Also found in: Dictionary, Medical.
Include organic materials such as bamboo, cordwood and straw bales, rammed earth, mud and clay, and other natural composites.
autoclaved aerated concrete blocks
Concrete blocks that are stronger, lighter, and a green alternative to conventional masonry blocks. They can be produced from fly ash, which make this composite eco-friendly and nontoxic, fire and insect resistant, with excellent sound absorbing properties and insulation values.
An organic, natural material that is lightweight, durable, flexible, biodegradable, and recyclable. It is fast growing and rapidly renewable. When treated, it becomes as strong as steel and may be used as the main structural material in small dwellings. It is a more renewable material than wood because it is a fast-growing grass/reed that can be harvested after only 4–6 years of growth, much shorter than the 30–60 years required for comparable wood species. Replanting is not necessary, as it regenerates on its own. It is stronger than oak, which is widely considered the most durable hardwood. When laminated, bamboo is nearly as strong as soft steel. Bamboo doesn’t swell or shrink as hardwoods do, making it a perfect material for furniture and flooring.
A practical, resource-efficient, renewable material that is usually obtained from timber and trees unsuitable for building purposes. Deadfall and standing dead timber are preferred, because they are partially seasoned and contain minimal rot.
A durable, low-maintenance, decay-resistant material with excellent thermal and acoustical insulation properties made of cork and recycled rubber. Its cellular structure traps air inside, which reduces noise and vibration, and gives floors natural shock absorption. A naturally occurring substance in cork repels insects and molds and protects cork from rotting when moist.
An environmentally friendly version of concrete produced with either non-CO2-emitting materials and/or non-CO2-producing methods. One of the most commonly used methods is to use indus-trial waste by-products such as fly ash from coal combustion and blast furnace slag from iron manufacturing to constitute the cement mixture used in producing concrete. One of the main advantages of this method is that it prevents these waste materials from entering landfills.
green form-release agents
These form-release biocomposites are non-petroleum alternatives to conventional oil products. They are typically water-based, nontoxic, biodegradable composites that contain very low VOCs (volatile organic compounds). These composites can be used to coat various types of concrete forms and liners, such as steel, aluminum, fiberglass, and plywood, and they are usable at below-freezing points.
green PVC alternatives
Green alternatives to the widespread use of PVC materials can be found in many building products. Clay, cast iron, and high-density polyethylene replace PVC piping. Wood, acrylic, and fiber-cement boards replace vinyl siding. Electrical insulation can be replaced with low-density polyethylene. Sheathing can be replaced with halogen-free, low-density polyethylene. Roofing can be replaced with soil and grass, or light metal. Natural biomaterials such as wood and bamboo, as well as ceramic composite tiles, can replace PVC flooring. Biofiber and polyethylene can replace PVC wall coverings. PVC window and door frames can be replaced with wood, fiberglass, and aluminum. PVC carpet fibers can be replaced with recycled biomaterials and natural fiber backing.
hybrid composite panels
Composite panels that are made with an aluminum core, coupled with wood, polymers, woven fiberglass, and fibers. They are very rigid, lightweight, high-strength materials with excellent impact resistance.
hybrid frame systems
A new generation of wood–polymer composites that are extruded into a series of shapes for window frames and sash members. These composites can be treated like regular wood. They are very stable and have the same (or better) structural and thermal properties as conventional wood, but with better moisture and decay resistance.
A green surface composite made from organic, biodegradable materials consisting of linseed oil as the binder, lime as the filler, and organic pigments as the color for the material. Natural fibers such as jute are used for stabilizing the material. Organic linoleum has significantly low-embodied energy, creates little waste during manufacturing, does not require constant maintenance, and can be fully recycled and reused. It has very low-VOC emissions when installed with low-VOC adhesives, and it does not contain formaldehyde, asbestos, or plasticizers.
mud and clay
Included in the most basic building materials are mud and clay. Mud is typically used as a type of concrete and for insulation. Mud and clay have excellent thermal-mass qualities and keep the indoor temperatures at a constant level. Overall, mud and clay are highly available, low-cost, energy-efficient, high-performance, ecologically green materials, but they may require constant maintenance and structural support.
A damp mixture of soil, sand, gravel, clay, and other stabilizers pressed against an external frame that produces a solid earth wall. It is an economical and versatile material, which is as effective for nonlinear surfaces, corners, curves, and arches as it is for straight walls. Rammed earth is a clean, recyclable, biodegradable, resource-efficient material with a high thermal-mass value. Its inherent insulation and radiation capability reduces the energy required for heating. Earth can be dug locally, thereby reducing transportation and manufacturing requirements.
A composite composed of recycled glass products, such as light bulbs, glass waste, and automobile windshields. Crushed glass is mixed with ceramic materials to produce the composite, creating a material that is cost-effective, durable, scratch and wear resistant, and easy to clean.
recycled rubber composites
A green composite for indoor and outdoor uses, such as sidewalks and vehicular roads. Indoor rubber composites are quite sustainable, slip resistant, and require very low maintenance. Recycled rubber composites are also used for wall panels, insulation, carpet underlayment, and roofing. They are water- and rust-resistant, and withstand extreme temperatures that cause curling, splitting, cracking, and rotting. In addition, rubber composite materials are lightweight, impact resistant, and energy efficient with high insulation values.
recycled wood/plastic composites
Composed mainly of wood fibers and waste plastics that include high-density polyethylene, the material is formed into both solid and hollow profiles and used to produce building products such as decking, door and window frames, and exterior moldings.
The hard, protective shells formed over rice grains resist moisture penetration and are excellent insulation materials, with a thermal resistance of about R 3.0 per inch. They are fire resistant and resistant to rot, molds, mildew, insects, rodents, and fungus. Rice hull interlocking panels exhibit excellent load bearing capability, sound absorption and fire resistance.
A thin block of grass held by its roots, usually used for turf and lawns, but can be used as a temporary building material. Like brick, sod is cut and laid in regular block shapes. The walls of a sod building are usually protected with a layer of stucco or wood panels.
An agricultural by-product made from the stems of cereal crops, sugar cane, wheat, oats, rye, rice, barley, and others. Low cost and general availability make straw bales a highly desirable, natural green material. A post-and-beam framework is the most common non-load-bearing construction method, where the framework supports the structure and straw bales are used as infill. Straw bale is a very economical material, but it must be protected from getting wet both during and after construction.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved