Whether you notice them or not, metal roofs are everywhere. You probably wouldn’t normally think to look at the roof on a home, but if you take a drive down any road in any city, you’re likely to find a house or building donning some kind of metal roof.
But how much do you know about metal roofing? Did you know that it often requires little to zero maintenance after it’s installed? Or that you can choose from a variety of looks and styles, like standing seam or stamped metal roofing?
Here at Sheffield Metals, we want to help you choose the best roof for your needs, which is why we think explaining the basics of metal roofing will assist in your decision-making process. In this article, we are going to discuss:
- Reasons to consider or choose a metal roof
- Common roof terms and definitions
- The different uses and applications of metal roofing
- Types and options available with metal roofing
Benefits & Advantages of Metal Roofing
There are a number of reasons to choose metal roofing over other materials, like asphalt shingles, tiles, or concrete. While metal roofing might be the best choice for some home or building owners, we understand that it’s not always to best material for every consumer. The best way to know if metal roofing is a good match for you is to consider some of the most common reasons people decide to buy:
Metal roofing is specifically engineered to last decades longer than any other roofing material. Actually, many consumers ultimately decide to purchase a metal roof because it’ll be the last roof that they ever have to put on their home or business. Depending upon the type of metal material used, most metal roofs last 60+ years without any signs of degradation or corrosion.
When comparing different materials, like wood, concrete, metal, plastic, or glass, metal easily stands out as the strongest and most durable. If properly installed, metal roofing is designed to withstand:
- Strong winds
- Debris (leaves, sticks, etc.)
- Rodents and other animals
Not to mention, metal roof materials are often Class A fire-rated and noncombustible, meaning its fire resistance is the highest grade possible. This proven durability against common roofing threats is one of the fundamental reasons metal roofing is so popular.
The level of upkeep needed to maintain a metal roof is generally minimal, especially if the roof was correctly installed. General upkeep would include looking for leaves, branches, and other debris that could get stuck on the roof and in the gutters around twice a year and after strong storms. In the event that dirt or other stains do not come off with rain, there are methods to clean your metal roof. Also, a concealed fastener roof will generally have less upkeep than an exposed fastener metal roof.
There are a number of reasons that metal roofing is environmentally friendly. First, most metal is highly recyclable, meaning that any tear-off metal, old panels, or even manufactured excess scraps can be recycled and used in future products. These metal materials can either come as pre-consumer or post-consumer recycled content:
- Pre-consumer recycled materials – Scrap content during the manufacturing stage that has been recycled for future use.
- Post-consumer recycled materials – Excess materials that have already been in the possession of a consumer at one point in time and have been recycled for reuse.
Second, there are even some metal roofing materials, including aluminum, that are made of already-recycled metal. Nearly 95% of all aluminum roofing is made up of recycled materials. Third, many metals, like zinc and copper, are found in the environment or in the Earth’s crust, which means they can be naturally replenished and sustained over time. Make sure to specify ahead of construction and installation that recycled content is important to you.
Lower Cost in the Long-Term
It’s true: Metal roofs are more expensive upfront as a one-time cost versus the cost of asphalt shingles or tiles. However, as mentioned before, metal lasts at least 60 years, while asphalt shingles last anywhere from 15 to 20 years. One metal roof can easily outlast at least three asphalt shingle roofs.
The two photos on the right represent a cost comparison between 60 years worth of both mid-range shingle roofing (three in total) and metal roofing (one in total). In this scenario, the mid-range cost for one architectural shingle roof is around $8,700 and the cost for one G-90 Standing Seam with Kynar 500, a high-end paint system, roof is about $17,400. Even if the shingle roof lasted 20 years, you would need to pay for the shingle roof three times and the metal roof one time in a 60-year span, making the metal roof a more economical choice.
Metal roof = $17,457 x 1 (1, 60-year lifespan) = $17,457
Shingle roof = $8,737 x 3 (3, 20-year lifespans) = $26,211
One of the best parts of owning a metal roof is the variety of warranty options made available by the metal manufacturers or suppliers. Two of the most common are weathertight warranties, which cover leaks in the roofing system, and paint warranties, which cover certain levels of degradation of the paint system that is applied to the metal substrate. Warranties can vary quite a bit depending on where you live, the climate the roof will be exposed to, the type of roofing material used, and the type of paint system used on the coil. Be sure to thoroughly read the warranty documents ahead of time and ask questions before you buy.
Note: Weathertight warranties are typically a tool used for architects and building owners of non-residential structures to ensure longtime system integrity from the system manufacturer.
Metal Roof Components, Accessories, Parts, and Definitions
In order to better understand a metal roof and how it works, let’s start with some components, common accessories, and other important roofing terms and definitions.
Metal Roofing Components
METAL COILS/SHEETS – Metal coils are long, continuous metal rolls that have been treated or coated with paint. All metal roofing starts out as coil or sheet metal, which is then rolled out, cut, and rollformed into a panel for installation.
PANELS – Panels are the rollformed pieces of metal coil that have been shaped into the desired profile/ribbing structure and are ready to be seamed together to form a roof.
SEAM – The side rib at which two metal panels come together and are connected. Seams are formed using a rollformer and are then snapped together or mechanically seamed together.
PROFILE – The shape metal panels are formed into. The profiles are what determine how the panels fit and connect together.
ROLLFORMING EQUIPMENT – The machinery, either stationary or portable equipment, that forms and shapes the coil into individual panels.
Metal Roofing Installation Accessories
UNDERLAYMENT – Underlayment is the layer of material that goes underneath the metal panels and provides protection from water and moisture, ice, high temperature, and vapors. Underlayment is generally installed mechanically or self-adhered with a glue backing on the roof deck. While there are many different types of underlayment, common materials are felt, synthetic (polypropylene or polyethylene), and fully-adhered peel and stick.
CLIPS – Clips are used to attach the metal roof panels to the deck. Clips are put on the standing seam portion of the bottom panel, which is then attached to the roof deck by fasteners. After the clip is put on the bottom panel, the top panel is placed over the clip and the two panels are snapped together or mechanically seamed into place, which securely attaches it to the structure.
FASTENERS – Fasteners are the screws used to attach the metal roof to the roof deck during installation.
RIVETS – Rivets are similar to fasteners, but require a special rivet gun to install.
SEALANT – Sealants are used during installation to seal out water, dirt, wind, and other substances that can get into small spaces, making the roof as weather-tight as possible. Sealants, which are typically made up of silicone or polyurethane, come out of the tube as a flexible sealing compound that will cure after application. Most sealants are available in colors matching the roof panels.
BUTYL TAPE – Butyl tape is used in a similar fashion as sealant by sealing cracks and seams on metal roofing. It’s also commonly used for trimming purposes. It differs from sealants because it’s in the form of one or two-sided tape and seals by compression.
CLAMPS – Clamps are small metal parts that are tightened and attached to the top of the metal roof at its standing seam. These clamps have screws at the top used to attach extra roofing items such as a snow retention system, solar panels, satellite dishes, signs, AC units, etc.
PIPE BOOT – A pipe boot is the cone-like fitting that is installed around an exhaust pipe that exits through the roof. These products are typically made up of EPDM rubber (silicone is also available for high-temperature applications). The pipe boot, which can be purchased in a color matching the roof, is cut to fit the diameter of the exhaust pipe and is then sealed to the pipe and the metal surface.
Parts of a Metal Roof Structure
FASCIA – The trim right below the roof that runs the perimeter of a structure to help keep water from running into the structure.
DRIP EDGE – A long piece of metal that is installed so water runs into the gutter and away from the fascia.
EAVE – A portion of the roof that extends past the supporting wall.
VALLEY – The internal angle at which two sloping roof planes meet.
HIP – The external or jutting angle at which two sloping roof panels meet.
RIDGE – The highest portion of a roof where at least two roof panels come to a point (commonly a horizontal line).
GABLE – The triangular section of a wall between the edges of a sloping roof. The trim occupying this article is typically called “gable or rake trim”.
CRICKET – A peaked saddle construction installed between a chimney and the roof surface to prevent against the accumulation of snow and water.
FLASHING – Sheet metal that is used to seal different portions of the roof, i.e. chimneys, valleys, etc., and provide extra weather-tightness.
CURB – An accessory used to mount additions (AC units, fans, signs) and provide a level resting structure on a sloped roof.
ROOF DECKING – The base or foundation that the underlayment and roofing material are attached to. Common roof deck materials are metal, plywood, and oriented strand board (OSB).
PITCH – The slope of a roof, which is measured using the roof’s rise divided by its run.
Common Uses and Applications for Metal Roofing
Metal roofing has the reputation of only being used on large industrial or commercial structures. While it’s true that metal is a good option for these applications, metal roofing goes far beyond this with use on homes, architectural buildings, and agricultural structures. Let’s discuss more common uses and structures to look for the next time you’re out in your city or town.
One of the biggest reasons metal roofing is commonly chosen in commercial applications is due to its superior weather resistance to wind and water, especially in areas where hurricanes or other tropical weather is a concern. Even when the structure isn’t in a tropical location, metal roofing gives business and building owners the peace of mind that their roof is destined to last and not need constant upkeep. Common uses:
- Schools and universities
- Government buildings
- Military structures
- Transportation buildings
The residential market is booming as homeowners begin to realize that metal roofing will actually save them money in the long run. A lot of homeowners don’t think their roof is big enough to warrant a metal roof, but we are here to tell you that the size of your roof doesn’t matter. Metal roofing systems can be used on something as small as a brick or stone mailbox.
There has also been an increase in metal roofing being used as an accent on an awning or as a part of the roof. Be sure to consult with the manufacturer before a contractor installs two different materials together, as they could potentially react and/or degrade one another.
Since metal roofing begins as a metal coil or sheet, it has the ability to be formed and cut into many different shapes, sizes, and lengths. This variety, along with the durability, variety of colors, and eco-friendly qualities, gives architects many benefits to using metal to create aesthetically pleasing structures.
Have you ever been inside of a warehouse, factory, or other industrial building where you look up and see the roof from inside? This is a good example of structural metal roofing, which is when metal panels are installed over open framing or on structures that span long lengths and are attached directly to the frame or purlins (additional support beams added to the roof frame).
Like structural applications, barns and other agricultural buildings are common uses for metal roofing. Agricultural structures traditionally use a lap seam profile, which is when the ends of the panels overlap each other and have sealant or exposed fasteners holding the two panels together.
Metal Roofing Types and Options
The popularity of metal roofing is often to due its versatility, variety of options, and ability to be customized for each individual structure, which includes color, shape, style, and much more.
Metal Material Types
Metal is a very broad term when it comes to roofing, especially because there are nearly 100 metals on the periodic table of elements. Some of the most commonly used metal roofing materials used in the industry are:
- Galvalume coated steel
- Galvanized steel
- Stainless steel
All of these metals are good options, but there are differing pros and cons associated with each one. Make sure you read up on metal roof material options to determine the best one for your location, style, and needs.
Metal Roofing Panel Styles
Standing Seam – Standing seam metal roofing refers to metal panels interlocked together at the edges to form a seam, which stands vertically. A true standing seam system uses the concealed fastener method of installation, meaning the clips and fasteners are hidden beneath the surface and not visible to the naked eye. This is what sets it apart from all other metal roofing. Standing seam roofing is considered the superior and the better-protected choice when compared to exposed fastener metal roofing.
Exposed Fastener – Exposed fastener metal roofing, considered the less expensive and more economical choice, is installed with the heads of the fasteners visible on the top of the panels. When an exposed fastener roof is installed, the fastener goes directly through the metal and into the roof deck. Exposed fasteners have classically been used in agricultural or industrial applications.
Stamped Profiles – If you like the look of shingles or more textured surfaces but still want the longevity, cost and durability metal offers, it’s possible with metal stamped profiles. There are many different stamped options to choose from, including:
Metal Panel Seam Types
Snap-lock – Metal roofing panels that have been carefully rollformed with specific panel profile edges that snap together and require no hand or mechanical seaming during installation. Snap-lock seams tend to be a little more popular in the roofing industry because they are engineered to defend against the elements while making installation a little easier on the contractor.
Mechanical Seam – Mechanically seamed panels are also rollformed with specific edges that line up with each other on the roof. Once the two edges are put together, a hand or mechanical seamer is used to bend the edges and lock the panels together. The locked seam resembles the shape of a paper clip. There are two kinds of mechanical seaming:
- Single Lock / 90-degree seam – One folds of the seam
- Double Lock / 180-degree seam– Two folds of the seam
Tee Panel – A type of standing seam where two panel edges come together and are connected at the top by a cap, which is then mechanically seamed in place to lock the panels together. Once the seaming is complete, the top of the standing seam is in the shape of a “T”.
Exposed Fastener Lap Seam – Exposed fastener lap seams are when the overlapping ends of the lap panels are fastened down to the deck from the top of the panel.
Panel Rib Rollers (Striations)
Rib rollers are the “patterns” or striations rollformed into a metal roofing panel between the seams. These can be used to assist with the installation of a metal roof or just for curb appeal. Common rib rollers include:
Flat – No indents between the seams
Ribbed – Some shape or indentation between the seams
- V-Ribs – “V” shaped panel indents
- Bead – Longer, rectangular panel indents
- Pencil – Circular panel indents
Striated – Small consistent indentation lines in the panel (can help reduce oil canning)
Corrugated – Larger, constant waving of the metal panel
Clip relief – A stiffening rib adjacent to the seam that allows the space for a clip
Common Metal Thicknesses
The metal coil that is rollformed into roof panels comes in many different thicknesses. We will discuss the disadvantages and drawbacks of differing panel thicknesses in a future article. Standing seam metal roofing comes in a variety of thicknesses (typically between 22 and 26 gauge) with the most common steel thickness being 24 gauge and aluminum between .032 and .040 inches. For face-fastened systems, 26 or 29 gauge materials are usually used.
Metal Paint Colors and Finishes
Having control over the color and overall look to your structure is one of the most appealing parts of choosing metal roofing. Because of the overwhelming demand for both bright and earth tones on roofing systems, paint companies, like Sherwin-Williams or Valspar, created tested and proven paint systems that add style to a home’s exterior while still reducing chalking, fading, chipping, and other color degradation.
In addition to every color in the rainbow being an option, you can even special order the finish of your choosing. If you want a blue roof with a matte finish, it’s possible. Or if you want a red roof with a glossy finish, that’s possible too.
If you’re new to metal roofing or just beginning to do your research on the benefits of this roof type, it can a complex topic. It’s true, metal roofing might not be for everyone. But more often than not, it’s a good option for a homeowner or business owner if:
- You want your next roofing purchase to be the last one you have to make
- You don’t want to pay more in the long-run to replace a shingle or tile roof every 15-20 years
- You want an eco-friendly, sustainable roof requiring little to no maintenance
- You want a roof that is recyclable
- You want a roof available in a variety of color, finish, or texture options
At Sheffield Metals, we understand the importance of choosing the best roof for your home or business. We are here to answer your questions and help you decide. Contact us today to speak with our metal roofing specialists.