The sustainability movement evaluates cradle to grave issues with building materials. A goal is to reduce the “ecological footprint” of human activity. After a few decades, most of the components of a typical house are replaced during remodeling. The idea of building materials that can be reused, recycled, or composted has appeal. There is an emphasis on “natural” wood and plant fiber products, metal and stone and a deemphasis on plastics and oil based polymers. For example, metal roofs may initially be more expensive to purchase and install than oil based shingles but the metal will last longer and can be recycled rather than landfilled when replaced.
Some synthetic materials such as urethane foams can produce toxic fumes if produced improperly or if they burn during fires. Concern about toxic vapors and potential allergies to synthetic chemicals is driving the search for alternatives.
Plant fibers such as hemp are increasingly used as alternatives to fiberglass or polyurethane foam insulation. Hemp can be composted, decomposed by an army of invertebrates (including insects) and bacteria. Fiberglass or polyurethane foam cannot be composted because insects and other living organisms are not adapted to using these materials as a food source.
Compostable, organic material can be a blessing when it is time to replace and dispose of the material. Compostable organic material can be a curse if insects refuse to wait to start feeding until it is time to be replaced. This is a problem with “Tatami” mats in Japan, the subject of a previous post.
French researchers have recently reported a case of allergy leading to asthma in a French woman living in a green home. Her room had been recently insulated (inappropriately) with hemp. The hemp was harboring significant populations of booklice (Identified as Liposcelis spp.). Allergy tests confirmed a strong reaction to an extract made from the booklice. The woman did not respond to other common arthropod allergens from cockroaches or dust mites, indicating a new allergen. The booklice were controlled by removing the hemp and the woman no longer suffered allergic reactions.
The money quote:
Use of new ecological building materials could favour development of new indoor allergenic sources.
No material, synthetic or organic, is free from all problems. Using a new material may solve one problem or address a specific concern but lead to new or different concerns. Entomologists are unlikely to run out of new challenges anytime soon.