The Anatomy of an Asphalt Roofing System
Research suggests that today it takes an average of more than five (see footnote 1) people in an organization to make a major purchase decision. For many companies, a more expensive purchase decision requires the work of a larger number of decision makers. It’s not unusual for a team to wade through a complex maze of information before they narrow down considerations and contemplate the details of a purchase.
When it comes to a major building expense like roofing, how can you prepare your team to best allocate resources, wade through the maze of information efficiently, avoid unnecessary effort and assure the best value for your organization?
Determining which kind of steep- or low-slope roofing system offers the best value for your company begins with understanding the core objectives for your property. It is important to have a clear sense of influencing factors including:
- What are your investment objectives?
- How long will you own/maintain the property?
- What are your warranty requirements?
- What is your risk tolerance?
- Is there sufficient capital available?
- How is the property used?
- Will business processes or roof traffic influence technology choice?
- Are there external factors that will influence your choice?
- Are there load (weight) limitations based on the construction of your building?
- Can you recover rather than tear-off and replace the roof covering?
Once these questions have been addressed, it’s time to consider the basics of project execution. Ask yourself the following questions:
- Are there qualified installers in your area?
- Are they associated with a manufacturer and eligible to provide the warranty that is in scope for the project?
- Are the accessory components of the roof system readily available?
- Are the components compatible with the roofing system you have selected?
- Are the components included in warranty coverage?
Major roofing manufacturers consider all of these factors and more when they create installation specifications for both individual products and whole roofing systems. Installing components that are designed to work together in a complete roofing system helps ensure everything from compliance with local building codes, to conformance with performance expectations and contractor familiarity with installation requirements.
An example of a low-slope roofing system.
Understanding Steep-Slope Roofing Systems
Roofing systems are comprised of more than what you can see from the curb. Several key components work together to form a whole roofing system and help increase the overall performance of the roof. The Asphalt Roofing Manufacturers Association (ARMA) recommends that steep-slope roofing systems generally include six components:
- Asphalt shingles
- an underlayment
- ice and water barrier
- a shingle starter
- hip and ridge shingles
- and ventilation, both for intake and exhaust
The six components that make up a steep-slope roofing system.
Each component serves a primary function. Ice and water barriers protect the vulnerable area of your roof where water has a tendency to flow, like valleys, around chimneys and other roof protrusions. Additionally, when installed at the eaves, ice and water barriers can help guard against water infiltration caused by water backup from ice dams. Heat transfer from roof assemblies that are under-insulated can trigger a melting and freezing of accumulated snow on the roof covering; this is especially important in older buildings. Underlayment provides an additional layer of protection between the wood deck and the shingles, and acts as a secondary water barrier. Starter strip products are the first step in the proper installation of shingles, and provide the first line of sealant needed to help prevent blow-offs and water penetration at the eave.
Asphalt shingles are another important part of a roofing system. They act as the principle water-shedding surface and provide the major visual impact for a roof. Hip and ridge products add definition and a finished touch while providing added protection to the roof. A balanced ventilation system allows heat and moisture to escape from the attic. It also keeps the attic temperature closer to the outside temperature, which helps eliminate problems like ice damming and premature shingle deterioration.
The combination of these roofing system components provides redundancy, durability, and variety in look, style and color unmatched by competitive technologies.
Understanding Low-Slope Roofing Systems
Compared with steep-sloped roofs, roofing systems with less than a 2” per foot slope are faced with even greater challenges in harsh weather conditions. When considering the protection of corporate assets, this makes it even more critical to assure that the components of the system you select provide proven, time-tested and durable performance.
Base sheets, interplies and cap sheets work together with asphalt and adhesives to create long-lasting, resilient and redundant installations. One of the major benefits of asphaltic technology is the overall protection provided by the multiple layers of the roof system, coupled with the flexibility of choice in product selection and installation method. Resistance to hail impact, harsh weather conditions, thermal shock, traffic from rooftop maintenance, and long-term durability of asphaltic roof membranes are unmatched.
Asphaltic roofing systems can be applied in a variety of ways, including heat-welding, self-adhesive, cold-adhesive technology and hot asphalt. These are key considerations for your team’s decision-making process, because installation methods impact everything from employee disruption to budgetary assessments. Within the three core asphaltic technologies- BUR, SBS and APP- there is flexibility in application technology.
Heat welding is one of many low-slope roofing application methods used by contractors.
These roof components can add durability, reliability and performance to a system, but they only work together if properly installed. For instance, cold adhesive application rates for the given substrate should be followed. Heat welded membranes should be fully fused together, and self-adhesive application instructions regarding temperature and proper substrate preparation and priming should be followed. Manufacturers publish installation specifications to ensure that compatible roof components are used together properly and will provide satisfactory performance. Taking the time to review these installation details and discuss the execution phase of the project with your contractor prior to the job starting helps ensure that your requirements will be satisfied.
In addition to providing application instructions, most major manufacturers test components based on industry standard criteria like those published by ASTM International, Underwriters Laboratories (UL) and FM Approvals. These agencies have developed testing criteria and procedures to measure physical and mechanical properties, fire and wind resistance and to comply with today’s most stringent energy-efficiency codes. Most major building codes require minimum performance ratings for these products to help assure safety within the built-environment. A roofing system tested with specific components helps assure compliance with code and regulatory requirements.
A low-slope asphaltic roofing system provides property owners with many benefits. One of the most important is the peace of mind in knowing that your building and its assets are protected by strong, resilient membranes consisting of redundant layers of water-resistant asphaltic products.
Whether choosing a low-slope membrane or a steep-slope system, asphaltic roofing protects your property using positive redundancy and can provide years of reliable performance. When an asphaltic roofing system is chosen, you can rest assured your team has selected a product that defines value and is ultimately a great decision.
For more information about the whole roofing system, please visit www.asphaltroofing.org.
Submitted by: Lynn Picone, member of the Communications, Marketing and Education Committee for ARMA.
1. ©2013 Corporate Executive Board