Avoiding Problems With Protective Film: Proper Usage, Storage, and Removal
Temporary protective film (TPF) protects metal roofing panels during handling, transportation, and installation. It helps prevent scratches, scuffs, and other damage before the panels are fixed in place.
However, not all films have the same characteristics. Understanding how substrates affect adhesion and how to properly apply, store, and remove protective films can mean the difference between a smooth metal roof installation and a major headache.
While it may seem like a simple job of stick-on and peel-off, there’s more to using TPF than you might think. From selecting the correct tackiness level and thickness for the coil coating to proper storage and removal, understanding how to best handle protective film can save you time, money, and frustration.
Whether you purchase metal coil pre-treated with TPF or are applying it yourself, you should know something about treating and handling panels with protective film.
For this article, we sought advice from industry experts to explain the dos and don’ts of using TPF. Their insights highlight the importance of careful handling and storage, how TPF adhesives work with different types of paint systems, and why it’s critical to get it right.
What is Temporary Protective Film?
First, it’s important not to confuse the protective film with the roof’s permanent PVDF (polyvinylidene fluoride) coating. PVDF is a paint system applied to metal coils to provide durability and corrosion resistance. In contrast, protective film is purely temporary—its only job is to protect the coil’s finish during handling and fabrication.
Temporary protective films cover a substrate surface, held on by an adhesive that will provide a protective layer to the panels until installation. TPF can be pre-applied to the coil or applied during the rollforming process with a laminator. The film is then removed prior to usage.
As Tom Southerland, National Account Manager at Sheffield Metals International (SMI), explains, “The film is just there to protect the coating in the rolling process and during handling. You tear it off before the panel goes up, or immediately after installation.”
Also, while it’s still sometimes referred to as PVC film, PVC (polyvinyl chloride) hasn’t been used in years as the industry evolved into more advanced protective film solutions. If a contractor or manufacturer refers to it as PVC, they probably mean another type of protective film and may not even realize PVC is no longer used.
Pregis® Protective Films & Coatings, Sheffield Metals International’s (SMI) partner for TPF metal coil applications, manufactures a PolyMask™ protective film. As Pregis Sales and Product Manager Bryan McMichael explains, “We supply Sheffield with a co-extruded product—a blend of LDPE and HDPE.” This superior composition improves performance, reduces costs, and is environmentally friendly compared to PVC, which has been banned or restricted in several countries and cities worldwide. Sheffield Metals is the sister company of New Tech Machinery.
How is Temporary Protective Film Used?
The film is a thin, flexible sheet that covers a material to protect it from scratching or other types of damage. Sometimes called PVC, strippable vinyl, peel coat, protective film, mylar, paper, strippable tape, masking, or paint guard film, it’s used for various purposes, such as:
• Protective covering on metal coils or sheets to prevent scratches and scuffs during handling or transportation.
• Packaging material for consumer goods, like new appliances.
• Products that need temporary protection, including glass, carpets, solid surfaces like countertops, etc.
In metal roofing and other fabrication processes, TPF is adhered to a panel and then peeled away once installation or transport is complete.
Choosing the Right Adhesive and Film
Not all TPFs adhere to metal finishes the same. Gloss levels, paint finishes, and metallic or matte surfaces affect how well the film adheres and how easily it can be removed later. A smoother surface will need less adhesive, whereas a textured metal, because it has fewer points of contact, will require a stronger adhesive.
SMI’s Director of Operations Eric Simonsen emphasizes the importance of tackiness: “When testing the proper tackiness level of the adhesive, different coatings need different recommendations. A metallic paint system, a matte paint system, or a textured paint system each requires a unique level of tack.”
In other words, carefully selecting the TPF that matches the substrate surface ensures you won’t end up with overly aggressive adhesion that makes removal a nightmare, or with an adhesive so weak that peels off under a ceiling fan.
• Textured or Matte Finishes: Often need higher adhesion and tackiness to hold because of the uneven surfaces of the materials.
• Metallic or Smooth Finishes: Typically work well with medium or slightly lower tackiness since the smooth surface is easier for the film to adhere to uniformly.
Manufacturers and distributors provide instructions on which level of adhesive to use for a given metal finish based on rigorous testing. Rollforming machine operators who administer the protective film with an applicator should follow manufacturer guidelines to ensure they use the level of tackiness recommended for a specific metal finish.
The film is just there to protect the coating in the rolling process and during handling. You tear it off before the panel goes up, or immediately after installation.
Thickness and Elasticity
Film thickness and elasticity also play a role in performance. Thicker films may provide more durability but can be harder to remove and less stretchy, which can complicate forming panels. Sheffield Metals, for instance, is moving towards a more uniform thickness across its products. According to Simonsen, “In 2025, we’re going with all 1.6 mil thickness product that has really good tensile strength and elongation.”
This shift aims to improve handling while maintaining adequate protection—ensuring the TPF can stretch, conform, and still peel away without leaving residue behind. If you’re applying the film using an applicator, you’ll need to pay particular attention to what type of adhesive you’re using. The wrong level of tackiness can render the peeling-off process a nightmare and leave a residue on each one of your panels.
How TPF Adhesive Strength is Measured and Rated
As mentioned, TPF used on metal panels is applied with different tackiness or adhesive strength levels, and manufacturers typically assign numbers or codes to indicate these levels. While there isn’t a single universal system across all suppliers, here are the common ways adhesive strength is measured:
- Peel Strength or Tackiness (Numeric Codes):
o Many suppliers use numeric designations to differentiate films. For instance, you might see a product labeled “2020” or “1666.”
o These numbers can relate to both film thickness (in mils or microns) and relative adhesive coverage or intensity (how “sticky” the film is).
o In some cases, a higher second number indicates stronger adhesion, whereas the first number might signify film thickness. Other times, the numeric system is proprietary to the supplier. Pregis uses a code that includes the film thickness, type, color, and adhesive type (see below for an example). - Ounces per Inch or Grams per Centimeter (Peel Test Values):
o Adhesive films are also measured by peel strength, often reported in oz/in (ounces per inch) or g/cm (grams per centimeter).
o This testing involves applying the film to a standardized test surface, then measuring the force needed to peel it back at a consistent angle (often 180°) and speed. - Thickness vs. Adhesive Composition:
o A thicker temporary protective film doesn’t always mean higher adhesive strength; film thickness primarily affects puncture resistance and stretch.
o Adhesion and tackiness (the type of glue and its coverage level) determines how well it bonds to metal or other surfaces. - Substrate-Specific Recommendations:
o Certain paint finishes or textures (e.g., metallic, matte, or textured surfaces) may require either higher or lower tack.
o Manufacturers typically provide charts or guidelines indicating which adhesive level pairs best with certain paint systems or gloss levels. Be sure to always follow the guidelines.
Takeaways:
• Numeric codes often refer to a mix of film thickness and adhesive tack level.
• Peel strength (in oz/in or g/cm) is a standardized way labs measure how firmly the film sticks.
• Always check the supplier’s guidelines to match adhesive levels to your metal’s finish and to ensure you remove the film easily when the time comes.
Example: Pregis Film Reference for Sheffield Paint Systems
Smart, Metallic, & Vintage paint systems
• 15CVU825C – 1.5 mil clear coextruded film with medium-low adhesion
Textured Low Gloss paint systems
• 251U877B – 2.5 mil blue monolayer film with very high adhesion
Don’t Bake, Freeze, or Dampen Your TPF Panels: Key Best Practices
One of the biggest pitfalls is leaving TPF panels or coils exposed to the elements. Heat, moisture, and especially UV rays can degrade the film and its adhesive. Southerland warns, “If it gets in the sun, that sun will bake that film on that panel, and you cannot get it off.”
In extremely hot climates, just a day or two of exposure can cause this problem.
Time is also a factor. Even if kept indoors, the longer PVC film remains on the panel, the harder it can be to remove. “If it sits on there for more than six months, even indoors or in a plant, the harder it is to get the protective film off—and after a year, you might not be able to remove it at all,” says Southerland.
Simonsen echoes these concerns: “It needs to only be on the coil or in flat sheet form for six months, and it needs to be kept in a certain temperature and humidity range,” he affirms.
It’s not only the temperature and conditions but the pressure of the coil itself that can chemically break down the PVC film and adhesive if the coil isn’t used within that six-month timeline.
Takeaways:
• Recommended Timeline:
o Apply the TPF within six months of receiving it. If it has already been applied to the coil by the supplier, use it within six months.
o Keep the material in a controlled environment, away from heat and moisture.
• Avoid Outdoor Storage: Leaving coated panels or coils in direct sunlight or rain for prolonged periods can cause the adhesive to break down and the TPF to become brittle. “If it’s exposed to too much UV, the plastics will actually start to degrade,” Simonsen points out.
• Pressure Matters: The weight of stacked panels or tightly wound coils can increase the bond strength over time, making the film harder to remove.
One of the biggest pitfalls is leaving TPF panels or coils exposed to the elements. Heat, moisture, and especially UV rays can degrade the film and its adhesive.
Storage recommendations (Pregis):
• Store protective film products in original packaging/ shipping cartons until needed.
• Do not store substrates for longer than 6 months with protective masking films applied.
• Maintain a storage temperature range of 50˚ F-60˚ F.
• Store TPF-treated substrates in the relative humidity (Rh) range of 40% – 60%.
• Keep away from exposure to temperature extremes, direct sunlight, water, solvent, and other contaminants.
• Rotate protective film inventory on a first-in, first-out (FIFO) basis, ensuring usage within the warranty period.
Failing to follow these recommendations may degrade the protective film.
Just-In-Time Application and Removal
Because prolonged storage, exposure to sunlight, and outdoor conditions all pose risks, it’s best to apply TPF as close to the installation date as possible—and remove it promptly once the panels are put into place. “You need to strip it off as you go when you’re installing it,” advises Southerland. Delaying removal can cause the adhesive to age and bond more tightly with the paint surface.
Also, you don’t want workers stepping on the TPF-treated panels too much, as it can further bond it to the substrate. “Some installers leave the film on after they’ve installed the panels, allowing their guys to run up and down on it,” says Simonsen. “That’s a bad practice.”
If you’re purchasing coil already treated with TPF, Simonsen stresses ordering the necessary amount of material so you don’t end up with coils stored for more than six months. “Absolutely, order according to the job rather than having it just to have in stock,” he suggests.
If there’s a run on a certain type of coil, it may be worth keeping in stock if you know it will sell fast. Otherwise, you’re gambling on having a job that might not come through in time.
Dangers of leaving the film on for too long, or under hot conditions, include:
• Spotting—where rings or spots appear on the substrate after the TPF is removed.
• Ghosting—a light haze that occurs when looking at a panel in a certain angle of light. This occurs when there is outgassing (a chemical reaction coming from the substrate) and the film adhesive is applied too soon after manufacturing.
• Adhesive residue—The adhesive left behind after the TPF layer is removed.
TPF application guidelines (Pregis):
• Ambient and substrate temperature should be within 60˚ F-90˚ F for best results. Colder temperatures than listed will lessen the initial bond to the substrate.
• Surfaces should be dry and clear of any lubricants, solvents, or other contaminants.
• Application pressure should not vary from initial, approved trials.
You need to strip it off as you go when you’re installing it,” advises Southerland. Delaying removal can cause the adhesive to age and bond more tightly with the paint surface.
What If it’s Too Late?
Extreme conditions will produce a range of variables when it comes to storing and applying temporary protective film. Heat, cold, and moisture are all enemies of TPF adhesives. Check below for what to do, depending on the situation.
Hot Temperatures
If the temporary protective film on the panels has been stored or applied in temperatures above 90˚ F, the adhesive bonding will have increased. Remove the film by pulling slowly from a 90˚ angle. That should result in less ghosting or spotting.
Cold Temperatures
If the TPF is applied in temperatures below 60˚ F, the adhesive may not stick properly to the substrate. Before applying, make sure that both the film and substrate are at a recommended temperature. For removal, the film and substrate should be above 45˚ F.
Moisture
If the TPF has been applied to the substrate and encounters moisture, whether from rain, morning dew, or humidity, allow it to dry completely before attempting removal. The film will take on a bluish-white casting (known as “blushing”), signaling that it is too wet for removal. It will turn water-clear when it has dried.
Excessive Sunlight
Some films may be UV-rated, which can help mitigate damage from overexposure to sunlight. The amount of time a non-UV-protected TPF can be left out in the sun may vary, depending on the manufacturer. Refer to the manufacturer guidelines to determine the maximum UV exposure allowed under their warranty.
If you have concerns about the adhesive used on your TPF-treated coil, contact the manufacturer. Sheffield Metals can track the coil number to determine the TPF used and whether the adhesive matches the metal finish specifications.
If you’re applying the TPF with an applicator to a Sheffield coil, the film should match our brand recommendation. Using another brand that hasn’t been tested with the paint system could lead to problems. For example, Sheffield Metals tested and validated the Pregis materials for all of their paint types. Therefore, only Pregis TPF should be applied to SMI products.
Removing Residue
Say you’ve left panels out in the sun or rain for an extended period. While you may be able to tear off the temporary film, the adhesive residue can remain on the panels. In order to remove the adhesive, you can use a liquid cleaner such as Cleansweep® by Watts® Removal Products, a Sherwin-Williams® approved solution. Be sure that whatever product you use is approved by the paint manufacturer so as not to void the paint warranty.
Also, as the remover is a chemical, make sure to use the proper PPE when administering it. To learn more about the product and its application, watch the Metal Roofing Channel video “How to Remove PVC Strippable Film Stuck to Painted Metal Panels.”
Does Everyone Get It?
The coil purchaser and panel manufacturer may know all the rules about dealing with TPF—the time limits it can be left on the metal, the impact of UV rays, and that if it’s on a coil, even if stored properly, the tackiness will strengthen over time. Again, six months should be the limit to keeping TPF-treated coil stored, even under the best conditions.
However, this information isn’t always communicated down the line. By the time the panels arrive on-site, the installers may not know that leaving them out in the sun will make removing the TPF difficult at best. Whatever your business, manufacturer or contractor, make sure everyone knows the rules of dealing with temporary protective film.
Running TPF Through Your Rollforming Machine
Testing and Guidelines
For those applying film themselves, it’s important to follow recommended guidelines for the adhesive and film type to match the metal’s surface characteristics. Deviating from tested combinations can result in poor adhesive performance.
Understanding the compatibility between protective films and metal panel coatings is essential for rollforming machine users. When buying Sheffield’s metal coil with Pregis TPF, customers benefit from rigorous testing. “We gathered a variety of different paints and surface samples from Sheffield, and sent them to our lab in North Carolina, where we measured the gloss levels of them all,” explains McMichael. “We tested 10 to 15 different material combinations on each. We had our team visually inspect for ghosting or adhesion residue. And then once we had our recommendations, Sheffield applied those to their coils for real-world production trials.”
These tests simulate various environmental conditions to ensure the film performs as intended without causing damage or leaving residue.
Rollforming TPF Coil
The thing to keep in mind is that if TPF lifts during forming, it can jam up in your machine’s rollers and dies. However, with proper machine operation, running TPF-treated coil through your rollformer shouldn’t be a problem. You may have to adjust for thicker films.
Application during the rollforming process is an option, as with NTM’s strippable TPF film applicator. The optional applicator attaches to the overhead reel rack and adheres the protective film onto the coil as it’s fed into the machine.
However, some machine users prefer to have the TPF already applied to the coil. Just make sure to keep an eye on it as it’s forming through the rollers. “The coil running through the rollers on your machine can cause some issues if too much pressure is applied,” says Simonsen. “Especially if the protective film doesn’t have enough elasticity.”
TPF should cover the whole painted side of the sheet. However, in some instances, if you’re using nail punching, be aware that it may come up during the punching process. The Pregis TPF used by SMI is puncture and abrasion-resistant, making it suitable for rollforming.
Check with the manufacturer regarding the durability of the protective film for rollforming.
Lastly, machines running TPF-treated coils should be cleaned and maintained more often to avoid buildup in the rollformer’s mechanics. Make sure the forming rollers stay clean and in proper working order.
Is Temporary Protective Film Worth the Trouble?
Temporary protective film is designed to protect your panels until installation; it is not a long-term barrier against the elements. By understanding which tackiness level matches your panel’s finish, storing materials correctly, avoiding prolonged exposure to heat and sun, and removing the film in a timely manner, you’ll prevent problems it can create.
Southerland says, “The biggest issue is just not leaving it on.” Likewise, Simonsen underscores the importance of careful planning and proper usage, noting that TPF “works correctly if we store it and use it correctly.”
All said, it’s better to avoid the pitfalls of using TPF than end up with scratched or damaged panels. So, whether you’re purchasing the coil with the TPF applied or applying it yourself, protecting the panels can save you time and money.
Using the right adhesive, communicating best practices down the supply chain, and following manufacturer guidelines can ensure a smooth experience using temporary protective film and preserve the finish of your metal roofing panels.
For more information on metal coil and protective film, contact Sheffield Metals. An account manager can help you determine what best fits your project needs.
For information on portable metal panel rollformers, contact New Tech Machinery.
