Design Process
What is the difference between buildability and site coverage on a plot of land?
We believe it is necessary to publish a slightly more technical post than usual to clarify a concept that comes up first when we have to decide whether to buy a plot of land and that defines how many square metres we can build and where. Today we will discuss the difference between buildability and site coverage on a plot of land.
Let’s begin!
What is the difference between buildability and site coverage on a plot of land?
Both buildability and site coverage refer to a number of square metres in relation to the total surface area of the plot.
However, buildability refers to the total buildable square metres, counting all floors built, while site coverage determines the percentage of the plot’s surface area that we can occupy with our home.
The units used to express both concepts are also different.
Buildability is expressed in m2/land, while site coverage is quantified as a percentage. To make the difference between buildability and site coverage on a plot of land clearer, we propose a practical example.
Example of buildability and site coverage on a plot of land
Let us assume we have a 900 m2 plot with a buildability of 0.5 m2/land and a site coverage of 30%.
What do these values mean?
In this case, with a buildability of 0.5 m2/land, we will be able to build half of the plot’s total surface area, i.e., 50%. In other words, on a 900 m2 plot we can build a house with a total of 450 m2, adding up the area of each floor.
The maximum site coverage will indicate whether we can build these 450 m2 on one floor or across several.
As we have a site coverage of 30%, this means we can only occupy 30% of the total 900 m2 of land; therefore, we must design a home whose footprint does not exceed 270 m2 (30% of 900 m2).
From here, we can build 2 floors until we reach the maximum 450 m2 of built area, i.e., until we use up the buildability.
Other factors to consider when buying a plot of land
Along with the difference between buildability and site coverage on a plot of land, it is important to consider other factors that will also influence the characteristics our home can have.
Location. One of the main factors that can determine both buildability and site coverage is the plot’s location.
Plots located in more urban areas usually have higher buildability and site coverage, while plots in rural areas tend to have lower values. This is due to the denser urban fabric of cities, where it is important to consolidate the urban grid.
By contrast, in areas farther from the city it is much easier to have gardens or open spaces within a plot, usually larger than on urban plots.
Permitted height. A concept closely linked to a plot’s buildability and site coverage is the maximum permitted height, as it will determine the home’s massing.
This value is regulated by the planning regulations of each municipality and sets the maximum level our building can reach. It is closely linked to buildability because, depending on the permitted height, we will distribute the total buildable square metres in one way or another.
Before buying a plot, it is important to check with the municipal technician—if it is not specified in the regulations—from which point the maximum height is measured. This is especially important on sloping plots, as measuring height from the street is not the same as measuring it from the midpoint of the plot’s overall slope.
Permitted number of floors. Closely linked to the maximum permitted height is the number of floors we can build. This value depends on the building typology of an area, depending on whether it is closer to the city’s historic centre or farther from the centre.
Sometimes, to standardise the buildings in a development, the city council sets very strict guidelines regarding the number of floors and their form; there are regulations that even govern the shape of the roof. It is important to check this to be clear from the outset what the massing of our home will be like.
Setbacks. Setbacks are the minimum or maximum distances we must leave from the plot boundaries. They are directly related to site coverage, as they will determine how we can lay out the total m2 we can use on the plot’s surface.
Generally, a setback to a neighbour is not the same as a setback to the street frontage, and these are expressly differentiated in the regulations. Especially in dispersed developments, the distance to the street-facing façade line is greater than the separation from neighbours.
On urban plots, by contrast, we may find that regulations require us to leave no distance either from the street or from the neighbour.
Minimum plot frontage. Minimum plot frontage is also linked to site coverage for the same reason as setbacks, because it will define how we can position our home.
In the case of very narrow plots, a minimum plot frontage is often established to ensure the space is wide enough to build a home.
In addition, plot frontage is closely linked to the amount of street frontage that corresponds to our land. This is important to consider in non-urbanised areas, as the urbanisation levy we will have to pay as owners will depend on the surface area of our plot and its frontage.
Interior courtyards. Finally, I would like to talk about interior courtyards, which are very important in home design, especially for homes between party walls.
The minimum size of interior courtyards will be directly linked to a plot’s site coverage, although we must take into account not only the total m2 of the courtyard, but also its configuration, such as the type of fencing or the treatment of vegetation in the outdoor space.
We hope this post on the difference between buildability and site coverage on a plot of land is useful in clarifying any questions you may have when buying a plot. You know you can contact us if you would like to discuss any questions about it!