Breaking Bad IAQ
During the past year, a net-zero beachfront house in Southern California recently built for Emmy Award-winning actor Bryan Cranston has garnered much attention from green building and design professionals. Known as “3Palms,” the 2,450-square-foot, three-bedroom beach house provides an excellent model for cost-effective, high-performance green residential building.
From the beginning, the goal of the project was to build a home that epitomized the balance between form and functionality while meeting the highest standards available for green residential building. To achieve this goal, Cranston assembled a project team headed by three California green building and design thought leaders—the architect of record, Alliance Design Group; the project’s designer, Turturro Design Studio; and builder, Allen Associates Construction. Through the team’s resourceful work, 3Palms is on target to receive both LEED for Homes Platinum and Passive House Institute U.S. (PHIUS) certifications—levels reached by only a handful of homes across the country.
3Palms’ impressive status as a net-zero home can be traced in no small part to its energy-efficient design. It utilizes Passive House design techniques such as radiant slap heating, an airtight seal and strategic window placement that are aided by high-performance materials like photovoltaic solar roofing and spray foam insulation.
For 3Palms’ homeowner, architect, designer and builder, creating a healthy interior with high indoor air quality was an equally high priority.
“High indoor air quality was very important to Bryan and his family, so that was one of the goals we were pushing for throughout the project,” says Bryan Henson, LEED AP, president, Allen Associates Construction. “If you’re going to build a home to meet the highest green building standards, you need to make the interior as healthy as possible. For us, this was a matter of limiting air pollutants by selecting building materials with low environmental and occupant impact and employing effective ventilation strategies.”
To avoid potential sources of volatile organic compounds (VOCs), the most common pollutant of indoor air, the project team opted to use only building materials and furnishings with little or no-VOC content. Off-gassing of VOCs from finishes and glues used with traditional building products are responsible for the strong, unpleasant smell often associated with new homes.
“That new-house smell is not good for you,” Henson says. “We took every precaution on this project to reduce the VOC content of the interior air. There’s no paint or standard finishes on the walls and no carpeting on the floors. All of the adhesives we used are low- or no-VOC, and we applied the finishes offsite. So, you walk into this house, there’s no new-house smell. All you smell is fresh air.”
Both floors of 3Palms are poured concrete in conjunction with the radiant slab heating systems. Another important component of the VOC reduction strategy was the installation of CertainTeed AirRenew IAQ Gypsum Board on the walls. AirRenew actively helps clean indoor air by capturing VOCs, such as formaldehyde and other aldehydes, and converting them into inert compounds that safely remain within the board. As new sources of formaldehyde—such as paint, rugs, new carpeting, furniture and cleaning supplies—are potentially introduced into the interior environment over time, the product will continue to scavenge formaldehyde, ultimately improving indoor air quality. Outside of its VOC-scavenging abilities, however, the product appears and installs like standard gypsum board, which appealed to the project team.
“AirRenew was a product that I was familiar with, having used it on a few other high-performance green building projects, and it fit well with what we were trying to do,” Henson says. “It’s easy to find, has a positive impact on IAQ and is installed just like regular gypsum board. So, if you’re already planning to install drywall on the project, there’s no added labor cost.”
The Allen Associates crew sealed the gypsum board with latex and finished it with a 1/8- to 1/4-inch layer of American Clay breathable earthen plaster, which absorbs excess moisture from the air and releases it as needed, regulating humidity. Since AirRenew’s VOC-scavenging abilities are uncompromised by any breathable finish or paint, even through multiple coats, the project team saw the gypsum board and earthen plaster as an appropriate, functional pairing.
“We believe the AirRenew gypsum board and the hand-troweled American Clay plaster are working in conjunction,” says John A. Turturro, principal of Turturro Design Studio. “The clay surface balances humidity and creates negative ions, which bond with airborne particulate matter, including VOCs, helping to draw them to the walls, which trap them. So, we’ve got multiple wall layers working together.”
Maintaining IAQ While Meeting PHIUS Standards
Creating an airtight seal around the home with spray foam insulation was essential for meeting PHIUS standards, but it increases the importance of developing an effective ventilation strategy to ensure that interior air is kept fresh and unpolluted. To address this issue, the team used energy recovery ventilators’ (ERVs) special exhaust fan units that remove stale interior air and allow new fresh air to enter. The fresh air is also preheated by the exiting air on its way out, which maintains a constant temperature in the room.
“Maintaining a balance between a tight seal and adequate ventilation is a common and crucial challenge for most energy-efficient homes,” Turturro says. “You don’t want to create a Petri dish of germs and pollutants with your interior air—you want good circulation. An ERV is a good way to provide that.”
A preservationist of common-sense ancient design trends that are sometimes overlooked by today’s green designers, Turturro used strategic window placement to enhance natural ventilation.
“The fenestration of the house is designed for cross ventilation, so you can crack a small window on the ocean side and a corresponding small window on the inland side and create a pretty nice passive airflow,” Turturro says.
One IAQ threat that many homeowners may not notice is the potential for exhaust from standard vacuum cleaners to pollute interior air. 3Palms, however, has a whole-house vacuum, consisting of a centralized reservoir in the garage connected to various wall ports throughout the home via hard piping through the walls. To sweep, the homeowner merely plugs a hose into one of the wall ports and switches on the vacuum. All debris is exhausted to the reservoir in the garage.
With all of these materials and design strategies working together, the 3Palms project team has produced an interior with excellent IAQ, through an abundant supply of fresh, unpolluted air, further solidifying its compliance with the high LEED and PHIUS standards. The project has already achieved both regional and national recognition through a series of tours and workshops for California green building and design professionals and has been featured on the TV program, Real Green. This attention from the green building and design community fits perfectly with Cranston’s desire for his new home to inspire and educate others in their own green building aspirations.
“Part of the owner’s objective was to use 3Palms as a showcase for innovative green building and design, and he has been very accommodating,” Turturro says. “When we’re done, several hundred people will have walked through this house. As a team, we are really excited to have been a part of this project. The exposure is important of course, but beyond that, the sharing of ideas for green building and design has been amazing.”