The pursuit of affordable sustainable housing in Beirut, Lebanon : exploring roof retrofits in warm and humid climates

Abstract

For the past 30 years, Lebanon has been struggling with housing. Specifically, Beirut’s housing sector faces social, economic, and environmental challenges with the unavailability of adequate housing, unaffordability of prices and lack of energy security. Being one of the oldest in Lebanon, Beirut’s residential stock requires maintenance at the envelope level to bring it up to current energy standards. This thesis focuses on the roofs of the existing stock as they are vulnerable fifth facades, subjected to a Mediterranean climate with 300 sunny days per year, precipitation, and hot and humid summers, and require solutions to reduce cooling demand for the top floors. Therefore, the aim is to shed light on Beirut’s housing challenges, identify areas where affordable sustainable housing ‘ASH’ can be provided and investigate roof retrofitting solutions that reduce cooling demand for vulnerable households. Thus, through literature review, a framework for ASH is synthesized to guide the study. Flat-roof passive strategies are examined to conclude with suitable scenarios. Then, a multimethod case study is adopted with six stages. First, the macro study area is established using interviews with experts, second, the site is surveyed to define a sample, third, a representative typology is selected, and buildings are categorized, fourth, one building from each category is surveyed and evaluated, fifth, modelling is done in Revit, and cooling demand is simulated using Green Building Studio’s cloud, and sixth, retrofitting cost, savings, and payback periods are computed to conclude with optimal scenarios. Final results found that foil-faced insulated roofs performed better than cool roofs, delivering a 30% reduction in cooling demand, 37% in bills, and a payback period of three years. Based on these results, policymakers, practitioners and tenants could consider the incorporation of foil-faced insulation to alleviate fuel poverty and reduce negative environmental impacts for a large portion of the urban population.