This is a Vocab List for Natural &/ Passive Building- you can find different building materials and methods, as well as relevant scientific & building terminology. That being said, there may very well be more terms that I didn't include. Keep Researching!

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Natural Material | Materials not made by humans, but derived from plants, animals, and/or the earth. This definition technically includes metals that are not man-made alloys.
  Natural Building focuses on sustainability, primarily using "green" materials that are renewable, recycled, and/or abundantly available.

  Materials like sand, clay, straw, wood, stone, and wool are natural materials. You can also repurpose waste like glass or plastic bottles, aluminum cans, old tires, or broken concrete into walls or windows, in which clear, plastic waste is also often used to provide further insulation.

Thermal Mass | A material's ability to absorb, store, and release heat.
  Thermal Mass Materials must be inside the buidling's thermal envelope in order to function as a heat source. Buildings located in cold climates can still efficiently use interior walls, floors, cob furniature and/or rocket stoves as a thermal mass.
  Some natural materials that have high thermal mass include sand, clay, stone, and water.

Insulation - Material boundry used to minimize the transfer of heat, electricity, or sound.
  Some insulative natural materials include straw or strawbales, wool, plant hulls like rice or buckwheat, air, wood, and recycled cardboard or paper.
| See R-Value : "Heat Loss Resistance"

Passive Design | Building guidelines to make both comfortable and energy efficient spaces.
  Passive Certified homes have a secure, insulative thermal envelope, are Net-Zero or are close to Net-Zero while using green-energy, and have air flow circulation which does not compromise internal temperatures.

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Adobe | Also called "Mudbrick"; Sun or air-dried clay bricks. Can be mortared together to make walls.
  The term can be used to refer to earthen architecture in general or, in some regions, specific earthen architectural styles like Pueblo and Territorial Revival.

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Bale-Cob Natural wall made using cob mortar between stacked strawbales with cob style siding, offering a mix of insulative and thermal mass benefits from the materials.
A bale-cob wall can have an R-Value of ~30-35.

  Be mindful of the amount of cob when creating exterior walls without direct sunlight (ei. the Nothern wall in the N. hemisphere), as cob is a poor insulatior.

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Bamboo | A fast-growing, hollow, sturdy, & tall grass from Asia with a wide range of uses including building, cooking, livestock-fodder, crafts, & more.

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Berm | Mound of dirt;
  In building, a berm refers to a mound of earth along an exterior wall which protects the building from the outside elements.

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Burnt Timber Cladding (Method) | Timber Siding that is burnt to preserve the wood.
  Some Native Americans would use fire to hollow out the inside of their canoes, making them resistant to water.
| See Also: Shou Sugi Ban, Yakisugi

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Carbon Footprint | Measure of greenhouse gases that something releases into the atmosphere, this includes carbon dioxide and methane.
| See Also: Net-Zero

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Cellar | Portion of a building where the distance from the floor to the grade level is more than the distance from the grade level to the ceiling.

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Cellulose | In building, a blowin-in, loose fill plant fiber insulation, often sprayed with fire retardants.
  Provides an R-Value of about 3.5 per inch, or about R28 in an 8 inch wall.

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Clay | Sediment with particles smaller than silt (~ 0.002 mm). Clay is plastic while wet, but will harden when dried or fired in high heat. It is found in soil, especially near dried or existing bodies of water.

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Cob | Mixture of clay, sand, and straw, able to hold its shape. It is covered in a protective layer, like lime, and oil to protect it from the elements- linseed oil being the most popular option.
  Cob can be used as flooring, walls, or furniture, and is highly customizable. However, it is a soft building material, and can dent under heavy weight like conventional furniture. Cob and its variants have been used as a building material by cultures around the world for millennia.
  Cob is fire, mold, earthquake, and strong-wind resistant, providing many benefits as a building material.

  Cob acts as a large thermal mass with little insulation, with a low R-Value of about 0.22 per inch. Meaning a 12 inch wall will have an R-Value of about 3, but it will store gained heat and release it over time, providing comfortable living temperatures when used in warmer climates or as interior walls in cold climates.

  Cob should not be used as an exterior wall in colder climates; always check local ordinacnes for minimum required R-Value and recommendations.

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Cord-wood | Debarked tree cores mortared with cob or masonry mixes. They can be sat up side by side for flooring or stacked up core-side-out for interior or exterior walls - be mindful of pests! Cordwood walls are often built with cavities filled with insulation to provide a higher R-Value.
  A 16 inch cordwood wall with insulation can rate R16-24.

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Cooling Tube | Tube(s) placed underground used to heat or cool entering air to the temperature of the ground (~55F, dependent on location).
  Add a physical barrier and a fan to opposite ends of the tube for pest prevention and on-demand air.

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Earthbag | Bags filled with sand and clay, stones, or hulls and used for walls, foundations, and basement walls. They are tamped and secured with barbed wire.
  Earthbags with sand and clay offer high thermal mass and very low insulation, but they can also be filled with high R-Value materials like hulls, perlite, or volcanic stone for an R-Value potentially exceeding R30.

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First-Flush System | Part of a water collection system that redirects the first gallons of water that fall during rain to prevent debris from the roof from getting into the stored water. The amount of water to flush is dependant on roof size.

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French Rubble Drain | Geotextile-lined, gravel-filled trench containing a perforated pipe. Slopes redirect water to desired locations.

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Gabion | A basket or container filled with earth, stones, or other material used in building.

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Grade | Ground-Level; Elevation of material on an external wall.

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Hempcrete | Hemp, lime, & sand. It is both a thermal mass and an insulating material. Like cob or strawbale, hempcrete allows moisure to pass through, and can only be covered by materials with the same hydrophobic quality. It is produced in a facility using respratory safety equipment, transported, and pressed into a wall caste. Hempcrete can also be used as prefabricated bricks or walls.
  The R-Value of a hempcrete is about (+-0.1) R2.4 per inch, and varies based on density. A 12 inch wall can rate R25.

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Hemp Insulation | An insulation made of industrial hemp and a binder, usually at a ratio of 9:1, and using all-natural materials. Hemp is a carbon-negative, renewable resource with building benefits comparable to strawbale and cob.
  The R-Value of hemp insulation is about 3.7 per inch.

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Hulls | Also called “Husks”; the outer coating or shell of a seed. Hulls can be bagged and used as a natural insulation.
  A rice-hull-packed earthbag can provide an R-Value of 24, measuring at over 3 per inch.

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Hydrophobic | The molecular tendancy to repel water.
  Natural materials like cob, hempcrete, or strawbale have this quality. These materials cannot be covered in non-hydrophoic matierals such as drywall or latex paint. Colored lime on/or cob is used in place of paint on siding.
  Floors and walls should be sealed to protect them from prolonged moisture exposure, commonly done using linseed oil.

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Light-Straw Clay | Cob covered straw (or woodchips, ect), used as infill in a wooden frame.
  Light-straw-clay can have an R-Value of about R1.5 to R2 per inch; a six inch wall can provide ~R9 to R12.

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Living Roof | A specially lined roof that holds soil and grows living plants.
  Though poor insulators when used alone, living roofs offer a large thermal mass to slow heating and cooling of the building, absorbing heat from sunlight and from the home itself.
  They can be insulated to provide R-Value, otherwise living roofs do not insulate and have an R-Value of zero.

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Mineral Wool | Matted, wool-like, inorganic fiber made from molten material or rock material.
  The R-Value of mineral wool is about 4 per inch.

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Net-Zero | Carbon footprint equal to zero (yearly).
| See Also: Carbon Footprint

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Permaculture | The method of recycling conventional waste into useful materials for new products, limiting waste going to landfills or outside facilities.
  It can be used in any industry, but is often used to refer to Agricultural Permaculture, specifically. This includes companion-planting and a wide use of animals on the farm, efficient and automatic watering techniques, and eco-friendly fertilization and nitrates for plants.

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Rammed Earth | Wall made of layers of earth-cement mixture, compacted in a temporary wooden or metal frame, and often reinforced with rebar. Visually appealing, high-load bearing, high-thermal mass, and high-insulation. Finish with beeswax to preserve the sandstone look.
  Natural Rammed Earth walls containing no insulation provide low R-Value and high thermal mass. They are able to store heat for up to 12 hours, making them highly efficient as an interior wall in any climate.

  Insulated mixes can be used to achieve higher R-Values, typically between R20 and R30, with some insulated walls reaching R100.

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Rocket Mass Heater | Also called Rocket Mass Stoves; a woodstove which uses a vertical combustion chamber and is covered in a significant thermal mass.
  They burn efficiently, requiring less wood, producing less smoke (both by 80-90%), and leaving behind nearly 0% of material burned; an access point may be installed in the cob for easy cleaning, which should be done when there is excess ash buildup, but a small layer of ash is safe to leave. Rocket Mass Heaters can warm rooms, furniture, floors, water, and food.

  Exercise extreme caution if attempting to install - poor ventilation or fire safety can be disastrous.

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R-Value | The measurement of heat-loss resistance.
| See Also: Insulation

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Shou Sugi Ban | Charred (Red) Cedar / Cypress wooden plank.

Uses the same Japanese kanji characters as Yakisugi, but with an alternative, westernized pronunciation.

| See Also: Burnt Timber Cladding, Yakisugi

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Strawbale | Straw compressed into shape and tied. Sometimes used as natural insulation and/ or load-bearing structures; buildings made using strawbale methods are fire, mold, earthquake, & strong-wind resistant, easy to build, and offer better insulation (a higher total R-Value) for those in colder climates.
  A 23 inch strawbale wall can provide an R-Value of 33 (and they come pre-measured & uniform for your convenience).

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Swail | Earthen ditch & mound systems built to catch or redirect runoff water in order to grow plants, increase biodiversity, and/ or replenish local aquifers.

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Tamp | To compress. In building, materials like sand or gravel are pressed flat using a tool called a tamper. Rammed Earth and Earthbag walls are tamped during building to increase wall density and strength.

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Thermal Envelope | The physical barrier between the inside and the outside of the building. A complete Thermal Envelope will block airflow between the outdoors and your well-insulated building, especially at the seams of doors and windows.

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Thermal Transfer | The transfer of heat energy from relatively hot to cold material due to temperature difference, the three main methods being convection, conduction, and radiation- phase change and mass transfer are also methods of thermal transfer. Examples in building:

  Convection | Affects air circulation throughout a building as hot air rises and cool air falls. Trombe walls and windows that can open on both the top & bottom also utilize this concept.
  Conduction | Important to consider when creating your thermal envelope and choosing insulation to avoid cold outdoor temperatures lowering indoor temperatures. Also, how heated floors and furniture will warm you.
  Radiation | Walls, floors, and furniture made of materials with high thermal mass will radiate heat into the space around it.
  Phase Change | Materials like salt hydrates or water can be used to store and release heat energy during phase changes. The results are similar to using thermal mass but are able to be used with conventional materials like drywall.
  Mass Transfer | The movement of particles (along with their heat energy) to another location. Considered when creating a thermal envelope, air ventilation & circulation, and cooling techniques using evaporation.

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Tombre Wall | One-pain window in front of an earthen wall with a small gap; vents at the top and bottom of the earthen wall allow for air flow and convection heat from the greenhouse effect to heat a space.

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Urbanite | Recycled concrete chunks mortared together. Often used in small outdoor structures like garden walls, beds, sheds, or as a foundation in buildings.

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Wattle and Daub | Frame with woven lattice walls and cob* infill, historically used in Europe. Wattle and Daub walls are an excellent thermal mass, but with no additional insulation, provide a low R-Value (R1-1.5) per inch and are typically only two to four inches thick- serving as a poor insulator and inappropriate for exterior walls for buildings located in cold climates.
*also historically contained wet soil and animal dung.

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Wool | Fiber from Sheep's hair.
Sometimes used as a natural insulation, it is fire-resistant, helps control a home's humidity levels without mold growth, and is eco-friendly.
  The R- Value of sheep’s wool is about 3.5-4.3 per inch.

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Yakisugi | Charred (Red) Cedar / Cypress wooden plank.
  Japanese preservation method used to permanently close the pores of a wooden plank with charcoal. The method includes soaking a plank of wood in water, then scorching the surface of the wood with flames until blackened with soot, which can be removed for aesthetic appeal and sealed with oil. This method prevents moisture, flames, bugs, and UV light from damaging the underlying wood. Be Careful when removing soot, as taking off too much will reduce this method’s benefits.

  The accurate pronunciation of the kanji used to refer to Shou Sugi Ban. | See Also: Shou Sugi Ban, Burnt Timber Cladding

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Safety Disclaimer

Please Consider:
While Cob is a Thermal Mass, without more straw it provides little Insulation; and while Straw is Insulative, it is NOT a Thermal Mass. Different combinations of these two materials can offer benefits for varying climates.
   The types of homes offered by local Natural Building institutions and/or those found in climates similar to yours- are an important indication of what type of building style(s) you will want to use. By looking at local sources first, you can benefit from others' time and effort spent on making the most efficient home, already considering Humidity, Temperatures, Natural Disasters, Costs, Availability, or more!

And of course, be careful! This is a project that could require heavy materials, machinery, hard labor, and some savings. Have a thorough plan with multiple options (back-up plans) ready well ahead of your start date.

Good Luck, Builders!