At first there was the will but not the way. The homeowner of this 1950s house on a wooded site in Ann Arbor, Mich., wanted to address the home’s many inherent performance issues using a sustainable approach but she was unable to find a building team that shared her mindset.
That all changed after an HVAC contractor suggested that the homeowner speak to local contractor Doug Selby of Meadowlark Builders, and Selby, in turn, recommended architect Michael Klement of Architectural Resource.
Klement was excited by the owner’s vision and her idea to use the need to repair a leaky roof as an "avenue to explore what might be a better form she could put that roof on.” The client’s approach meshed well with the architect’s “long-life, loose fit” philosophy, and the project came to include a second story addition and an enclosed porch.
Green practices and products fulfill the clientís desire for a sustainable house
Michael Klement says that his long-life, loose-fit strategy minimizes the need for invasive interior work to alter a house when homeowners’ needs change, and it doesn’t require modifications to the building shell.
“As responsible architects, designers, or remodelers ... this is a value-added component that we can bring as industry professionals,” Klement says. And, as remodeler Doug Selby points out, Klement’s long-life loose-fit philosophy meshes with aging-in-place design and “building a home so it’s useful in all stages of life.”
Klement wants his clients to consider other factors, such as resale value, in their remodeling plans as well. For example, although the client for this particular project didn’t require extra space, Klement’s design expanding the small house takes into consideration the needs of future owners who might. The new second story loft, which the current homeowner uses as her art studio, could, in the future, “be converted into additional bedrooms for an in-law suite or nursery,” Klement says.
In another nod to future needs, the home’s exterior cladding is attached to 1½-inch furring strips, so that if the homeowner wants to change the existing cement board siding, it can easily be unscrewed and replaced.
Klement has “future-proofed” other projects as well. Some examples include:
- Separating spaces by using a non-load-bearing partition that can be removed to provide a wider entry/wheelchair access.
- Including a long covered front porch that could later be converted into a wheelchair ramp with a 4-foot turning radius at either end.
- Installing conduit from the roof to the home’s lower levels so that clients can easily install solar panels in the future.
A Whole New Dimension
It was during the exploratory design phase that the team discovered the existing home’s 2x10 ceiling joists at 16-inch centers — enough to support a floor. “That [was what] led us on the path to add up,” Klement says. “It’s almost as if the original builder thought about long life, loose fit. He passed the baton to us.”
Once the decision was made to add a second floor, the team sought the most efficient design for the new upper level. They considered the sphere (least surface area), and from that, a related shape: the cylinder.
The team opted to use structural insulated panels (SIPs) to create the cylindrical shape, basing the roof’s design on the dimensions of the vendor’s largest available panel: 8 feet by 24 feet. The roof uses five panels, with zero waste. This green strategy stemmed from the decision to pursue LEED Platinum certification for the project. “Green can be as simple as designing with modular dimensions,” Klement says.
In addition to SIPs for the roof, the team used advanced framing techniques for the walls. Klement says that standard framing has double top studs with the floor and deck on top, but AFT takes a different approach: “If you get the roof rafters to align with the wall stud and joists, you have a continuous load path.” The studs are 24 inches on center, rather than 16 inches. “You pull 30% of the lumber out of the package and add more insulation with a higher R-value,” Klement says. With AFT, lumber and labor costs are lower than a standard 16-inch-on-center wall, but with a nominal increase in the cost of insulation and drywall (thicker product to span a wider opening).
On the Move
To capture warm air that stratifies under the barrel vault, Klement designed three ducts that feed into a mechanical ventilation system that draws the warm air from the loft to the lower level. The air warms brick pavers in the entryway on the main level, which Klement explains, act as a “modest radiant floor.”
Klement also exploited the air temperature differential and prevailing wind direction to create a passive cooling system. Rising warm air that collects in the vaulted second floor is exhausted through motorized operable awning windows on the home’s eastern side. The air exchange is enhanced both by the shape of the building, and it’s orientation on the site. Opening first-floor windows takes advantage of positive pressure from prevailing western breezes, while low pressure on the eastern or leeward side pulls air out through open windows on the second floor. This passive cooling eases the load on the forced-air system.
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Green practices and products fulfill the clients desire for a sustainable house.
A. Improved Existing Shell
Remodeler Doug Selby’s crew filled existing wall openings with low-density open cell polyurethane foam and covered the exterior with high-performance sheathing and a combination air/vapor barrier by VaproShield to create a more airtight shell.
B. Water Conservation
Ultra low-flow water fixtures (0.5 gpm faucets, 1.0 gpm showerheads) and dual-flush (1.6/0.8 gpf) toilets conserve water. The rainwater catchment system sends water collected from the standing seam metal roof on the front half of the structure to a sand-filtered water storage tank. Rainwater from the rear half of the roof is collected in rain barrels for irrigating the landscaping.
C. Thermal Siphoning
This system uses hot air that rises to the top of the loft to heat pavers on the main level. (See “On the Move.”)
Architect Michael Klement specified an energy recovery ventilator, noting that high-performance homes like this one have minimal natural air exchange, so contractors should use energy or heat recovery ventilators to provide continuous ventilation with a minimal energy penalty.
The homeowner was concerned that her old furnace would break down, so Selby installed a geothermal heat pump a year before the remodel, sized for the future renovation. In addition to heating and cooling the home, the geothermal system provides hot water for the house. An on-demand gas hot water heater was added to boost the water temperature by 5 to 10 degrees if needed at the remote bathrooms.
E. Solar Panels/SIP roof
The barrel-vault roof shape is ideal for optimal placement of solar panels. The roof design was based on the dimensions of the structural insulated panel’s (SIPs), minimizing waste.
—Nina Patel, senior editor, REMODELING.