Drywall. Gypsum board. Plasterboard. Call it what you will, but it's terrible stuff.
Architect and writer Steve Mouzon once summed up its problems: "They call that boring white stuff we put on our walls 'drywall' because so long as you keep it dry, you have a wall. But just as soon as it gets wet, it turns to messy mush. And even if it doesn't fall apart, it loves to host mold and mildew and make your family sick." It's why I am always writing about alternatives from my desk surrounded by plywood and concrete block. There is also the not-so-small matter of carbon: According to the recent EMBARC study, interior finishes are responsible for as much as 10.8% of material carbon emissions in a new home.
Now, there is a drop-in drywall replacement on the horizon that actually stores carbon: Breathaboard from British startup Adaptavate.
Former plasterer and contractor Tom Robinson developed Breathaboard as his thesis while doing an MSC degree. Adaptavate has been selling lime plaster as it gears up to build a pilot plant in Bristol, England and begin production. The company recently announced it raised $2.9 million (2.16 million Pounds sterling) of investment.
“This investment will enable us to revolutionize the way construction materials are made without forcing any change on end users," said Robinson in a press release. "We’re using industrial carbon absorbing processes to produce a healthier, high performance product that is better for the health of people and planet and a genuine drop-in replacement for gypsum plasterboard. It’s a fundamental re-think and re-design of the current system and we are excited to scale this approach around the world."
The board is made of agricultural feedstock mixed with lime and pressed between paper. Robinson tells Treehugger the components might vary. In North America, they are looking at using hemp or canola stalks.
Lime (calcium oxide) is made by heating limestone (calcium carbonate) which releases carbon dioxide (CO2). In the lime cycle, CO2 is absorbed, turning it back into limestone while binding everything together. Adaptavate plans on using CO2 from the industry so it is storing carbon in two ways: in the stalks of the agricultural waste and the calcium carbonate.
In the EMBARC study, switching from drywall to compressed strawboard meant that instead of emitting 965 kilograms of CO2 in a typical house, it stored 6,357 kilograms of CO2. One would probably see similar results with Breathaboard.
Then there are all those things we hate about drywall—Breathaboard avoids most of them because, as the name suggests, it breathes. According to the company, "Breathaboard passively regulates the moisture in the internal space through its breathability and moisture buffering capabilities. Reducing pollutants in the air, the likelihood of condensation and mould or mildew occurring and occupant health problems such as asthma."
Robinson told Treehugger it is alkaline, which resists mold and bacteria. And, unlike drywall, it doesn't emit hydrogen sulfide gas when it gets wet.
Hydrogen sulfide isn't just a smelly problem—it is highly corrosive and can be flammable. That's why drywall scraps, about 10% that is lost due to cutting and trimming, can't just be thrown in the dumpster and are treated as hazardous waste. In the U.S. alone, between 2.6 and 3.12 billion square feet of the stuff has to be handled separately. This is a huge, unsung advantage of Breathaboard: It is totally compostable and is "completely biodegradable and non-toxic and the waste or off-cuts can even be used as a fertiliser."
Other benefits include reduced noise transfer, lighter weight, and better insulation properties. Like drywall, it is also fire retardant. Robinson tells Treehugger: “It has been tested in accordance with the recent standards but full-scale fire testing will be done in the next year as part of this next phase of certification. We aim for it to be as good as standard drywall and our testing to date confirms this.”
About the only issue with it appears to be that it will likely cost twice as much as the cheapest drywall. But Robinson told Bloomberg that "about half the plasterboard market is for 'premium' products that offer benefits such as better noise insulation, and that’s where Adaptavate’s climate-friendly board could compete." It is certainly going to be cheaper than some of the alternatives we have proposed on Treehugger.
In terms of carbon emissions, this is a very big deal. A study from the University of Bath, which Robinson was part of, notes that drywall "causes approximately 3.5% of the UK’s greenhouse gas emissions." The recent EMBARC study found an average home emitted 40 tonnes of upfront carbon. Because of its carbon storage capacity, Breathaboard could possibly, by my rough calculations, reduce that by 20%.
For years I have been saying on Treehugger that it is time to hang up on hanging drywall. We may finally have found a material that can replace it. It's about time.
"Emission of Material Benchmark Assessment." Builders for Climate Action.
Huang, X., and T. Tolaymat. "Characterization of Drywall Products for Assessing Impacts Associated with End-of-Life Management." U.S. Environmental Protection Agency, 2020.
"What is the Volume of Drywall Waste in America?" MCF Environmental Services.
Maskell, D., et al. "An Alternative to Gypsum Plasterboard." University of Bath, pp. 93-99, 2017.
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