Variables to consider
As previously stated, roofing projects face a wide range of variables that can affect the final product, particularly during the installation phase. The following paragraphs offer an overview of individual variables designers and engineers should closely consider to ensure a smooth roofing installation on upcoming projects.
A primary consideration during the design phase is the intended use of the building. The interior can be crucial in determining the roof system to eventually be applied to the exterior of the building. For example, based on the needs of the facility, the choice of assembly can vary widely between schools, office buildings, hospitals, manufacturing facilities, and warehouses. Considering the end user’s needs during the design phase will help avoid time-consuming issues during the installation process.
Roofing materials play an important role in our environment. Light-colored roofs reduce heat load on buildings, and dark-colored roofs increase heat load. Highly reflective materials return ultraviolet (UV) rays back into the atmosphere, raising overall temperatures as they bounce off the ozone layer. Roof designs incorporating vegetation reduce water runoff into municipal sewer systems, cool the environment, increase roof longevity, reduce energy use, and even calm the soul.
Another variable to consider is whether a particular R-value requirement needs to be met when installing the roof. This measure of thermal resistance represents the ratio of the temperature difference across an insulator and the heat flux through it. The necessary R-value speaks to the energy efficiency of the building; it must be taken into account when planning the roof installation.
Another factor to take into consideration is the possible return on investment (ROI) of installing photovoltaic (PV) panels. The technology offers considerable benefits in terms of energy reduction and cost savings on electricity, but the transition does not always make sense from a financial standpoint, depending of the nature of the building.
Several different types of roofing systems can be selected, depending on the needs of the building. Mechanically attached roofs are some of the most common—with this system, the building has a metal deck, then a layer of insulation, and then the roof. In this scenario, the membrane roll is screwed down and successive rolls are added piece by piece. A waterproof seal is then created by welding the membranes together, creating a flat, waterproof surface.
Adhered roofs are different in that they are glued directly to the insulation below them. This method can be more expensive and quite challenging, as large amounts of glue need to be applied at specific times and temperatures. These adhered roofs generally only make sense in very specific climates.
Ballasted roof systems can also be an attractive option due to their quick installation times. They also have one of the lowest life cycle costs of any roof system commonly used in the market. In a ballasted roof system, stones or pavers hold the roofing components in place. Through this process, nearly all the adhesives and fasteners required by other systems are eliminated. This can greatly reduce the cost of the roof.
There is also the question of access—what difficulties are there in getting to the job, and how can they be overcome? For example, powerlines may act as an obstruction or building occupants may need to be taken into consideration. Often, particularly potent odors can emanate from a roofing install, presenting a potential issue for multi-family residential projects, hospitals, and schools.