Sustainable alternative, the green roof improves thermal comfort and helps combat heat islands in cities
Submitted at May 17, 2025, 8:00 AM
Universidade Tecnológica de Nanyang, Singapura. (Jeryl Teo/CASACOR)
The discussion about urban sustainability has led architects, landscapers, and engineers to seek increasingly more integrated with nature solutions, even in densely built areas. In this scenario, the green roof emerges as an intelligent and functional alternative, capable of transforming conventional rooftops into living surfaces, with multiple benefits for the projects and for people's well-being.
Whether in residences, commercial or public buildings, this technology combines aesthetics, ecology, and thermal efficiency, becoming a viable resource even in highly verticalized urban centers.
Visão de superior do telhado verde, no nível abaixo, um deck de madeira com uma piscina. (Projeto: Arhtur Casas/ Fernando Guerra/CASACOR)
A green roof is a technique that consists of covering the roofs of buildings with vegetation, creating a living surface where there would normally only be concrete or conventional tiles. This solution combines architecture and nature to transform the upper parts of buildings or houses into functional green areas. It is a sustainable strategy that contributes to the environmental balance in cities, where urban density often eliminates much of the original vegetation.
(FGMF/CASACOR)
In addition to being an interesting aesthetic resource, the green roof is structured with several technical layers that ensure the safe cultivation of plants without compromising the waterproofing of the building. It can be implemented on different scales, from small residential roofs to large corporate or institutional coverings. By providing environmental, economic, and social benefits, the green roof has been gaining space as an effective response to contemporary urban challenges.
The green roofs offer a series of environmental benefits that directly impact the quality of life in cities:
Reduction of heat islands Vegetation replaces impermeable and dark surfaces, absorbing less heat and reducing the surrounding temperature. This effect helps balance the urban microclimate and makes spaces more pleasant.
Improvement of air quality Plants filter atmospheric pollutants, capture suspended particles, and release oxygen, contributing to a cleaner and healthier environment.
Retention of rainwater The substrate acts as a natural sponge, absorbing rainwater and releasing it slowly, which reduces the risk of flooding and overload of urban drainage systems.
Thermal and acoustic insulation The green roof serves as a natural barrier against heat and sound, reducing the need for artificial climate control systems and contributing to the comfort of interior spaces.
Urban enhancement and increase of green areas By integrating vegetation into architecture, green roofs expand the presence of green areas in cities, stimulate biodiversity, and offer opportunities for urban gardens or leisure spaces.
(Reprodução/CASACOR)
The structure of a green roof consists of several layers that work together to ensure the proper functioning of the system. Each one has a specific role — from protecting the slab to supporting the vegetation — and must be installed correctly for the roof to be efficient, durable, and sustainable. Below, we detail the main layers that form a functional green roof:
Waterproofing layer The base of everything is the waterproofing of the slab, essential to prevent leaks and protect the structure of the building from moisture. This layer can be made with asphalt membranes, PVC, or other products specifically for use in greened roofs. The durability of the green roof depends largely on the quality of this stage.
Root barrier To prevent plant roots from penetrating and damaging the waterproofing, a root protection layer is added. Some systems already integrate this barrier into the waterproof membrane itself, but it can also be applied separately.
Drainage layer Essential to avoid water accumulation, the drainage layer allows excess rainwater to drain efficiently. It can consist of polyethylene plates, drainage mats, gravel, expanded clay, or other lightweight and porous materials.
Filter mat (geotextile) Above the drainage, a filter mat prevents the substrate from washing away with the water, avoiding clogging and preserving the efficiency of the system. This mat acts as a filter, retaining solid particles and allowing only water flow.
Substrate Also called technical soil, the substrate should be light, well-aerated, and rich in nutrients. It is responsible for supporting the vegetation and ensuring its healthy development. The depth varies according to the type of green roof:
Extensive systems (with low-maintenance ground cover): 5 to 15 cm of substrate.
Intensive systems (with shrubs, lawns, and social use): above 30 cm, with reinforced structure.
Vegetation layer (gardening) The choice of plants depends on the type of coverage and local climatic conditions. In general, native, ground-covering, and drought-resistant species are more suitable to reduce the need for irrigation and maintenance. It is also possible to use the space for gardens, ornamental gardens, or even leisure areas, according to the project.
(Pinterest/CASACOR)
The implementation of a green roof requires technical planning and attention to all stages of the process:
Structural assessment A specialized professional must check whether the slab can support the additional weight of the system, which includes vegetation, substrate, drainage, waterproofing, and accumulated water. In lighter constructions, modular systems can be chosen.
Waterproofing and drainage It is essential to apply a durable waterproof membrane to protect the structure against leaks. On top of it, a drainage layer is installed with materials like expanded clay or drainage panels, which ensure proper water drainage.
Vegetation selection Native, ground-covering, and drought-resistant species are ideal for extensive systems that require less maintenance. Intensive systems, which allow for more robust vegetation, necessitate deeper substrates and constant care.
Irrigation system To maintain the health of the plants, the project can include automated irrigation with moisture sensors. Water capture and reuse systems enhance the sustainability of the proposal.
Continuous maintenance Maintenance includes pruning, pest control, checking drainage, and any necessary substrate replacements. A simple schedule, combined with regular inspections, ensures the proper functioning and durability of the green roof.
[/caption>CASACOR Publisher is an exclusive content creator, developed by the CASACOR Technology team based on the knowledge base of casacor.com.br. This text was edited by Yeska Coelho.
