The most important urban planning terms – explained simply. You will encounter these terms on the playing cards and they help to understand urban design relationships.
An urban building block is a real building on its associated plot within an urban context. Unlike a purely architectural view, the focus is not only on the building itself, but on its interaction with its surroundings: access roads, open spaces, neighboring buildings.
In URBAN PLAY, the 24 urban building blocks are divided into six categories: Work (A), Education (B), Retail (H), Mixed Use (N), Single-Family Housing (W1) and Multi-Family Housing (W2).
Density describes how intensively an area is used. In urban planning, density is a key planning instrument: high density enables short distances and efficient infrastructure, while low density creates space for greenery and recreation.
The density values on the URBAN PLAY cards translate different use intensities into comparable figures: residential units, jobs, educational addresses or retail floor space – each per hectare. In the mixed-use category, it corresponds to the number of combined uses.
→ Detailed explanations can be found on the Density Values page
The site coverage ratio (GRZ) specifies what proportion of a plot may be built upon. It is expressed as a decimal between 0 and 1.
Formula: GRZ = (Building footprint + ancillary structures) ÷ Plot area
What counts towards the GRZ? In addition to the building footprint, ancillary structures are also included: garages, parking spaces, driveways, terraces and other sealed surfaces (pursuant to BauNVO §19). Ancillary structures may exceed the GRZ by up to 50%, but may not exceed a total of 0.8 (§19 Para. 4 BauNVO).
Example: GRZ 0.4 means: on a 1,000 m² plot, a maximum of 400 m² of ground area may be occupied by buildings and ancillary structures. The remaining 600 m² remains as open space.
Important: The GRZ says nothing about height – a single-storey flat building and a high-rise can have the same GRZ.
→ More details and typical values on the Density Values page
The floor area ratio (GFZ) specifies how much floor area may be built in relation to the plot area. Unlike the GRZ, it can be greater than 1.
Formula: GFZ = Sum of all above-ground floor areas ÷ Plot area
Example: GFZ 1.2 means: on a 1,000 m² plot, a total of 1,200 m² of floor area may be built – e.g. three floors of 400 m² each.
GRZ and GFZ together determine the building form: low GRZ + high GFZ = high-rise (small footprint, many floors). High GRZ + low GFZ = sprawling development.
→ More details and typical values on the Density Values page
Commercial in URBAN PLAY refers to manufacturing and craft trade – workshops, manufactories, production facilities, and craft businesses. The term corresponds to the commercial zone (GE) of the German Building Land Use Ordinance.
Distinction from other categories: In the interaction profile, industry is separate from office (services, administration, knowledge work) and retail (individual retail, local supply). This distinction is important because these uses have different impacts on their surroundings.
Why is this relevant? An architecture firm barely disturbs residential areas – a joinery can generate conflicts through noise, dust and delivery traffic. The interaction profile makes these different impacts visible and helps plan mixed use deliberately.
Examples of industry: Joinery, car workshop, print shop, bakery production, metalwork, brewery, textile manufacturing, maker space.
The gross floor area (BGF) is the sum of all floor areas of a building, measured at the outer edges. It includes all storeys including basement, attic and ancillary rooms.
According to <strong>DIN 277:2016</strong>, the BGF is divided into structural area (KGF – Konstruktions-Grundfläche) and net room area (NRF – Netto-Raumfläche). The NRF comprises usable area (NUF), technical area (TF) and circulation area (VF). The BGF is an important reference figure for cost estimates, space efficiency and urban planning metrics.
For facilities with multiple buildings (e.g. schools with a gymnasium), the BGF includes all associated buildings of the facility.
The plot size indicates the area of the building plot in square metres (m²). It is the reference figure for calculating the GRZ and GFZ.
In URBAN PLAY, the plot size shows how much area the respective urban building block occupies. It varies greatly: a detached house stands on a few hundred square metres, while a university campus can cover several hectares.
Simplified plot (*): For some cards, the building shown shares a plot with other independently built structures. In these cases, a simplified plot is derived from the site plan, encompassing only the urban building block shown. This keeps the key metrics comparable. More on this → Simplified Plot.
Some buildings share their plot with other structures that were built independently — for example a school on a church site or a residential building on a larger hospital complex. In these cases, the GRZ, GFZ and density values would not correctly represent the building type shown, because the total plot is much larger than the actual footprint of the urban building block.
Affected cards therefore use a simplified plot: only the area attributable to the building shown is derived from the site plan — building footprint plus associated open spaces. This keeps the key metrics comparable across all 24 cards.
Three cards use a simplified plot and are marked with an asterisk (*):
Key metrics (also: key figures) are measurable quantities that make urban planning characteristics quantifiable. They enable objective comparison of different projects.
In URBAN PLAY, seven key metrics are shown on each card:
The arrows on the cards (↑↓) indicate whether higher or lower values tend to be advantageous from a sustainable urban development perspective – but this is precisely where the interesting trade-offs arise!
Access road refers to the connection of a plot to public roads and infrastructure: streets, paths, supply and disposal lines. An important basic rule is: every plot must be accessible!
The access road width on the URBAN PLAY cards indicates how wide the accessing street or path is (in metres). This value shows the land requirement for transport infrastructure and influences the character of the urban space: narrow paths (5–8 m) are suitable for residential streets, wider access roads (15–25 m) for arterial roads or mixed profiles with cycle lanes and tree rows.
Parking spaces refer to the number of car parking spaces required or provided for an urban building block. In Germany, the state building regulations govern the parking space requirement.
Parking demand varies greatly by use: residential units typically require 1–2 spaces per unit, offices around 1 space per 30–40 m² of usable area, retail significantly more.
For sustainable urban development: fewer parking spaces mean less sealed surface area, more space for greenery and public life – but also less car traffic. The metric reveals the land-use conflict between mobility and urban space quality.
The interaction profile shows how an urban building block affects other use categories. It visualises the interactions between different urban functions.
Mixed use describes the coexistence of different functions in a building or neighbourhood: housing, working, education, shopping, leisure. Good mixed use is considered a quality feature of vibrant urban districts: short distances, lively streets at different times of day, social surveillance.
But not every use is automatically compatible with another. Some urban building blocks fit together very well, others tend to be more conflict-prone. The interaction profile on the URBAN PLAY cards makes these relationships visible.
H-mixed use (Horizontal mixed use): Different uses are located side by side on the same level – e.g. housing next to industry on the same floor or on adjacent plots.
V-mixed use (Vertical mixed use): Different uses are stacked on top of each other – the classic example: shop on the ground floor, housing on upper floors.
Retail in the interaction profile refers to everyday supply – all facilities offering goods for daily, weekly and occasional needs.
Differentiated by frequency of need:
Distinction: Retail covers the sale of goods, but not food and beverage (→ Leisure) or services (→ Office). The interaction profile shows which urban building blocks require or support retail uses in their vicinity.
Leisure groups three related use categories in the interaction profile that share similar location requirements and interactions.
The three sub-areas:
Why grouped together? These uses have in common that they animate ground floors, generate footfall and are often active in the evenings. They can create synergies with housing (vibrant neighbourhood) but also conflicts (noise, visitor traffic). The interaction profile makes these effects visible.
Spatial definition describes how buildings define and enclose public space. An urban building block with high spatial definition creates clear spatial edges and well-defined street or square spaces.
Positive spatial definition: Closed perimeter blocks, buildings directly on the street, clear facade alignments create urban spaces with high amenity value.
Low spatial definition: Free-standing buildings with large setbacks, solitary buildings in green spaces – they create open, flowing spaces, but less defined urban spaces.
The scale on the URBAN PLAY cards shows the spatial definition effect from −2 (dissolving) to +2 (strongly defining).