Paper homes

Our culture doesn't look kindly on homes built of unusual stuff. Even fairy tales frown on them: The big bad wolf blew right through that piggy's straw house. Ditto the porker's house of sticks. And the old woman who lived in the shoe? She didn't know what to do. A house made of paper would then sound crazy, right? Hold on.

Buildings made of paper are real -- and they don't simply turn to mush in a rainstorm. The most well-known of these, the shelters designed by Japanese architect Shigeru Ban, are crafted of cardboard tubes. Resilient and sometimes elegant, Ban's designs have housed people after earthquakes in Japan, India and Turkey.

A handful of paper homes in the U.S., including an experimental one at the University of Arizona, also have been constructed of baled wastepaper.

But perhaps paper's most promising use in home construction is as a key ingredient in what's often called "papercrete." In a nutshell, it's an industrial-strength papier-mâché that can be made by almost anyone, cheaply, formed into blocks and used like bricks.

"The interest in this has exploded in the last three years worldwide" as people look for cheaper, more environmentally friendly ways to build, says Barry Fuller, alternative building specialist and creator of the Web site "Living in Paper."

Papercrete's reach is still extremely small, but it's growing: from fewer than 20 papercrete structures in the U.S. three years ago to around 100 now, according to Fuller. He's also consulted with papercrete enthusiasts across the world, from South Africa to Great Britain.

A simple mixture

In its purest form, papercrete is simply paper, water and Portland cement. People often add sand for extra strength, fly ash to make the mix set harder or dirt in place of cement for a more earth-friendly, adobelike substance.

There's some disagreement over what type of paper is best to start with -- some say newspaper, while others claim almost anything will do. (One of the first discoverers of papercrete, a printer named Eric Patterson of Silver City, N.M., used junk mail in his original recipe.) Either way, it must first get pulped with water. Since papercrete homes are almost always built by individuals, to create this mash people build what essentially are huge, homemade kitchen blenders, often in 200-gallon tubs, with a lawn-mower blade as a stirrer.

The final, oatmealy slurry is poured into forms -- usually fat bricks resembling thick boards or cinder blocks.

The resulting blocks are "like a really light-feeling pine. They sound like wood when you tap on them," Fuller says. "And they give a little bit when you push hard on them."

The blocks' drying process can take weeks, even in hot, dry weather, which explains why most papercrete homes appear in the Southwest. And a finished home often looks like an adobe building or a straw-bale home.

Surprisingly durable

If all of this sounds a touch experimental, it should. Papercrete hasn't yet been tested for its use as a building material -- at least to the evaluation standards of the International Building Code, which is used by most of the country. In fact, there's not yet even any established means for evaluating papercrete as a building material. Only when it's been tested successfully might the IBC be altered to accommodate it. This entire process is expensive and can take years, those familiar with the process say.

Still, papercrete might surprise you in a number of ways, including its response to the elements:

• Fire. You might think a house made with paper would be a tinderbox. Not so much. "The blocks will burn, if you throw them on your campfire," says inventor Patterson. But when a flame is held to a wall, the papercrete mostly just smolders, say those who have tried it. And some who've worked with papercrete say brushing boric acid on blocks around outlets and other more fire-prone areas fireproofs them.
• Rain. Water isn't the nemesis you might guess, either. While papercrete enthusiasts say they wouldn't necessarily encourage someone to build a home in the rainiest climate -- say, in a rain forest -- structures are going up everywhere from rainy western Washington state to thunderstorm-prone Missouri. Some experts do advise using sealant on walls, though, and not using papercrete as an outer roofing material.

Overall durability seems good, too. In his search for old papercrete structures, Fuller found a large, abandoned sheep-shearing shed with wings made of papercrete north of Alamosa, Colo., built in a floodplain, that he guessed was at least 20 years old, and made by another papercrete innovator, Mike McCain. Other than some cracks in the stucco, "it was in remarkably good shape,” he says. "The wood trim on it was in much worse shape than the papercrete itself."

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