Ventilation for steep-slope roof assemblies is often misunderstood. One must not only understand the code requirements, but be able to translate them into real-world installations. Building codes have requirements for ventilation of steep-slope attics and enclosed rafter spaces. Balanced ventilation — nearly equal amounts of intake and exhaust — typcially provides efficient ventilation. Transitions between low-slope and steep-slope roof areas require more distinct intake and exhaust details than traditional eaves/soffits and ridges.
Thermal insulation is an important part of commercial roofing assemblies. The aim of this article is to examine the factors influencing the thermal resistance, known as R-value of polyiso. The prediction of long term R-value and the influence of climate, i.e. temperature, have been of significant interest over the past few decades as building energy budgets have increased in importance. Recent discussions as to what R-value the designer should use and the importance of ambient temperature are reviewed and discussed.
Wind uplift is a primary concern when installing a retrofit single-ply roof system (RSPRS) over a structural metal panel roof. ASTM E 1592 physical testing was performed on three test roof assemblies in order to determine the wind uplift resistance of an RSPRS installed over existing structural metal panel roof systems fastened directly into purlins. This paper presents the findings and conclusions of that analysis.Read the full paper Physical Testing for Wind Resistance of Retrofit Single-Ply Roof Systems Over Structural Metal Panel Roof Systems.View more white papers from GAF on our Architect & Specifier Education Resource Page.
Is thermal mass a lost art form after centuries of use in temperate regions?In building design, the thermal mass of a building enables it to store heat, providing "inertia" against temperature fluctuations. It reduces the impact of external daily temperature swings on internal heating and cooling requirements. This thermal inertia has been an on-off again topic of discussion for some time. Proponents of adding thermal inertia point to Mediterranean area buildings constructed with thick stone walls and ceramic tile floors etc. Such buildings have kept occupants cooler than lighter weight buildings in many temperate areas of the world for centuries. In the quest to improve the energy efficiency of buildings, further gains are becoming increasingly harder to come by.
With the latest version of ASCE 7, Minimum Design Loads For Buildings and Other Structures, wind design for roof systems has become much more challenging for roof system designers and roofing contractors. This paper explores the similarities and differences between the three relevant versions of ASCE 7 and the roofing industry-developed methods to determine loads. It also provides insights regarding the application of the traditional Factor of Safety in various design methods, as well as design enhancements for improved long-term performance.Read the full paper here: Simplifying the Complicated Process of Wind Design for Roof Systems.
By Don Kilcoyne
In part 1, Retrofit Single Ply Roof Systems: An Assessment of Wind Resistance, we provided information about the following: Four (4) methods to re-cover a metal panel roof The many options for attaching a single-ply system to a metal panel roof An example calculation for wind uplift design pressures and appropriate fastener patterns that provide the necessary resistance capacity Industry concerns about wind uplift when not attaching the retrofit single-ply system into every purlin
Examining attachment optionsThere are more adhesives and application methods for single-ply roof assemblies available today than ever before. This article looks at the various options and discusses the increasing number of advantages to using adhered systems, including:
Introduced as a roofing membrane in the 1960s, and first marketed in the U.S. as a commercial roof membrane in the early 1990s, thermoplastic polyolefin (TPO) has, within the last two decades, become the fastest growing commercial roof membrane on the market. TPO now represents nearly 50 percent of the installed low-slope roofing in the United States.
By Don Kilcoyne
In the first Value Engineering post about the attributes of high performing roof designs, value engineering is defined as "a concept that states there are less expensive ways to get equivalent performance," and the post described the performance attributes that make for a long-lasting, high-performing roof system. These performance attributes include: images
There can be a perception in the market that a "green building" is a better building, and that the risks associated with "building differently" are inherently covered by the green certifications driving the industry forward from a sustainability standpoint. Both better buildings and risk mitigation can be accomplished by green buildings, and this article will discuss some of the key principles to accomplish this for building enclosures and roof assemblies.
Wind design of roof systems is one of the more complicated things that an architect deals with during the design of a building. And with the latest version of ASCE 7, "Minimum Design Loads For Buildings and Other Structures" (ASCE 7), it has become that much more challenging for roof system designers and roofing contractors. Different editions of building codes exist, and therefore, different versions of ASCE 7 are being used in different parts of the country. The three versions that are currently in use are ASCE 7-05, 7-10, and 7-16, with the "-xx" representing the year of publication.
Part 1 of our discussion of parapets (Continuity of Control Layers) explored the many reasons continuity of water, air, thermal, and vapor control layers are necessary for long term performance.In Part 2 of our discussion of parapets (Navigating Codes) discussed the challenges involved in navigating the range of national model codes and standards that will influence your design.