When it comes to commercial roofing, one of the most debated topics among contractors is the use of single-ply roofing systems. While single-ply membranes like TPO, PVC, and EPDM have gained popularity for their cost-effectiveness and ease of installation, not all commercial roofing contractors are fans. In fact, many experienced roofers prefer more traditional systems such as modified bitumen, BUR (built-up roofing), or metal roofing for certain projects. So, why do some commercial roofing contractors shy away from single-ply roofing? Let’s explore the reasons.
1. Perception of Durability and Longevity
One of the main concerns contractors have about single-ply roofing systems is their durability. Unlike multi-layered systems such as built-up roofing, single-ply membranes consist of just one layer of material that serves as both the waterproofing and protective barrier.
While high-quality single-ply membranes can last 20–30 years, contractors often argue that they are more vulnerable to punctures, tears, and mechanical damage compared to thicker, layered systems. On high-traffic roofs or those exposed to debris, this can lead to leaks and expensive repairs.
For this reason, many roofing professionals prefer more robust systems for industrial or heavily used commercial roofs where durability is a top priority.
SOLUTION: Stay off the roof unless necessary and if worried about high wear or traffic areas, install walkways for additional protection.
2. Sensitivity to Installation Quality
Single-ply roofing requires precise installation techniques to perform properly. TPO and PVC membranes, for example, are typically heat-welded at the seams, a process that demands skill and experience. If the welding temperature is too low or too high, it can lead to weak seams and premature failure.
Contractors who have seen improperly installed single-ply roofs fail within a few years often develop a distrust of the system itself, even if the issue lies with workmanship rather than the material.
Compared to systems like modified bitumen, which can be more forgiving during installation, single-ply membranes are less tolerant of mistakes.
SOLUTION: Use a qualified and approved installer ensuring proper and relevant guarantees are in place.
3. Thermal Movement and Shrinkage Issues
Over time, single-ply membranes, particularly older EPDM or TPO systems, can experience thermal expansion and contraction due to temperature changes. This movement can cause stress at seams, flashing points, and penetrations, leading to cracks or separations.
While newer formulations have improved flexibility and UV resistance, contractors who’ve dealt with older systems may still associate single-ply roofing with long-term maintenance headaches related to shrinkage or seam separation.
SOLUTION: The newer materials are designed to withstand this and speak with your installer beforehand to help disperse your concerns. Regular maintenance will also prevent these issues.
4. Limited Resistance to Harsh Conditions
Single-ply roofs perform well in many environments, but some contractors find them less ideal for extreme weather conditions or chemical exposure.
For instance, PVC membranes can degrade when exposed to certain industrial oils or exhausts. EPDM, while durable, can be sensitive to solvents and roofing adhesives. In regions with frequent hailstorms, high winds, or foot traffic, single-ply systems can be more easily punctured compared to built-up or spray foam roofing.
Contractors serving industrial clients or harsh climates may therefore prefer more impact- and chemical-resistant roofing systems.
SOLUTION: The system you use should absolutely suit the environment and location of the roof. This goes for any system, and it should be specified accordingly. Manufacturers will often give free specification advice based on location and exposure.
5. Warranty Limitations and Liability Concerns
Roofing warranties are crucial in commercial projects, but single-ply systems often come with strict warranty requirements tied to the manufacturer’s installation guidelines. Any deviation, even minor, can void coverage.
For roofing contractors, this creates additional liability risk. If a leak occurs and the manufacturer denies the warranty due to installation errors, the contractor may be held responsible. This level of risk can make some professionals hesitant to recommend or install single-ply membranes unless the conditions are ideal.
SOLUTION: Use a bonified and proven contractor who has a good reputation and will help in instances of warranty claims. Often the specifying manufacturers will report and liaise throughout installation to ensure that the product in installed compliantly and to the desired standard to satisfy potential claims in the future.
6. Preference for Proven, Traditional Systems
Finally, many seasoned contractors simply trust what they know works. Systems like built-up roofing and modified bitumen have been around for decades and have proven track records in commercial applications. These systems offer multiple layers of protection, excellent waterproofing, and easier patching for repairs.
While single-ply technology continues to evolve, some contractors prefer to stick with systems that have consistently performed well over time, especially on critical commercial facilities like hospitals, manufacturing plants, and data centres.
As with all systems and installers they will have their preferences. There is absolutely nothing wrong with this, but they should keep an open mind as to the best system for each project. Single ply should be one of these options.
The Pros of Using It
Single-ply roofs are popular because they offer a cost-effective, lightweight, and energy-efficient solution for commercial buildings. They are easy to install, provide excellent UV and weather resistance, and come in reflective white options that help reduce cooling costs. With several options available, single-ply systems deliver reliable waterproofing and flexibility across various climates. Their low maintenance requirements and long lifespan make them a practical choice for many property owners and facility managers.
Read more about why contractors DO like using single ply HERE
Conclusion
Single-ply roofing systems offer undeniable advantages, they’re lightweight, cost-effective, and energy-efficient. However, not every commercial roofing contractor considers them the best option for every building. Concerns over durability, installation sensitivity, and long-term performance make some professionals hesitant to rely solely on single-ply membranes.
Ultimately, the choice of roofing system depends on building type, climate, foot traffic, and budget. A trustworthy contractor will evaluate all factors before recommending the best system, whether that’s a single-ply roof or a more traditional multi-layered solution.
