Are there any cost-cutting shortcuts for planting a green roof on my urban townhouse?

— Rachel Diamond, Harrisburg, PA

Answered by Mark Schrieber on August 25, 2009

What are the sustainable options for re-roofing our 30-year-old home?

— Jennifer Marks, Tiburon, CA

Answered by Cynthia Phakos on November 26, 2008