The Orpinela house was designed to fit in aesthetically with the surrounding woods and meet the chemical sensitivity needs of the occupant. The spacious common area includes a utilitarian galley kitchen, music practice room/bedroom and bathroom on the first floor. A second story loft bedroom has a bird’s eye view of the surrounding trees as well as the common area below. Windows, sliding glass doors, and decks provide access to the outdoors. The ecoroof forms a constantly changing camouflage that links the building to its landscape while minimizing the building’s environmental impact. The 2 bedroom, 1 bathroom structure is smaller, 720 square foot, thus using fewer materials and reducing operational energy demand.
The idea to install an ecoroof came after the building was framed and the owner realized her view, once of trees, would now be dominated by a metal roof. After doing some Internet research, ecoroofs were discovered and identified as a potential solution. Russo expanded on this research by meeting with Tom Liptan of the City of Portland’s Bureau of Environmental Services and Ecoroofs Everywhere to learn more about ecoroof design and resources.
The ecoroof presented the opportunity to go beyond mitigating negative impacts by restoring positive site characteristics valuable to the local ecology. The roof is planted with drought-tolerant native species (primarily sedum, sempervirens, and coastal strawberry) in a 2" Pro-Gro aggregate mix of pumice, digested fiber, and recycled paper and is designed to require no supplemental irrigation. The fortuitous wooded setting, made up mostly of deciduous trees, provides shade in the summer and sunlight penetration in the winter- conditions conducive to a high plant survival rate.
From an aesthetic standpoint, the roof sits just below the tree canopy and resembles the vegetated slope of a hillside rather than a uniform, flat metal surface. Russo wittingly comments, "It’s a Corbusian kind of thing in a much more environmental way". Ecologically, the living roof provides habitat for insects and other microorganisms that, in turn, provide food for birds and create healthy soil. Orpinela notes, "I’ve noticed birds and squirrels on the roof. The squirrels jump from the tree limbs to the ecoroof and dig around…I guess they forgave us for cutting down all those trees and stuck around."
The plants and soil soak up rainwater and slowly release it over an extended period of time. This reduces the stormwater delivery rate to the City’s storm/sewer system and the resultant stress on wastewater treatment plants and outfall waterbodies during storm events. The project lies within the Johnson Creek Watershed, the nearest impacted water body, and the ecoroof helped mitigate the project’s impact on this urban water body.
Equal attention was paid to the building’s impact on its indoor occupants as was to its outdoor occupants. The owners communicated the importance of a healthy indoor environment to the architect who, in turn, researched and specified low toxicity materials to the contractor. The two parties also went through an exercise to test Shawn’s sensitivity to particular materials. "It was like scratch and sniff," notes Russo, "we would have him touch the material and then see how he reacted. If nothing happened we would have him sleep overnight in the same room as the material." Essentially, they increased his exposure to the material over time to ensure that no materials were installed that would require costly removal after occupation. Such diligence, however, does not ensure success, "You have to be careful about guaranteeing results to the client…you never know how the individual materials will interact with each other once contained in the same structure."
The building’s climate and context-responsive design enables it to operate with great efficiency. Thermal comfort is maintained during the summer solely by passive measures. Minimal glazing on the south and west façades coupled with ample shading from the surrounding deciduous trees reduce the amount of direct solar radiation penetrating the building. In addition, the metal clad wood windows are low-e, argon-filled, and double paned thus significantly reducing thermal heat transmission in and out of the building. The woods act as an advantageous cool-air reservoir and operable windows and sliding glass doors allow cool breezes to pass through the building when desirable. The ecoroof may add additional insulation value to the roof as well although this has not been tested.
Heating was a particular challenge given the occupant’s chemical sensitivity. Forced air was ruled out because the forced air would suspend irritating particulates. Radiant floor heating was a viable alternative but required the use of a less-efficient electric, versus gas, water heater because no internal combustion could occur inside the building. The team sacrificed some energy efficiency in favor of a healthier indoor environment by choosing radiant floor heating fueled by an Apollo super-insulated electric water heater. "We made the decision with the mindset that, in the future, the electric water heater could be powered by solar or wind energy" notes Russo.
The radiant floor heating system is a network of tubing installed in the ground floor and upstairs wall that circulates heated water to and from the hot water heater on demand to heat the house. As the water travels through the house it radiates its heat upward through the floor and into the connected living space. These systems are more energy efficient than forced air because water has a much greater capacity to store heat ("specific heat") than air.
Electrical lighting needs are minimized by abundant glazing on the building’s north facade and two skylights located in the building’s sloped roof. The skylights are particularly effective in the wooded setting where most daylight comes from directly above the building. Corner windows provide a view corridor towards the city and sliding glass doors on the ground floor provide a clear transition to nature. All of these passive and active design measures reduce the building’s energy demand and related operational costs while increasing the occupant’s connection to the verdant surroundings.
Keys to Success - Design:
- Design a smaller, more efficient, space to reduce energy and material requirements
- Install an ecoroof to better blend into the wooded setting
- Minimize glazing on the west and south facades and maximize glazing on the north façade
- Specify high-efficiency, double paned windows to reduce winter heat loss and summer heat gain
- Design interior to accommodate operable windows and cross ventilation
- Install a high-efficiency hot water system and radiant floor heating
- Install skylights to further promote daylight penetration