The co-benefits of green roofs/facades include [1,3,4,7,8]: 

• Sustainable natural resource management, due to the use of km0 materials (i.e., stone, rammed earth) 

• Promote the materials cycle 

• Improved air quality 

• Boost local business (km 0) 

• Climate resiliency, by reducing the effect of heat waves 

• Reduced natural resource depletion 

• Increased food security 

• Reduced energy poverty 

Green roofs may be more expensive than traditional roofs. 

Green roofs, especially intensive green roofs, might mean an increase in weight load an extra maintenance. 

Literature 

[1] Alim MA, Rahman A, Tao Z, Garner B, Griffith R, Liebman M. Green roof as an effective tool for sustainable urban development: An Australian perspective in relation to stormwater and building energy management. J Clean Prod 2022;362:132561. https://doi.org/10.1016/j.jclepro.2022.132561. 

[2] Pérez G, Vila A, Rincón L, Solé C, Cabeza LF. Use of rubber crumbs as drainage layer in green roofs as potential energy improvement material. Appl Energy 2012;97:347–54. https://doi.org/10.1016/j.apenergy.2011.11.051. 

[3] Al-Kayiem HH, Koh K, Riyadi TWB, Effendy M. A Comparative Review on Greenery Ecosystems and Their Impacts on Sustainability of Building Environment. Sustainability 2020;12:8529. https://doi.org/10.3390/su12208529. 

[4] Bevilacqua P. The effectiveness of green roofs in reducing building energy consumptions across different climates. A summary of literature results. Renew Sustain Energy Rev 2021;151:111523. https://doi.org/10.1016/j.rser.2021.111523. 

[5] Coma J, Pérez G, Solé C, Castell A, Cabeza LF. Thermal assessment of extensive green roofs as passive tool for energy savings in buildings. Renew Energy 2016;85:1106–15. https://doi.org/10.1016/j.renene.2015.07.074. 

[6] Yang W, Wang Z, Cui J, Zhu Z, Zhao X. Comparative study of the thermal performance of the novel green(planting) roofs against other existing roofs. Sustain Cities Soc 2015;16:1–12. https://doi.org/10.1016/j.scs.2015.01.002. 

[7] Manso M, Teotónio I, Silva CM, Cruz CO. Green roof and green wall benefits and costs: A review of the quantitative evidence. Renew Sustain Energy Rev 2021;135:110111. https://doi.org/10.1016/j.rser.2020.110111. 

[8] Cook LM, Larsen TA. Towards a performance-based approach for multifunctional green roofs: An interdisciplinary review. Build Environ 2021;188:107489. https://doi.org/10.1016/j.buildenv.2020.107489. 

[9] Gracia A De, Castell A, Medrano M, Cabeza LF. Dynamic thermal performance of alveolar brick construction system. Energy Convers Manag 2011;52:2495–500. https://doi.org/10.1016/j.enconman.2011.01.022. 

[10] Fernandes J, Mateus R, Gervásio H, Silva SM, Bragança L. Passive strategies used in Southern Portugal vernacular rammed earth buildings and their influence in thermal performance. Renew Energy 2019;142:345–63. https://doi.org/10.1016/j.renene.2019.04.098. 

[11] Verbeke S, Audenaert A. Thermal inertia in buildings: A review of impacts across climate and building use. Renew Sustain Energy Rev 2018;82:2300–18. https://doi.org/10.1016/j.rser.2017.08.083. 

[12] Serrano S, Barreneche C, Navarro A, Haurie L, Fernandez AI, Cabeza LF. Use of multi-layered PCM gypsums to improve fire response. Physical, thermal and mechanical characterization. Energy Build 2016;127:1–9. https://doi.org/10.1016/j.enbuild.2016.05.056. 

[13] Charai M, Mezrhab A, Moga L. A structural wall incorporating biosourced earth for summer thermal comfort improvement: Hygrothermal characterization and building simulation using calibrated PMV-PPD model. Build Environ 2022;212:108842. https://doi.org/10.1016/j.buildenv.2022.108842. 

[14] Serrano S, Barreneche C, Cabeza LF. Use of by-products as additives in adobe bricks: Mechanical properties characterisation. Constr Build Mater 2016;108:105–11. https://doi.org/10.1016/j.conbuildmat.2016.01.044. 

Websites 

https://research-and-innovation.ec.europa.eu/research-area/environment/nature-based-solutions_en 

https://www.iea.org/topics/buildings 

https://www.iea-ebc.org/buildings-tcps 

https://greenroofs.org

• Energy savings 

• The use of green roofs in the cooling season contributes to 7-16% energy savings [1,5,6] 

• Yearly energy savings achieved by green roofs can be as high as 30% [3,4,7] 

• Costs 

• Green roofs can be 50% cheaper than conventional roofs, but they can also be up to 100% more expensive [1,7] 

• Some green roof systems might have some maintenance cost due to the need for fertilisers and watering [1] 

GREEN ROOF SYSTEMS – FP7-PEOPLE funded project (GA 230636) promotes an innovative extensive green roof technology (very lightweight, low maintenance, vegetated roof surfaces) for implementation in the retrofitting of buildings, especially in central Europe. 

NATURVATION – H2020 funded project (GA 730243): Development of advanced assessment approaches to i) capture the multiple impacts and values of nature-based solutions to deliver a robust evidence base for decision-making; ii) enable innovation to identify the most promising governance, business/finance, and participation models and how to overcome the systemic conditions posing limits to system integration; and iii) generate momentum to realise the potential of nature-based solutions through co-design, co-development, and co-implementation in new partnerships, generate knowledge, recommendations, processes, and tools required to build capacity, enable replications, and foster cultural change. 

URBAN GreenUP – H2020 funded project (GA 730426), focusing on the development of a tailored methodology to support the co-development of renaturing urban plans focused on climate change mitigation and adaptation and efficiency water management, and to assist in the implementation of nature-based solutions in an effective way. 

proGIreg – H2020 funded project (GA 776528): Three font-runner cities and four follower cities around Europe cooperate to innovate on nature-based solutions and their deployment, but also on co-designing, co-creating, and co-implementing these solutions with local communities, and developing new business models. 

URBiNAT – H2020 funded project (GA 76783): Regeneration and integration of deprived social housing urban developments through an innovative and inclusive catalogue of nature-based solutions, ensuring sustainability and mobilising driving forces for social cohesion. Seven EU cities supported by local partners, with collaboration with cities from outside Europe. 

GREEN SURGE – FP7 funded project (GA 603567): Identification, development, and testing ways of connecting green spaces, biodiversity, people and the green economy, in order to meet the major urban challenges related to land use conflicts, climate change adaptation, demographic changes, and human health and wellbeing. The project did provide a sound evidence base for green infrastructure planning and implementation, exploring the innovation potential, and linking environmental, social and economic services with local communities. 

REGREEN – H2020 funded project (GA 821016): Investigating nature based solucions to restore, improve, enhance and conserve natural capital and biodiversity. It will help build climate resilience in cities, improve liveability, and contribute to building inclusive communities, in line with urban priorities. Together with urban planners, citizens and businesses in urban living labs, REGREEN aims to speed up the transition toward equitable, green and healthy cities. 

URBAN GreenUP – H2020 funded project (GA 730426): Development of a tailored methodology (1) to support the co-development of Renaturing Urban Plans focused on climate change mitigation and adaptation and efficient water management, and (2) to assist in the implementation of NBS in an effective way. NBS classification and parametrization will be addressed and some resources to support decision making will be established as part of the project activities.