building density 2

8/15/2019 Building Density 2

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Measuring

The cases in this atlas show three different quantitative measurements of density: dwelling

units per hectare or acre, people per hectare or acre, and floor area ratio. Although these are

common measures of density, they are often used alone, without respect to the other

measures. It is important to look at all three numbers to obtain an accurate depiction of

density.

The diagram below details the three measures.

Why these three measures These are the three most commonly used measurements of

density and each describes density from a different perspective. !ach measurement looks at a

different aspect of density and alone, each measurement is used to plan for a specific set of

needs. "rban planners often are most concerned with #A$ measures% realtors are often most

concerned with dwelling units due to their focus on renting and selling% and government

agencies care most about population numbers, which are tied to city services and

infrastructure needs. Although each measurement provides good information about a place,alone, they do not paint a complete picture of the density of a neighborhood.

A better understanding of the density of a place comes not only from the additional

information supplied from each of the three measurements, but also through looking at the

three measurements relative to each other. #or e&ample, two areas may have the same number

of dwelling units, but may feel more or less dense based on the relationship of those units to

the number of people and the #A$ in the area.


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FAR + Coverage

#loor Area $atio '#A$( is the ratio of built area 'a building)s total si*e( to the lot area 'the

property upon which the building is built(. It is a measure used by planners, regulators, and

developers to discern the intensity of a development. +y itself, however, it is not sufficient todefine density.

Coverage

overage is the relationship between the ground floor area of enclosed buildings and the area

of the lot. -evelopment scenarios with the same #A$ but different coverage will produce

varying types of development: for e&ample, lowrise or highrise.The e&amples below are a

classic case of varying perceptions of density for two areas with identical #A$.

http://densityatlas.org/measuring/metrics.shtmlhttp://densityatlas.org/measuring/metrics.shtml


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Dwelling Units

Another measure of density is the number of dwelling units built on the lot, often used by

realtors or developers, as their focus is the marketable number of units in a given area. The

density of an area can change based on the number of dwelling units / although we use

individual dwelling units as a measurement, we don0t measure the si*e of the units. 1arge

buildings may take up the same amount of space as small ones, resulting in similar levels of

#A$. Is an area filled with 2c2ansions as dense as an area filled with the same number of

rowhouses



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Population2easuring the number of people in a given area is helpful to measure density, however, it

does not measure the amount of living space per person. Are dwelling units a comfortable

si*e Is there public space for people 3ow many people live in each household

It is clear that there are complications with using only one of these three measures to analy*e

the density of an area. When looking at cases, you will understand the importance of looking

and comparing all three measures. #or e&ample, +attery 4ark ity may feel dense, however,

individual unit si*es are fairly large, with few people per household / a case of an area with

high #A$, medium number of dwelling units medium to low population. Informal

developments, by contrast, have low #A$, and a medium to high number of dwelling units

and population, which can yield less square feet of living space per person.

"nderstanding these numbers will help city planners and others determine the best mi& ofthese measurements for their neighborhood or town. Two urban areas with very similar



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density levels can be arranged in very different ways. 3ow a planner or developer manages

the urban design process and qualitative factors of an area is critical in developing an area

appropriately to its cultural conte&t.

And of course, the feel of a place is also dependent on the urban design features, lot coverage,

open space, architecture and street design. These factors will contribute to the feel of a place but are independent from the quantitative measures of density. 5ur collection of case studies

allows one to compare places to understand the similarities and differences caused by

different levels of density. Two places may have the same quantitative measurement while

looking very different.

building density 2

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