With the economic troubles of Greece and now China filling our news feeds, it’s nice to come across good news. And let’s face it—over the last several years, particularly since 2009, there hasn’t been a whole lot of good news for roofers or the construction industry overall.
Recession Effects & A Positive Outlook
Roofing demand fell between 2009 and 2014 as nonresidential building construction spending and residential reroofing activity declined due to the recession, according to an article recently published on Building-Products.com. But this same article says U.S. demand for roofing is projected to rise 3.9 percent annually to 252 million squares in 2019, valued at $21.4 billion, according to a new Freedonia Group study.
Metal Roofing Outlook
In particular, metal roofing will see above-average demand gains through 2019. The article goes on to say metal roofing demand will be helped by its durability and ability to support solar panels used to generate electricity. Building Products also sites metal roofing systems provide additional insulation as a boost to energy savings.
New building construction activity is expected to account for increased demand for roofing through 2019. New non-residential demand will come in the areas of office and commercial construction. Demand in the institutional and industrial segments will also increase as more schools, hospitals and manufacturing sites are built, correlating to an increased demand for such low slope products as metal roofing.
Writing project features about breathtaking structures and buildings has its appeal, but having the chance to write about buildings with purpose is far superior. That being said, I introduce you to the House of Love and Hope Orphanage in Croix des Bouquets, Port au Prince, Haiti. Founded by a single mother of two, the House of Love and Hope is home to over twenty children. This summer, through charitable donations, the orphanage expanded its facilities to include a second story.
The Haiti Lutheran Mission Society, by way of Dick Beuthe, invited Quentin and Janel Lange, of Kearney, Neb., to visit their project locations. When visiting the orphanage, the owner Josie Antoine expressed her dream of completing the second story and the need of a roof. They then formed a list of objectives, which included the orphanage’s roof, and measured the addition by walking it off by foot.
The two of them, through Green Steel Buildings, supplied a 26-gauge PBR metal roof, ridge cap and fasteners from MBCI. Metal roofs, especially R-panel, are standard throughout Haiti due to their inclement weather.
House of Love and Hope Orphanage’s new second story
Quentin Lange of Green Steel Buildings said, “MBCI in Omaha, with the leadership of Kelly Danker and Mark Van Saun, expedited delivery to ensure it made it onto the Orphan Grain Train cargo container on time.”
The PBR metal roof installed on the orphanage
The Orphan Grain Train shipped the materials to Haiti, along with 2,000 books collected by Kathryn Holland. Simultaneously, the Messiah Lutheran Church of Lincoln, Neb, raised funds to hire local labor for construction, guided by a team led by Pastor Kunze, Kenny Blair, Mark Miller and Jim Schmersal. The second level and new roof took roughly two weeks to complete.
We discussed water shedding standing seam metal roofs in my last post, and the fact that despite their water shedding properties, you still really must guard against water infiltration. Today I’ll discuss water barrier roof systems, which are structural standing seam roofing systems. These panels can withstand temporary water immersion over the panel seams and end laps. They normally have factory applied mastic in the seams to insure weather integrity. End laps, when needed, are installed using high quality tape and/or bead sealant supplied by the manufacturer. The trim designs used with these systems are much more water resistant as well.
The advantage these water barrier SSRS systems offer:
They require no deck. This is a tremendous savings on the in-place roof cost.
Many systems can be installed on roof slopes as low as ¼:12. This allows greater design flexibility and can also save on the in-place roof cost.
Because they are the only thing between the interior of a building and the weather, these are the most tested metal roof systems available. Manufacturers spend a lot of time and money testing these systems for air and water intrusion, dead load, wind uplift and fire.
Water barrier SSRSs can be further divided by seam type—trapezoidal or vertical rib.
Trapezoidal systems usually have a rib height of 3 inches. The most common panel width is 24 inches, although some manufacturers offer them in other widths as well. Trapezoidal systems are traditionally thought of as commercial or industrial standing seam systems. They are used on warehouses, factories and buildings where the roof is not meant to be seen from the ground. However, some designers have taken these systems and incorporated them into architectural applications with stunning results.
But be careful. Trapezoidal rib systems are much harder to seal at hips and valleys than vertical rib systems. The outside closures at the hip must be cut on a compound bevel with a trapezoidal system. At a valley, the panels are harder to seal because they require an inside closure; the vertical rib panels do not.
Vertical rib systems have traditionally been thought of as non-structural. However, there are now many vertical rib systems available that can span purlins or joists. These systems are available in a wide variety of panel widths, ranging from as little as 10 inches to as much as 18 inches wide. Rib heights vary from 1 foot to 3 feet.
Vertical rib systems are usually easier to install than the trapezoidals. There are fewer parts to the typical vertical seam system, which makes for a simpler, quicker installation. Because there are no inside closures, valleys are much easier to seal and quicker to install. Hips are easier to seal because the outside closures can be cut quickly and simply from a stock length of zee closure.
For these reasons, the vertical rib systems are often a better choice for applications on high-end architectural roofs. Ask just about any metal roof installer, and he will tell you that he prefers the vertical rib system over the trapezoidal system in this application.
Bottom line, when selecting a roof system, choose function first, then aesthetics. When you use the wrong roof system for a given function, the installation process becomes complicated, and results less than ideal. With so many great metal roof options, don’t make life more complicated and uncertain than it need be.
And to make things simple, safe and sound, choose from MBCI’s array of metal roofing system products. Find out more.
A standing seam roof system, or SSRS, has exposed fasteners only at the eave and at specially designed end laps. The concealed clips installed at the panel seam typically allow the panel to float during thermal movement. These systems are normally manufactured in 24 gauge, though 22 gauge is often used.
People tend to classify SSRS as either structural or architectural, but those two distinctions aren’t absolute. There are many architectural SSRS that are structural systems, and most structural SSRS can be used in an architectural application. I think the better distinction is that SSRS are either water shedding or water barrier systems.
Water Shedding SSRSs
Water shedding panel systems are architectural SSRS, meaning they rely on gravity to shed water from the roof before it can build up on the metal panels. The steeper the roof slope, the faster the water will run off. However, in certain instances, these roofs still may allow water to infiltrate.
The following precautions can be taken to avoid this:
Water shedding panel systems must be installed on a minimum roof pitch of 3:12 or greater. Panel manufacturers typically advertise the minimum recommended slope for each of their products.
They must be installed over a solid deck, since they are not structural panels.
The deck must be covered with a moisture barrier or membrane. This is critical as the moisture barrier is the last line of defense once water gets under the metal roof panels. The industry standard for years has been #30 felt. I think this should be considered the absolute minimum.
A better, though more expensive solution is to use a peel and stick membrane. These are much more tear resistant and they will self-seal to nails and screws. Check with the membrane manufacturer about ventilation requirements as these membranes can trap moisture in the attic space if it is not well ventilated.
Keep the design simple. Because these roofs only shed water, intricate trim details are usually not as watertight as those used with water barrier systems. Valleys, hips and other architectural effects can certainly be utilized, but with them comes a much greater chance for water intrusion.
Next post, I’ll get into the applications for water barrier standing seam roof systems
A standing seam metal roof system from MBCI is one of the most durable and weathertight roof systems available in the industry. So when your design requires a roofing system that is both aesthetically pleasing and structurally sound, choose one of MBCI’s six standing seam metal roof systems. Read more.
It should be no surprise that I’m a strong advocate of the outstanding benefits of metal roofing. It is extremely, durable, low maintenance, energy efficient, recyclable –yes, I could go on and on. And it’s not just functional; it’s attractive. Its versatility is a designers dream when it comes to achieving today’s architectural elements—hips, valleys, slope changes, transitions and dormers are all possible.
But as great as these roofs are, care must be taken to select the right type of metal roof system for the job at hand. In fact, the designer must specify a roof panel that can be used in each of the design elements he or she intends to incorporate into the roof project. Design, coupled with the choice of roof slopes, trim details and how the panel is to be fastened to the substructure are deciding factors in choosing the proper roof. When the roof system chosen isn’t the right one for the job, the result can be a roof that leaks and doesn’t function as designed.
Though most metal roofing manufacturers are able and willing to discuss the application parameters for each of their products, it would be wise to arm yourself with at least a general idea about the parameters of some of the most common profiles. To arm you as simply as possible, I’ll separate metal roofing into two broad categories—through fastened and standing seam.
Through-Fastened Roof Systems
Exposed, or through-fastened panels, are available in a variety of widths, usually from two to three feet wide. They also come in various rib shapes, heights and spacings. Typical gauges are 29 and 26, but they also come in 24 and 22 gauge.
There are structural and non-structural through-fastened panels. Structural panels are capable of spanning across purlins or other secondary framing members such as joists or beams. Non-structural panels must be installed over a solid deck.
Through-fastened roofs generally have two great advantages: (1) they are relatively inexpensive and (2) they are simple to install. Structural though-fastened panels have the additional advantage of providing a diaphragm, which is important in the wind bracing of metal buildings.
But most through-fastened roofs also have two big disadvantages: (1) they can leak if not fully seated to the panel or if the purlin is missed, and (2) they do not allow the roof to float during thermal movement. This can cause the roof panel to tear around the fasteners, causing leaks and possible roof blow off.
For this reason, through-fastened roofs are best suited to small- and medium-sized metal buildings and residential applications. In both instances, the panel runs are limited to shorter lengths where thermal movement is typically not a problem.
To support our customers’ design flexibility, MBCI offers 11 different metal roofing panels with exposed fasteners, each with its own unique profile. Most of these roof panels can also be used in wall applications and designed for both vertical and horizontal installation. Read more.
Reroofing is and always will be the predominant project type in the roofing industry. Roughly 70-90% of all roofing projects (depending on the year) are performed on existing buildings. Understanding the reroofing requirements in the building code is critical to proper design and construction. And fortunately, the reroofing requirements are not all that complicated.
The 2015 International Building Code, Section 1511, Reroofing provides the building code requirements when reroofing. Reroofing projects are divided into two types: recovering and replacement (which includes full removal of the existing roof).
Metal panel reroofing projects must meet the same fire, wind, and impact requirements for roof systems for new construction; however, they do not need to meet the minimum slope requirements (¼:12 for standing seam; ½:12 for lapped, nonsoldered and sealed seams; 3:12 for lapped, nonsoldered, non-sealed seams) if there is positive drainage. Also, reroofing projects do not need to meet the secondary drainage requirements (i.e., installation of emergency overflow systems is not required).
The requirements for metal panel and metal shingle roof coverings are in Section 1507.4, Metal roof panels and Section 1507.5, Metal roof shingles of the 2015 IBC. These apply for new construction and reroofing, and include information about decks, deck slope, materials, attachment, underlayment and high wind, ice barriers, and flashing. The 2012 IBC has the same requirements; the 2015 IBC added new language about deck slope and attachment requirements for metal roof panels. Nothing was changed for metal roof shingles.
In general, recovering is only allowed if there is one existing roof in place, except if a recover metal panel roof system transmits loads directly to the structural system (bypassing the existing roof system). This provides a great advantage for metal panel roofs! The existing roofs do not need to be removed, but new supports need to be attached through the existing roof (typically a metal panel roof) directly into existing purlins.
If metal panels or metal shingles are installed over a wood shake roof, creating a combustible concealed space, a layer of gypsum, mineral fiber, glass fiber, or other approved material is required to be installed between the wood roof and the recover metal roof system.
Good roofing practice is codified in the reroofing section of the IBC; contractors who design and install a recover or replacement metal roof are legally required to follow locally adopted code requirements. And, of course, all metal roofs must be installed according to the manufacturer’s approved instructions.
As is often the case when it comes to your investments, it’s always a good idea to diversify. This also applies to the investment of your construction expertise as a roofing contractor. Even with the mild uptick in new construction activity of late, contractors are smart to explore the additional revenue stream that can come from roof renovations and retrofits.
Most metal roof retrofit work entails adding slope to an existing flat- or low-sloped roof. According to a 2013 article in Metal Construction News, about 25 percent of U.S. commercial, institutional and public buildings are 55 years old or older and consist of flat-roof stock that has reached the end of its service life. Two years later, that percentage is surely higher.
To transition from a flat roof to a sloped roof is a good move, because it will result in lower energy and maintenance costs for years to come. It is also environmentally smart, because metal is one of the most recycled materials used in construction, and metal roofing is 100 percent recyclable at the end of its service life. A metal roofing system provides for additional insulation, as well as the installation of solar panels that reduce reliance on electricity. And in most circumstances, a new metal roof can be installed without having to remove the existing flat roof. A metal retrofit may carry a higher initial cost, but when total life-cycle cost is considered, a metal retrofit will end up being the lowest cost alternative.
A large number of buildings with flat membrane or built-up roofs require a framing system to produce an adequate slope. But this particular type of retrofit can be challenging. In general, the retrofit market is more specialized and much more technical than what roofing contractors are likely used to in the existing metal building market. At the same time, the retrofit market can be very profitable and is worth getting up to speed on.
Whether you’re doing a small retrofit project or a complete renovation, MBCI can assist you with developing a preliminary budget, estimating, engineering, as well as providing a complete set of shop drawings for your retrofit project.
Stay tuned for future posts where we’ll provide some guidelines on how to successfully navigate the design process of retrofitting a flat or inadequately sloped built-up or membrane roof. Adding this diversity to your portfolio of roofing skills will likely net a high return on investment.
Kickapoo Tribe Government & Community Building features MBCI’s CF Architectural Insulated Metal Panel
Are you familiar with “Net Zero Energy?” No, it’s not that sense of power you got from using that early dial-up Internet browser of the 1990’s (The company, by the way, is still in existence, and comes up in searches for the term Net Zero. Who knew?). The Net Zero Energy I’m speaking of is the enviable, sustainable state achieved when the creation and use of energy within the same building system are equal.
Though achievable, the cost and capacity for producing energy within a building system is greater than that of creating energy efficiency in one. The good news is that metal roofing and ,a href=”http://www.mbci.com/products/wall-products/”>wall panels are extremely useful on both sides of the equation.
On the energy efficiency side, insulated metal panels (IMPs) provide roof and wall systems with the thermal and radiative performance needed for sustainable design. Insulated wall and roof panels provide continuous insulation and eliminate thermal bridges. As building and energy codes become increasingly more stringent, insulated metal panels are an ideal choice for thermally efficient building envelopes.
Baker Hughes features MBCI’s CF Mesa Insulated Metal Panels
On the other side of the equation, a common method of generating energy is through the use of photovoltaics (PVs), and metal roofs provide the best possible surface to host a photovoltaic (PV) array. Solar photovoltaic systems and solar water heating systems can be installed on a metal roof, penetration-free, resulting in high performance with minimal risk. Both the use of IMPs and the installation of PVs on metal roofs can be used with proper designs to maximize building energy efficiency.
Of course, metal roofing, known to last 40 years or longer, is the only type of roof that can be expected to outlive the PV system mounted on it, which results in virtually zero maintenance and a very low in-place cost for the roof and PV system together. A sustainability win, a durability win, and, of course, an aesthetic win. The result is anything but a zero sum game.
The majority knows that metal roofs are durable, but it wasn’t until recently that a study showed the longevity of low-slope unpainted 55% Al-Zn alloy coated steel standing seam roofing (SSR) systems- 60 years. With the service life of a commercial building being 60 years, according to LEED version 4, this means that essentially the metal roof system described above, and commonly referred to as Galvalume® metal roofs, does not require replacement. To put this into context, by comparison most non-metal roofs require at least one replacement during the same period. This study also reveals that the longevity of a 55% Al-Zn alloy coated standing seam roofing system far surpasses the typical warranty period granted, which is 25 years. Basically, this is a game changer and we, manufacturers, are thrilled!
Technical Director of MCA Scott Kriner said, “This study is a breakthrough for the metal construction industry because it finally provides third-party, scientific data that backs up the long held stance that 55% Al-Zn coated steel standing seam roofing systems are very durable, economic and can be better for the environment.”
Let’s take a closer look at the study. The Metal Construction Association (MCA) and Zinc Aluminum Coaters (ZAC) Association sponsored it. The study involved three independent consulting firms testing 14 buildings in five climate zones. The variety of structures and climates allowed them to analyze how Galvalume metal roofs perform in a range of temperatures, humidity and precipitation pH, or acidity, levels. All of these can affect the metallic corrosion rate of roof panels, their sealants and components, and that’s what the consulting firms analyzed.
Here were some of their findings:
First, the sealant life is the primary deciding factor in establishing end-of-life for Galvalume metal roof systems. In certain structures analyzed that were 35 years old, the sealant was considered “entirely adequate and without issue.” Based on the sealant performance, the study conservatively projected the lifespan of such roof systems to be 60 years.
Secondly, although a Galvalume metal roof is moderately maintenance-free, all roof systems require a periodic inspections and maintenance in order to achieve such long lifespans.
Thirdly, while the roof system as a whole was projected to last up to 60 years, components may need to be replaced during this period. The cost of replacing components, however, is considerably less than 20% of replacing an entire roofing system, which is the value deemed by this study as excessive to the point of constituting the end of service life for a roof system.
Lastly, the study unveiled that even on areas typically most susceptible to corrosion, such as panel profile bends, there was an absence of significant rust after 35 years; even at its most vulnerable areas, a Galvalume metal roof system performs well.
So what does it mean for architects and building owners? Speaking from a purely biased manufacturer’s prospective, specify and purchase more metal roofs! All jokes aside, this study displays the appeal in selecting a metal roof because it reduces the maintenance costs of the building. It also changes and increases the accuracy of Life Cycle Cost (LCC) or whole building Life Cycle Assessment (LCA) associated with Galvalume metal roof systems by providing tangible research as opposed to previous calculations based on roofing professionals’ opinions. To find out more information or to download the full report, visit http://www.metalconstruction.org/index.php/education/technical-resources.
It is an industry standard that we use the word “gauge” to describe the thickness of steel coils and sheets. Metal roof and wall panels rolled from coil come in a range of gauges, with many of our panels’ standard being 24 gauge. This format is based on the Manufacturer’s Standard Gauge (MSG) which is a remnant of an outdated standard. It’s not until you take a closer look do you realize that specific gauges, such as 24, can equal a range of thicknesses.
When steel coils were rolled decades ago, manufacturers lacked the technology to consistently produce material thicknesses to the tolerances regularly achieved today. Therefore, a relatively large tolerance range was established for the MSG system and this tolerance determines what range of thicknesses qualifies as a particular gauge. For example, as you can see in the table below, 24-gauge panels can range from 0.0269-0.0209 inches.
www.engineersedge.com
As time went by and technology improved, coil manufacturers could produce material down to the thousandth of an inch of thickness, and the MSG system was considered outdated by many in the industry. Instead, the Standard Decimal System was introduced. This system defines gauges by specific minimum thickness expressed in decimal numbers instead of a range, eliminating the tolerance. Although widely accepted throughout the industry, the architectural community has been reluctant to adopt this system when specifying building products.
Because the architectural community is still specifying buildings using the MSG system, manufacturers still list their products by it as well. This leads to some manufacturers taking advantage of the MSG system’s large tolerance and producing panels with the minimal thickness allowed to qualify for that gauge. For 24-gauge panels, for example, they might roll it to 0.0209 inches, instead of the nominal 0.0239 inches. Although still technically allowed it seems misleading to me, especially when you consider other manufacturers who spend more money to achieve the specific gauge advertised true to the intent of the MSG system. In addition, this difference in thickness, even in the thousandths decimal place, leads to a difference in structural performance and strength. This can potentially lead to inaccuracies in architects’ specifications or even worse, under expected performance. That said, I think it’s worth the extra effort to take a closer look before selecting products and that it is the manufacturers’ responsibility to present their products honestly.
