What’s Up with Green Roofs? : A study on why property owners should invest in Green Roofs and what benefits tenants receive from it.

Abstract: The building sector has for a longer period of time been responsible for a considerable part of the negative environmental imprint. The increased interest for the environment and sustainability in the industry has led to technological developments which has reduced the negative environmental impact from buildings. This, combined with the fact that buildings take up more space in cities reducing green spaces, has increased the use of green roofs. This research paper includes a study on the competitive advantages green roofs can offer property owners and what the driving forces behind the use of green roofs are. The study also includes a research on what benefits tenant’s experience from having offices in properties that have green roofs. Lastly, the study attempts to present why buildings should have green roofsand what motivates property owners to use them more often. The literature review reveals that green roofs have become popular due to their ability to absorb carbon dioxide, cool down cities, manage urban runoff and increase biodiversity. The literature review describes both the practical aspects of constructing a green roof and the management of green roofs. It also examines the cost of green roofs compared to conventional roofs. The main challenges with green roofs are said to be the increased risk of leakage, increased weight on roofs and the steep slopes of Swedish roofs. Green roofs are said to have a longer lifespan compared to regular roofs. The literature review also discusses market value and the parameters which affect the market value of a property. The research results demonstrate that it is difficult to link green roofs to an increased market value. Due to the regulation against particular, structural requirements the municipality cannot require property owners to implement green roofs. However, the municipality of Stockholm have requirements stating that each property owner is responsible for the management of urban runoff within the property lines. One way of solving this management is by using green roofs. The municipality may also require the GYF factor to be fulfilled during new construction, which means that a certain amount of green space is required. This is something green roofs can help property owners achieve as well. The LEED and BREEAM green building certification programs also require a certain amount of green spaces in order to generate a higher rating. Here, too, green roofs could be used for this aspect. The study also examines if LEED and BREEAM have any economic benefits. Interviews were conducted with property owners, tenants, architects and employees at the municipality of Stockholm. The results were relatively similar to that of the results of the literature review. Among the most important factors when considering building a green roof according to the property owners, were green certifications, the factor of green areas (GYF),stormwater management and biodiversity. The study revealed that the most important benefit for tenants was the ability of green roofs to help companies with their environmental profiling. The conclusion of the study is that the main driving factor for utilizing green roofs above all is that it helps the property owner to achieve a higher certification rating. For property owners this is important as they want to profile themselves in a sustainable and environmentally friendly way, which attracts tenants and investors. Certification programs are also leading to economic benefits for the property owners. Other driving forces for property owners to use green roofs are to meet the requirements of the municipality regarding urban runoff management and to reach the level of GYF required. As tenants often have strict sustainability policies, green roofs provide an added value as they are sustainable. In terms of cost, green roof is said to have initial costs of 300-600 kr/m2 which is higher than for conventional roofs. The short-term risk of leakage is refuted by this study, but the longtermrisk is still unknown. Even though higher initial cost and unknown long-term risk of leakage the study believes that implementing a green roof is justifiable; the positive environmental and social aspects outweighs the higher costs. Green roofs can provide a financial profit for the property owner when it’s combined with a green building certification;green roofs are a factor to implement in order to reach higher levels of green building certification systems LEED and BREEAM, which, in turn, can lead to a higher market value.The study also reveals that accessible green roofs can result in an increased revenue for the property owner.