What is Papercrete?

The vast majority of homes built in the United States are stick-built, meaning that the structure of the home is made from 2x4s, sheets of plywood, and other lumber. According to the National Association of Home Builders, the typical 2,000 square foot house uses around 16,000 board feet of lumber. When translated into standing trees, it comes out to be between 50 and 60 trees that need to be cut down, milled, and transported to build the average home.

Sustainable forest management can help limit carbon emissions and other harmful effects of the logging industry. The hard truth is that humans cut down an average of 15 billion trees each year. According to a research report published in the journal Nature, the global tree population has fallen by 46 percent since the beginning of human civilization.

We use trees to build houses, but at the same time, the logging industry cuts down billions of trees each year for the paper industry. During the last 40 years, world consumption of paper products has grown by 400 percent, and 35 percent of all trees cut down (over 4 billion trees each year) are used in paper industries worldwide. The average American uses upwards of 680 pounds of paper products each year. Most of this paper ends up in our landfills, and paper waste accounts for about one-third of all municipal waste.

What if we could find a way to turn the paper waste that flows through our homes and offices into a sustainable building material? Instead of cutting down billions of trees to make 2x4s, sheets of plywood, and paper, what if we could recycle some of this material into home construction products that reduce our demand for lumber?

What is Papercrete?

Papercrete is an innovative construction material that consists of re-pulped paper fiber that is stabilized with Portland cement and/or clay soil. While papercrete was first experimented with during the 1920s, it has recently made a comeback as a sustainable construction method that has the ability to recycle millions of pounds of paper waste.

How is Papercrete Made?

Papercrete is made by gathering recycled paper from newspaper offices, junk mail, used phone books, etc.. Then, a mixer is used to turn the paper into a fibrous pulp. Portland cement is then mixed with this pulp, and the mixture is placed in forms to dry in the sun. The procedure is similar to the process for making adobe blocks. The result is a 10 to 12-inch block material that can be used to build walls, and that has an estimated R-value of 2-3 per inch of construction. This compares favorably to a 12-inch cinderblock that has an R-value of only 1.89. Papercrete is also lighter weight than a comparable adobe brick or concrete block, making it easier to assemble and less expensive to transport.

Is Papercrete Waterproof?

Due to its water absorption rate, papercrete should not be used for external walls and near-ground walls unless the surface of the walls is waterproof. A research paper from Heriot-Watt University in the United Kingdom also found that using silicon or epoxy also aided to waterproof papercrete. When considering waterproofing agents, it's important to select a method that is non-toxic and will not off-gas.

Is Papercrete Fire Resistant?

Papercrete is fire resistant. Fire resistance can be increased by adding more Portland cement or mineral material. Unlike wood, which, when on fire, can spread quickly, will often smolder in a confined area resulting in less damage. Professors from CSMSS Polytechnic College and Government College of Engineering in Aurangabad, India, found that coating papercrete with boric acid and borax could make papercrete blocks fireproof. They also found that coating papercrete with a concrete sealer made the blocks waterproof.

Is Papercrete Load-bearing?

Mixing additional sand increases the compressive strength of papercrete. Nonetheless, it is not a load-bearing material. For this reason, it is not approved by the International Council Code and cannot legally be used to support a roof in most U.S. cities. The most extensive use for papercrete is as an infill for homes.

Interview with Barry Fuller 

Rise recently sat down to talk with Barry Fuller, an expert in papercrete construction. Barry runs the website Living in Paper, which, besides offering basic information on this innovative home building alternative, also offers in-depth studies related to the structural integrity of papercrete. Barry has traveled across the country to interview people who have built papercrete buildings and homes. Barry made a model papercrete test structure called Paper Palace One. It was electronically tested for three years to research the structural and livability conditions.

Could you explain to us the basics of papercrete construction?

Papercrete construction is building homes and other structures from recycled paper. In the United States, we discard enough paper each year to build a wall 48 feet high around the country's entire perimeter. Even though about 45 percent of discarded paper is recycled annually, 55 percent or 48 million tons of paper is thrown away or goes into landfills. Figuring conservatively, it takes about fifteen trees to make a ton of paper. That means that 720 million trees are used once and then buried in a landfill each year.

How many buildings across North America use papercrete?

There are hundreds of homes built with papercrete, most of them in the Southwest, but some in northern locations like Washington, Oregon, Wisconsin, and even upstate New York.

How does papercrete construction work in terms of insulation?

Papercrete has been tested by several people with differing R-Value results. Papercrete made with sand is denser and has a lower R-Value. R-Values of 1.7 to 3.1 per inch have been reported.

Where do people who build with papercrete source the paper they need?

Some people get paper from their local newspapers; others collect it from their neighbors, and some purchase it by the ton from recyclers or brokers like Waste Management.

Can you tell us how your Paper Palace One was electronically monitored and what the findings were in relation to the structural properties of papercrete?

We installed a Data Acquisition System in the test cottage we call Paper Palace One (PP1). Sensors were implanted in the walls and roof, and an energy monitor was installed in the electric panel. We measured heat transfer, moisture penetration, creep (meaning structural movement), and energy consumption.

A weather station was attached to PP1, and its data fed to the Data Acquisition System (DAS). That way, we could monitor the effects of weather on the readings sent from the DAS. For example, we would expect there to be increased moisture readings if it were raining outside.

We monitored the data for three years and found that:

• There was no structural movement (creep)
• Moisture never penetrated the walls or ceiling (that is true to this day—eleven years after construction)
• Energy consumption to keep the structure 75 degrees year-round was 6kW per day. At the time, that was 66 cents per day or about $19.80 per month. PP1 is 500 square feet, so a home of 2,000 square feet would have run (at that time) about $80.00. That’s pretty good, given that it costs me about $500/month in summer for 1800 square feet.

We read that you are currently planning Paper Palace Two, a 5,500 square foot zero energy home. It is being made with a new form of papercrete called BetR-blok, engineered to meet building codes everywhere. What is the BetR-blok, and in what ways is it different enough to pass building codes?

Most localities require that papercrete construction be done using the post and beam method. PP1 was built without post and beam, but it was an experimental structure. Our new iteration of papercrete called BetR-blok (pronounced better block) is manufactured with sufficient load-bearing strength to be acceptable to the codes without using the post and beam method to support the roof.

In what ways is papercrete construction more sustainable and environmentally friendly than traditional house construction?

Papercrete uses waste but never becomes waste. We can use old blocks to make new ones—so there will be no papercrete construction waste in landfills. While there are many other reasons, one main reason is that the foam products used in traditional home construction for insulation and waterproofing are hazardous materials. They are persistent in the environment (they do not break down or decompose) and can give off lethal gases if they catch fire.

Bottom Line

Papercrete construction is an innovative home building material that can help reduce waste and our reliance on cutting down trees. Indeed part of the future of our circular economy. If you are considering building with Papercrete, though, it’s essential to check with local building codes to make sure it has been approved, as more innovative products are often more slowly adopted into practice.