Is it greener to renovate or rebuild?

­All of the refuse that results from the demolition of a house (or any other structure) falls into the category of construction and demolition waste. This waste stream is a wide and deep one in the United States. On average, it adds up to about 136 million tons of waste annually -- or a whopping 40 percent of the solid waste dropped off at municipal dumps every year [source: EPA].

Gutting a house entirely and saving only the exterior and internal load-bearing walls helps cut down on the waste generated by remodeling the home. If you compare the amount of trash generated by each process, renovating is greener than rebuilding. Again, however, the devil is in the details when it comes to determining what's green. Think of it this way: A homeowner who puts notices on sites like Freecycle.org or Craigslist.org to offer salvage materials will seem greener than someone who renovates and sends all debris straight to the dump to rot.

Renovation still tends to be greener than rebuilding, especially for waste reduction purposes. This is especially the case with small startup green demolition companies, like the Seattle-based nonprofit RE Store. The group salvages and sells as much of a house undergoing demolition as possible and recycles whatever remains -- down to the nails. In 2007, four of the company's projects received recycle or reuse ratings of between 70 and 97 percent from the Environmental Protection Agency [source: Stiffler].

It takes considerably longer to deconstruct a house by hand than it does to bulldoze it, but the green approach to demolition is catching on. Even if a home is demolished in an eco-friendly manner, keeping an existing structure standing will require less heavy machinery when the home is rebuilt. This means that the land surrounding the house will remain undisturbed, leaving trees and other greenery intact.

­When it comes to green building, renovating beats rebuilding. However, exactly what's done with the remodeled or rebuilt house makes an enormous difference as well. There isn't much point to having a green demolition crew demolish a home -- or even consider the question posed in this article -- if the final product's going to be an ecological nightmare.

As eco-consciousness continues to rise in popularity with consumers, the building industry has birthed a slew of sustainable vendors -- and some that just aren't. Let the buyer beware: The green living magazine New Life Journal suggests that home renovators do some investigating before jumping at a green price tag. A lot of products marketed as green due to their energy efficiency ratings may use less electricity than some of their counterparts on the market, but may also be constructed out of wholly unsustainable materials or made in environmentally harmful ways. What may appear green might not be green at all. This is a marketing ploy known as greenwashing [source: Cramer].

Other companies have gone in the opposite direction. Traditionally toxic products that feature prominently in home remodeling projects, like paints and varnishes, are now appearing on the market in vastly less toxic forms. Volatile organic compounds (VOCs), additives and ingredients that can prove carcinogenic in humans, are beginning to disappear from some housing materials. For example, bamboo flooring is becoming a popular choice among green remodelers because the plant grows quickly, decreasing the environmental impact of its harvest.

Contractors also are taking an increasingly Earth-friendly approach to home remodeling. They're gravitating toward environmentally conscious standards, like Leadership in Energy and Environmental Design (LEED) certification, in the building industry. As the concept of green building hits its marketing stride, it makes good business sense.

Of course, there's also Craigslist and Freecycle.org. Old materials no longer wanted in one house can be salvaged to remodel another one. And what's greener than reusing old materials?