A family in Wilmington, N.C., boasts the area's first residential green roof. Different varieties of Sedum help mitigate rainwater runoff and reduce temperatures. Green roof construction grew by 30% in North America last year and costs between $10 and $20 per square foot. But, as one expert noted, it can reduce heating and cooling costs and "can double the life of a roof so replacement costs can be cut significantly."

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