Image Credit: Root Design-Build Inc.
Image Credit: Root Design-Build Inc.
More Green Building News
If during a tour of northwest Oregon you happen to venture east of Portland, you’ll likely take in sights in and around the town of Hood River, which offers everything from orchards and wineries to breathtaking views to the swift and steady winds that attract expert sailboarders and kiteboarders to the Columbia River Gorge.
For a least one lucky homeowner-to-be in Hood River, spectacular views – in this case, Mt. Hood to the south and Mt. Adams to the north – will be one of the first-rate amenities of a house being built on a plateau above the town. Another amenity will be the quality of construction going into the structure, which is being built to Passivhaus standards by Portland-based designer and builder Root Design-Build.
As Root Design-Build points out on its website, the house is on a busy street and so has been separated into two buildings – a shop and garage, just off the road, which acts as a buffer for the main house, which is set back about 70 feet from the street.
The shift
Root says that the separation of the two buildings allowed the design team to focus more intently on the materials that would be used in the main building and on strategies for maximizing solar gain. The designers bisected the house’s rectangular layout with an entry foyer and staircase, then split the rectangle in the east-west direction and shifted the two pieces 10 feet, creating porch/balcony “pockets” at both ends of the building.
Hence Root’s name for the home: Shift House.
The main house, which is scheduled for completion in early 2010, is being built to include R-42 walls, an R-60 roof, triple-pane windows, well-sealed construction joints, and a heat recovery ventilator to help meet its Passivhaus requirements.
A Root co-owner, Milos Jovanovic, told Sustainable Industries magazine that SIPs will be used on the exterior walls but in a nonstructural capacity, since they will be attached to standard framing. Jovanovic’s team calculates that energy demand in the 2,200-sq.-ft. house will be so low that an 8 kW solar power system should be enough to bring its operational performance to net zero energy.
What’s more, he says, construction costs should be only about 10% higher than they would be for a conventional home of the same size, since Shift House will not require a central HVAC system.
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4 Comments
building department
i am curious to see how all involved fared with the building department when they explained there would be no hvac system?
...and sections
Could you invite the designers to show us some details. Whenever I see a project that is claiming to meet PH standards I am intently interested in understanding how they met this rigorous standard (though the geographic location is an early clue - its just easier in that climate). In this case, it looks like a slab on grade, so I'm interested in the details that are vulnerable to thermal bridge effects at the wall/floor/ground junction.
It would also be interesting to see how they resolved the desire to capture what sounds like a dramatic view to the north with minimal glazing to that orientation. I'm here to learn not just what people are doing, but how they are doing it.
... and though this is not a building without HVAC (just no conventional HVAC, and that should be explained) I am also interested in the experience with permitting what is going to be an unfamiliar building system to most officials.
answer for - building department
This is an excellent question - in order to get our building permit we had to include electric radiant wall panels in each room. We will try to get away from using these in the future but this being our first project of this nature we felt that this battle was not worth fighting. Once we have a house like this and can prove with hard facts that such heat sources are superfluous we will have a strong case to eliminate them from future projects.
Wall details
The envelope of a Passive House is the most important system of this building type. Once we get to such high levels of insulation and air tightness thermal bridges become one of the key concerns. The question is how to have foundation to wall and wall to roof connections without solid members spanning the entire width of the wall (this condition is also a concern at door and window openings). In order to eliminate thermal bridges we designes a double wall that has wood framing, structural element on the inside and a SIP panel exterior that is hanging from the wood stud wall. Once the SIP panel becomes non structural we can eliminate all solid members that span the width of the wall. This translates into having no need for a bottom or a top plate at the SIP portion of the wall and a totally insulated 8" section at all intersections. We will be publishing the section details on our web site as we progress with the construction process at rootdesignbuild.com
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