Page 43 - BusinessWest December 8, 2025

“Operational
carbon is really
important; it
adds up over
the lifetime of a
building. But all
of that embodied
carbon happens
now.”
foam insulation is flammable, he added.
“Lots of people worry about fire, justifiably. But
compressed straw, when compressed in a panel,
behaves like timber, which means that, when exposed
to fire, it chars on the outside and protects its inner
core. With a straw panel, we can get a one- or two-
hour fire rating, so it’s actually far less fire-prone than,
say, any fluffy insulation that allows air movement,
because you need oxygen movement to fuel fire, and
when you’ve got this incredibly compressed structure
that doesn’t allow any air movement through it, it’s
really fire-resistant.
“Straw-based building systems have been used for
millennia,” Bossie noted. “But actually encasing straw
— compressing straw into a wood frame and panel-
izing it in this way — is really an innovation of the last
maybe 12 years or so. It’s a combination of two well-
worn building technologies — wood frame and straw
bale building combined into one system.
“That allows us to utilize the advantages of off-site
construction methodology, meaning that we can do all of this in a
climate-controlled environment,” he went on, while walking Busi-
nessWest through the shop where bales of hay are stacked, ready to
be compressed and panelized.
“One of the risks of traditional straw bale building, particularly
in our climate, is that, during construction, it can be exposed to a
lot of moisture. Straw panels allow us to work in a controlled envi-
ronment,” he noted. “We can compress the straw into these wood
panels, wrap those panels in weather-resistant barriers, and then
install them on site in a relatively short period of time, so that we
can limit any potential water exposure during that time. Roof panels
tend to take a little bit longer than wall panels, but we can basically
assemble this high-performance envelope very quickly.”
Building a Passion
Bossie went to school for architecture and worked in that field
for a number of years, but when he moved to Massachusetts from
Compressed straw panels, like those in this home under
construction, are both structural and insulating.
California in 2011, he ended up co-owning a company called Stone
Soup Concrete, which specializes in concrete countertops. Later,
he was project manager for a design-build company working in the
residential sector.
“That got me into building science and high-performance build-
ing. But I really felt that I wanted to push further into a values- and
mission-based structure, particularly around the use of bio-based
building materials and internal structure.”
That idea became Rare Forms, which was just Bossie at first,
actually doing the construction before the company started to grow;
it now totals about a dozen employees.
“We were doing residential design-build, primarily retrofit and
addition work to start, and then got into doing some new construc-
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