"Green buildings use durable materials that are salvaged, have recycled content or came from rapidly renewable resources. These materials significantly reduce the environmental destruction associated with the extraction, processing and transportation of virgin materials."

So reads a prominent display in the building department of one of America's most environmentally progressive cities. It's meant to exhort architects, builders and homeowners to reuse building materials that already exist - an extremely worthy goal, to be sure.

The trouble is that the building codes enforced by this very same department often make it difficult or impossible to follow the advice. It is not just one city's problem. Current building codes simply aren't formulated to accommodate the reuse of salvaged materials, leaving well-intentioned green builders caught in a classic Catch-22: As a matter of public policy, many progressive cities encourage the recycling of building materials, yet as a matter of administrative practice they make their use either economically impractical or else outright illegal.

A common example: Modern codes require safety glazing in all glass doors and in many windows. Yet the overwhelming majority of glass doors gleaned from architectural salvage, along with most of the windows, have plain glass, which cannot comply with these requirements.

What's more, the cost of re-glazing, say, a pair of old French doors with code-compliant glass would typically far outstrip their value. Faced with this reality, most homeowners will either install such noncompliant doors on the sly or else abandon the whole idea of using recycled materials and buy new doors instead.

As you might guess, the legal reuse of salvaged electrical items is equally problematic. Many local jurisdictions, for instance, require all newly installed lighting fixtures to carry an Underwriters Laboratories label - a standard that many old fixtures, even those rewired with modern components for safety, cannot meet. What's more, many state energy conservation codes no longer permit fixtures that use traditional incandescent bulbs (which constitute the vast majority of the salvage stock) in rooms such as kitchens, baths, laundries and garages, making it even more difficult to recycle such items.

On top of everything else, local restrictions dealing with lead paint and asbestos (the sale of both was outlawed only in 1978) may further dissuade those wishing to use salvaged materials.

Lead paint is practically a given on older items such as doors, windows or cabinets. Asbestos can show up in vintage ironing board cabinets, clinging to the backs of old heating registers, and in older appliances such as toasters and heaters. The presence of these materials can hardly be considered a dire threat inasmuch as they're also found in millions of existing homes, and in general, building officials tolerate them in existing work. Still, as regulations dealing with lead and asbestos inevitably become more restrictive, they, too, will become barriers to widespread recycling.

As if these troubles weren't enough to discourage would-be green builders from recycling old materials (many of which are far superior to new ones), there are other hurdles to negotiate. Next time, we'll look at some more instances in which well-meaning green builders can find themselves colliding with the codes.