How Green Are Seoul's Rooftops?

In a city as densely built as Seoul, finding room for a new park is not easy.

But look down at the city from above and there is still a lot of open surface. The roofs of buildings.

Around Gasan Public Knowledge Industry Center. Source: Seoul Green Roof Guideline (2026)

Making that roof a place where plants can grow is what a green roof is. Seoul defines it the same way — creating space on a building's roof where vegetation can live — and treats it as a way to add the urban greenery the city lacks.

Source: Seoul Green Roof Guideline (2026)

A green roof is not a set of planters on a rooftop. Soil the plants can live in, a layer that drains rainwater, and layers that protect the building from water and roots all work together as one system.

Seoul's guideline groups these into three parts: the vegetation layer at the top (plants and ground cover), the planting base beneath it that the plants grow in (soil, filter and drainage layers), and the structural layers that protect the building (protection, root barrier and waterproofing).

The root barrier matters especially — it stops roots from pushing through the waterproofing. Because putting soil on a roof is bound up with keeping the building dry, a green roof is a landscaping job and a construction job at the same time.

🌡️ Heat — Moisture evaporates from the soil and the plants transpire, which lowers the temperature. The roof no longer bakes in direct sun, so the building spends less on heating and cooling.

🌧️ Rain — The vegetation and soil hold rainwater for a while, reducing what runs straight into the sewer.

🌿 Space — It becomes habitat for insects and wildlife, a stepping stone in the city's ecosystem. For people, it becomes somewhere to rest.

Seoul's guideline adds one more: green roofs extend a building's life by limiting the expansion and contraction of the waterproofing and concrete beneath. Putting soil on a roof sounds like it would damage the building. Done properly, it protects it.

That is what a green roof is. Now — how much of it does Seoul actually have?

The city has run green roof programs since the early 2000s: pilot projects in 2000–2001, a subsidy program from 2002, rooftop parks from 2008, and green roof and rooftop garden programs since.

We tallied the record Seoul publishes^?. From 2012 to 2024: 254 sites, 88,739 m².

It is front-loaded. 20,771 m² was built in 2012 alone — 23% of all thirteen years. The first three years, 2012 to 2014, account for 47%. The most recent three years, 2022 to 2024, come to 11% combined.

Private participation follows the same shape. Between 2012 and 2015, 44% of new sites were private buildings. From 2016 to 2019 that fell to 8%, recovering to 22% after 2020.

It is hard to picture what these numbers mean. Thirteen years of work adds up to about 12.4 football pitches. In terms of Seoul Plaza, 6.7 of them. Averaged out, the city has been adding roughly one pitch a year.

That is 0.015% of Seoul's total area.

Click a point for the facility name and area. Circle size shows area; color separates public (teal) from private (green).

They are not spread evenly. Seocho, the largest, has 8,989 m²; Yangcheon, the smallest, has 456 m² — a 20-fold gap.

One thing here is worth a closer look. The ranking by count and the ranking by area are different.

Gwanak has 17 sites, the most of any district, but ranks 6th by area. Seocho has 12 sites, 9th by count, but ranks 1st by area. A dozen small roofs and a few large ones cannot be counted the same way.

That said, every one of the 25 districts has at least two. There is no district with none.

Seoul's green roofs have grown by about 12 football pitches over thirteen years. For a city this size, that is still a small number.

One caveat. This data covers only what the city built through its programs. Rooftop gardens people paid for themselves are not in it. Seoul's actual green roofs are more numerous than this figure.

Even so, the direction is readable. The city started big and has done less over time, and some districts have twenty times what others have.

Neighborhoods with nowhere to plant a street tree still have roofs. When looking for ways to add greenery to a city, there is a wide unused surface still sitting over our heads.

This data includes only green roofs built through Seoul's own programs. Rooftop gardens created privately, or rooftop landscaping required as a building permit condition, are not included.

Areas are as of the time of construction. Whether a site has been maintained, or is still green today, cannot be determined from this data.

Point locations on the map come from geocoded street addresses and may differ somewhat from the actual buildings.

- The layer diagram and the Gasan aerial photograph are reproduced from this document