Are plant based spray foam insulations environmentally
friendly? You may be surprised by the answer.
In my quest for an environmentally building insulation, I came across
this short video of my friend and the former publisher of Mother Earth News,
Bryan Welch. He and Danny Lipford of Today’s Homeowner talk about cotton denim
batt insulation and soy-based spray foam.
I had never
heard of soy-based spray foam, so I began to look into it.
Spray foam insulation benefits
- In general, spray foam insulation has
many appealing benefits, when installed correctly:
- In general, spray foam insulation has
many appealing benefits, when installed correctly:
- In new construction, it is sprayed on the
inside of exterior walls. It completely seals up the joints where air can leak
into and out of your house, wasting heating and cooling energy.
- In a retrofit, insulation is sprayed into
wall cavities by removing a small piece of siding, which gets patched
afterwards.
- For small touch-up jobs around the house,
spray foam comes in aerosol cans for homeowners.
- Spray foam insulation has an R-value of
5-6 per inch, higher than that of traditional insulation.
- It gets into hard-to-reach places around
plumbing, wiring, windows, and angles.
- Spray foam protects against moisture and
water damage, reducing the likelihood of mold and mildew.
- As all insulations, it reduces heating
and cooling bills, saving money and natural resources, and has good acoustic
qualities.
Not so ‘green’
Spray
Polyurethane Foam (SPF) is made of a blend of petroleum-based chemicals that
are mixed as they are being sprayed. Isocyanates, including MDI (methylene
diphenyl diisocyanate), are toxic and regulated by the EPA. Exposure can cause
severe respiratory and skin problems, and prolonged exposure can cause death.
These
volatile organic compounds (VOCs) are emitted during the spray process,
endangering installers. Workers need to wear respirators and be covered in
protective clothing, since the chemicals can also be absorbed through the skin.
Homeowners using canned foam are even more endangered, if they do not
understand the dangers and how to protect themselves.
Toxicity issues
Supposedly,
when the foam hardens, the chemicals become inert, making them ‘safe’. But
tests have shown that if the chemicals are not mixed in the right proportion or
conditions are not prime for application, the foam may never harden, leaving
the final product to off-gas.
Furthermore,
if some of the insulation needs to be removed for repairs or remodeling, dust
from the project can be as dangerous as when the insulation was applied. In the
event of a fire, the foam releases its locked up VOCs out back out into the
atmosphere.
The EPA and insulation
industry are aware of the problems of SPF and are testing isocyanate-free
alternatives.
Are bio-alternatives eco-friendly?
You can
probably see why soy-based spray foam insulation is so appealing to me!
Bio-based spray insulation sounds like heaven, doesn’t it? Plants are
non-toxic, renewable, and recyclable, and the great insulating properties of
spray foam are not lost.
The oil of
soybeans, castor beans, and cashew shells is extracted from the plant to
replace the isocyanates and MDI.
But! It only
replaces roughly 15%, leaving 85% petroleum based material.
The ‘eco’ in
eco-friendly spray foam insulation usually means it is sprayed with water, not
fluorocarbons that damage the ozone layer. It doesn’t mean it’s completely
plant based.
Not so good news
I wish I
could report that I found the perfect spray foam insulation. I’m pretty
disappointed to see such a large percentage of petroleum in a so-called
bio-based product.
I am so
sensitive to petroleum based products (WD-40 is not my friend!) that even a
soy-based spray foam would probably make me wheeze.
Onward in my
search for the perfect, environmentally friendly and effective insulation!
