Materials matter.
It’s why we do what we do.

Peek inside a Croft wall and you’ll find straw, sheep’s wool, and locally sourced spruce and pine from the forests of Maine. While it may seem surprising at first, these outstanding materials deliver health & performance benefits in ways that few others can.

And if that wasn’t enough, these materials also capture and store heaps of atmospheric carbon while they grow, allowing that same carbon to be safely stored inside the walls of your building for generations to come.

Diagram of a high-performance building with a chimney emitting 52 tons of smoke, illustrating 260 tons of embodied carbon released.
Diagram of a building showing that it is code compliant. The building emits 120 tons of embodied carbon and produces 59 tons of emissions from a smokestack.
A diagram showing a comparison of carbon emissions from a Croft house. The house emits 52 tons of operational carbon, while the Croft prefab building captures 146 tons of embodied carbon through the use of straw insulation in a prefab assembly.

Operational Carbon comes from heating, cooling, and keeping the lights on.

Clouds in the sky

Embodied Carbon comes from the materials the building is made from.

Blank blackboard with some writing on it
Interior view of a building under construction with wooden framing and bio-based, straw insulation material installed between the studs.

Health

Build shelter. Not too much. With mostly plants.

Why do we use plant-based materials? Because research shows these abundantly available rising stars outperform conventional, synthetic construction materials—all while avoiding the toxicity risks and performance issues that so many modern construction materials pose.

With biogenic materials like straw, there’s no off-gassing, no toxic binders, and no synthetic flame retardants—you can handle everything we use in our panels with bare skin and enjoy the peace of mind that what is in your walls has a supply chain a single link long.

A field of straw ready for harvest and inclusion in prefab construction.

Performance

Home, grown.

Straw naturally contains much of the chemistry that is artificially added to other insulation materials to help them perform.

Besides being a great insulator and acoustical isolator, straw is able to also satisfy a Class A Fire Rating (the highest rating achievable through ASTM E84 testing) due to its silica content, which it naturally accumulates from the soil in which it grows. This silica also deters pests, without needing any harmful or noxious chemicals added.

Straw does this all while capturing and storing carbon from the atmosphere and while remaining bio-degradable at the end of its service life.

A straw based structural insulated panel S-SIP against a blue sky

Environment

Good for people, planet, and pocketbook.

As straw grows, it pulls carbon out of the atmosphere through photosynthesis (3.7 pounds of the gaseous stuff for every pound of carbon in the plant). This means that straw can hold up to 60 times more carbon than is emitted through growing, processing, and transporting it to our building sites.

If that wasn’t already exciting enough, there is enough straw currently growing in the U.S. that we could super-insulate every new home constructed within our borders using only one fifth of what we’re already growing for food production. That’s the carbon equivalent of taking 4.7 million passenger vehicles off the road each year, every year.

All we need to do is stuff this plentiful, wondrous material into the walls and roofs of our buildings—making them quieter, cozier, and more resilient all in one go. How many birds is that with one stone?

Stacked hay bales on a rusty farm trailer inside a barn or shed.

Farm Partnerships

Organic, locally-grown buildings.

Croft is proud to supercharge our agricultural partners by turning construction dollars around to farms at every possible opportunity. Instead of burning through energy to make synthetic insulations, we get to ride in hay wagons, encourage the growing of more local grains, and provide a stronger local food economy to boot. What’s not to like?