A roof is the first line of defense against the elements, protecting critical infrastructure in warehouses, universities, hospitals, data centers, and manufacturing plants. Downtime caused by roof failure can be costly, reinforcing the importance of this investment for commercial property owners.
When evaluating this investment, many factors should be considered. Upfront cost, ongoing maintenance needs, and the eventual cost of replacement all contribute to your roof’s total cost of ownership (TCO). The equation looks like this:
TCO = [Initial Cost + Sum of Maintenance Costs over Lifetime + Replacement Cost] / Service Life
While it’s easy to focus only on the initial cost of installation and materials, the true cost of your roof system is determined by its service life. Not all roof systems deliver the same returns.
In this article, we’ll explore maintenance best practices and common issues, how to evaluate the condition of commercial roofs, and how different roof systems stack up in terms of TCO.
Maintaining Commercial Roofs: A Closer Look
Because lifetime maintenance costs play a significant role in calculating TCO, it’s worth examining best practices for maintenance and repair.
Problems that can impact the integrity of your roof don’t always make themselves obvious, which is why commercial roofs should be inspected a minimum of two times per year. A good time for these scheduled inspections is in the fall and spring, so as to evaluate any potential stresses resulting from the harsher summer and winter months. Additionally, it’s good practice to inspect your roof following any extreme weather event.
An inspection will evaluate general membrane condition and should identify any areas that require repair. Some common things to look for include:
- Punctures and abrasions from impact damage
- Stresses on seams and fasteners caused by thermal expansion and contraction
- Degradation from chemical or UV exposure
- Open seams or flashing issues
- Failed sealants and caulking around penetrations, edges, and seams
- Debris buildup, including organic matter and foreign objects
- Blocked drainage paths or other drainage issues
- Damage to interior components such as water stains, discoloration, or peeling paint that would indicate a roof leak
If any of these issues are found, it’s important they are rectified swiftly. The longer an open seam or puncture damage is allowed to linger, the greater the risk of significant damage. Partnering with roofing professionals to perform regular inspections and quick repairs when they are required are good best practices and are part of an effective overall asset management program.
Maintenance and Total Cost of Ownership
Of course, repairs aren’t free. Costs for common individual maintenance repairs can range from hundreds to tens of thousands of dollars.
Here, it’s important to consider how different types of roof membranes perform as they age. For example, compare TPO and EPDM, two common material choices for commercial roofs. TPO can be challenging to weld consistently due to its sensitivity to temperature variations. Precise control of welding temperature and speed is crucial to avoid cold welds. If the job has not been performed properly, a seam may be more likely to open. Further, as the material ages, its weldability diminishes, making it more difficult to properly repair, increasing the likelihood of repeated maintenance needs.
EPDM seams, comparably, are joined by applying primer and double-sided seam tape. While this eliminates weldability concerns, the seams depend on adhesive bonding, making them susceptible to failure due to aging, environmental exposure, and improper installation, ultimately requiring more maintenance. Additionally, EPDM has a tendency to shrink as it ages. This can cause greater stress on the adhered seams and membrane securement, resulting in more frequent repair and other issues.
Puncture resistance is also a critical performance characteristic. While TPO and EPDM membranes tend to offer minimal puncture resistance, higher-performing alternatives with greater puncture resistance are available. A membrane that consists of a structure produced using tightly knit fabric and ketone ethylene ester (KEE), for example, is better able to resist punctures, tears, and abrasions, all while remaining flexible and weldable for decades, helping to minimize maintenance requirements over comparable periods of time.
Roof Condition Score: An Objective Measure of Roof Health
In addition to the cost of maintenance, the cost of replacement is another contributor to TCO. The roof condition score (RCS) is a method commonly used for evaluating the holistic condition of a roof and to determine when to plan for replacements.
RCS is an objective evaluation of the condition of the roof and uses a 100-point scale that takes into consideration the major roof components. It provides an objective snapshot of roof condition that can be used to evaluate the relative condition and provide a benchmark of condition compared to other facilities. A category breakdown is as follows:
- Good condition (RCS 71-100). Extensive life remaining. Continue investing with regular inspection and preventative maintenance.
- Fair condition (RCS 41-70). Midway through the anticipated life cycle. Continue maintenance and restoration using best practices.
- Poor condition (RCS 0-41). Approaching failure. Maintenance and repairs may become ineffective and costlier than replacement.
Total Service Life: How Different Membranes Stack Up
The final TCO factor to consider is total service life. Again, different membranes offer different expectations.
TPO and EPDM, along with other common choices like PVC and modified bitumen, tend to deliver a life expectancy of between 20-25 years. But as referenced earlier, a membrane constructed from tightly knit fabric and KEE polymer have been proven to deliver an anticipated service life of more than 40 years, as well as lower total maintenance requirements over that time. This was determined through a 2024 study conducted by independent consultant Mantis Innovation1 that showed roof systems using this KEE-based membrane deliver substantially lower TCO than alternatives. Using RCS as a key metric, the results demonstrated that the KEE-based roof system can deliver service life twice that of TPO, PVC and EPDM, and result in overall TCO reductions of more than 40% compared to these materials.
Commercial property owners have choices when it comes to selecting their roof membranes, and it’s worth evaluating everything that entails. High-performance roof membranes with longer lifespans and lower maintenance needs can drive substantial cost savings over time.
When considering your operational security—and the cost of facility downtime—selecting the right roof system can make all the difference.
1 “Total Cost of Ownership Report – 36- & 45-mil FiberTite®,” 2024, Mantis Innovation
