Things are taking shape on the Carpenter St. project as the finished floors go in and the rainscreen system goes up on the front façade. While this rainscreen was designed primarily for its drainage and drying capabilities, as you can see in the photos, it also happens to look great!

The Rainscreen System

Rainscreen façade systems work by pulling the exterior cladding of a building (the “first line of defense”) away from the rest of the wall assembly, creating an open air space between the two that allows for water drainage and ventilation. Any number of durable materials can be used for this type of exterior cladding, including ceramic tiles, fiber-cement panels, composite boards, and weather resistant exterior woods. Cladding is installed with small gaps between the individual panels, allowing the system to ‘breathe,’ and minimizing the capillary forces that would typically pull or wick water toward the building’s interior. Any water that does make its way through this open-jointed exterior cladding, due to wind or gravity, will either evaporate in the ventilated air space, or run as droplets down the back of the cladding and away from the building. The building’s interior and insulation are protected from this moisture by a water resistant air barrier.

This layered approach to wall construction eliminates many of the problems associated with water damage, wall cavity condensation, and mold. It can also improve the performance of the building and the comfort of its occupants by dissipating radiant heat in the ventilated air space, limiting thermal bridging, improving the wall’s insular properties and minimizing temperature fluctuation. From a design perspective the system also adds a great deal of visual interest to the façade, creating dramatic open reveals and shadow lines.

For information on rainscreen technology:

Rainscreen Cladding (wiki)
Rain Screen Designs for Absorptive Claddings (National Association of Home Builders)
Rain Screens Eliminate Moisture, Improve Efficiency (Ecohome Magazine)
NBS Building Regulations

The drawings above map out the approach that we’ve taken to rainscreen design on the front façade of the Carpenter St. project.  Our wall construction includes high density fiber-cement rainscreen panels, a self-adhering, vapor permeable building wrap by Henry, called Blueskin, and Henry Permax closed-cell spray foam insulation (installed by Northend Barriers).  Thanks to Peter Taylor at PPSI, LLC (Preserving and Protecting Structures’ Integrity) our building envelope consultant, for his help throughout the design process.

Check out the links below for information on any of the products that make up our wall assembly:

USG (US Gypsum) – recycled content from a local plant

Henry (Permax Insulation)

FSC (Forest Stewardship Council) – third-party certification

CBF (Cement Board Fabricators)

Henry (Blueskin building wrap)

Northend Barriers (insulation installers)