Value Beyond Cost Savings - Green Building Finance Consortium

Value Beyond Cost Savings: How to Underwrite Sustainable PropertiesBuilding durability is significantly influenced by its flexibility and adaptability to changingtenant and investor demands. Buildings are frequently torn down or substantially retrofitteddue to functional or economic obsolescence, not just structural, product or material failures.Flexibility of space has been studied in the corporate real estate sector for years and is a keyattribute sought by corporations. Flexibility and adaptability can be aided by underfloor airdistribution and many other design and construction techniques.One of the problems with durability is that it is difficult to define. Should it be defined asthe lifespan of a building, the durability of its components, the level of operations andmaintenance required, or some combination of the three? In the GreenSpec Directory©,durability and low maintenance are considered together as a criterion for productselection. 50 Durability can be defined or rated through review of specific building orproduct requirements, evidence of performance, or through documentation of a process topromote durability.LEED Canada has directly addressed durability for a few years. LEED Canada’s “Materialsand Resources Credit 8 – Durable Building” requires building designers to develop aBuilding Durability Plan to ensure that the predicted service life of the building and itscomponents exceeds the design service life. The credit draws from Canadian documentCSA S478 –“ Guideline on Durability in Buildings” to establish requirements andminimum benchmarks to achieve the point. A project team is required to demonstrate thatthe building has been designed to achieve the established service life by “documentingeffectiveness, modeling, or testing in accordance with Clauses 7.3, 7.4, and 7.5 of CSAS478” and by completing several tables within the Guideline.A thorough, more convincing set of recommendations and guidelines for increasing thedurability of buildings can be found in Building Science Digest 144, “Increasing theDurability of Building Constructions,” written by renowned building scientist JosephLstiburek. In this paper, the author describes building failure mechanisms, what we alreadyhave in codes and federal requirements to minimize failures, what we cannot control anddesign for, and the four remaining things that we can design and plan for: water, heat,ultraviolet radiation and insects. These four “damage functions” are the main focus of thedocument and arguably address more than 90 percent of current industry durabilityissues.” 51Key elements of durability include 52 :50 “Durability, a Key Component of Green Building,” Environmental Building News, November 2, 2005.51 “Straight Green: Green Building Rating Systems and Building Durability: Walls and Ceilings,” Chris Dixon, June24 th , 2008.52 This list is summarized from the article “Durability, a Key Component of Green Building,” Environmental BuildingNews, November 2, 2005.74