By Jim Tierney
From the November 2013 issue of Today’s Facility Manager
Heading into the winter and anticipating cooler temperatures, it is important for facility managers (fms) to focus on their roofs and to consider the latest trends and advancements in safety, maintenance, and warranties. Cold weather—especially when it turns severe—can take a toll on the entire building envelope. This is especially true for roofing systems, which can take the brunt of heavy rains, increased precipitation, and snow. Making sure the roof is in tip-top shape is integral to maintaining high facility performance and limiting risk.
Rooftop safety programs and protocols are not new. However, the industry focuses on improving measures to ensure everyone from contractors to fms are safe when inspections or work on the roof are needed. It is especially important to take safety measures when dealing with specific areas of the roof, such as access points (ladders, hatches, and doorways) and around mechanical equipment requiring maintenance. Extra safety precautions are also necessary in the winter months or following a storm since roofs can be slick after rain, frost, or snowfall.
A recent trend is the use of safety guards around roof hatches and “ladder up” safety posts on roof hatch ladders. Roof hatch safety should be taken very seriously, and guards and posts can help to minimize the risk of falls.
Another trend is an increased use of safety tapes and markings around roof perimeters and hazards. These products serve to create a perimeter around the roof edge, mechanical equipment, and other hazards by visually drawing attention to these areas.
Walkway pads can be another essential item that helps increase safety levels. Walkway pads serve two purposes. First, these provide a non-slip surface for those accessing the roof. Second, the pads actually protect the surface from wear and tear associated with individuals accessing the roof for maintenance and repairs. Walkway pads safeguard people and roof systems year round, but these are also ideal for the winter months as they can be manufactured to display cold flexibility.
Another important aspect for fms to note is awareness. Rooftop access should be restricted to trained professionals who are mindful of their surroundings. Safety protocols and products are being driven by organizations like the Occupational Safety and Health Administration (OSHA) as well as rising insurance costs. By making safety a priority, fms can minimize risk and accidents, keep insurance premiums low, and help to maximize the service life of their roofs.
Inspection And Maintenance
A rooftop is a valuable asset for a building and can help increase facility performance. In order to protect this investment, fms should ensure roofs undergo periodic inspections and maintenance to maximize performance and maintain their warranties. Strategies fms can use to extend the life of their roofing systems include:
- The roof should be inspected at least twice yearly and after any severe storms. A record of all inspection and maintenance activities should be retained, including a listing of the date and time of each activity as well as the identification of the parties performing the activity. Roofing contractors are the best people to perform these checks. However, a maintenance person can remove debris from the roof—specifically at drainage points (drains, scuppers, or gutters)—and do a visual inspection for issues.
- Proper maintenance and best practices require that a roof does not have ponding water (industry standards state water should be gone within 48 to 72 hours after it stops raining). Roofs should have positive slope to drainage, and drain areas must remain clean. Facility staff should bag and remove all debris from the roof since such fragments can be quickly swept into drains by rain. This allows for proper water runoff and prevents overloading.
- The roofing system should not be exposed to acids, solvents, greases, oil, fats, chemicals, etc. If it does become exposed to any such materials, these contaminants should be removed immediately, and any damaged areas should be inspected by a manufacturer’s licensed or approved applicator and repaired if necessary. (See sidebar below for tips to protect a modified bitumen roofing from acids, greases, etc.)
- A roofing system is designed to be a waterproofing membrane, not a traffic surface. Any traffic other than periodic visits to maintain equipment and conduct occasional inspections should be prohibited. In any areas where roof traffic may be required to service equipment or to facilitate inspection of the roof, protective walkways should be installed by a licensed applicator as needed to protect the roof surface from damage.
- All metalwork, including counter-flashings, drains, skylights, equipment curbs and supports, and other rooftop accessories, must be properly maintained at all times. Particular attention should be paid to sealants at joints in metalwork and flashings. If cracking or shrinkage is observed, the joint sealant should be removed and replaced.
- Any alterations to the roof, including but not limited to curbs, pipe penetrations, mounted accessories, and tie-ins to building additions, must be performed by a licensed applicator.
- Should a facility experience a leak, facilities staff should check for the obvious—clogged roof drains, loose counter flashings, broken skylights, open grills or vents, and broken water pipes. Staff should also note the conditions that result in leakage. Heavy or light rain, wind direction, temperature, and time of day that the leak occurs are important clues to tracing roof leaks. Fms should note whether the leak stops shortly after rain occurs or if it continues to drip for hours until the roof is dry. If an fm is prepared with the facts, the diagnosis and repair of the leak can proceed more rapidly.
Modified Bitumen: Combating Grease, Oil, And Chemicals
Contributed by the Asphalt Roofing Manufacturers Association
Roofing systems are intended to provide protection from natural elements such as rain, snow, hail, and sleet. Systems that are properly designed, installed, and maintained should provide satisfactory protection from these elements. Some roofing systems, especially those on factories, restaurants, and fast food chains, require special care in design due to the presence of greases, oils, bacteria, and/or other agents that tend to affect the integrity of the roof membrane adversely. Depending upon the number and type of contaminants present, facility managers must select a roofing system that will best satisfy their performance requirements. Following is information that highlights the effects various contaminants may have on polymer modified bitumen membranes.
Oils And Greases
Modified bitumen roofing membranes can be adversely affected by exposure to cooking oils (animal or vegetable) and greases. Membrane degradation typically occurs around exhaust vents, where the roofing membrane has repeated contact with these contaminants. The organic substances contained within these contaminants typically weaken and eventually break down the polymer-bitumen network, causing premature degradation of the roof.
Bacteria And Fungi
Factories that produce foods such as potato pulp and dry milk have reported cases of modified bitumen membrane decay due to bacteria. Such deterioration, which usually starts as “mud cracking,” may ultimately lead to the total decay of the modified bitumen membrane and any surface coating. The degree of degradation is dependent upon the type of microorganism, temperature, and other climatic conditions as well as the composition of the bitumen. Fungus growth, which typically occurs in hot, humid regions, does not cause the same detrimental effects as bacterial attack and usually poses only aesthetic concerns.
Effects Of Other Chemicals
Other chemicals, such as solvents, acids, bases, and oxidizing agents, can cause varying degrees of harm to polymer modified bitumen roofing membranes. Non-polar solvents can temporarily swell and soften polymer modified bitumens, causing slumping and poor traffic resistance. They can also cause the polymers to “separate” from the asphalt. While polymer modified bitumens have excellent resistance to various inorganic acids and bases, some of these chemicals may attack and degrade glass and polyester mats as well as fillers, such as talc and limestone. Organic acids, such as acetic acid, are also known to have detrimental effects. Strong oxidizing agents can attack both the polymer and the bitumen in a membrane. Additionally, when ponding water is present, inert, solid dusts can contribute to “mud cracking.” All of these effects may lead to premature failure of the roofing membrane.
- Wherever possible, reduce or eliminate exposure to contaminants.
- Determine the types and concentrations of contaminants that may be present. When reroofing, investigate what effects, if any, contaminants had on the existing roof before specifying and applying a new roofing system.
- Use commercially available traps and/or filters to prevent contaminants from being exhausted onto the roof.
- Establish a maintenance program to monitor affected roof sections and to maintain traps or filters properly.
- Provide positive drainage (i.e., at least 1/4″ per foot roof slope) to prevent ponding in the affected area.
- If contaminant effects are minor, increase the number of plies, and/or add resistant coatings to provide adequate protection.
- Investigate alternate venting designs that minimize or eliminate contamination.
The Asphalt Roofing Manufacturers Association is a trade association representing North American manufacturers and suppliers.
Duration Of Warranty
When it comes to warranties, fms often purchase preventive maintenance programs from commercial building manufacturers in order to maximize the life of their roofs and follow warranty guidelines. There is a trend of moving away from purchasing the standard 10 year warranty and investing in 15 year or even 20 year warranties.
A commercial roof is an investment. Preventive maintenance is one of the best ways for fms to protect and extend the life of their roofing systems. So, as the weather changes, it is a good time to evaluate the facility’s process to validate current procedures reflect best practices and to kick off the cold weather season feeling confident in the performance of a facility’s roofing system.
Tierney is the building owner services manager at Firestone Building Products, a manufacturer and supplier of a comprehensive “Roots to Rooftops” portfolio of products for commercial building performance solutions.