needs to be entirely sealed up,” she told Facility Management Media.

It’s not easy being mould free

And the process isn’t simple.

When designing mechanical engineering services such as airconditioning, Bailey says the engineer needs to understand precisely how a building or home will be operated in reality, which may vary significantly from the intentions of occupants.

This could include a study of occupant habits, such as opening part of the building while airconditioning is running. According to Bailey, a common example was aged care facilities, where residents tend to open their windows and doors, meaning her team must design for “mixed mode services”.

A solution might include designing air locks at entrances and exits to maintain consistent internal air temperature.

Another method was integrating high tech “moisture removing systems” in commercial buildings, which had unrealistic costs for the mass market.

Other sources have argued that with a changing climate, buildings now need to be designed differently.

The downside was potentially higher costs.

Experts also say to consider these additional factors:

• Avoid an overengineered stormwater system
• a flat roof
• installing downpipes every time the roof changes in direction
• watch out for condensation in small roof cavities –condensation from the inside will undermine the energy efficiency of the house within weeks
• inadequate passive ventilation
• built in timers for moisture removing exhaust systems
• designs that favour natural cross ventilation and well shaded windows

Warning on chemicals from indoor furniture and fittings

Another problem is the supply chain.

Nicole Bijlsma said that clients often source textiles and furnishings from Asia that use unregulated chemicals such as flame retardants and formaldehyde, which exposes occupants to significant chemicals in houses that don’t have enough passive ventilation to dilute them.