Ethylene propylene diene monomer (EPDM) and modified bitumen are two of the most common materials used in low-sloped roofing installations. The former is a popular rubber roofing solution that offers strength and flexibility while the latter comes with factory-fabricated layers of asphalt that are “modified” using a rubber or plastic component for increased durability. Like any other residential and commercial roofing system, however, both can suffer significant damage due to a wide range of issues, such as shrinkage.
What Is Roof Shrinkage?
Shrinkage, also referred to as contraction, tenting or bridging, is defined as the irreversible dimensional shortening of the roof membrane. This significant change induces extra forces on the lap joints, flashings and base-securement details like fasteners and adhesives along the perimeter or angle changes. Rupture near or around these areas may become evident as the tensile forces within the membrane increase. When this happens, the roof’s waterproofing ability becomes compromised.
Causes of Roof Shrinkage
Problems resulting from shrinkage may be associated with various factors. Here’s a detailed look at each one:
Physical and Chemical Changes in the Material
EPDM membrane roofs contain oils that are added during the manufacturing process. These components facilitate the mixing and processing of the ingredients, and are used together with the polymer content in the EPDM membrane to achieve its desirable physical properties. The loss of oil, however, may result in lower flexibility, causing dimensional changes in the form of shrinkage. Changes in the molecular structure of the roofing membrane can also play a role. This happens as a result of temperature fluctuations due to long-term weather exposure.
Faulty Roof Design
Contractors take into account the roof’s design when installing roofing materials like EPDM or modified bitumen. In particular, they take note of penetrations and other rooftop installations, and plan accordingly. If the roof happens to be designed appropriately, the roofing material is less likely to shrink. As a result, its lifespan is preserved and even extended through routine maintenance.
Installing low-sloped roofing systems requires time, patience and, of course, professional expertise from trusted roofing contractors. Substrate preparation helps ensure the longevity and performance of roofing material. Also, in EPDM applications, the material needs time to relax before applying it to the substrate. Unfortunately, it is easy for inexperienced roofers to overlook these crucial steps in the process.
Fasteners that keep the roofing membrane in place could pull out if the previously sound substrate starts showing signs of deterioration. A prime example would be plywood dry rot resulting from condensation. When this happens, expect the membrane to experience shrinkage.
Lack of Maintenance
Modified bitumen and EPDM are flexible and durable roofing options for residential and commercial applications, but they still need regular inspections for them to last throughout their average lifespan. Overlooking this critical aspect of building management or home maintenance can lead to considerable expenses in the long run. Significant roof damage will most likely result in a necessary replacement.
The Effect of Roof Shrinkage
Failure to address the problem of roof shrinkage can lead to disastrous consequences. With the substrate exposed along the seams and attachments, expect water to penetrate your home or building. If the actual source of the leak isn’t addressed, you’ll be dealing with more problems down the line, including the following:
Dripping water from the ceiling can damage your belongings or the inventory and equipment in your place of business. Turn to your trusted contractor that can help determine the source of the leak and stop water intrusion, at least temporarily.
Leaks form puddles on the floor can disrupt the daily operations of your business. Their mere presence can increase the risk of slips and falls inside the property. This could mean liability for your company in the form of workers’ compensation and lawsuits if you don’t take the necessary action.
Experiencing this problem can prevent you from enjoying significant energy savings. While identifying and removing wet insulation helps, it would be better if you have your roof inspected for any signs of damage, including shrinkage. This way, you can minimize leaks that can cause damp insulation.
Mold Growth and Insect Infestation
Leaks caused by shrinkage help promote mold and mildew growth. The resulting wet insulation and dry rot on the substrate can also attract insects, easily turning the roof into their breeding grounds. Mold remediation and pest eradication are significant expenses, not to mention cause business disruptions and building code violations. You’ll be better off addressing the issue of shrinkage instead through regular inspections and repairs.
It is your responsibility as a homeowner, business owner or facilities manager to extend the lifespan of your low-sloped roofing system and hold off replacement as long as possible. Water getting under the membrane because of shrinkage can cause further damage to the deck, seams and mechanical fasteners, compromising your roof’s structural integrity. In colder climates, ice can form under the lap joints, adding unnecessary stress to both your roof and property. Before your roof starts failing prematurely, be sure you give it the care and attention it deserves.
How to Prevent Roof Shrinkage
Proper installation remains the best way to prevent the problem of shrinkage in modified bitumen and EPDM roofs. In modified bitumen installations, contractors stagger laying the bitumen or asphalt in between hour-long intervals to give the material some room to expand and contract. For EPDM roofs, ballasts are used as a protective layer to lessen the amount of heat that they can absorb.
Working with a reputable roofer is the key to ensuring the success of rubber or asphalt roofing installations. When looking for one, don’t just hire anyone who comes up on your web search. Get to know your prospects and see to it that they have the necessary licenses, insurance and certifications. In addition to this, make sure the materials you choose for the project come from established and trusted manufacturers. Check out their features, and if you have any questions about their performance and longevity, don’t hesitate to ask the pros.
AQ Roofing LLC is dedicated to giving homeowners and commercial property owners high-quality roof systems that last for decades. Our professional roofers install, repair and maintain residential and commercial roofing systems in the local area. Let us be the team you trust to keep your roof functional and safe. Call us today at (501) 951-1683 to get started. You may also fill out our contact form to request a free estimate.