Low-Cost Mid-Rise, High-Value Amenities

With these economic realities in mind, multifamily developers and their architects are focused on efficient layouts, maximizing unit density, and low-cost building solutions. “Many of these new urban infill, mid-rise developments are gravitating to wood mid-rise solutions, including wood frame over a one- or two-story concrete podium, which help maximize how many units you can fit on the site,” says WoodWorks' Podesto. “There are also major cost savings, period. Savings of 30 percent would not be out of the question, though of course it depends on the project design and the system it's being costed against.”

Examples include the first phase of the University of Washington's West Campus housing in Seattle, which added 1,700 new beds in three residential halls and two apartment buildings designed by Mahlum Architects. The 668,800-square-foot complex uses five stories of light-frame wood over two stories of concrete structure, which cost about $177 per square foot to build in 2012. “Currently we're seeing a majority of our projects leveraging this 'five over one' typology, mainly due to budget constraints,” says Anne Schopf, FAIA, design partner with Mahlum. “This is a common construction type here in Seattle.”

For the West Campus, each building has upper floors of Type V-A construction over two lower floors of a Type I-A concrete, clad with manganese flashed brick and topped with roofs of engineered wood trusses and plywood sheathing. The podium and upper floors are separated by a three-hour-rated floor assembly, and the wood-frame floors use 2x4 and 2x6 wood studs and plywood sheathing in both exterior and interior load-bearing walls and partitions. Schopf specified engineered wood I-joists and plywood sheathing for the floors and stair treads, with landings of glued laminated beams and engineered laminated strand lumber (LSL) for the rim board stringers. Heavy timber blocking throughout affords fire protection, though all floors are fully sprinklered.

Similar techniques are validated at Morgan Park Place in Nashville, a 72-unit, mixed-use residential and retail development located parkside in the historic Germantown neighborhood and designed by Dryden Abernathy Architecture Design. After winning a competition for this project, the architects put into action their eco-friendly, “urban village” concept for a live-work-play hub of townhouses, carriage houses, single-family houses, and upstairs flats in mixed-use buildings. The units, in compact sizes ranging from 750 to 2,200 square feet, were priced at $150,000 to $550,000.

The hybrid structures combine precast insulated concrete form (ICF) walls and light-frame wood using advanced framing techniques, such as ladder corners, which allow for better insulation. Various cladding materials “ensure a timeless, modern landscape,” say the architects. The tightly sealed enclosures are heavily insulated with open-cell spray foam for larger surface areas and closed-cell foam for enclosure joints. Between the studs, blown-in cellulose from recycled blue jeans provides ample R-value. Interior materials include sustainable bamboo flooring, Energy Star-rated appliances, on-demand water heaters, recycled rubber, and highly efficient heating and cooling equipment.

The enclosures also benefit from windows and doors with low-emissivity (low-E) triple-pane glazing, according to Pella's Zeimetz. Between-the-glass window treatments increase each opening's energy efficiency, helping to substantially reduce heating and cooling costs. Convenient for users and flexible in terms of design, the integral window treatments snap in and out, so homeowners can change them as desired, choosing from blinds, shades, grilles, or decorative panels.

Earning an EarthCraft House certification, the new complex offers living spaces that are 50 percent more energy-efficient overall than conventionally built homes—and with less square footage. “When you have a premium product on the marketplace, you have to offer advantages—especially when it is a small space,” says Darrell Crawford, director of New Urban Construction LLC, one of the developers. “Our customers want personalization, and the windows help meet that need.”

In other situations, especially where energy efficiency is critical, so-called “premium vinyl” windows are useful in not only meeting aesthetic needs but also providing high levels of insulation. Some of these units, which can look like traditional double-hung and picture windows, are specified for admitting plenty of sunlight while helping to ensure good thermal performance.

At the Prestwick Chase mid-rise senior development in Saratoga Springs, New York, for example, architect Ethan Hall of Rucinski Hall Architecture specified about 1,500 high-end vinyl windows with low-E glass and an argon gas fill. The thermal control helps reduce unwanted heating in the building's sunlit atriums and window-wrapped common areas.