Building Blog #3 – Foam Foibles / by Sustainable

Written by: Brad Tapson + Melissa Nguyen

In this series of blog posts, we answer Frequently Asked Questions, offer helpful tips and advice when it comes to how your home works – and doesn’t work! – and how methods employed by Sustainable can get you the most efficient, comfortable, and healthiest home for you and your family.


I’ve been hearing a lot about spay foam insulation lately. The handsome contractor on TV told me I should be using it, is that true?

Not exactly. We’re not big fans of spray foam here at Sustainable, but to explain why, it may help to understand why it’s being recommended in the first place. In some instances, spray foam can help to insulate hard to reach places, especially around plumbing, wires and irregular-shaped spaces. Additionally, it can make for easy installation for small renovation jobs and can be bought by the homeowner in small aerosol cans. Of course, these are all small wins in comparison to the large number of hazards it poses.


The TV Contractor seems so trustworthy! Why would they recommend something that isn’t actually good?

The underlying reasons for installing spray foam insulation are sound. In a house, air leaks mean more money being wasted in electricity and heating bills to make the interior space comfortable. By sealing these up and creating an airtight building envelope one can increase thermal performance, thereby lowering energy use. Increased air-tightness = increased heat retention and saved energy. Also, compared to traditional fibreglass insulation, spray foam is much more durable and resilient to decay, mould and pests. Evidently, its ease of installation can also be a time saver for contractors.

It sounds like these are all good reasons. Why wouldn’t I want to use spray foam?

You’re right, imaginary conversation participant! Those reasons are all great, and adding insulation to your home is one of the most effective and efficient ways to lower your energy usage and save money on your utility bills. It’s the foam itself that is the problem.

You see, spray foam has some dark secrets. For one, it is composed of many unsavoury and unhealthy ingredients. Ever noticed that professionals installing spray foam are always covered head to toe in safety gear? There is a reason for that! Spray foam is the end result of carefully curating the mixture of two petroleum-based chemicals on-site (one of which is a substance called, methylene diphenyl diisocyanate, a known allergen and toxicant). During the mixing and spraying process, toxic gas (volatile organic compounds) are emitted through off-gassing and uncured chemical dust. While the professional installer wears a hazmat suit during initial spray, uncured mixture can linger undetected for much longer – this is when it affects you, the homeowner. A horrible smell is associated with incorrectly installed spray foam even after the curing time is complete, but the smell is just a by product of the danger which include asthma, lung damage, and respiratory problems. It isn’t unheard of that people have had to abandon or evacuate their homes due to poor spray foam installation jobs. While correct installation is an extremely important process, the substance itself is no less harmful. Bad for you and the environment, it’s always better to cure the source than the symptoms.


But wait, what about all those ‘eco-friendly’ spray foams on the market? Aren’t they made of soy?

A quick search on the interweb will give you various companies promoting their ‘eco-friendly’ spray foam insulation. And yes, while these “environmentally-friendly” spray foams are plant-based and replace some percentage of the toxic chemicals with natural products, they do not replace all of them. Only roughly 10-15% of hazardous chemicals are replaced, and that’s a relatively hopeful estimate. So, while you may hear some companies exclaim that their product is eco-friendly because of its soy content, its presence is actually minimal and completely outweighed by the other components. The major percentage of toxic chemicals still results in off-gassing, which is compounded with improper installation.

And like their non-eco-friendly companions, these spray foams stick to EVERYTHING, meaning that foam-insulated building materials cannot be recycled or reused, only adding more waste to landfills.


So, if not spray foam, what can we use to insulate our home that is affordable and healthy?

At Sustainable we are huge advocates of Roxul Insulation which is a product made from mineral wool. It is made from recycled industrial waste, is non-toxic, fire resistant / non-combustible, provides a level of sound-proofing, and is able to retain its shape and insulating properties even after getting wet. This avoids Styrofoam or any other petroleum-based products. Another added benefit of Roxul Insulation is that it is manufactured locally, so fuels required for transportation to the construction site are minimized.


Another exciting option for new build homes is straw bale construction. Straw bale is a natural waste product from the farming industry that takes little energy to grow (an annually-renewable resource), easily transported and available pretty much everywhere! Additionally, straw bale is a great insulator and is extremely affordable. A great example of a project we did using straw bale construction is the Hunter House, an entirely off-grid, straw bale home, it boasts a 48% energy saving rate!


In terms of air-tightness, these efficient and stable thermal insulation methods work best as part of a building envelope assembly, in tandem with barrier systems such as Blueskin. These products keep the weather and bulk water out of your home and provide an air-tight seal that will boost your home’s thermal performance. In many cases, they come with the added benefit of being vapour-permeable – allowing your home to breathe in response to the prevailing temperature and humidity and making for a more comfortable living space. For more information on vapour-permeable barrier systems, check back in on this Building Blog in the future!


Well, I’m convinced. Spray foam seems like a good option in some ways, but the environmental costs outweigh the benefits.

Congratulations! You’re now on your way to a more efficient, comfortable, and environment friendly home through the magic of mineral wool insulation and increased air-tightness!

There are many options for home insulation and many sources of seemingly reliable information. It seems like spray foam is in the news a lot these days, but it is important to understand the underlying reasons why. Increasing air-tightness and insulation are the first things we at Sustainable look at when undertaking a renovation project, but it is important to consider how these components will affect the comfort and health of your family, and that of the environment.