Green Product Category: Exterior Finish & Trim

The exterior finish is a building’s first defense against the weather, and its most visible aspect.

Building systems that rely on the exterior finish as the sole weather barrier are susceptible to failure—especially in climates with wind-driven rain or without good drying conditions. The driving forces of wind and other air-pressure factors will force moisture through even the smallest openings. Because of this, siding or curtain wall systems designed around the rain-screen principle are much more effective and durable. This strategy uses a vented exterior finish and a tightly sealed secondary barrier that work together to equalize the pressure on both sides of the exterior finish, taking away the forces that would otherwise drive moisture inwards.

Among the product options:

• Recycled-wood-fiber composite siding and trim are more stable than materials made from natural wood, hold paint better, and generally cost less. Some hardboard products have had durability problems when improperly installed or when installed without adequate drying provisions in wet climates.
• Fiber-cement siding is very durable, looks like wood when it’s painted, and provides a fire-resistant surface. The wood fibers provide strength, elasticity, and good paint-holding ability.
• Locally produced brick and stone are long-lasting, low-maintenance finishes that reduce transportation costs and environmental impacts. Molded cementitious stone replaces the environmental impacts of quarrying and dressing natural stone with the impacts of producing cement.