Cork has more sustainable qualities than most any other single material. Cork also offers a unique combination of benefits for flooring applications. Cork is:
- a rapidly renewable resource (made of bark from the cork-oak tree, which regenerates)
- anti-microbial; resistant to common pests such as termites, as well as to mold and mildew (contributing to improved indoor air quality)
- fire resistant; does not release toxic gases on combustion
- insulating (thermal and acoustic)
- moisture resistant
- relatively low in embodied energy (depending on transport distances)
- about as durable as hardwood (with proper maintenance and management of puncture sources such as stiletto heels and narrow furniture legs)
- cost competitive
That said, almost any flooring material is an improvement over carpet from an indoor air quality perspective. Carpet traps contaminants such as dust mites, pet dander, mold, and pesticides.
Carpet manufacturers have been working hard over at least the past couple of decades to improve their product's sustainability, but they have mostly limited their concerns to recyclability, component offgassing, and factory pollution control. Improved recycled content and recyclability?to keep carpet out of landfills and improve cradle-to-cradle performance?will help reduce the impact from natural resource extraction and pollution. Still, each year in the U.S., four billion pounds of carpet are discarded, nearly half the amount of all new carpet sold. According to the EPA, carpet comprises two percent, by volume, of solid waste sent to landfills. And according to Inform, Inc.: "The incineration of discarded carpet (especially products with PVC backing) can release toxic chemicals, including dioxin, into the air."
Cork, on the other hand, is biodegradable and, without chemical additives, healthy for indoor air quality. You asked about the use of fiberboard in cork flooring. It is indeed used in the manufacture of cork floating-floor panels, but not in solid cork tiles. To avoid the toxins associated with fiberboard, look for cork products with low or no added formaldehyde content. You can further protect your home's indoor air quality by choosing tile adhesives with low or no VOC content.