If western culture spends 90 per cent of its time indoors, it stands to reasons we are going to give our floors a pounding. Which, then, is the greenest flooring? It’s a question with no singular answer, but there are a variety of materials that should, between them, cover most scenarios. Warren McLaren takes a brief peek at some below.

Bamboo

Bamboo is a fast growing grass, needing little or no fertiliser and pesticide, and pandas do not favour the species used for flooring — Moso. Attaining its maximum height of 24m in a mere two months, it takes six years to fully mature. Depending on the flooring brand, Moso is usu­ally harvested after four to five years of growth. Bamboo flooring is offered in four main vari­ants: horizontal grain, vertical grain, veneer and strand (bamboo particle board). Production is centred in China and Vietnam. Formaldehyde adhesives are commonly used to bind together the thin strips of bamboo, although a few formaldehyde-free options have recently become available, as has a Forest Stewardship Council (FSC) certified chain of custody. A factory applied, seven-layer polyurethane/ aluminium oxide coating is normally applied to bamboo floor systems.

Carpet

Carpet was once considered a contributor to west­ern society’s rising levels of asthma. However, research suggests the opposite may be the case. Carpet fibres capture dust which can later be extracted by a high efficiency vacuum. Hard sur­faces, however, tend to allow airborne particulate to be kicked up by household activity into the breath­ing zone. The three predominant carpet materials, in order of cost, are polypropylene, nylon and wool. The first two, being petroleum-based, usually pro­vide less than a half of the life of good wool carpets, which should see out 20 to 30 years. Synthetics take thousands of years to break down, and while recy­cling facilities exist, they are rare, especially in Australia (where an estimated 80 per cent of carpet is sent to landfill.) Wool, on the other hand, derived from a renewable resource, is compostable. Carpets, in general, offer high acoustic and thermal insulating properties. A great deal of green innova­tion has gone into carpet tiles for commercial instal­lation and refurbishment.

Cork

Cork is the bark of the Quercus suber oak tree, which can live more than 250 years. After a tree reaches 25 years of age, its bottom two-thirds of bark can be harvested or peeled off the trunk. The tree is left for nine years for the bark to regenerate before the next harvest. Cork is sourced from countries with Mediterranean type climates, in particular, Portugal and Spain. With a honeycomb cell structure of nearly 90 per cent air, the bark provides unique qualities of heat and sound insulation, as well as having a highly recoverable compression that is soft to walk on. Cork flooring is made from the ground-up waste leftover from cork bottle stopper production. It is bound with a resin, which may include cashew tree extract, (but might also involve formaldehydes) and kiln baked dry into sheets and thence cut into tiles. The surface is usually treated for abrasion resistance with a polyurethane coating.

Natural fibre

Coir, Seagrass, Jute and especially Sisal are names which mostly identify natural fibre floor coverings. Though other fibres are also available, such as bamboo, paper, hyacinth, Abacá (banana leaf) and so on, Coir is the fibre found between the husk and the outer shell of a coconut. India and Sri Lanka constitute the vast bulk of global coir production. Seagrass is derived from a shallow coastal water marine plant that provides important fish habitat. Jute is a bast fibre (like hemp and flax), and is extracted from corchorus plants, mostly in India and Bangladesh. The leaf of the Agave plant yields the fibres used to produce Sisal. All these readily renewable fibres are woven into rugs and area mats, sometimes utilising a natural latex rubber backing. Their main environmental impact is, in some cases, resource depletion and pollution wastes from processing.

Polished concrete

Polished concrete is a relatively recent arrival on the sustainable flooring scene, having come into vogue in the past 20 or so years. Initially the phrase described a concrete slab that had a wax and chalk layer added, then polished to a shine with a soft cloth. These days the term also cap­tures the technique of grinding (or honing) con­crete floors with various grades of abrasives until a desired ‘polish’ is attained. In specifying a pol­ished concrete floor it is important to establish which process is to be employed. While waxes are still used in some methods, they are now more likely to be petroleum based, rather than the original beewax variety. A polished concrete floor will provide impressive longevity, with easy maintenance. Used in concert with passive solar design, they can capture and release the warmth of winter sun. It is even claimed they reduce lighting loads by being highly reflective.

Stone

Like polished concrete, masonry flooring such as slate, limestone, sandstone, marble, granite, etc, is ideally suited to absorbing the heat of a winter sun through a north facing window. So long as a low VOC sealant is selected, when protecting against scratches and accidental stains, no indoor air quali­ty issues should be present. If treated with respect, solid stone flooring will last hundreds of years, if not more. It is eminently reusable or recyclable. However, unlike timber and bamboo, stone flooring is a non-renewable material. Its extraction through quarrying or mining can be energy intensive and polluting. Additionally, due to its heavy weight, stone flooring’s transportation is an energy hog.

Timber

Once hidden by carpet and linoleum, exposed timber flooring has been the subject of a sus­tained renaissance, if mostly for its most obvi­ous natural aesthetic. Solid wood has low embodied energy, (the energy used to process it), particularly if air dried. Timber exhibits huge potential for a long life of reuse. Its significant environment impacts are therefore mostly relat­ed to harvesting. Although a very renewable resource, trees are also a key component of a forest. Their removal has considerable impact on water quality, soil erosion, as well as plant and animal biodiversity. Salvaged timber is therefore the greenest. Two of most trusted and independent certifiers of sustainably managed forest products is the Forest Stewardship Council (FSC) and the Australian Forestry Standard (AFS). Timber from old growth or endangered rainforests should never be speci­fied. Plantation or radially sawn timber is a far better option. Laminated timber products should be checked for their level of adhesives, like formaldehyde, which will off-gas volatile organic compounds.

Other

Of course there are many other flooring options that we do not have the space to delve into here. They include poured earth, which has its legion of fans for its warmth underfoot and very low embodied energy; recycled glass (from not only bottles, but also windshields and even light bulbs) has been fashioned into attractive, durable tiles; and rubber flooring can either be made from rubber tree latex or recycled rubber products.