There are still people on both sides of the PVC issue, but let's go ahead and assume that most green builders don't like the stuff — mostly because of its upstream and downstream environmental burdens. PVC taken in isolation from its birth and death enters murkier territory. There's a product available that decreases a building's heat loss, doesn't increase materials costs, decreases installation time, provides a termite shield, prevents damage commonly inflicted by the landscaping crew and ongoing grounds maintenance... and contains a fair amount of PVC. It's a stay-in-place form for slab-on-grade construction called EnergyEdge that insulates, finishes, and protects a slab's exterior face. Dan Morrison wrote a blog post about it over on GreenBuildingAdvisor.com that sets the stage:

"Slab on grade construction is extremely common in the southeast and southwest US because it's a fast, affordable way to get out of the ground and into the house. Slabs are also a great way to incorporate hydronic heating into a house."

But (he goes on)...

"Slab foundations can be energy sieves if not insulated on the outside with rigid foam. Both heat and cold can penetrate deep into a house through an un-insulated slab edge in summer and winter."

The product was also given a brief presentation in the first issue of Insider, the print newsletter distributed to GBA Pro members (where it's got a Michael Chandler byline), which notes:

"EnergyEdge saves labor costs because you don't have to add foam later or strip the forms. And the product is comparable in price to 2x8 forms or modified insulated concrete forms."

(As a bit of an aside, both GBA pieces mention that the PVC is recycled from post-industrial sources [i.e., pre-consumer], which in the scheme of things is usually a baby-step or less removed from virgin PVC. However, something is askew somewhere. A company representative told me on the phone that they're "looking into" using recycled PVC with only a thin virgin wear layer. It could be that the company is investigating the use of post-consumer PVC as the bulk, which would be great... though using a recycled PE, rather than PVC, would probably be better.) So where's the line? The GreenSpec research crew has had quite some discussion about it. The product has a lot going for it... but as a general rule, GreenSpec doesn't include PVC products. This one, though, can contribute to significant energy savings, which translates into better environmental health. What would you do?