Idle speculation: podium apartments, floating above a parking lot

Podium construction: if it's good enough for these guys, it's good enough for you

As of 2015, the IBC now permits multi-story concrete podiums. At first, this was mostly of interest because it permitted even taller “double podium” apartment buildings, with up to eight stories framed mostly in wood.

This diagram (by Nadel, Inc. for Multifamily Executive) shows the effect between The Podium and The (Double) Podium: you can squeeze an additional floor in above grade, and because it’s concrete (heavy line) it can be used for residential, retail, or parking.

Yet using that magical concrete-framed second floor for residential (which could just as easily be wood-framed) seems like a bit of a missed opportunity. Instead, the second floor could be a mezzanine parking level for the wood-framed residential above — as was done in the mixed-use Grey House at River Oaks District pictured above, or in this mixed-use development on LA’s Olympic Blvd.

The real breakthrough possibility for the parking mezzanine isn’t atop retail, though: it’s atop yet more parking.

It just so happens that a 65-75′ wide module fits either a double-loaded apartment building or a double-loaded parking aisle. Therefore, a four-story building (three floors of Type V residential, one level of parking) can be stacked atop an existing aisle of parking — without diminishing the existing parking lot, and without excavating any parking.

It’s the suburban infill version of “have your cake and eat it, too”: keep your parking and add infill housing, too.

3 over 2

Developing these air-rights infill parcels used to require some pretty tremendous trade-offs. The first such projects that I saw were designed by Gary Reddick, a Portland architect who won a CNU Charter Award in 2004 for two such projects. Jury chair Ellen Dunham-Jones subsequently wrote about these in HDM:

In Seattle and Portland, where there are very good markets for residential development, Sienna convinced a variety of non-residential building owners to sell the air rights over their parking lots or roofs for housing. In Portland’s desirable and compact Northwest neighborhood, Sienna saw the parking lot of a specialized medical center as a potential housing site. After producing a pro forma, the firm approached the owners and showed that it could provide them with a covered, forty-three-space parking lot (with only three fewer spaces than before) and a million-dollar profit in exchange for stacking an additional layer of parking (with a separate entry) and two stories of condominiums. The built project, Northrup Commons, screens the parking with duplexes entered from the streets and adds two floors of apartments.

This turns out to be tough to replicate elsewhere. Because the residential comes with its own parking requirement, fully replacing the on-site parking requires adding parking somewhere else — either building a new parking lot elsewhere, or digging underground, at super-high cost ($11 million at one Seattle project). Most of the Sienna projects, including Northrup, used sloping sites (common in the Northwest) to tuck one parking level partially or fully underground.

tyson

Since the resulting buildings would block visibility and doesn’t result in an active ground-floor frontage, this particular infill seems best for infilling around Class B offices that currently sit adrift in a moat of parking — such as the above complex on Old Courthouse Road, at the southern fringe of Tysons Corner (image from Bing Maps). Or, many properties along this stretch of the infamous Executive Boulevard near White Flint (image from Google Earth):

exec

* A rough assumption here is that each 1,000 sq. ft. apartment would have one parking space, which works out to about 3:1 residential:parking floor space. The ratio seems to work for the Houston example, which promises its residents the ability to park in-building rather than having to venture outdoors. Sufficient parking for rich Houstonians is probably enough for anyone.

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Recently: winning the war on sprawl, over-preservation, office to residential, shared streets, tax bill

I’ve recently published several articles over at GGWash.

  • Sprawl is slowing, but that doesn’t have to mean higher housing prices.” The downtown high-rises under construction only tell half the story of Greater Washington’s housing growth story. While all those cranes are easy to see from afar, what isn’t immediately apparent from the airport (but might be from a plane) is that many fewer acres of the countryside around us are being bulldozed for subdivisions–which for the past century has been where most lower-cost, low-rise housing was built. As a result, the region as a whole isn’t building enough housing for our rising population… Not only is supply overall not keeping pace with demand, but a large fraction of the new supply is in the housing market’s priciest segment: expensive high-rise construction, on expensive downtown land.
  • DC has more historic buildings than Boston, Chicago, and Philadelphia combined. Why?” Nearly one in five properties in DC are protected by local historic designation laws. DC is so prolific at handing out historic designations that we have more historic properties than the cities of Boston, Chicago, and Philadelphia combined, which together have almost eight times as many properties as DC. While this policy has ensured harmonious architecture across much of central Washington, it also means that Washingtonians are much more likely than residents of other cities to have their construction plans delayed or denied on subjective grounds by a historic review board.
  • Historic preservation in DC saves the loudest neighbors, not the finest buildings.” DC’s surfeit of historic structures results from several factors, notably the broad application of rather vague criteria for designation. As Roger Lewis has written, “the HPRB decision is inevitably a judgment call because much of the evidence for historic designation is inherently subjective.” Since every resident “squeaky wheel” is invited to request historic designation for just about any site in the District, many do — and overwhelmingly, they succeed.
  • DC’s countless thirtysomething office buildings stare down mid-life crises.” No other region can match Greater Washington’s density of 1980s and 1990s office buildings — we built over a million cubicles’ worth, almost as many as in the much-larger New York and Los Angeles regions. Now, these buildings are facing mid-life crises; many require substantial additional investment, as key building systems (like air-conditioning, plumbing, elevators, and roofs) require overhaul or replacement, just as the office market has changed.
  • Not every obsolete office building is cut out to become apartments.” Some, but not all, of these old offices can become residences, depending on their location, price, and layout. Despite considerable media coverage, office conversion has been comparatively limited in greater Washington for a variety of reasons, including a relatively healthier office market and a lack of specific incentives for the practice. Residential conversion offers some promise, but will not be a panacea for either the over-supply of offices, or the under-supply of affordable homes, because not every obsolete office building can be converted to housing.
  • Metro needs a loop to lasso riders from this growing corner of DC.” The way the District is growing is creating another rail bottleneck on the other side of town that will have to be addressed in the future. The Capitol Riverfront is easily the fastest-growing part of DC right now, and by some accounts one of the fastest-growing neighborhoods in America. If all 11,978 new housing units proposed within the Capitol Riverfront get built, the area around Navy Yard station would have the largest household population of any Metro station. Metro’s ridership forecasts, which now factor in development proposals, foresee that the area’s rapid growth might require additional investments, like a new subway line.
  • How are the Wharf’s shared spaces working out?” When the Wharf opened last month, it instantly became the largest expanse of “shared space” streets in the country. Over the past few weeks, it seems like these streets are largely working as they were designed. Even though a few of our commenters were skeptical about whether the approach would work here, so far there haven’t been any major complaints or adjustments needed.
  • The GOP tax plan would make housing and infrastructure more expensive.” Eliminating Private Activity Bonds and New Markets Tax Credits, as the House GOP’s tax code overhaul proposes, would have deep ramifications for funding infrastructure and affordable homes in the region.
  • The latest Republican tax bill changes commuter benefits, but probably not yours.” Tax law will only indirectly affect most area commuters.
  • Added 26 January: “A bold California bill would ease transit oriented development. How would a similar approach affect DC?” A bill recently introduced into the California legislature boldly proposes that every transit corridor in the state be rezoned to permit mid-rise apartments. In Slate, Henry Grabar writes that it’s “just about the most radical attack on California’s [housing] affordability crisis you could imagine.” In the Boston Globe, Dante Ramos writes “the bill may be the biggest environmental boon, the best job creator, and the greatest strike against inequality that anyone’s proposed in the United States in decades.”

 

Brand-new timber loft offices, now for lease

N. Vancouver Ave. frontage of One North

Last week, I published a ULI Case Study about One North in Portland, an architecturally inventive response to my previous speculation that “new-build loft offices could be popular in similar downtown-adjacent submarkets, and transformative for Sunbelt cities where sparse ‘warehouse districts’ have little competing product.”

Indeed, the anchor tenant at One North is a mid-sized tech company that had outgrown its space in Portland’s Central Eastside. As in many other growing cities, there just wasn’t a cool old loft big enough, so instead they found a cool new loft.

T3 Minneapolis under construction

Southwest corner of T3 Minneapolis, showing CLT column stacked above concrete podium

I also had a chance last week to check in on T3, Hines’ new cross-laminated timber office building in Minneapolis. Less than a year after groundbreaking, the structure is complete and the facade is almost completely hung — almost a year faster than a comparably sized concrete building takes to build. The superstructure took less than 10 weeks to build.

The model is so successful that Hines is now replicating the T3 building at another location that’s even hungrier for lofts: Atlantic Station in Midtown Atlanta.

Here in DC, one great location could be the PDR-2 zoned land (90′ height permitted with setback, no residential) on the west side of the Met Branch Trail along Eckington and Edgewood, one of the hottest corridors in town. Another could be around Union Market/Gallaudet, where JBG’s Andrew VanHorn says “we see the tenant base there evolving. The pre-lease opportunities we’re talking to for our office building are all private market, very young companies, as far as their employee demographics.” Or maybe this is what his firm has in mind for the “creative loft office” at RTC West.

An aside: this is another strike against “Investment Ready Places.” It sounds counter-intuitive, but it’s easier to move buildings to people than to move people to buildings. The “good bones” that economically unviable places have can have “good enough” replicas in New Urbanist settings like Atlantic Station and Reston Town Center. Not to mention that building all of the new infrastructure to overcome IRPs’ deficient locations, and then rehabilitating their buildings to code, would be much more expensive than just building anew in prime locations. It’s cheaper and easier to build new lofts in Reston than to rehab lofts in West Baltimore, and to build the new rail connection that would make West Baltimore feasible for NoVA’s growing companies.

Cities are built around people, not the other way around.

2017 update: Construction has started on an 800,000 sq ft HT building on the Brooklyn waterfront.

Friday photo: A balcony to nowhere

Twinbrook Hilton, faux John Portman

Twinbrook Hilton, Rockville, Md.

Architect John Portman was fond of putting “balconies” around the edges of his hotels’ massive atria. Perhaps this was part of the concurrent “conversation pit” trend that afflicted malls of that era, maybe people really did just pause and gawk at the tremendous volumes while walking to/fro the elevators, or maybe he liked the “columns around the Forum” look that they lend to the interior. Yet… nobody quite knows what to do with them today.

Who, after all, has need to stop and gather in a hotel hallway, the very definition of a neither-public-nor-private space? Why not go to the lobby, if it’s a public conversation, or into a room?

At the faux-Portman Twinbrook Hilton in Rockville,* the management was sick of complaints from atrium-facing rooms (one-third of the total) about nighttime noise. One option was to replace the atrium-facing windows with airport-style noise-insulating glass, but ultimately it proved cheaper to just wall off the entire atrium with a curtain-wall system – including putting these silly aluminum doors to wall off the balconies. Maybe someday they’ll put furniture out there, which surely will just gather dust. Or maybe there really are people who use these spaces, like maybe gossipy 8th graders on school trips who don’t want to keep their roommates/chaperones awake. (Isn’t that what Snapchat is for?)

Of course, that particular solution is still better than the temporary option I once spotted at the true-Portman Bonaventure, apparently aimed at LA’s exhibitionist-fitness-enthusiast crowd:

Pod people

Westin Bonaventure, Los Angeles, Calif.

* I remember once staying here as a child and getting evacuated from the building by an overnight fire alarm, in my first (but definitely not last) high-rise fire alarm experience.

How Chicago’s zoning excludes small apartments from the neighborhoods

chizone

Chicago’s zoning code has a built-in bias against smaller apartments – except in a few high-density zoning districts, which cover a vanishingly tiny slice of the city.

The zoning ordinance regulates building size and density in three ways: through floor area ratio (FAR), “minimum lot area per unit” (MLA, a backwards way of saying dwelling units per acre), and through various setback regulations. Yet these don’t follow a linear relationship at all; instead, the interaction between FAR maximums and MLA minimums encourages larger buildings with fewer apartments in lower-density districts, and more apartments per building in higher-density districts.

What this graph shows is: If I have a standard city lot in a given zoning district, and I build the biggest possible building with the most possible units, how large would those units be? The answer varies tremendously across the city, from a low of ~600 square feet in high-density districts like RM-6 and DR-7, to “impossible” in the lowest-density districts (note 1).

Most of the city’s neighborhoods, from the Bungalow Belt through the Zone of Two-Flats (mostly zoned RS-3) and into the Zone of Three-Flats (mostly RT-4), is zoned for the lowest-density (left-most) third of this graph. From RM-4.5 on down, the average apartment that can be built at the maximum density must be 1,250 square feet or larger (the size of a large two-bedroom apartment). Sure, you could build studio and one-bedroom apartments, but then you’d have to build huge three- and four-bedroom apartments, too.

Only for RM-5 and above, high-density zoning classifications pretty much only found in a narrow band along the lakefront, do the average apartment sizes permitted begin to dip into one-bedroom territory.

Someone who wishes to build new smaller apartments, like one-bedrooms or studios, in order to accommodate shrinking households can only do so in neighborhoods like Lakeview or Logan Square by either (a) under-building the FAR, at a considerable opportunity cost, or (b) getting rezoned to a denser category. Anyone who goes the latter route might as well build a lot bigger and higher, too.

Methodology notes:

  1. I assumed a standard 25′ x 125′ (3,125 sq. ft.) city lot. In RS-1 and RS-2, you cannot build on a lot that small, hence those values are excluded.
  2. The MLA chosen is the number specified for efficiency apartments, a distinction made in higher-density districts which would skew their figures down.
  3. “BCD” here refers to mixed-use zones that can be designated Business, Commercial, or Downtown depending on the use. What’s important for these purposes is the numeral in the zone name, which defines the density allowed. These zones all permit (and indeed, require) substantial amounts of commercial floor space, which counts against FAR but not MLA; for these zones, I assumed an apartment building with 0.5 FAR of commercial space, and the rest residential. This skews the figures upwards for downtown districts, where one would reasonably expect more than 0.5 FAR of commercial space.

Friday photos: Tokyo’s small scale, and how I learned to love Modernism

Cube

No less an authority on great streets and great cities than Holly Whyte, guiding spirit of the Project for Public Spaces, wrote in City: “But the most fascinating of Tokyo’s streets are its ordinary ones. Mile after mile, they are consistently more interesting than ours. In the Shinjuku district there are more streets to savor than in most U.S. cities put together, and for sheer sensory impact there is nothing to match its back alleys…” (And Whyte’s comparison set was NYC in the 1980s, which hardly lacked for “interesting” streets that packed in “sensory impact.”)

Narrow flatiron

Tokyo disabused me of any notion that classical architecture was integral to creating walkable, human-scaled places, or that newness per se is the problem. Japanese cities show that fascinating places can exist with mediocre 20th-century architecture. And because they’ve shown that it’s possible to build fantastic, prosperous, massive, and efficient cities in the 20th century, they’re much more powerful examples for city-builders in our time than European antiquities.

Tokyo was a megacity in the pre-industrial era: it boasted a million residents back when New York was a mere town of 50,000 cowering on the edge of a vast wilderness. But Tokyo was leveled by an earthquake in 1923, then firebombed in World War II. Unlike other societies, which would use those catastrophes as excuses to re-plat and re-organize, the Japanese rebuilt their cities with largely the same warren of narrow streets and the same itty-bitty lots, but modernized the architecture with the very latest in cement-block schlock. It’s as if Rome were rebuilt by Angelenos in the 1970s. And it’s fantastic.

Here’s just a random intersection I walked through near Fudomae station, southwest of the city center and outside the Yamanote Line “beltway,” where a friend of mine happened to let me stay in her inexpensive flat. Yet it’s quiet, livable, affordable, fascinating to walk around, and completely illegal in America due to its narrow streets, mixed uses, Byzantine street pattern, high lot coverage, and high density — in other words, its small scale.

Many smaller buildings will create a much more lively streetscape, and more opportunities for cool urban spaces, than fewer but larger buildings. The critical deficiency in American cities, by comparison, is not limited to fixing a single profession, like architecture or even engineering. Rather, our entire system is tilted towards gigantism: our suburban-era parcel sizes, our High Modern-era zoning (which almost require large buildings), our mortgages, our street design manuals, our nonsensically upside-down parking requirements.

inside the void

If the stupendous urbanism yields such terrific results in the hands of ordinary architects, it becomes sublime in the hands of masters like Tadao Ando.

Friday photo: Shared space, residential parking-lot edition

Sofia Lofts, San Diego, CA

The ULI Case Study that I wrote about Sofia Lofts, a 17-apartment development in a neighborhood in eastern San Diego, was recently posted. I was particularly intrigued by how the developer/architects used shared space to maximize usable open space while meeting the letter of the law with regard to parking requirements:

For the balance of the 21 [parking] spaces planned, six more garages are accessed via the courtyard. The plans show seven more spaces within the courtyard itself, immediately in front of the garages — but to keep the space inviting, the spaces in the courtyard are off limits for tenant parking. It’s a small net loss for NDD, which discounts the rent for some tenants who forgo on-site parking, but results in a common area that looks like an expansive garden, rather than a parking lot.

The materials used within the courtyard were also chosen to make the garden feel like a place where cars just happen to be allowed. Part of the driveway near the alley is paved with concrete, but the center of the property is covered in pea-sized gravel. The texture of the gravel slows down cars to walking speed, adds visual and auditory interest, and permits rainwater to filter through. Its inspiration comes from a house in Italy that the Nakhshab family lived in; as Soheil recalls, “The courtyard we would always play in had that type of gravel, and we are seeing the tenants’ children doing the same thing.”