Four-Plus-One's are built on either single or double lots. The common Chicago lot is 125 feet deep and 25 feet wide. Four-Plus-Ones built early on in 1961 or 1962 are often on single lots, while later examples and the majority of the type are built on double lots. Because Four-Plus-One's were designed to be economically expedient money generators, it follows that nearly every example occupies as much of the lot as possible. This is always done in the same way. The building straddles the sides of the lot but is set back about fifteen feet, the minimum, from the sidewalk. These buildings are squeezed into lots, fulfilling the minimum requirements of zoning and building code, while maximizing the number of units.
The term is “Four-Plus-One” is unique to Chicago. In other cities with five-story apartment buildings with underground parking, it is very likely that people refer to them as “apartment buildings” or “condos,” whichever they may be. Four-Plus-One refers to two things; the height of the building, and a separation of functions (the parking lot). This implies that the elements of height and functionality are the ones that define the Four-Plus-One. As these elements are among the reasons that these buildings are so reviled, we can further deduce that “Four-Plus-One” is not a neutral term. It is a pejorative term that more accurately describes a period in the history of Chicago’s Lincoln Park and Lakeview neighborhoods, rather than a building type.
On one hand, Four-Plus-One's provide an elegant solution to the issue of parking. What could be simpler and more efficient than simply elevating the structure? However, Four-Plus-One's are comprised of studio and one-bedroom apartments and are also very efficient when it comes to packing many of these units into a small space. These two efficiencies are incompatible if every occupant owns a car or two.
The Public Safety concerns were straw man  arguments that are aesthetic concerns in disguise. The argument that Four-Plus-One's are fire hazards is a particularly absurd one. The use of wood in construction does not automatically qualify the building as a fire hazard. By this logic, the entire Back of the Yards neighborhood is a fire hazard. It is more likely the case that any building with objectionable aesthetics is considered by some a ‘fire hazard'.
The most common arguments against the Four-Plus-One dealt with Community Character, including issues such as neighborhood charm, population density, and family-friendliness. The gentrifiers were more often not young parents looking for a good place to raise their children. Four-Plus-One's cater to a market that is marginalized with an influx of single families. Young couples, single people, and the elderly were the common tenants of Four-Plus-One's.
Community Character arguments, such as “these buildings replace beautiful homes and are ugly, cheap, and tawdry” are nothing more than class-based conflict veiled as aesthetic value judgments. Four-Plus-One's can most commonly be found along the lakefront north from Lincoln Park to Rogers Park, and south between Hyde Park and South Shore. It is a very important and telling detail that the only resistance and complaint toward Four-Plus-One's occurred in Lakeview and Lincoln Park. These areas were among the first to gentrify, and the new residents were keen to preserve their investment and lifestyle through exclusion.
There are two types of Four-Plus-One's, differentiated by the visibility of parking. If the parking lot is visible from the sidewalk, the more likely it is to be considered an ‘eyesore’ by the passerby. If the parking is hidden – it's out of sight and out of mind. It is very difficult to determine why the sight of parked cars is so greatly disliked. Of course, it is a matter of aesthetics, but any deeper reasons are hard to quantify.
While the outsides of Four-Plus-One buildings are brick and the separation between the parking level and residential floors is concrete, the only separation between units is a wood-framed wall or floor. This can often result in terrible acoustic privacy between units.
Compiled by Dr. Neil Gale, Ph.D.
 Chicago zoning codes explained: SecondCityZoning.org/zones
 'Nimby,' a person who objects to the siting of something perceived as unpleasant or potentially dangerous in their own neighborhood, such as a landfill or hazardous waste facility, especially while raising no such objections to similar developments elsewhere.
 'Straw Man,' is a common form of argument and is an informal fallacy based on giving the impression of refuting an opponent's argument, while actually refuting an argument that was not advanced by that opponent. The so-called typical argument creates the illusion of having completely refuted or defeated an opponent's proposition by covertly replacing it with a different proposition and then refute or defeat that false argument instead of the original proposition.