We Spend 90% of Our Lives Breathing Our Buildings. What Did We Build Them Out Of?

A few years ago, the office next door to mine had their timber floors varnished.

I didn’t see it happen. I didn’t need to. I walked in the next morning, and within an hour I had a headache that stayed with me for days. Not a niggle — a proper, violent, can’t-think-straight headache. It was horrible.

I’m more sensitive to this than most people. Varnishes are the worst of it for me, but they’re far from the only thing; there’s a long list of ordinary products that will set me off. For years I assumed that was simply my problem to manage.

It isn’t. I just get an early warning most people don’t. It’s made me think about healthy building materials a lot longer, and a lot harder, than most people ever have to.

Because healthy building materials aren’t a niche concern for the unusually sensitive. We spend around 90% of our lives indoors. That is the overwhelming majority of every breath any of us will ever take, drawn inside a box we assembled out of glues, sealants, paints, finishes, foams, and engineered boards — most of which nobody, at any point in the process, asked a single question about.

We check the label on everything except the house

We read the ingredients on a jar of pasta sauce. We look up what’s in our shampoo. We have strong opinions about seed oils.

Then we sign off on an entire house — the thing we will spend most of our lives inside — without ever asking what’s in the adhesive under the floor our children will be crawling on.

It isn’t carelessness. It’s that nobody tells you it’s a question you’re allowed to ask. Selections meetings are about colours and finishes and handles. They are rarely about emissions. The tin gets specified by someone who has never met you, chosen on price and coverage, and by the time it arrives on site, the decision was made months earlier — nobody ever stopped to check whether it counted as one of the healthy building materials your home actually deserves.

The bit that surprises people: Europe wouldn’t let you buy some of it

Here’s what most Australians don’t know.

In the European Union there are legally binding limits on how much VOC a decorative paint or varnish is allowed to contain. Not a guideline — a condition of being allowed to sell it at all. Matt interior wall paint is capped at 30 grams per litre. Interior and exterior trim paints and varnishes are capped at 130. Exceed the limit, the product cannot go on the shelf. From August 2026, the EU is also restricting formaldehyde emissions from wood-based panels and other products.

Australia has nothing equivalent for what is actually in the product. We regulate industrial emissions reporting, and we set workplace exposure limits for people handling this stuff professionally. But there is no mandatory national limit on the VOC content of the paint an ordinary person picks up on a Saturday morning. That space is filled instead by voluntary schemes — APAS, GECA, Green Star and the various third-party certifications — which are genuinely good, and entirely optional.

Which means a fair number of products sitting on Australian hardware shelves right now could not legally be sold in parts of Europe.

We aren’t choosing between safe and unsafe products. We’re choosing blind, because nobody here is required to tell us which is which. Healthy building materials shouldn’t be something you have to go looking for — they should just be what’s on the shelf.

Airtightness changed the maths

There’s a second thing going on, and I want to be careful with it, because it gets misread.

Over the last couple of decades we’ve made homes considerably more airtight. That is a good thing. It’s why a well-built home today is cheaper to run, quieter, more comfortable, and free of the draughts that made older houses miserable to live in.

But a leaky house was accidentally diluting its own indoor air, all day, every day, using your heating bill to do it. Seal that house up and whatever the materials release now stays in the room with you.

The answer isn’t to go back to draughty houses. It’s the two things that should always have travelled together: choose healthy building materials that emit less, and ventilate deliberately rather than by accident. A proper mechanical ventilation system brings filtered fresh air in continuously and takes stale air out — which is precisely why every Passive House has one.

Airtightness without ventilation is the problem. Airtightness with ventilation is the entire point.

What we did in our own homes

I’d love to tell you I worked all this out professionally. Honestly, my nose got there first.

When we renovated our old house, we finished the timber floors with natural oils rather than a conventional varnish — partly because I knew exactly what a freshly varnished floor does to me, and partly because once you start paying attention to one product you find yourself looking at all of them. We became far more deliberate about what we specified: the adhesives, the sealants, the boards, the finishes. Not everything, and not perfectly. But on purpose. In hindsight, that was just us learning to prioritise healthy building materials, one room at a time.

When we built our own Passive House in 2022 with Hamish and the team at Sanctum Homes, that thinking was in the project from the very beginning rather than bolted on at the end. It’s so much easier that way. Specifying low-emission materials from the start costs little more than specifying whatever happens to be standard. Changing your mind after the builder has ordered it costs a great deal.

And the house is calm to be in. That’s the part that’s hard to put in a spreadsheet.

What to actually ask for

If you’re building or renovating, here’s where to spend your attention — in rough order of how much difference it makes for how little effort. Really, it’s just a shortlist of healthy building materials worth asking for by name.

Paints, varnishes and floor finishes. The single biggest lever, and the easiest swap. Ask for low- or zero-VOC paints, and consider natural oils or hard-wax oils on timber floors instead of polyurethane.

Adhesives and sealants. The forgotten ones. Nobody ever asks about the glue, and there is a surprising amount of it in a modern house — under the flooring, behind the tiles, around every window.

Engineered boards. Particleboard, MDF and plywood are held together with resins. Ask for low-formaldehyde grades (E0 or E05) rather than whatever turns up on the truck.

Soft finishes. Carpets, underlay, vinyl and synthetic textiles all emit, and they cover very large areas.

Ask for the certificate, not the adjective. “Low-VOC” means nothing legally in Australia — anyone can print it on a tin. What means something is third-party certification: GECA, Global GreenTag, Greenguard Gold, Eurofins Indoor Air Comfort, Blue Angel, natureplus. Ask for the certificate or the emissions data sheet. A good supplier will have it ready.

Use the tools that already exist. Evitat is an excellent Australian resource for exactly this — a platform that pulls together verified data on the health and environmental credentials of healthy building materials, so you can compare options properly instead of trusting the marketing. It’s built for designers and specifiers rather than homeowners, and there’s a free tier if you’d like to look around yourself. If you’re working with a designer, ask whether they use it. It turns “I think this one’s alright” into something you can actually check.

Ask early, and put it in writing. Materials get locked in at documentation and specification stage — long before anyone turns up on site. Written into the specification, it costs almost nothing. Raised during construction, you’re asking someone to send things back.

Then let it breathe. Even good materials emit most in their first few weeks. Ventilate hard before you move in, and keep ventilating properly afterwards.

The question worth asking

None of this requires you to be sensitive, or unusually cautious, or willing to spend more.

It requires one question, asked early enough to matter: what is this actually made of, and what will it be releasing into the air we breathe? Ask it consistently enough, and you’re most of the way to choosing healthy building materials without ever needing to become a chemist.

Most people never ask it. Not because they don’t care — because nobody ever told them it was a question.

Now you know it is.

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Have you ever walked into a freshly painted or renovated room and felt something you couldn’t quite explain? We’d genuinely like to hear about it — come and tell us in the reimagined sustainable living tribe.

~ reimagined habitat