What Are Metal Roof Installation Details & How to Avoid Detail Problems
Manufacturer installation details for how to properly install a standing seam metal roof are critical to the success of a metal roof system. Learn about some bad installation examples and what to look out for before the installation begins.
Have you ever purchased a new desk or bookshelf from one of those big-box stores where you had to take it home and assemble it? The recommended instructions and step-by-step details for items like this make it far easier to put together, right?
Now, let’s think of it on a larger scale. Would you want something as important as their roof put on your property without the installers following any set guidelines or tested methods of installation?
The answer is probably no. Whether you’re a property owner, roofing contractor, or installer: The metal roof should be installed according to the manufacturer’s recommended installation details.
At Sheffield Metals, we put a significant amount of time and testing into our installation details for all of our engineered standing seam metal roofing profiles. These guidelines for how to properly install the flashing materials are critical to the success of the roof system, and that’s why we want to share:
- What installation details are and why they’re important
- Inadequate/inferior installation detail scenarios
- How to avoid problems from bad installation details
What Are Metal Roof Installation Details?
Metal roof installation details provide an in-depth product guide detailing the location of components and accessories, and then explains basic practical installation methods for these products at various points on the roof.
What to Look for on Installation Details
Installation details will vary depending on the manufacturer, but most details are broken down according to (or a combination of these attributes):
- Panel profile type
- Roof deck substrate and assembly (i.e., included insulation)
From there, details are typically long documents that outline the information of the panel profile, applicable industry standards or testing, maintenance, warranties, hemming, and then the installation details shown as drawings.
For example, let’s look at the details provided on the SMI 1.5” SnapLock 550 Plywood Installation Details. On this set of installation details, you can find details of how to install at the:
- Eaves with a gutter
- Penetration points
- Hips and ridges
- Vented ridges
- High side eaves
- Roof transitions
- Lightning protections
- Roof/fascia transitions
All of these roof points have a detailed, layered drawing of how the components come together and are to be installed, including the order, types, measurements, exact locations/spacings, and special installation instructions. Commonly, details should include the installation of:
- Бутиловая лента
- Pipe boots
- Miscellaneous accessories
Your installation details will coordinate to the layout of your roof plan, which will show:
- Where the panels are at in that region of the roof
- How the building looks at that region of the roof
- Any other roof structures or penetrations that might affect that region of the roof (i.e., vent pipes, etc.)
Why Should You Use Metal Roofing Installation Details?
Not having or not using any installation details for a metal roof system provides no frame of reference for installers to follow. While some contractors or installers might be able to get by with little guidance, failing to use details often results in a guessing game of how the manufacturer wants their products installed. This simply doesn’t benefit the property owner, contractors, or anyone else involved.
Keep in mind that manufacturers of the metal/profile system put a lot of time and money into their installation details to ensure their details are weathertight and structurally sound.
Considerations About Installation Details to Remember
#1: A bad installation doesn’t mean the roof looks bad.
Installation details exist solely to protect the roof from leaking and failing, which then prevents damage to other parts of the structure. Just remember that because the roof looks good on the outside doesn’t mean that it was installed to the manufacturer’s recommended details. That’s why it’s critical to verify this fact with the contractors.
#2: Just because the installation details don’t match the manufacturer’s details doesn’t mean they’re invalid.
While it’s typically recommended that you follow the details provided by the manufacturer of the metal, this doesn’t mean that other details won’t work as well. Just be aware of this fact and discuss any concerns with the manufacturer before the installation.
#3: Do not use details that are illegible, unorganized, or difficult to understand.
If you run into a situation as a property owner or installer where you don’t understand the details, the measurements are off, or the document is unorganized, it’s best to question if you should use them. Again, the best course of action is to talk to the manufacturer to see if you can get clarity on their details, or find other, more concise details to follow before the installation takes place.
#4: As a property owner, it’s recommended that you go over the installation details with your contractor.
Not only does going over the details give you some insight into how the roof will be installed on your property, but it also helps verify the installation details are appropriately utilized.
10 Bad Metal Roof Installation Details That You Should Avoid on Your Project
Bad detail #1: Putting rivets in valleys.
If installed correctly, there should be no need for rivets in the valley. When you drill a hole for a rivet, you are pretty much ensured to poke a hole in the underlayment, which can create a spot for potential leaks. On top of that, the center of the rivet has a hole in it. So, now not only do you have a hole in the underlayment, but now there’s a hole in the center of the rivet to allow water in.
Bad detail #2: Exposed fasteners that go through the flat portions of the panels.
Luckily, exposed fastener metal roofing is a category of its own and is different from the standing seam metal roof systems that we’re referring to here. If there are any panels on your roof that have an exposed fastener (this does NOT include flashing points), the potential of springing a leak increases significantly. It also can pin the panel if fastened through to the decking, which will stop the thermal movement of the panel and create stress points.
Bad detail #3: Double pinning the panels at the eave and ridge.
In standing seam roofing systems, the panels generally aren’t double pinned (if installed to our recommended details). Not double pinning the roof means that the panels can expand and contract better, which reduces the likelihood of oil canning, fasteners backing out, etc. For reference, SMI’s details pins all panels at the top to allow the expansion to take place at the eave.
Bad detail #4: Putting pipe boots over the seam.
Pipe boots are not designed to make sharp right angles to properly fit over a standing seam on a metal roof, which means it won’t make the penetration completely water-tight and you are counting on caulking for water-tightness.
Bad detail #5: Using sealant as a primary defense against water.
Sealant is added to a roof system as a secondary defense against water intrusion at flashing laps or penetration locations. In other words, you shouldn’t see sealant if you’re looking at the roof, especially big globs of it being used as a primary water defense.
Bad detail #6: Modified J (or J-channel).
A J-channel is a type of flashing material that is used in metal roofing. However, we’ve seen these materials trap water and dirt, which can accelerate corrosion of the metal in some instances. On top of that, J-channels can restrict the expansion and contraction of the roof system as well.
Bad detail #7: Using a C/Z-closure (especially in snow environments).
In this detail, the top of the panel is slid into a receiver at the ridge cap. Most of the time, the top of the panel is not fastened off, which could allow the panel to slide down the roof. Also, you are counting on sealant as the primary defense against water intrusion, which is never recommended.
Bad detail #8: Any roof penetration that isn’t correctly flashed.
Details exist to tell you or the installer exactly how to install the flashing materials around penetration points correctly. However, there are some flashings, such as those for skylights, that come with kits or other “recommended” installation directions. These are often NOT recommended by the manufacturer for use on a metal roof system.
Bad detail #9: Large, visible gaps of any kind.
Gaps are the recipe for leaking – it’s as simple as that. There shouldn’t be gaps at any point in your roof system, so if there are, it’s critical to correct it immediately. Gaps can also invite unwanted “guests,” such as insects, rodents, and other destructive critters.
Bad detail #10: Leaving exposed edges where there isn’t a hem on the metal.
Painted metal sheet and coil are rollformed to make the panels, trim, and flashing materials, which means it needs to be slit to the correct size for the project. When there’s an exposed edge from a cut to the metal, it needs to be hemmed to avoid edge creep and excessive rusting that can be detrimental to a metal roof. Plus, a hemmed edge generally is more tidy and aesthetically pleasing.
Additional Detail Concerns to Look for
Beyond the ten we’ve listed above, there are other inadequate metal roof installation details and practices that you should look out for and avoid, including:
- Lapping sheet metal to look compressed. You should have a minimum 4-inch lap on your flashings (except valleys [12-inch lap]), and these laps must go in the same direction as the water flows and have sealant installed at the laps.
- Using drywall or other generic fasteners instead of metal roofing specific fasteners.
- Seams on a mechanically seamed system that look mangled, unengaged, or improperly seamed.
- Cutting panels with saw blades not designed to cut metal.
- Drilling pop rivets into the roof without a barrier on top of the panel, which can lead to swarf particles creating rust.
- Leaving dead valleys, narrow valleys, and other improper water drainage spots.
- Installing the wrong panel profile for your low-slope or steep-slope roof application.
- Using too much touch up paint or the wrong color (touch up paint will fade differently than the rest of your roof).
- Running metallics or other lot-specific finishes in differing directions instead of the same direction.
How to Protect Your Installation from Bad Details
When trying to avoid bad installation details, the best course of action involves being proactive instead of reactive, so it’s easier to fix an aspect of the installation before it’s complete. That’s is why it’s critical to educate yourself and, if you’re a property owner, go through the installation details with the installer before the project begins.
Here are some steps you can take to avoid any metal roofing issues related to details before it even begins:
- Talk to a specific manufacturer and ask for referrals to contractors who they know will follow their verified installation details. Doing this will help take some of the guesswork out of finding a contractor on your own.
- During the consultations with the contractors, you can stipulate that you want to install a specific set of details on your project. If the contractor is unable or unwilling to use the details you want, it’s best to find a more qualified contractor.
- Ask questions. You’re encouraged to ask questions during the consultation process. Whether it’s a question about the right profile for your roof, how much sealant you should use, or what the details are for the installation — the contractor should be able to confidently and clearly answer your questions.
- When in doubt, check the contractor’s reviews and ask for referrals. You can learn a lot about a business by its ratings and reviews on Google, social media channels, and other ratings-based websites. And don’t just stop there either. If you have a friend, family member, or neighbor who recently had a metal roof installed on their home or business building, they are one of the best places to look. Ask them who they hired as their contractor and if their contractor followed the manufacturer’s details.
- When going through the installation details with a contractor, look for secondary protections used on the roof, such as laps or sealant. For example, all of our details at SMI have a secondary defense component if something drastic were to happen to the original flashing.
- If you’re still questioning the installation details, you can always hire a third-party consultant who can come in and be there during the installation. They’re more likely to be objective and ensure installation details are followed accordingly. However, keep in mind that this is an expensive course of action to take.
Final Thoughts on Metal Roofing Installation Details
Your roof is the first and last defense from the elements that have taken their toll on everything around us. Why not protect the inside of your property and the roofing project in the best way possible by ensuring it’s done right the first time?
One thing to keep in mind is that nothing will ever be “perfect.” And just become something doesn’t look perfect on your roof, doesn’t mean that it’s wrong — it might be exactly what the manufacturer recommends.
Remember this fact when considering installation details: It’s much easier to make sure the right manufacturer’s installation details are used from the start than it is to go back, tear up various parts of the roof, and then redo it.
For nearly 25 years, Sheffield Metals has been continuously perfecting our installation details to make sure that if followed, a roof using our metal sheet/coil is installed to last decades. We have an entire Technical department that works with contractors and installers to assist with any installation-related questions.
To discuss installation details or if you have any other technical questions, contact the Sheffield Metals Technical department today!
О Шеффилд Металз
Компания Sheffield Metals является лидером в сфере продаж изделий из металла с покрытием и без покрытия, а также металлических кровельных и стеновых систем со стоячим фальцем (SSMR). Мы специализируемся на поставках окрашенного Galvalume® и алюминия для производства металлических панелей, ориентированных на архитектуру. Sheffield Metals имеет возможность удовлетворить широкий спектр потребностей, постоянно имея на складе более 50 цветов. Мы также можем подобрать практически любой нестандартный цвет для любого проекта.
Установка металлической крыши
Every year, more and more homeowners opt for a metal roofing system. With a lifespan of 40+ years, energy efficiency, and low maintenance costs, it’s tough to beat the value that metal roofing provides, especially when you consider that long-term metal roofing costs less than shingles.
One of the most important factors with your new metal roof is finding a quality contractor with experience installing metal roofing. Like conventional shingle roofs, faulty installations and poor workmanship can lead to performance (such as leaks) and aesthetic issues.
A roofing contractor with experience and expertise in metal roofing can also help you select the best metal roofing system.
Once you have hired your roofing contractor, they can answer questions specific to your metal roof project. In the meantime, here are some general thoughts about what you can expect with a typical metal roof installation.
Metal Roof Installation Methods
Metal roof installations are either new construction or retrofit.
Строительство нового здания
Metal panels may (or may not) offer spanning capabilities depending on the panel profile selected. Panels without spanning abilities require the application of a plywood deck over the trusses or rafters before the metal panels can be installed. Panels like our Meridian require a plywood deck and represent a great option for residential applications.
Once the plywood is installed, the decking material is then covered with an underlayment material. While underlayments help shed water during construction, the building envelope is not considered watertight until the final roofing material is installed. The same holds true for shingle applications.
Consequently, on new construction projects, finish trades such as drywallers never start their work until after the final roofing system is installed.
For retrofit projects, the roofing contractor has two primary options – recover/overlay or remove and replace.
The recover/overlay option involves installing the new roof on top of the existing roof. While this isn’t always a viable option (more on that below), when possible, recovering the existing roof eliminates the cost and labor of removing and disposing of the existing roof and related components.
Beyond the obvious cost savings, since shingles take 300 years to decompose, leaving the shingles in place also helps to reduce landfill pressures.
When considering whether to leave shingles in place, it is important to remember that steel panels can act like a mirror and telegraph deck inconsistencies and curled shingles through the new metal panels.
On some projects, recover/overlay is not a viable option, so the contractor will recommend a remove and replace approach. As the name implies, this approach involves removing all roofing materials to the original plywood deck and installing new metal panels over the decking.
Contributing factors in this decision are many, but two common reasons to remove and replace follow:
- Local building codes often dictate if a remove and replace is required. Most jurisdictions allow recover applications for either one or two existing layers of shingles. If the number of shingle layers exceeds code requirements, it will be necessary to remove the shingle roof before installation of the new metal roofing.
- If the existing roof has been leaking, water-damaged wood decking may require replacement. Decking that is soft (or rotten in extreme cases) should never be covered with new roofing material. Instead, comprised wood decking should be immediately replaced. After a thorough inspection, your roofing contractor should be able to provide good direction on the possibility of decking material replacement.
All things being equal, tear-off, demolition, and decking repair all increase material and labor costs. When deemed necessary, those steps should be taken; however, in many cases leaving the existing roof in place helps reduce overall cost and install time without sacrificing expected performance.
Metal Roof Installation Components
The following represent the core components of any metal roof installation project.
Refers to the material used to cover the rafters and joists. Typically, this can be plywood, planking, or OSB (Oriented Strand Board) attached to the top of the roof framing members to create the roof surface for the underlayment and metal panel attachment.
Most metal roofing contractors utilize synthetic underlayments, which offer many benefits compared to the early generation felt paper options.
Synthetic underlayments are easier to install, offer improved durability, and can be left exposed to nature’s elements for longer.
Give “What’s the Best Underlayment for a Metal Roof” to learn more about metal roofing underlayment options.
Металлические панели крыши
Metal roof panels come in various sizes, profiles, colors, and budgets. You can even purchase metal panels that look like shingles!
Generally speaking, exposed fastener products represent the most economical panel style to purchase and install; however, they can require fastener replacement after 20-25 years. While fastener replacement is not expensive nor a difficult task, some homeowners prefer concealed fastener (also called standing seam) style roofing panels to reduce the opportunity for leaks and maintenance.
Your metal roof supplier or contractor can help you sort through all of the available options. Or check out the resources below:
– You can upload a photo of your home if you’d like!
Fasteners and Clips
Depending on the type of metal panel you select, your roofing contractor will use clips and/or fasteners to attach the roofing panels to the decking.
Обрезка и мигание
Trim and flashing refers to the components that are installed at the intersections and terminations of the metal roofing system to seal the roof and prevent water from entering the roofing system and building envelope.
Герметики и замазки
Butyl tapes and sealants are used for metal-to-metal connections, such as laps or junctions that intersect trims and panels.
The sealant must adhere to painted metal surfaces and provide some elasticity (for movement) as the metal expands and contracts with the changing weather.
Check out this Meridian installation video to see many of the components used when installing a metal roof.
Job Site Requirements
Every job site is different, but here are the key points to consider to ensure your new metal roof installation goes as smoothly as possible.
Establish a flat area for material storage, vehicle parking, and a dumpster (if needed) for your contractor and their installers.
Depending on your roof, the installers will need clear access on all sides of the building to position and install the panels and trim.
Your contractor will need a power supply for their cutting and fastening tools. To avoid tripping breakers all day, have the installers use different outlets for powering their tools and equipment.
Some contractors provide a generator for their installers to use.
Safety should always be a high priority, especially when there are occupants in and around the building during the metal roof installation.
Metal roof panels and trim have sharp edges, so only the installers should handle them.
Other Installation Resources
For instance, all of our installation manuals are available for download on our Downloads page. The installation manuals provide general product notes, details showing suggested guidelines for proven methods of construction, as well as contact information for our technical service department.
These manuals do not, nor are they intended to, cover all building requirements, designs, installation methods, or codes. Again, the best resource available to you is an experienced contractor.
You can learn more by visiting our metal roof resources page if you still have questions about a metal roof installation. Here you can download different metal roof guides, access our project visualizer, or watch project videos.
Узнайте все, что вам нужно знать о жилой металлической кровли. Ознакомьтесь с нашими ресурсами по металлическим кровлям, чтобы получить вдохновение и ответы на ваши вопросы.
О МакЭлрой Метал
С 1963 года McElroy Metal обслуживает строительную отрасль, предлагая качественную продукцию и превосходное обслуживание клиентов. Штаб-квартира семейного производителя компонентов находится в Боссье-Сити, штат Луизиана, и имеет 13 производственных предприятий в Соединенных Штатах. Качество, сервис и производительность были краеугольным камнем философии бизнеса McElroy Metal и способствовали успеху компании на протяжении многих лет. McElroy Metal, будучи предпочтительным поставщиком услуг, будет по-прежнему оставаться в центре внимания модели наряду с ориентацией на клиента.
Proper installation procedures & tools for metal roofing & cladding panels
In the majority of roofing and cladding applications, metal panels are installed onto substructures. Although seemingly trivial, the selection of the correct tools and the application of proper installation procedures is paramount for the completion of a successful job. This document will outline the necessary tools and techniques required to ensure installers successfully complete projects without damaging fasteners or application substrates
Select the correct drive bits & metal panel installation procedure
Selecting an incorrect drive bit can result in serious efficiency and performance issues. It is recommended that a recessed magnet is used for external drive fasteners, and the correct size and design drive bit is always used for internal drive fasteners.
It is equally important to properly tighten fasteners into the application substrate. The majority of roofing and cladding fasteners will feature some type of bonding washer to provide a water-tight seal. Care must be taken to correctly drive these parts into metal panels. Use the image below as a guide.
Metal panel installers should also take care to select a drill gun set to the correct rotational speed (RPMs). The following charts can be used as general guides for selecting the correct installation speed. However, it is a good idea to check with the fastener manufacturer for exact specifications.
Carbon Steel or 410 Stainless Steel
Нержавеющая сталь серии 300
Source: (Metal Construction Association)
Which to use for metal roofing or cladding panels: drill guns or impact drivers?
Although similar in appearance, drill guns and impact drivers have differences that will affect the performance of SFS fasteners. During metal panel installation, drill guns provide a constant rotational torque. In contrast, impact drivers produce more torque applied in short bursts. This results in “impacts” which drive screws more effectively. In addition, impact drivers are typically more compact and tend to slip less frequently.
On the surface, impact drivers appear to be an obvious improvement over drill guns. However, the increased torque and “impact” action may result in damages to the fastener, the sealing washer, and the installation substrate.
Fasteners can be damaged in three different ways by impact drivers. First, for painted fasteners, chipping and damage can occur. This will result in both unfavorable appearance and increased corrosion risk on most parts.
Second, depending on the material composition of the fastener, the internal or external drives can be damaged. For soft stainless alloys and zinc/aluminum alloys, the use of an impact driver can permanently deform internal drives and “grind-down” external drives. In some cases, the drive will wear down prior to full installation. In addition, repair teams will have difficulty uninstalling the part if roof replacements are required.
Finally, the rotating and cutting action caused by drill points can cause fasteners to “burn up”. At increased torques, installers risk generating excessive heat that damages the fastener points. This will result in the inability to install the fastener and can cause damage to the substrate. Slower RPM screw guns tend to avoid these potential issues.
The increased rotational speed and torque of impact guns can result in the overdriving of parts. In addition to damage caused to the head of the fastener, there is an increased risk of water damage. If a fastener is overdriven into the metal panel, the assembled washer may not properly seal or be irreversibly damaged. This may result in future leaks and water damage.
The application substrate can also be seriously damaged by using the incorrect tool for fastener installation. For instance, increased rotational speed (RPMs) can result in the formation of burrs on metal panels. These burrs can compromise sealing washers and increase corrosion risk.
In wood and composite applications, RPMs above 2500 can result in damage to the attachment substrate. This results in compromised holding strength and can sometimes lead to application failure below provided design values.
Frequently asked questions about metal panel attachment
Should I use a regular drill gun or an impact gun to install metal roofing panels?
Installers should always use regular drill guns to install metal roofing and cladding panels. Impact guns apply increased rotational torque which can damage the parts and make installation impossible.
Does it matter what speed I set my drill gun to when installing metal roofing panels?
Yes, the rotational speed or RPM should be set in accordance with the roofing application. Wood substrates and metal substrates should be installed at different speeds. Refer to the tables above to determine the correct drill speed for your application.
Do metal shavings, burrs, or pigtails cause damage to the roof?
Metal shavings and pigtails cause damage to exposed fastener roof systems. It is important to avoid the “canning” or burring that occurs when installing fasteners into metal roofing applications. They can contribute to corrosion, cause leaks, and potentially lead to serious damage. Always ensure the proper drill gun is used and set to the correct rotational speed.
How do I avoid damaging rubber washers in metal roofing applications?
When installing fasteners with attached rubber washers it is important to avoid squash out failures. This occurs when the fastener is over-driven into the application substrate. To avoid this type of damage, always use a standard drill gun set to the correct RPM. See the above charts and images for guidance.
Key takeaways from our metal panel installation tips
Contractors should always ensure their teams are fully aware of proper installation procedures and tools for metal panel applications. Refer back to this guide anytime for guidance in future projects, or contact SFS for additional tips and strategies.