Rapidly renewable materials are plants, or products derived from plants, that are fast growing and therefore regenerate in fewer than 10 years. Examples include bamboo, cork, straw, hemp, flax, jute, and pineapple leaf fibre. Rapidly renewable materials (RRMs) are an important part of green building because they reduce demand for non-renewable materials such as metals, and long-term renewable materials such as wood. The following RRMs are often used in the green building industry:

Bamboo
While a hardwood forest requires 120 years to mature, this plant matures in just 3 to 7 years. It is also quite easy to grow, as it does not require replanting, and can continue to grow from existing cut stalks. Technological advancements in the processing of bamboo have revealed methods that allow this material to be weaved into mats, glued to mat boards, and ultimately used in building construction to make up walls boards, doors, and ceilings. The strength of the end product is comparable to plywood, while also offering increased moisture and pest resistance. The substitution of this type of bamboo product for plywood would help to protect forests in many developing counties, while also creating job opportunities for the labour force in rural areas (1).

Cork
Also an important RRM, cork is harvested on a nine year cycle for over 100 years. Decorative cork tiles are used in flooring, walls and ceilings. Its inherent antibacterial and antifungal properties make this material desirable for various building applications, and contribute to increasing its lifespan to more than double that of equivalent wood products (2). In terms of cost, cork flooring is also comparable to hardwood. As a natural product, it is superior to synthetic alternatives such as vinyl, which release toxic phthalates known to cause asthma development.

Hemp
An RRM which is becoming increasingly popular in the green building industry, hemp is harvested on an annual cycle. Only one acre of hemp can produce over four tonnes of material each year. Hemp fibres are used to produce a variety of building products, including wallboard, panneling, insulation, roofing tiles, and bricks. Hemp fibres may also be incorporated into foundation walls, resulting in a foundation that is seven times stronger than traditional concrete, and offers increased flexibility to improve resistance to earthquakes and other ground movement (3). Unlike traditional insulation, hemp fibre is naturally pest resistant and does not require chemical treatment to prevent moth infestation. It is also produced using a low dust method, and as a result many individuals are more able to tolerate exposure to hemp fibre insulation than to conventional insulation materials.

Sources:
¹ Muenier, J., 1998.  Tackling Deforestation in Viet Nam: Learning from Ethnic Minorities.  International Development Research Centre (webpage).
² Maistry, P., 2007.  Rapidly Renewable Materials. Green Alberta (webpage).
³ Priesnitz, R.B., 2006.  Hemp for Houses.  Natural Life Magazine (March/April 2006 edition).