Why Use Papercrete?

Kelly Hart, who is your host at greenhomebuilding.com, has been involved with papercrete from the early days of its popularization. He included interviews with papercrete pioneers Mike McCain, Eric Patterson and Sean Sands in the video he produced: A Sampler of Alternative Homes: Approaching Sustainable Architecture. He also chronicled his own use of this amazing material in his video: Building with Bags: How We Made Our Experimental Earthbag/Papercrete House. Kelly has built and used both an electric barrel mixer, and a McCain-designed tow mixer. His house is plastered inside and out with papercrete and can be seen here. He can speak from his experience with this novel stuff, and is frank about both its pros and it cons.

Questions and Answers

Q: What makes papercrete so special/unique?

A: It's plastic nature makes it adaptable to a wide range of shapes or forms; it can be shaped into building blocks or poured into forms. It is also uniquely insulating as a building material.

Q: How is papercrete used when it comes to sustainable housing?

A: Papercrete used as building material has special value because of its insulating qualities (about R-2 per inch), and because it utilizes an often wasted material, such as old newspaper, junk mail, magazines, etc. It can be used either as building blocks for walls or poured into forms for walls. Papercrete offers a fairly inexpensive way to build well-insulated walls for houses and potentially reduces waste paper that would otherwise be sent to the dump.

Q: Do you use papercrete just because it is 'green' and good to recycle newspaper or is it better as insulation than traditional mortar?

A: All of the above.

Q: With Papercrete housing can you elaborate more on the effects on the environment besides not using trees and very little cement? How else does this help the environment?

A: In addition to what you mention, using papercrete for building houses can be beneficial to the environment by:
Recycling a material that frequently gets taken to the land fill.
Creating a highly insulated building that saves energy, and thus pollution.
Using a local material that does not need to be transported great distances.

Q: How will papercrete ultimately affect the environment in the future?

Well-built papercrete homes can be energy-efficient, which is good...and they can keep some waste paper out of landfills. On the negative side, papercrete does use some Portland cement, the manufacture of of which releases a lot of CO2, a greenhouse gas that contributes to global warming. But the amount of cement in papercrete is considerably less than concrete blocks or walls. Another drawback of making papercrete is that it really requires fabricating some specialized equipment to mix it, and this equipment is not easily purchased. Ordinary cement mixers do not do the job, since the mixer needs to be able to repulp the waste paper, like a big blender would.

Q: I may be replacing my basement concrete slab (not insulated and is in contact with soil). I am intrigued by papercrete. I want to add three inches of gravel and a vapor barrier to separate the basement floor from ground moisture. Should I consider using papercrete instead of concrete for such an application (567 sq.ft.)?

A: I don't recommend the use of papercrete as a floor. It does not wear well and takes forever to dry out.

Q: Could you use papercrete to build a cheap driveway; if so how would you mix it?

A: Papercrete would not hold up over time to the rigors of a driveway...better stick with gravel, pavers, etc.

Q: If I were to build a 10,000 sf foot house from papercrete, roughly how much would I end up paying per sq feet after all the extras like plumbing, electrical, etc.? I understand it has a lot to do with the design, but I'm trying to figure out how much papercrete is going to save me on my sq footage.

A: I frankly don't think you would end up saving much at all. The walls or shell of a home represents perhaps 20% of the cost, with the rest being components that you can't make from papercrete. Then consider the cost of labor and time and materials to fabricate a papercrete mixer, mix all of that papercrete, and form it into the walls. With a 10,000sf house, this would be a huge undertaking. Why such a large house? Sustainability comes in small packages.

Q: What are the operating and capitol costs with using papercrete as a material in comparison to regular concrete?

A: Concrete and papercrete have very different properties and uses, and they cannot replace each other. Concrete is a solid masonry material that can be used for foundations, etc.; papercrete is a soft, absorbent, insulating material that must be kept away from damp situations, since it can mold and abrade. Papercrete is generally cheaper to make.