Metal Roofing Blog

What Homeowners Need to Know About Metal Roof Seaming

Property owners all over are making the switch from traditional asphalt shingle roofs to new metal roofs for many reasons. A metal roof can improve a home or commercial building many ways, offering property owners surprising benefits in addition to tremendous value and long-term cost of ownership. However, it’s vital to invest in experienced professional installation to get maximum value from a new metal roof. The unique installation process is the most critical part of any new metal roof installation, so choose a reliable and experienced roofing team to handle this job.


Depending on the type of metal roof a property owner chooses for a residence or commercial building and the structural style of the building, the roofing team will need to use different seaming techniques to complete the roof installation. The metal roof installation process entails and what to expect from the experience.

Choose the Right Roofing Crew

Take time to thoroughly research a roofing contractor before agreeing to their services. Check the roofer’s website and look for verified credentials, testimonials from happy past clients, and the number of years the contractor has served the area. Don’t assume an inexperienced contractor offering a lower price will be a good deal; metal roof installation requires careful work and attention to detail, so work with a roofer that has a strong track record of success.

Be sure to check beyond the roofer’s own website for reviews. It’s easy for any company to pick out the most glowing reviews to feature on their site, so check third party review sites like Google, Angie’s List, and Yelp. It’s also wise to check if the contractor has any complaints against it registered with the Better Business Bureau.

As you scan a roofer’s reviews, look for any trends among them. For example, if you notice many reviewers stating the roofer overcharged them or surprised them with hidden fees, take this as a strong sign that the roofer may not be upfront about billing. Similarly, if you notice a trend of positive reviews across different review sites, take this as a sign that the roofer may be a great choice.

Ensure Complete Removal of the Old Roof

If a roofer claims that installing a new metal roof on top of your existing asphalt shingle roof would add an extra layer of protection, beware. This is not only untrue but potentially dangerous.

Old roofing shingles have rough surfaces that will essentially grind against the bottom side of your new metal roof panels. This will erode the protective coating and create an opening for rust and corrosion. Asphalt shingles can also telegraph through the metal roofing panels. Pressure will cause the horizontal lines of the shingles to appear through the metal roof panels, diminishing the appearance of the new metal roof.

The Hand Crimping Process

Different metal roofing material manufacturers have specific crimping and clamping procedures for ensuring effective and safe installation. If you hire a roofing team to handle your metal roof installation, make sure they have extensive experience with the brand you have chosen. Most roofers will sell materials from the manufacturers with which they have the most experience, so this is generally the safest option.

Hand crimping is a delicate process that requires precise measurements. The roofer you select should be able to explain the hand crimping process for your brand of roof in detail so you can make your decision with extra confidence. Poor hand crimping is one of the most common causes of bad seaming, which can cut the lifespan of your new metal roof short and lead to expensive repairs.

The Electric Seamer

Once your roofing team completes the hand crimping process, they will use an electric seaming device to complete the metal roof installation. The full installation process involves preparing the roof bed, including fixing any old or damaged insulation and padding, and ensuring the roof is ready to accept the metal panels. Next, they will place the panels, clip them into place, and then hand crimp them to start the seams. The final step is electric seaming, which requires the roofing team to work together very carefully. The roofers will need to bring their own AC/DC generator to supply power to the electric seamer; these devices require more power than a typical exterior home outlet can provide.

The roofers will need to carefully guide the electric seamer over every seam. It may be necessary to pause the seamer to remove debris out of the way, but they should not move and replace the seamer at all during the seaming process. This will result in gaps in the seam as it is very difficult to place the seamer back into the exact same position after moving it. Just one miniscule hole in one seam can compromise the safety and integrity of the entire metal roof.

Safety Is the Priority for Every Roofing Job

An electric seamer is a complex, heavy, and potentially dangerous piece of equipment. Before agreeing to a roofing contractor’s service, ask them about their safety standards and how much training every member of the seaming team has using this device. Also, ask about what steps they take to ensure the safety of their seaming team and what type of safety training their team members complete. Any reputable and trustworthy roofer should be happy to answer these questions to earn your business.

The seaming team should use safety lines attached to the electric seamer in case it detaches from the roof during the seaming process. Should this happen, the safety lines will prevent it from crashing to the ground. The seaming team should also wear appropriate safety equipment to complete the seaming job as safely as possible, including eye protection, head protection, heavy-duty gloves, and fall protection devices. Working on any roof, even one on top of a one-story building, is potentially dangerous. The electric seamer is a heavy piece of equipment that adds an extra layer to risk on an already dangerous job.

This information should help any property owner approach the metal roof installation process with greater confidence. A new metal roof can be a tremendous investment for any property, outlasting asphalt shingle roofs by a significant margin and offering fantastic long-term cost of ownership. However, it’s only possible to achieve these benefits by working with an experienced roofing contractor committed to job safety.

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