Green roofs have been shown to improve comfort levels of rooms directly below them, since they act as insulators; however, global research suggests that the performance of green roofs in attenuating temperature extremes is dependent on local climatic conditions. This study is located in Johannesburg in the South African interior, in a climate that has not previously been researched. Using heat sensors on the exterior and interior, it explores the thermal performance of a scale model of a vegetated roof in comparison with a soil roof devoid of planting and a tile roof during the dry winter season. Four different methods of enclosure were used to simulate various walling conditions. The maximum, minimum and mean temperatures for the upper and under sides of each roof were compared with the ambient temperature. Exterior temperatures for the green roof closely matched ambient temperatures, suggesting that this roof type would help in minimising the urban heat island effect. The soil roof returned the highest minimum temperatures, thereby achieving the best thermal comfort levels at night; however, this roofing solution is not recommended since the exterior maximum temperatures were considerably higher than the ambient temperature. However, the interior under the green roof has a minimal improvement on ambient temperatures and well below the recommended minimum interior temperature of 19 °C promoted by SANS10400-XA. This study forms part of a broader research initiative into energy-efficient low-cost housing solutions.
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Alexandri, E., & Jones, P. (2008). Temperature decreases in an urban canyon due to green walls and green roofs in diverse climates. Building and Environment,43, 480–493. https://doi.org/10.1016/j.buildenv.2006.10.055.
Ayata, T., Tabares-Velasco, P. C., & Srebric, J. (2011). An investigation of sensible heat fluxes at a green roof in a laboratory setup. Building and Environment,46, 1851–1861. https://doi.org/10.1016/j.buildenv.2011.03.006.
Bevilacqua, P., Coma, J., Perez, G., Chocarro, C., Juarez, A., Sole, C., et al. (2015). Plant cover and floristic composition effect on thermal behaviour of extensive green roofs. Building and Environment,92, 305–316. https://doi.org/10.1016/j.buildenv.2015.04.026.
Carter, T., & Jackson, C. R. (2006). Vegetated roofs for stormwater management at multiple spatial scales. Landscape and Urban Planning,80(1–2), 84–94. https://doi.org/10.1016/j.landurbplan.2006.06.005.
Castleton, H. F., Stovin, V., Beck, S. B. M., & Davison, J. B. (2010). Green roofs; building energy savings and the potential for retrofit. Energy and Buildings,42, 1582–1591. https://doi.org/10.1016/j.enbuild.2010.05.004.
Deschenes, O. (2014). Temperature, human health, and adaptation: A review of the empirical literature. Energy Economics,46, 606–619. https://doi.org/10.1016/j.eneco.2013.10.013.
Djedjig, R., Bozonnet, E., & Belarbi, R. (2015). Analysis of thermal effects of vegetated envelopes: Integration of a validated model in a building energy simulation program. Energy and Buildings,86, 93–103. https://doi.org/10.1016/j.enbuild.2014.09.057.
Dunnett, N., Nagase, A., & Booth, R. (2008). Influence of vegetation composition on runoff in two simulated green roof experiments. Urban Ecosystems,11(4), 385–398. https://doi.org/10.1007/s11252-008-0064-9.
Dvorak, B., & Volder, A. (2010). Green roof vegetation for North American ecoregions: A literature review. Landscape and Urban Planning,96, 197–213. https://doi.org/10.1016/j.landurbplan.2010.04.009.
Dyson, L. L. (2009). Heavy daily-rainfall characteristics over the Gauteng Province. Water SA,35(5), 627–638.
Feitosa, R. C., & Wilkinson, S. J. (2018). Attenuating heat stress through green roof and green wall retrofit. Building and Environment,140, 11–22. https://doi.org/10.1016/j.buildenv.2018.05.034.
Ferreira, R., & Ulhoa, M. L. (2016). Mechanical and thermal behaviours of stabilised compressed earth blocks. Science and Engineering Journal, 25(1), 125–135. ISSN 1983-4071.
Fitchett, J. M., Robinson, D., & Hoogendoorn, G. (2017). Climate suitability for tourism in South Africa. Journal of Sustainable Tourism,25(6), 851–867. https://doi.org/10.1080/09669582.2016.1251933.
GBCSA (2017). Green building council SA. https://www.gbcsa.org.za/about/. Accessed 7 June 2017.
Gohnert, M. (2012). The effects of thermal loading on masonry structures. In Key engineering materials (vol. 517, pp. 689–694). https://doi.org/10.4028/www.scientific.net/KEM.517.689.
Gohnert, M., Fitchett, A., Bulovic, I., & Bhikhoo, N. (2013). Structurally efficient housing incorporating natural forms. Journal of the South African Institution of Civil Engineering, 55(3), 96–102. ISSN 2309-8775.
Goldreich, Y. (1992). Urban climate studies in Johannesburg, a sub-tropical city located on a ridge—a review. Atmospheric Environment. Part B. Urban Atmosphere,26(3), 407–420. https://doi.org/10.1016/0957-1272(92)90016-L.
Gunawardena, K. R., Wells, M. J., & Kershaw, T. (2017). Utilising green and bluespace to mitigate urban heat island intensity. Science of the Total Environment,584–584, 1040–1055. https://doi.org/10.1016/j.scitotenv.2017.01.158.
Härdle, W., & Simar, L. (2007). Applied multivariate statistical analysis. Berlin: Springer.
Herrera-Gomez, S. S., Quevedo-Nolasco, A., & Pérez-Urrestarazu, L. (2017). The role of green roofs in climate change mitigation. A case study in Seville (Spain). Building and Environment,123, 575–584. https://doi.org/10.1016/j.buildenv.2017.07.036.
Huang, K.-T., & Hwang, R.-L. (2016). Future trends of residential building cooling energy and passive adaptation measures to counteract climate change: The case of Taiwan. Applied Energy,184, 1230–1240. https://doi.org/10.1016/j.apenergy.2015.11.008.
Ismail, A., Husin, H., & Rahman, A. M. A. (2008). Literature review on green roof technology: A way to improve thermal performance and energy consumption in building. https://scholar.google.co.za/scholar?cluster=819278602368586788&hl=en&as_sdt=0,5. Accessed 17 June 2018.
Jaffal, I., Ouldboukhitine, S.-E., & Belarbi, R. (2012). A comprehensive study of the impact of green roofs on building energy performance. Renewable Energy,43, 157–164. https://doi.org/10.1016/j.renene.2011.12.004.
Kamarulzaman, N., Hashim, S. Z., Hashim, H., & Saleh, A. A. (2014). Green roof concepts as a passive cooling approach in tropical climate—an overview. In E3S web of conferences, 3: EDP sciences. https://doi.org/10.1051/e3sconf/20140301028.
Klein, P. M., & Coffman, R. (2015). Establishment and performance of an experimental green roof under extreme climatic conditions. Science of the Total Environment,512–513, 82–93. https://doi.org/10.1016/j.scitotenv.2015.01.020.
Kohler, M. (2006). Long-term vegetation research on two extensive green roofs in Berlin. Urban Habitats,4(1), 3–26.
Krebs, L., Johansson, E., Krebs, C., Fedrizzi, B., & Grala da Cunha, E. (2017). Influence of extensive green roofs to the local microclimate: Cooling assessment for a social housing project in the South of Brazil. In Proceedings of PLEA 2017 Edinburg: Design to thrive (vol. II, pp. 2880–2887). ISBN 978-0-9928957-5-4.
La Roche, P., & Berardi, U. (2014). Comfort and energy savings with active green roofs. Energy and Buildings,82, 492–504. https://doi.org/10.1016/j.enbuild.2014.07.055.
Laakso, L., Vakkari, V., Virkkula, A., Laakso, H., Backman, M., Kulmala, M., et al. (2012). South African EUCAARI measurements: Seasonal variation of trace gases and aerosol optical properties. Atmospheric Chemistry and Physics,12, 1847–1864. https://doi.org/10.5194/acp-12-1847-2012.
Lin, B.-S., Yu, C.-C., Su, A.-T., & Lin, Y.-J. (2013). Impact of climatic conditions on the thermal effectiveness of an extensive green roof. Building and Environment,67, 26–33. https://doi.org/10.1016/j.buildenv.2013.04.026.
Liu, K. K. Y. (2002). Energy efficiency and environmental benefits of rooftop gardens. National Research Council of Canada, NRCC-45345.
Liu, K., & Baskaran, B. (2003). Thermal performance of green roofs through field evaluation. National Research Council Canada, NRCC-46412.
MacIvor, J. S., & Lundholm, J. (2011). Performance evaluation of native plants suited to extensive green roof conditions in a maritime climate. Ecological Engineering,37(3), 407–417. https://doi.org/10.1016/j.ecoleng.2010.10.004.
Maxim Integrated Products (2011). iButton: Revolutionary iButton digital temperature and humidity temperature loggers. www.maximintegrated.com/products/ibutton/ibuttons/thermochron.cfm. Accessed 23 July 2013.
Murray, B. K. (1982). Wits, the early years: A history of the university of the Witwatersrand, Johannesburg, and its precursors, 1896–1939. Johannesburg: Witwatersrand University Press. ISBN-13: 978-0854947096.
Naicker, N., Teare, J., Balakrishna, Y., Wright, C. Y., & Mathee, A. (2017). Indoor temperatures in low cost housing in Johannesburg, South Africa. International Journal of Environmental Research and Public Health,14, 1410. https://doi.org/10.3390/ijerphl1411410.
Nicholson, S. E. (2000). The nature of rainfall variability over Africa on time scales of decades to millennia. Global and Planetary Change,26(1), 137–158. https://doi.org/10.1016/S0921-8181(00)00040-0.
Overen, O. K., Meyer, L. E., & Makaka, G. (2017). Thermal, economic and environmental analysis of a low-cost house in Alice, South Africa. Sustainability,9, 425. https://doi.org/10.3390/su9030425.
Parizotto, S., & Lamberts, R. (2011). Investigation of green roof thermal performance in temperate climate: A case study of an experimental building in Florianópolis city, Southern Brazil. Energy and Buildings,43, 1712–1722. https://doi.org/10.1016/j.enbuild.2011.03.014.
Peng, L. L. H., & Jim, C. Y. (2015). Economic evaluation on green-roof environmental benefits in the context of climate change: The case of Hong Kong. Urban Forestry & Urban Greening,14, 554–561. https://doi.org/10.1016/j.ufug.2015.05.006.
Rizwan, A. M., Dennis, Y. C. L., & Liu, C. (2008). A review on the generation, determination and mitigation on urban heat island. Journal of Environmental Sciences,20(1), 120–128. https://doi.org/10.1016/S1001-0742(08)60019-4.
SABS (2011). SANS10400-X and XA. http://sans10400.co.za/download/SANS10400-XA%202011-DSS3.pdf. Accessed 7 June 2017.
Silva, C. M., Gomes, M. G., & Silva, M. (2016). Green roofs energy performance in Mediterranean climate. Energy and Buildings,116, 318–325. https://doi.org/10.1016/j.enbuild.2016.01.012.
Solcerova, A., van de Ven, F., Wang, M., Rijsdijk, M., & van de Giesen, N. (2017). Do green roofs cool the air? Building and Environment,111, 249–255. https://doi.org/10.1016/j.buildenv.2016.10.021.
Susca, T., Gaffin, S. R., & Dell’Osso, G. R. (2011). Positive effects of vegetation: Urban heat island and green roofs. Environmental Pollution,159, 2119–2126. https://doi.org/10.1016/j.envpol.2011.03.007.
Takebayashi, H., & Moriyama, M. (2007). Surface heat budget on a green roof and high reflection roof for mitigation of urban heat island. Building and Environment,42, 2971–2979. https://doi.org/10.1016/j.buildenv.2006.06.017.
Theodosiou, T., Aravantinos, D., & Tsikaloudaki, K. (2014). Thermal behaviour of a green vs. a conventional roof under Mediterranean climate conditions. International Journal of Sustainable Energy,33(1), 227–241. https://doi.org/10.1080/14786451.2013.772616.
Van Hooff, T., Blocken, B., Timmermans, H. J. P., & Hensen, J. L. M. (2016). Analysis of the predicted effect of passive climate adaptation measures on energy demand for cooling and heating in a residential building. Energy,94, 811–820. https://doi.org/10.1016/j.energy.2015.11.036.
Yaghoobian, N., & Srebric, J. (2015). Influence of plant coverage on the total green roof energy balance and building energy consumption. Energy and Building,103, 1–13. https://doi.org/10.1016/j.enbuild.2015.05.052.
Zinzi, M., & Agnoli, S. (2012). Cool and green roofs. An energy and comfort comparison between passive cooling and mitigation urban heat island techniques for residential buildings in the Mediterranean region. Energy and Buildings,55, 66–76. https://doi.org/10.1016/j.enbuild.2011.09.024.
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Fitchett, A., Govender, P. & Vallabh, P. An exploration of green roofs for indoor and exterior temperature regulation in the South African interior. Environ Dev Sustain 22, 5025–5044 (2020). https://doi.org/10.1007/s10668-019-00413-5
- Vegetated roof
- Thermal regulation
- Indoor climate