How To Make Hybrid Adobe

This Page Contains a Quick Summary of Hybrid Adobe Recipes and Small-Batch Manufacturing Tips

Disclaimer: This building method is relatively new and may still be considered to be in the experimental stage as builders are coming up with the best recipes for their needs, and adding new ingredients. Even though these buildings are remarkable, remember building with Hybrid Adobe, papercrete or fidobe is done at your own risk. Improperly built structures, as with any material or procedure, may collapse causing injury or death. You are responsible for the safety of yourself and those who use your building. It is up to you to build properly and safely. Adhere to local building codes where applicable.

Glossary of Terms:

Hybrid Adobe (aka hybradobe, hybridobe, and hyperadobe) is a mixture of papercrete and fibered adobe (aka fidobe). It may also include medicinal herbs, other fibers, and glass

Papercrete is made of paper, water and cement (or clay/lime mix, AKA Roman cement)

Fidobe (Fibered Adobe) is made of paper, water and earth

To try to avoid general confusion the term "Hybrid Adobe" will be used unless the application is specific to papercrete or fidobe.

Hybrid Adobe Recipes:

There is no exact recipe, allowing one to be less careful than in making concrete. If you add or forget a shovel full of clay or cement, use too much water or not enough paper, your Hybrid Adobe will still be usable, however the properties will change.

Main ingredients by Volume

Here are four typical mixes. Recipes are given in percentages, by volume. These can easily be converted into shovel-fulls or pail-fulls, for instance by calling each unit 10%. Note that Roman cement can be substituted for Portland cement if you want a more natural mix. The earth you use should have a high clay content. What is referred to as "wet paper pulp" has been drained on a screen and still contains a lot of water. Add water if necessary during the mixing to adjust the consistency depending on your application. Recipe number 1 will result in the most hard and dense material, and the following recipes result in lighter and softer finished material as you go down the list.

1. 50% wet paper pulp/ 30% damp earth/ 10% dry sand/ 10% Portland cement/
2. 60% wet paper pulp/ 20% damp earth/ 15% dry sand/ 15% Portland cement/
3. 65% wet paper pulp/ 25% damp earth/ 10% Portland cement/
4. 70% wet paper pulp/ 15% damp earth/ 15% Portland cement/

Note: Earth can be sandy dirt, clay, clay/sand mix, etc. (you don't need to purchase washed sand. Usually digging a hole in your yard will work, but conserve your precious topsoil. Some clay is beneficial. It's a good idea to screen the dirt to get rocks and debris out, especially if you are mixing a finish coat)

Main ingredients by 200-gallon mixer load:

• 1-2 large bags of Portland Cement OR use a clay/lime mix (approximately 100-200 lbs.)
• 5-25 shovel fulls of Earth
• 70-80 lbs. of paper (4-5 bundles of newspaper, approximately 12" thick)
• Approximately 160-190 gallons of gray water, city water etc.

Additional optional ingredients to be added to the mix:

• Small amounts of aggregate (small pebbles etc.) to increase thermal mass.
• Herbs (sage, eucalyptus leaves, tea tree leaves, lavender etc.)

As an optional fibrous addition to the paper pulp, one can use:

• Sawdust (sawdust has proven to be a less-than-ideal fiber. Experiment before planning your project with this.)
• Dried weeds or grass clippings
• Straw (traditional adobe uses mixed-in straw for strength, often from manure)
• Hemp fiber (an amazing fiber imported from Canada)

Additional items to be added to walls during construction:

• Glass bottles to let light through the walls.
• Miscellaneous items to embed in the walls, get creative!
• Plastic is currently not recommended due to potential outgassing of petrochemicals over time.

Suitable Paper Products for Paper Pulp:

• Newspaper (best source)
• Magazines (magazines are excellent because the magazine paper has a small amount of clay in it)
• Junk Mail (better to first remove plastic envelope windows)
• Phone books
• Office paper
• Corrugated cardboard from boxes
• Packaging boxes (egg containers, cereal boxes, etc.)

Important things to remember:

• Use at least one bag of cement per 200-gallon mixer load, any less and the material can be slowly pulled apart. A full bag is recommended.
• The more cement you use, the harder the final product will be, but there is a limit. Two bags should be plenty.
• The less earth you use, the lighter in weight the final product will be, and the quicker it will dry. If you use no earth it will shrink and potentially show small cracks. Some sand or clay is recommended.
• Experimentation is fun. Try different ratios and ingredients, and applications. There is no one way to make Hybrid Adobe, papercrete, or fidobe.
• Soaking the paper overnight will help break the paper down into a pulp and will save wear and tear on the mixer motor. This is highly recommended.
• Try to keep small rocks and other extraneous materials out of the mix before it is pulped and blended. They will only wear down your blades faster and make the motor work overtime. They can be added later if desired.
• Don't over fill your mixer with paper or water, as then you must drain some ingredients out, and that adds a lot of work.

Basic Procedure:

• Collect paper
• Create a mixer or build one with friends and share the costs
• Obtain Portland or Roman cement as your bonding agent
• Create or find forms (small cardboard boxes, old drawers, used dimensional lumber screwed together)
• Set up your work area (get screens placed over corrugated metal, tarp what you don?t want to be splattered, set up a way to reuse gray water if desired
• Soak the paper overnight
• Load the mixer with water and paper about half full
• Blend into a pulp (the consistency of cottage cheese where you can no longer read any of the newsprint)
• Add cement, earth or clay/lime mix and blend it in
• Pour the load into a draining area or directly into forms (if you use cement it is best to use the material before 12 or 18 hours passes because the cement will begin to set-up in a chemical reaction)
• Pour into forms and let dry
• Cut the material smaller (if desired) within 2-4 hours after pouring, but not much sooner
• Remove the forms after a few hours or overnight
• Place the blocks off the ground on pallets or some way to also dry the bottom. These blocks can also be baked.
• When they are hard and lightweight you can use them with the same wet material for mortar (use enough cement)
• Build your walls and finish the walls with a sheathing coat to strengthen them further

Applications for Hybrid Adobe, papercrete and fibered adobe:

• Bricks, blocks, and logs
• Tilt-up walls
• Mortar
• Sprayed walls
• Interior insulation panels
• Exterior "out-sulation" panels
• Sheathing
• Scratch coat
• Final surface
• Poured floors (use harder mix with more clay and cement)
• Roofs (recommended to be sealed, covered or in some way protected)
• Sculptures and furniture

For more in-depth information on how to make and use Hybrid Adobe, you may want to purchase The Hybrid Adobe Handbook.