Solid wood flooring is expensive because each board contains a thick strip of top-quality wood which has been harvested from older and more valuable trees. Engineered wood, on the other hand, uses a thin hardwood veneer as the top wear layer. While the veneer may come from old trees, the under layers are made from faster growing, smaller-diameter trees.

Laminates are popular, easy to install and look quite nice. Laminates are made with a printed image of wood that is glued to a fiberboard substrate (ground up wood particles bound with an adhesive). It is topped with a plastic coat for protection and made into planks that fit together. Not all laminate is green however. Be sure that the manufacturers are using FSC certified fiberboard cores and zero or low urea formaldehyde emissions.

Bamboo is another green option. Bamboo looks and feels much like wood but is actually a grass. It is beautiful, it holds up as well as hardwood, and it is reasonably priced. Bamboo is fast growing and can be harvested every 3-5 years.

Cork is harvested from the outer bark of the cork oak trees without cutting down the trees. The tree regenerates its bark and can be harvested again in 10 years. Cork is durable, cushioning and naturally insulating.

Terrazzo is more often seen in commercial buildings than in homes but contains recycled content, is durable, and is and easy to clean. Terrazzo consists of small chips of marble, granite, quartz, or glass in cement or resin based matrix.

Ceramic tile is made primarily of clay, which is an abundant natural resource. Ceramic and glass tile are low-toxic and inert although the caulking and sealant may be less kindly to the environment. Be sure that eco-friendly grout and sealants are being used.

Three other possibilities are brick, concrete and stone. Brick is green and healthful, and it comes in an array of colors and patterns. Natural stone is lovely but is a little more expensive. Fortunately, it ages well and can be expected to last a lifetime. Concrete is available in a wide array of colors and patterning techniques. Concrete floors are serviceable but expensive and not for everyone.

We've talked about a lot of interesting options here, but before you run out to buy new flooring for the whole house, do remember that--from a resource conservation standpoint--it is better to maintain or restore the floor that you already have rather than tearing out and installing a whole new surface. But if you need to replace your floor, try to salvage what you tear out to be reused on another project, or find ways that the material can be recycled.