Having lived in a 1,200 sq ft loft (30‘x40’) with 13’ ceilings at the time of my injury I knew the beauty and adaptability of an open floor plan. A typical house consists of rooms connected by hallways and corridors. Once you put some furniture in there it becomes difficult to move about in a wheel chair. Therefore, the fundamental design concept was maintaining an open floor plan.
The site/lot geometry was literally a pie-shaped wedge of ground resulting from a 1934 lot split. Not only was there a 30’ front yard setback but, furthermore, the historic district ordinance required new construction to align its building facade with that of the adjoining structures. Fortunately, the side yard setbacks were only 5’ and the rear yard setback wasn’t a concern as the narrow end of the pie-shaped lot limited what could be built regardless of the setback. Consequently, the backyard is a small, intimate garden area with a flagstone patio. Granted, the footprint of the house takes up a large percentage of the real estate. That said, the front yard is over 100’ wide as this falls at the widest end of the pie-shaped lot. The fact of the matter is: I’m in a wheelchair and cannot rake leaves or mow lawns, so this limited landscape is perfect for my wife to tend.
Once you decide to utilize an elevator, you open yourself up to infinite design opportunities. Personally, I’ve never cared for ranch-style architecture. Something about having my bedroom on the first floor just never set well with me. Obviously, given a tight urban site to build on, square-foot efficiency necessitated vertical construction. As we live in the Midwest, basements are commonplace. Therefore, we designed a three-story structure with an elevator servicing all three floors. Essentially the house is a 2,600 sq ft, two bedroom, two bath home (basement’s unfinished, plumbed for a half bath).
The genius of McMillan House was building a loft-like open floor plan in a two-story residential structure. In order to achieve this open floor plan, the second floor is supported by structural steel/wood beams. In a sense McMillan House is built like a small commercial building. There are no load-bearing interior walls on the first or second floors. Interior walls are only present on both floors as required to define pantries, bathrooms and bedrooms. Believing architecture is best when it’s allowed to express itself, we chose to expose the structural support beams. In both the first and second floors, you see the support beams slicing through the ceilings.
The exterior walls are made of SIP panels. Structural insulated panels (SIPs) are a high performance building system for residential and light commercial construction. The panels consist of an insulating foam core sandwiched between two structural facings, typically oriented strand board (OSB). SIPs are manufactured under factory controlled conditions and can be fabricated to fit nearly any building design. The result is a building system that is extremely strong, energy efficient and cost effective. Building with SIPs saved us time, money and labor.
Building with SIPs generally costs about the same as building with wood frame construction when you factor in the labor savings resulting from shorter construction time and less job site waste. Other savings are realized because smaller heating and cooling systems are required with SIP construction. The walls were comprised of 6” thick by 4’ wide panels while the roof materials were 8” thick. When a window was required we simply cut out the opening and framed it in with 2x6s. The exterior walls were first wrapped in Tyvek, then tar paper. Vertical nailing strips were nailed through the tar paper and the Tyvek then into the OSB of the SIPs. The final skin of the building was horizontal lengths of Brazilian redwood nailed into the vertical nailing strips. Other areas of the Tyvek-wrapped SIPs were clad in either stucco or stone.
WIth the exception of the garage doors, all the windows are Weather Shield double-paned, filled with argon gas. All the windows which open are casement windows. As a paraplegic, I don’t have the dexterity to slide a window up and down. The crank lever on a casement window is a simple design choice which restores my ability to open and close the windows in my house.
One other aspect of McMillan House which makes it energy-efficient is its earth contact design. There was about six to eight feet of grade change on the site. Consequently, we buried the north side of the house approximately six to eight feet into the hillside. If you look closely at the kitchen wall clad in blue tile and cabinetry you’ll notice the windows are mounted above the cabinets. As a result of this earth contact, the first floor maintains a moderate temperature winter and summer. The summer temperature is about 72-74 degrees. If we’re having a dinner party we’ll turn on the A/C to compensate for the added body heat.
The stairwell/elevator complex in the northwest corner of the house required additional structural engineering. Essentially, that corner of the house is a three story open area. As neither the first or second floor joists abut that corner of the house, additional support was factored in for added structural stability.