What If Our Walls Were Part of the Ventilation System of Our Homes?

Not in the conventional sense of moving air through a building, but by helping to manage what is already present in the indoor environment.

It is a question worth asking because the air inside our homes can have a significant influence on our health and wellbeing. We spend around 90% of our time indoors, surrounded by materials, furnishings and building systems that all contribute to the environment we breathe.

And indoor air quality is about much more than fresh air.

Moisture and mould are a good example. The World Health Organization estimates that indoor dampness affects between 10% and 50% of indoor environments across countries including Australia, Europe, India, Japan and the United States. Its review of the evidence found that people living or working in damp or mouldy buildings have increased risks of respiratory symptoms, respiratory infections and asthma exacerbation.

A major meta-analysis of the research found that building dampness and mould were associated with approximately 30–50% increases in a range of respiratory and asthma-related health outcomes.

For people designing and building homes, these aren’t abstract statistics. They point to a simple reality: the indoor environment matters, and the way we construct buildings can influence that environment.

Moisture, mould and the buildings we create

Mould doesn’t simply appear because a building is old or poorly maintained. It needs moisture.

Leaks, condensation, inadequate ventilation, thermal bridges, poor insulation and other building conditions can all contribute to persistent dampness. Once moisture becomes established, it can create the conditions for mould and other microbial growth.

This is why good building design matters.

Managing moisture is one of the most important things we can do to protect indoor air quality. Ventilation is part of that equation, but so are building envelope design, material selection, thermal performance and construction detailing.

The goal isn’t simply to create buildings that keep the weather out. It is to create buildings that can manage heat, moisture and air in a way that supports a healthy indoor environment.

And this brings us to another part of the indoor air quality conversation: the materials themselves.

The invisible chemistry of our interiors

Even when moisture is well controlled, the air inside a building can contain a range of other pollutants.

Volatile organic compounds, or VOCs, are a broad group of chemicals that can become airborne at room temperature. They can be released by many everyday products and materials found inside buildings, including paints, adhesives, flooring, furniture, finishes and manufactured products.

Not every VOC presents the same level of concern, and concentrations vary depending on the products used, building conditions, ventilation and how recently materials were installed. But the broader point is important. The air we breathe indoors is influenced by the things we choose to put inside our buildings.

Ventilation can dilute and remove pollutants, but it raises an interesting question: could the materials themselves also play a role in managing what is already in the air?

From passive material to active participant

Traditionally, we tend to assess building materials according to their physical performance.

Does a wall provide insulation?

Does it control sound?

Can it meet fire requirements?

Is it durable?

What is its environmental impact?

These questions remain fundamental. But the idea of healthy buildings invites us to consider another dimension of performance: what does a material contribute to the environment around it?

Some materials have porous structures that can interact with compounds in the surrounding air. One process involved is adsorption, where molecules are captured on surfaces within or on a material.

This is different from absorption. Rather than simply taking a substance into itself, adsorption involves molecules adhering to available surfaces within a material.

Natural and plant-based materials can be particularly interesting because their structures contain complex networks of fibres and pores.

The potential of plant-based materials

Agricultural by-products are increasingly being explored as resources for building materials.

Straw is one example.

Large quantities of agricultural straw are produced as a by-product of grain production. Turning some of this material into building products creates an opportunity to use an existing biological resource in a new way.

Compressed straw panels transform these fibres into a functional construction material. But their potential goes beyond simply replacing another type of wall lining or panel.

The physical characteristics of the straw itself can create opportunities for interaction with the surrounding indoor environment.

This leads to a broader question about how we specify materials.

Instead of selecting products that each perform one particular function, could we choose materials that contribute to several aspects of building performance at once?

A material might contribute to thermal comfort, acoustic performance, fire performance and resource efficiency while also having properties that influence indoor air quality.

Designing for the people inside

This approach becomes particularly relevant in buildings where people spend long periods of time.

Homes, schools, workplaces, healthcare environments and community buildings are ultimately designed around human occupation. Their performance matters because people experience these environments every day.

For architects and designers, this creates an opportunity to think more holistically about specification.

Sustainability, thermal performance, acoustics, fire safety, moisture management and indoor air quality are often treated as separate considerations. Yet the materials selected for a project can influence several of these areas simultaneously.

This doesn’t mean a particular wall material can replace mechanical ventilation or air filtration. It can’t.

Good indoor air quality still depends on appropriate ventilation, moisture management, source control and good building design.

But material selection can form another layer of that strategy.

Rethinking what a wall can do

Perhaps the most interesting part of this conversation is the shift in perspective.

We often think of a wall as an enclosure. It separates inside from outside, divides rooms and provides a surface for finishes and fixtures.

But a wall can do much more.

It can help regulate temperature.

It can control sound.

It can contribute to fire performance.

It can be made from renewable or recovered resources.

And, depending on the material, it can interact with the air around it.

This opens up an interesting direction for healthy building design: instead of relying entirely on mechanical systems to correct the indoor environment, we can also consider how the building fabric itself can contribute.

The future of healthy buildings is unlikely to come down to a single technology or material. It will be about combining good ventilation, moisture control, thoughtful design and materials that perform well across multiple measures.

The question is not whether our walls can replace ventilation. They can’t. The question is whether we should expect more from the materials that make up our homes.

Where prefab panels fit in

This is one of the ideas behind Durra Panel, a building panel manufactured from compressed agricultural wheat straw.

Independent testing reported by Durra Panel found that the material reduced airborne VOC concentrations by up to 86% under controlled test conditions. The testing examined reductions in a range of VOCs and compared Durra Panel samples with a control environment.

Durra Panel has also developed the Wellness Wall, which incorporates biochar, a highly porous, carbon-rich material intended to further support the adsorption of airborne VOCs.

The concept is interesting because it broadens the way we think about building materials.

Rather than asking only whether a material can meet the technical requirements of a wall, we can also ask what else it might contribute to the people and environment around it.

Healthy buildings will always need good ventilation, moisture management and sound building science. But perhaps we should also start thinking about the walls, floors and ceilings as participants in the indoor environment — not simply the things that contain it.

Learn more about the Durra Panel Wellness Wall and its VOC testing.

References

World Health Organization: Guidelines for Indoor Air Quality — Dampness and Mould

WHO evidence review: Health effects associated with dampness and mould

CDC: Health Problems Associated with Damp Buildings and Mold

Fisk et al., Meta-analyses of the associations of respiratory health effects with dampness and mold in homes