The ‘Shamrock Shack’ Retrofit – A Family Style of Green
General Specs and Team
Location: Pacifica, CA
Living Space : 1745 sqf
Interior Design: Alden Miller, Alden Miller Design
Architectural Design & Green Building Consultant: Ann Edminster, Design AVEnues
Contractor: Dan Miller, Daniel Miller Construction
Structural Engineer: Bruce King, Bruce King Consulting
Energy/Mechanical Design: Bill Dakin, Davis Energy Group
• Spray foam insulation added to roof, walls, and floors
• High efficiency Phoenix gas water heater backing up a solar thermal system
• 5 heating zones with programmable thermostats
• All new Marvin windows (double low-e, argon-filled) and doors
• Window treatments that modulate solar heat gain and loss
• Grid-tied PV array
• Enclosed stone fireplace to block thermal bridging
• Fireplace replaced with high efficiency Jotul wood stove insert, old chimney sealed
• Energy Star GE refrigerator (GTH22KBRWW)
• CFL, electronic ballast FL, and LED lamps
• Sola Tube skylights for natural daylight
• Bosch (SHV68M03UC) dishwasher
• Whirlpool Duet (WFW9400SW) front load clothes washer
• Toto Aquia (CST414M), dual flush toilets
• Hansgrohe Croma low volume shower heads
• Tub with water saving cross-section
• Remote switch recirculates hot water on-demand to remote bath
• Gray water diversion plumbed in at installation
• Gutters and downspouts designed for catchment and reuse
• Landscaping plan (underway) with native and climate-adapted plants
Indoor Air Quality
Green Materials and Resource Efficiency
• Reuse of materials (including much of the original wood which was itself reused by Carl McCarthy, the original home’s builder, from demolition of old buildings in San Francisco in 1938 to the early 1940s)
• Salvage of burnable unusable wood for firewood
• Donation of still usable items (Building REsources)
• Minimal volume of demo materials to landfill
• High R-value spray insulation in walls, floors, and ceilings
• All new wood was FSC-certified
• High-volume fly-ash concrete with lower CO2 footprint was used for all new foundation work
• Decorative transparent paneling by 3-form
• RPI 100% HDPE decking
This Bay Area project features family ties to green design and construction spanning three generations
In 1938, Carl McCarthy started his “Shamrock Shack,” a small (700 square feet) weekend retreat overlooking the golf course in Sharp Park (now part of Pacifica), Calif., while he and his wife, Grace, lived 10 miles north in an apartment in San Francisco. He had virtually no building experience and no power tools.
Pat Kremer, Carl’s daughter (and with her husband, Jim, the current owners), remembers the original home this way: “It was totally uninsulated, a ‘one-butt’ kitchen (6 by 8 feet), a bed in the living room, and a bathroom — that’s it. The name Shamrock Shack was just a whim of a young Irish-American couple feeling lucky to have a weekend retreat in those days.”
Carl and Grace moved to Sharp Park full-time at the start of World War II, freeing up their San Francisco apartment to wartime housing demands. Between then and 1952, Carl cobbled on additions to the home as the family grew, until the structure had three bedrooms and two baths, with living space of 1,434 sq. ft.
The Kremer family approach to green
In 2008, Jim and Pat Kremer, approaching retirement, decided to gut and rehab the McCarthy family home as their own.
According to Jim and Pat, this was their challenge: “How do we incorporate environmentally sensitive green practices and materials, retain the tone and feel of Pat’s original homestead, yet upgrade to a modern, cozy, livable, resource-efficient home?”
More than 60 years after the McCarthys’ move-in, the home was still uninsulated and comprised a charming but not very functional warren of interior spaces, along with a decidedly dated aesthetic. Razing it would have been simpler and probably more economical, but the Kremers – and ultimately their entire team – shared a strong drive to honor both the spirit and the materials embodied in the original home.
Jim and Pat started the process by building a project team that wove together family and local building expertise. Daughter and interior designer, Alden Miller; son-in-law and contractor Dan Miller; neighbor and leading green building consultant Ann Edminster; local leading green structural engineer/building materials expert Bruce King; and energy-savvy mechanical engineer Bill Dakin of Davis Energy Group — all worked shoulder-to-shoulder throughout the project.
Their charge was this unifying theme: in design, construction, materials selection and use, weave together the history of the Shamrock Shack (green in its own right) with 21st-century high performance and resource-efficiency.
Focus: integrating the whole – team and building
Ann Edminster: “You could look at all the themes and goals addressed in this project and wonder how it could possibly all fit together. But the team effort was enormously constructive, and the design came together beautifully. There are not many projects that when finished, I think to myself, I could live here, but the Kremer home is absolutely one of them. It feels like home.”
Edminster, although trained as an architect, is a long-time consultant and had not done hands-on design for many years when the Kremers approached her. However, Pat assured her (in all innocence), “There’s really not much design involved; we just need help with energy and other green issues … and if you can help us get the drafting done, too, that would be great.” As it turned out, the design challenges were quite significant and optimizing the design involved a lot of integration among the team members. There was a host of unusual structural, thermal, building code, and local zoning issues -- including some very tight clearances -- added to the typical array of functional, aesthetic, and green performance objectives. However, Edminster’s practice focuses on integrated design, and so the project, she says, was “pure pleasure. I think we succeeded quite artfully in accomplishing what Pat and Jim wanted.”
Alden Miller was integral from the start, delivering the design brief on her parents' behalf, contributing key input throughout the process, and taking the helm toward the end of design development to work closely with her parents on end-stage refinements. Edminster was seconded in the earlier stages of design by architect Karen Chan; both worked closely with King on structural improvements, with Dakin on energy strategies, and with Dan Miller on constructability and budget. Edminster says that Dan, new to green construction, “was completely on board with the program and executed the design with meticulous attention to detail.”
Focus: interior design
Alden Miller worked extensively with her parents on a detailed floor plan from the beginning of the team collaboration. Her efforts to envision multi-use spaces within the modest footprint while accommodating her parents' prize possessions created the starting point that was critical to the project's trajectory.
Alden Miller: “In approaching this project, my top-level focus was on three things: retaining the character of the original home, green design, and improving/unifying the functionality of the home."
Retain the character of the original home: “We made sure to reuse many of the existing materials. A good 95% of the wood floors are existing material, that themselves were salvaged by my grandfather from a Barbary Coast dance-hall when he built the house. To reuse the beadboard paneling in the back bedrooms we removed the paneling to strip and refinish. It was then reinstalled almost as a jigsaw puzzle after the window/door layout changed and insulation was added. We kept key elements like the stone fireplace, exposed rafters and non-structural trusses in the living room and the knotty pine wood paneling in the dining room.”
Another way to retain the character so important to Pat and Jim was with the floor plan. “My parents did not want a larger home or to unnecessarily change the feel of the spaces. We only added about 300 square feet of living space, leaving the dining room largely untouched. Although only one or two of the interior walls are in the original location, many rooms are in basically the same space allowing for the home to feel a lot like what it was. Even the new 'jungle' room is located where the original house had a very small exterior space, so it felt natural to design that space with a more 'exterior' feel.”
Green Design: “Sustainably responsible decisions were important to the design of the floor plan and the material selection. The floor plan was finely tuned in order to avoid purchasing any new furniture. For example the niche in the dining room was made deeper to accommodate both an heirloom sideboard and use the existing dining room table.”
“When selecting materials throughout the project it was important to not only design to the aesthetic of my parents but to create a home that was a natural extension of the unique woods/ocean landscape. We used doug fir for the window and door casing, built-in bookcases and all cabinetry. It was important to select a wood that was not exotic and doug fir added the needed warmth in addition to being FSC-certified. The one exception was the wood for the stair guardrail/display shelf. Here a medium stained walnut was used to compliment the darker furniture in the dining room and the end of the hall, and to set it apart from the other cabinetry. Together with the translucent Varia Ecoresin (40% pre-consumer recycled resin by 3-form) with embedded seagrass fronds, the walnut shelf makes a very nice focal point to the hallway.”
Unify and improve functionality: “I worked very hard developing a floor plan to give most every space a double function. For example, the small hall that takes you to the guest room/study off the living room also takes you to the bathroom and the utility storage room. The hall in the middle of the house (great design input from Ann [Edminster, project architect] to have this space open) is not just a pathway to get to the back bedrooms but is the entrance to the dining room, the landing for the top of the stairs, entrance for the jungle, place to stand at the phone niche, and a visual showcase for the furniture-like bookshelf/guardrail housing personal treasures.” Edminster adds, "I've learned over the years that the stairway is always a primary driver of form in multistory projects, so working this out -- along with the location of the jungle -- was a critical piece of the overall design puzzle."
Not only were the bathrooms and kitchen not terribly functional, but the existing windows and dark walls caused major day lighting issues and glare. Again, Alden Miller: “By adding skylights, using translucent glass panels for the interior doors and increasing the sizes for the non-view windows, we were able to bring a balance of natural light. Not only was the glare eliminated, but seldom is there a need to turn on lights during the day."
Pat Kremer sums up Alden’s work on the home’s interior design this way: “Alden contributed immensely by creating a unified whole that incorporated so many disparate aspects that we cared about.”
Focus: salvage and reuse
Carl McCarthy set the standard for reuse in this home back in 1938: he framed with used lumber, used windows and doors salvaged from sites in and around San Francisco, built the hearth with cobblestones being pulled out as the city paved its streets, and gathered river rocks for the chimney during every family road trip in their Model A Ford.
Dan Miller: “All deconstructed materials and off-cuts from the new construction process were separated on site for reuse. Still usable fixtures, doors and hardware from the original home that were not used on site were donated to a building materials salvage yard, Building REsources of San Francisco. And if reuse was not possible, materials were used for firewood or eventually recycled off site.”
Focus: design for permanence of place and people
Pat Kremer: “Our home is a family project started in 1938 but designed to meet our needs in retirement and the next generation’s needs as a growing family. Jim and I can age together here but we can also accommodate plenty of family when they visit or someday when this could be their family home. It’s a small home, but packed with purposeful spaces and family history.”
Focus: energy efficiency
Jim Kremer: “It’s not easy to honor the original structure and ambiance while dramatically improving the home’s energy profile. One good example of a solution: adding a required structural ridge to the main part of the house and then building a ‘second’ roof structure on top of the first created a deep space for plenty of insulation while leaving the original rafters exposed.
"And the performance of the state-of-the-art mechanical systems matches the efficiency of the structure so that our renewable energy systems approach our reduced energy needs. We are not net zero energy, but we are getting pretty close.”
Edminster also insisted on encasing the exterior of McCarthy’s salvaged-rock chimney – a big thermal bridge in the original structure – with an insulated wall that also embraces a new window seat and media niche. Thus the vintage character was not compromised, even while dramatically improving energy efficiency.
Jim and Pat Kremer are really happy with their "new" home. But the performance of their heating system is just not what they were expecting.
Jim Kremer: "Radiant hydronic heat is highly touted and considered to be so green. But we feel it has some drawbacks for our lifestyle and our benign climate. Consider that the system has to heat up the subfloor, the maple hardwood, and in some cases a nice carpet. Under the best of circumstances, this means the lag time to respond is quite long. Unless you keep a room/zone up to temperature full-time, you have to work this lag into the heating program.
"The main living space — living Room, dining room and hallway — are all open and connected. They are served by three PEX zones controlled by one thermostat. I have been using a modest setback at night (at 10 p.m., down to 63°F) and try to heat it up for the morning (by 7 a.m., up to 68°F). Now, when the outside night temperature is in the low 50s, this works OK and it warms OK. But when we got our coldest nights last winter (low 40s — and this is not THAT cold), the system had been unable to get up to temp. Even with progressive recovery set ON with the thermostats, it does NOT bring the space up to heat during the cold snap. And during more normal winter stretches, it is taking 4 hours or more to get up to temp after the setback. If we did NOT set back at night, we could probably keep it at 68°F, but this is certainly wasteful and I am not willing to do that so far.
"The master bath — It is far from the Phoenix water heater/boiler, and the PEX runs along the wall of the Jungle, under the slate floor. It is insulated below, but unless the Jungle is up to temp, the PEX runs quite a ways in the cold slate bed before getting to the bath. So, instead of a small bath area that would heat up quickly, it is slow and very demanding of heat (a large drawdown of the water tank temp — I've monitored it) to warm the floor enough to notice with your toes.
Jim Kremer is determined to optimize the performance of their radiant system. "It's a work in progress; we will learn more about how to tune the system, balancing it's performance with our patterns of use."
- Jim Kremer
- Alden Miller
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