Watch Ask This Old House Season 5 Episode 20 Online

Landscape contractor Roger Cook shows a homeowner how the brick stairs in front of his house have created a blistering "micro-climate," causing damage to an adjacent shrub. Together, they remove the ailing shrub and replace it with a heat-tolerant yew. Then Roger, along with host Kevin O'Connor, general contractor Tom Silva, and plumbing and heating expert Richard Trethewey ask, "What is it?" Afterward, Tom improves the ventilation in an attic by installing a solar-powered roof fan