durability Archives | Page 2 of 2

Proper Fastening Helps Prevent Leaks and Callbacks

Posted on December 18, 2017 by Randy Tweedt

Installing metal roofing and siding requires placing and aligning metal panels over the structural supports. But ultimately it requires installers to spend a fair bit of time fastening them in place, typically using a great many fasteners. It is easy to get complacent about this repetitive activity, but the reality is that every fastener plays a crucial role in the integrity and longevity of the installation. Properly selecting, installing, and using the right tools, allows for a proper fastening process that assures a weathertight installation. But if a few fasteners are installed poorly, causing water or air leaks, then the installer is called back to correct the condition. Do a lot wrong, and warranties can be void, with the durability of the building left compromised, possibly requiring a total do-over.

What’s the difference between a good fastening installation and a problematic one? Here are some of the things to pay attention to onsite:

Fastener Types:

The most common type of fasteners used in metal buildings are self drillers, which vary based on diameter, length, head shape, and material. They are also specifically designed for use in metal substrates. Different fasteners are also available for wood versus metal, and either type can be sized for different substrate and panel thicknesses. Zinc alloy or stainless steel fasteners are common choices for durability, longevity, and avoiding galvanic action with other metal products. Selecting and using the right fastener type for each of the different locations on a metal building begins with determining what is being attached and what is it attaching to.

Fasteners can also be colored to match the roof or wall panel.

Weathertightness:

Fasteners of any type cannot be relied upon by themselves to keep out the elements. Instead, a sealing washer is used that is compressed between the fastener head and the metal panel as the fastener is tightened to form the weathertight seal. High-performance or long-life fasteners may be required for a durable approach to weathertightness and/or may be required by the metal building manufacturer to receive a weathertightness warranty.

Installation Process:

With the right fasteners onsite, the success of the installation now rests with the field crews. A few minutes to review the different fasteners and match them with the right tools and settings for installation is time very well spent. Since electric screw guns with or without impact drivers are common on the jobsite, it’s easy to think any tool will do, when it probably won’t. The wrong tool at the wrong setting can place too much torque or other force on the fastener, causing it to crush or damage washers or even the metal panels. Impact drivers are rarely needed in most cases and, while the fastening needs to be tight, overtightening is never a good thing.

Fastener Locations:

In addition to weathertightness, fasteners provide a structural function as well. Their location and spacing will directly correlate to the ability of a panel to resist wind and other forces after installation. Therefore, it’s always best to use information prepared by a professional engineer on the proper fastening locations, spacing, and sizes. The calculations behind such information can prove to be the difference between a successful installation and one that creates problems.

Understanding the importance of fasteners and the role they play in the integrity of the building, and corresponding warranties, allows installers to see beyond the repetitive task of fastening and into the craft of assembling a durable, long-lasting building. To find out more about fasteners for metal products and systems for your next project, contact your local MBCI representative.

Urban Heat Island, Part 2: How Cool Metal Roofs Benefit Building Owners

Posted on August 22, 2016 by Candy McNamee

In our prior blog post, Urban Heat Islands, Part 1: How Cool Metal Roofs Benefit the Community, we identified the existence of urban heat islands and their contribution to higher air temperatures that are found in urban areas compared to surrounding locations. We also identified a high Solar Reflectance Index (SRI), on a scale of 0-100, as the means to specify materials that can help reduce urban heat islands and benefit entire communities. In this post, let’s focus on the specific benefits to the building owner when cool metal roofs are used.

The Boundy Residence features a cool metal roof

Energy Savings for Cool Metal Roofs

In many commercial and industrial buildings, energy use is one of the largest ongoing operating expenses, meaning that building owners and operators are usually quite interested in lowering or controlling that expense. Cool metal roofs with a high SRI rating can help with that quest. For instance, since air conditioning is commonly a larger cost that heating for many such buildings, it is a natural place to target. Lowering the temperatures at the roof means there is less heat surrounding the building, reducing air conditioning load and directly impacting energy costs.

Comfort in Outdoor Areas

Some building types, such as restaurants, retail, and entertainment facilities, rely on outdoor seating or gathering areas to support their business. If urban heat islands make these spaces uncomfortable to spend time in, the business usually suffers too. Providing these buildings with high-SRI metal roofing can improve the situation.

Long-Term Durability

Building materials can degrade prematurely if they routinely exposed to high heat. The heat can cause them to dry out, become brittle, or simply decompose faster than expected. Using high-SRI roofing is not only good for the longevity of the roofing, it can be good for the durability of the materials directly under the roof as well. Roof sheathing and other substrate materials directly in contact with the roofing receive the same intense solar radiation that the roofing surface does.

Attic spaces below the roofing plane also receive the heat, making attic temperatures in excess of 130 degrees common, causing degradation of materials in those spaces, including mechanical and electrical equipment. That could mean more expansion and contraction of connections and joints or it could mean that air conditioning duct work is being heated, contrary to the efficient operation of the system. In any of these cases, a cool metal roof will help alleviate the negative impacts of solar heat and allow materials to achieve full life expectancy.

Supports LEED Certification

In the Sustainable Sites category of the LEED rating system, Heat Island Reduction can be selected as a credit to receive either one or two points toward certification. This credit relies on both roof and non-roof strategies and looks for calculations of solar reflectance (SR) and demonstrated Solar Reflectance Index (SRI) levels on specified products.

Favorable Payback

All of these benefits above can translate to financial benefits to the building owner or operator. Any cost premium incurred for selecting a high-SRI cool metal roof can likely be realized very quickly in energy cost savings, increased business, or maintenance and durability savings. In addition, the benefits of human comfort and achievement of LEED or other sustainability goals can be realized for the life of the building.

Metal Roofs and Solar Energy: An Ideal Match

Posted on March 23, 2016 by Candy McNamee

Everyone is talking about—and doing something about—sustainability. Metal roofs fit nicely into the sustainable-material equation because of their myriad traits, such as recyclability, reflectivity, longevity and durability. Another major component in the sustainability equation is renewable energy—the production of energy from renewable resources like sun and wind. A metal roof is the ideal location for solar energy production on homes, commercial buildings and recreational applications.

Why Solar Panels and Metal Roofs?

One of the key factors for long-term success of rooftop solar energy is the quality of roof under the solar panels. Roofs under photovoltaic (PV) systems should be durable and have an equivalent service life to the solar panels. However, too many traditional roof systems do not have a service life that matches, let alone exceeds, the service life of the PV panels. This is where metal roofs excel.

Service Life of Metal Roofs

A study of roof system longevity presented at the Fourth International Symposium on Roofing Technology by Carl Cash, a principle at Simpson Gumpertz & Heger, showed that metal panel roofs have the longest service life when compared to asphalt-based roofs and single ply roofs. The study showed that the average life of metal panels is 25 years. BUR and EPDM were second and third, respectively, at 16.6 and 14.1 years of average service life. Exceeding the Cash study, a more recent study conducted by the Metal Construction Association (MCA) and Zinc Aluminum Coaters (ZAC) Association showed the longevity of low-slope unpainted 55% Al-Zn alloy coated steel standing seam roofing (SSR) systems is 60 years.

Service Life of Solar Panels

Solar panels will last 25 to 30 years. In fact, some of the very first PV panels from the 1960s and 1970s are still producing energy. While their efficiency might decrease over time, solar panels will make electricity for many decades. For the most cost-effective rooftop solar energy installation, the longevity of the roof should be equivalent, or greater, than the solar panels so that the roof doesn’t need replacement during the life of the solar energy system. Metal panels are the most reliable, long-term roofing system for solar energy installation projects.

Built to Last

Solar Roof Panels on Real Salt Lake City Stadium

Simply put, installing solar energy on rooftops that don’t have an equivalent service life is a mistake, especially for solar projects that cover a large portion of the rooftop. The cost of decommissioning, removing, and replacing rooftop solar energy can cost 20% to 100% of the original installed cost. The cost tends to align with the percentage of rooftop covered with solar panels. Much of the cost to remove and reinstall is labor, but an older solar energy system will likely need some new components—most likely new wiring—when reinstalled, also adding to the cost.

Rooftop solar installations continue to grow year over year. And with the extension of the federal investment tax credit for five years, expect more solar energy installations on roofs. Pair solar energy with a metal roof, and you’ve hit a sustainable “home run.”

Learn other ways to implement Net-Zero Energy strategies into your building and learn how MBCI’s products contribute.

Storms and Safety: Metal Building Systems, Standing Strong

Posted on September 17, 2015 by Brad Johnson

Brester Construction features eco-FICIENT Royal panels

Welcome to hurricane season, says NOAA! Erika was a near miss, and Henri went off to sea, but with multiple storms stirring up the Pacific and a major El Niño threatening severe weather this year, building teams are focused on resilient, high-performance envelope and roofing assemblies.

The Durability of Metal Roofs

Resiliency is the watchword, and the stringent Miami-Dade County code language or similar standards are being adopted in many communities. The Florida Building Commission, as well as FEMA and NIST, have done studies of building performance during severe storms, and metal buildings were shown to perform exceptionally well. According to MBMA reports, insulated metal panels (IMPs) perform well under stresses of high winds and projectiles such as hail and wind-borne debris.

The post-storm studies everywhere from Texas to New Jersey confirmed the durability and resistance to driving rain and severe pressure differentials, too. Standing-seam roof systems and IMP façades remained intact during Katrina even as winds hit 120 mph. According to Metal Roofing Alliance, “metal roofing can have a 140-mph wind rating, meaning it can withstand wind gusts up to 140 miles per hour.” MBCI, which has achieved these ratings, has also pointed to another critical standard: wind uplift testing in accordance with Underwriters Laboratories’ UL 580, Standard for Tests for Uplift Resistance of Roof Assemblies.

Performance During Storms

Detailing of the roof-wall interface is essential to protecting against uplift. To reduce damage from wind-driven rain, manufacturers like MBCI use test protocols from Miami-Dade or the ICC (TAS No. 100-95). These standards show the security and integrity of the seams in IMP and metal roofing systems. For hail and wind-driven projectiles, the metal systems often are able to absorb impact and remain functional and retain their protective metal layers intact even if they may suffer cosmetic damage, as MetalRoofing.com forums have shown. Last, IMPs and metal roofing systems perform very well during lightning strikes — a fact that is counter intuitive but proven. In fact, use of metal roofs does not increase the chance of a lightning strike, as scientific studies show and the Metal Construction Association reported in BD+C, and as you can read more about in our blog post.

Similar to the three pigs of fable, some buildings will do well through hurricane season, while others nearby will suffer from softer connections, more porous materials and less stringent assembly designs. Many building owners will do well with metal roofing and vertical assemblies: with rugged embossed metal sandwiches over high-R-value, rigid insulation, held firmly in place with interlocking joints or lapping seams.

Best of all, the systems are complete assemblies that install as weather-tight barriers without coordinating various components and trades. They also have higher rated values than, for example, EIFS planks or fiberglass panels, some of which may suffer lost R-value when wet. With these benefits – and following the damage and disruptions caused by Hurricanes Katrina and Sandy in the United States – metal is an attractive roofing choice for weather resistance.

Sustainability Begets Resiliency…In Practice

Posted on August 4, 2015 by Brad Johnson

Sustainability is the buzzword started by USGBC that is pushing us to design and build environmentally friendly buildings. And that’s a good thing. However, from a practical—and roofing—standpoint, what we can most readily do with roofs is design them to be resilient. Roof system resiliency is the tangible aspect of sustainability that the “regular” population can get their heads around. Resiliency—the ability to bounce back—is understandable.

Loosely speaking, a resilient building can withstand an extreme weather event and remain habitable and useful. It follows that a resilient roof system is one that can withstand an extreme weather event and continue to perform and provide shelter.

What makes a metal roof system resilient? It needs to be tough and durable, wind and impact resistant, highly insulated and appropriately reflective, and perhaps be a location for energy production.

An extreme weather event typically means high winds. A resilient metal roof system needs to withstand above-code wind events. Remember, codes are minimum design requirements; there is nothing stopping us from designing metal panel roofs above code requirements! If a building is located in a 120 mph wind zone, increase the design/increase the attachment as if it were in a 140 mph wind zone. And, very importantly, increasing the wind resistance of the edge details is critical to the wind resistance of a roof system.

Toughness is important. Increasing the thickness of a metal panel roof system increases resistance to impacts and very likely increases service life (of the metal panel, at least). Tough and durable seams are important, too. A double-lock standing seam is one of the best seam types for metal roofs. A little bit of extra effort at the seam can go a long way for durability, weatherproofing, and longevity.

Highly insulated and appropriately reflective are also traits of resiliency. High R-value means less thermal transfer across the roof assembly. Two layers, staggered or crisscrossed, provide a thermally efficient insulation layer. Using thermal breaks between the metal panels and the metal substructure adds to the thermal efficiency. Reflective roofs help reduce heat transfer through the roof assembly. The effectiveness of a roof’s color and reflectivity to save energy depends on many items, such as location, stories, and building type.

Enhanced wind resistance, improved impact resistance and toughness, high R-value, and reflectivity and color are passive design elements that increase the resiliency of a building’s rooftop. And let’s not forget that rooftop energy production can provide electricity to critical components of a building, such as a freezer section of a grocery store. Hurricane Sandy put resiliency on the public radar; resilient buildings are here to stay.