A Utah developer includes 12-foot-wide (3.7 m) townhouses to densify a two-acre (0.8 ha) block in the downtown of a new community southwest of Salt Lake City.

With the post-pandemic surge in demand for more affordable, socially distant single-family living, free of communal indoor spaces such as lobbies, hallways, and elevators, developers are turning to more economic variations of the classic urban townhouse, the quintessential form of single-family-attached housing. Unlike condominiums, they also permit market-attractive, fee-simple landownership.

Townhouses already economize the use of expensive urban land, so it follows that the narrower the dwelling, the more economic it is. In fact, scale and dimensions are critical. Even in larger cities, the width of townhouses traditionally varies from about 15 to 25 feet (4.6 to 7.6 m). For example, the average width of a townhome in New York City is 18 to 20 feet (5.5 to 6 m) while Washington, D.C.–area townhouses average 16 to 18 feet (4.9 to 6 m) wide.

Narrower townhouses exist but are unusual. A 19th-century 10-foot-wide (3 m) townhouse located at 44 Hull Street in Boston—reported to be the city’ thinnest—was recently listed at $1.2 million. Another, at 523 Queen Street in Alexandria, Virginia, is even thinner, measuring only seven feet (2.1 m) wide. In the 20th and 21st centuries, townhouses as narrow as 12 feet (3.7 m) engender special news articles.

Narrow micro-townhouse exteriors were designed to appear as larger buildings with smaller-scale elements such as trellis-covered roof terraces, projected bay windows, porches, and stoops. (UDA)

As suburban land has become more expensive, Sego Homes, a South Jordan, Utah–based homebuilder, is testing the market for 12-foot-wide (3.7 m) townhouses to economize on both land and building costs. The thin micro-townhomes will be located in Daybreak, a new, 4,126-acre (1,700 ha) community 20 miles (32 km) south of Salt Lake City. The community was originally planned by Berkeley, California–based Calthorpe Associates for 20,000 units and was initially developed by Kennecott Land Company, but has been under the stewardship of Sandy, Utah–based Larry H. Miller Real Estate since April 2021.

Sego’s thin micro-townhouses, called Urban Townhomes at Daybreak, are under construction on a two-acre (0.8 ha) site at the northwest corner of Lake Run Road and Black Twig Drive in the new 400-acre (162 ha) downtown carved from a 12-acre (4.9 ha) superblock that lies across from newly developed 240-by-600-foot (73 by 183 m) blocks.

The project architect, Eric Osth, chairman of Pittsburgh-based Urban Design Associates (UDA), says, “We are certainly not the first to take on this challenge of a ‘micro-townhouse’ and historically it has served as a component of our favorite cities for years. We are just finally looping back to this as a new direction.”

Density

The challenge to optimize density starts with site size and block configuration. Since townhouses are mostly rectilinear, architects sliced off a 5,000-square-foot (465 sq m) triangular sliver at its south end to use as a green on which to face 10 of the thin townhouses at its entrance. That squared off the site to 240 by 360 feet (73 by 110 m), into which they projected a 100-by-50-foot (30 by 15 m) green peninsula around which they sited 15 more townhouses.

Although each narrow townhouse has a one-car garage, none faces an external street, three of which border the site. Vehicular access is from an internal Z-shaped 20-foot-wide (6 m) drive running from the east side to the west side.

The north side is a 20-foot-wide (6 m) tree-lined allée bordering the next group of townhouses. The resulting site plan yields 51 of the 12-foot-wide (3.7 m) townhouses and is interspersed with six 20-foot-wide (6 m) townhomes that take advantage of irregular spaces “to maximize the layout of the site,” says Spencer Corbridge, Sego’s vice president of operations.

Density reaches 28 units per acre (69 per ha), which is comparable to that of three-story multifamily garden apartment buildings.

Osth declares that thin micro-townhouses are a “great urban model for human-scale streets, far more permeable for pedestrians, and easy to implement for local builders,” who can sell them on a fee-simple basis.

While that density for thin micro-townhouses appears high, it is only half that the 240-by-360-foot (73 by 110 m) block could contain if planned for hypothetical maximal base density. This would require integrating five shared pedestrian/bicycle/vehicular and green 24-foot-wide (7.3 m) woonerfs (a Dutch term meaning “living streets”) between six rows of 12-by-40-foot (3.7 by 12 m) townhouses.

Such shared multifunctional green streets are usually developed with pervious paving draining toward the center. In this illustrated diagrammatic alternative, a 24-foot-wide (7.3 m) green, tree-lined allée also courses through the block and divides 108 micro-townhouses into groups of nine, thus achieving a density of 54 units per acre (133 per ha) with a 1.4 parking ratio, including 48 on-street spaces.

“In our initial prototype testing, we did test an ideal block for peak densities to nearly 40 units per acre [98 per ha]; as this is a new product for Daybreak and the Salt Lake Valley, we wanted to create a high density without compromising livability. As the product catches on, we may build denser blocks,” Osth explains.

Sego’s Daybreak layout creates individually platted “lots that are typically 12 by 57.5 feet [3.7 by 17.5 m], although some of the lots are longer and allow for a driveway that allows the buyer to park a second car,” says Corbridge. With 63 garage spaces and 18 more in driveways, the parking ratio yields 1.4 parking spaces per unit.

“This site is a half block away from a light-rail station and is within walking distance of restaurants, hospitals, and grocery stores, which allows us to provide homes that are focused on urban lifestyles and not cars,” he says.

Even in larger cities, townhouse width traditionally varies from about 15 feet (4.6 m), like these 19th-century townhouses in Savannah, to 25 feet (7.6 m). (Macht & Company)

Narrow Unit Design Challenges

Thin micro-townhouses can lower building area costs, too, but they present a variety of design challenges. The staircase core consumes one-quarter of the floor area on each floor and its placement determines the size and character of different rooms containing different functions.

“When developing a floor plan, the staircase is always the first place we start since it has such a major impact on the plan; clustering the stairs in the middle opened up the plan and allowed for more light and interconnectivity between floors,” Osth says.

The length of the garage also determined the location of the staircase, which, in turn, defines the lengths of the kitchen, the living room, and bedrooms above. A difference of even a few feet can make a significant difference in the flexible uses of spaces. The 12-foot (3.7 m) width can house a single car, which, in turn, helps define the market attracted to them. Sego’s 20-foot-long (6 m) garages accommodate all cars but reduce to 10 feet (3 m) the length of a flex space, living room, and bedroom at the front of the house.

Since most cars are shorter than 16 feet (4.9 m), if the garage were reduced to 18 feet (5.5 m), even an extra two feet (0.6 m) could allow for a full bathroom to be built in an enlarged flex space, enabling its use as a guestroom or third bedroom, as well as altering the flexibility of the living room and front bedroom on the floors above.

The staircase core divides kitchen and living spaces on the second floor. Sego ameliorates this by offering a $3,900 metal railing option to permit partial views between those spaces. A half-bathroom and laundry closet are located beyond a 12-by-12-foot (3.7 by 12 m) kitchen. If a bathroom on the first floor supplanted the half-bathroom on the second, the kitchen sink counter could be relocated along the end wall below a six-foot-wide (1.8 m) window, flanked by a laundry closet behind bifold doors on one side and a refrigerator in a matching space on the other. That could leave enough space for both a parallel kitchen island and a separate dining area.

On some units, UDA enlarges the 10-by-12-foot (3 by 3.7 m) living room with a four-by-eight-foot (1.2 by 2.4 m) projected bay. A further variation of the projected bay concept might include cantilevering the full width of second and third floors by four feet (1.2 m) on one or both ends, which could enhance their flexibility beyond the 48 square feet (4.5 sq m) that it could add to the floor area at each end.

The third floor is divided into two bedrooms and one bathroom accessible from the hallway. An extra cantilevered four-foot (1.2 m) length could change it to an en-suite master bedroom as well as permit the addition of a second bathroom on the third floor, which would transform the character of the thin micro-townhouse to one with dual master bedrooms. A four-foot (1.2 m) cantilever at the kitchen end of the second floor would enlarge a separate dining area.

An optional fourth floor is provided for 37 units, which have a third bedroom and a bathroom on one end and a 10-by-12-foot (3 by 3.7 m) roof terrace under a trellis on the other end. The fourth floor could also be designed as an enclosed space.

“Roof terraces typically are not more cost effective due to the complexity of waterproofing a walkable roof space for all-season use, but buyers prefer to have the roof terraces to take advantage of the views” to the surrounding Wasatch mountains, Corbridge says.

Sego Homes offers a metal staircase railing option to permit partial views between living and dining spaces. (Sego Homes)

Costs

Osth says that the UDA/Sego team’s intent was to “address affordability by design—high land, material, and labor costs. Thus, we have to deal with the areas we can control–unit size and land utilization.” Density decreases the unit land cost, while narrow widths reduce building areas per unit, thereby enhancing affordability. Narrow units also reduce the cost of facades, typically more expensive than developing additional interior space.

One-third of the thin micro-townhouses are three-story, 1,136-square-foot (106 sq m) units (including two bedrooms, one and one-half bathrooms, a flex space/home office, and a single-car garage) properties whose prices start at $300,000. Two-thirds of the thin micro-townhouses are 1,440-square-foot (134 sq m) units that add a fourth story, which adds 304 square feet (28 sq m) containing an optional second bedroom, a full bathroom, and a 10-by-12-foot (3 by 3.7 m) roof terrace covered by a trellis.

Base prices start at $375,000 in a market where reported median home sales prices were about $537,000 in July 2021. Average home sizes in Daybreak are larger, at about 2,000 square feet (186 sq m). Corbridge notes that with “lower lot costs, the buyer saves money with less exterior material costs and also lower HOA landscape management expenses.”

A basic strategy for Sego Homes was to design a base-unit plan for buyers with a variety of options that provide market choice for buyers and price flexibility for developers. Options include the fourth story with a roof terrace as well as the number of bedrooms, bathrooms, stair railings, closets, and kitchen island.

“It is worth noting that we did not include standard closets in the initial design since they drive the way a room is used; any room can have multiple functions such as a bedroom, sitting room, home office, or gym,” Osth says, adding that affordable after-market closet systems—some of which integrate home offices—can provide similar storage, efficiently maximize the use of space, increase the flexibility of various rooms in thin micro-townhouses, and contribute to lower building costs.

When the manufacturers of narrower 24-inch-wide (61 cm) kitchen appliances lower their prices to or below those of wider models, developers of thin micro-townhouses will be a natural market to economize space for buyers. Wall beds, flexible furniture, and storage systems also can enlarge their functional space.

Although it might seem logical that narrow 12-foot-wide (3.7 m) units would be cost effective for modular prefabrication, Corbridge says that his company’s experience has been that modular building does not, in fact, save time or labor costs. In addition, it could complicate multiple building options and make design variation more difficult.

Osth says, “We approached the exteriors to appear as larger buildings with human-scale elements such as porches, stoops, and bay windows,” all of which might offset prefabrication economies for this application.

A prefabricated modular system of functional louvered screens lining wide but shallow units was developed by Urban Splash on its MoHo project in Manchester, United Kingdom. (Urban Splash Group Limited)

A system of louvered screens to create functional facade variation has been devised for larger prefabricated modular projects—for example, the MoHo condos in Manchester, United Kingdom. (See Will Macht, “MohoModules Modernize Manchester,” Urban Land, February 2007, pp. 114–117.) But prefabrication works best at a large scale for projects built simultaneously. Like those of most American single-family builders, Sego’s projects are erected over a timeline that matches expected sales absorption time.

“We have been building our 12-foot-wide [3.7 m] homes for roughly nine months and expect to be building out the site for another nine months,” Corbridge says. At that time in August 2021, Sego had sold 26 of 28 then-available micro-townhouses.

As an initial project at the periphery of Daybreak’s 400-acre (162 ha) new transit-oriented downtown, UDA’s design experimentation with thin micro-townhouses matches Sego’s commitment to create a neighborhood with an urban character for a location 20 miles (32 km) from a major city. Their thin micro-townhouse building form demonstrates a replicable example for other community builders to diversify building types and produce more affordable housing options.

WILLIAM P. MACHT is a professor of urban planning and development at the Center for Real Estate at Portland State University in Oregon and a development consultant.

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