metal roof panels Archives

Are Metal Panels An Ideal Low-Slope Roofing Material?

Posted on July 22, 2019 by MBCI

Many large, commercial, low-rise buildings often don’t benefit from steeply-sloped roofs the way residences and small commercial buildings might. This is because a steep roof slope would add unwanted height and unnecessary construction cost. Buildings like warehouses, retail stores, etc. are more appropriately built with low-slope roofing, commonly known as “flat roofs”. The National Roofing Contractors Association (NRCA) defines low-slope roofs as those with “a slope at or less than 3:12″. Anything steeper qualifies as a “high-slope roof”. With this in mind, let’s look at some key points to consider when designing and constructing a low-slope roof.

Low-Slope Roofing Materials

When it comes to selecting low-slope roofing products, there are generally three fundamental choices:

Asphalt/ Bituminuous Products: The traditional commercial roofing norm for many years, the use of asphalt/bituminous products has dwindled as newer, more appealing options have emerged.
Flexible Membrane Roofing: This roofing material can be made from a variety of types of plastic/polymer-based materials (commonly known as EPDM, TPO, PVC, etc.). Rolls of the chosen membrane are laid out on the roof structure and secured in place either with mechanical fasteners (screws with large washers) or with a continuous layer of adhesive.
Metal Roofing: Sometimes overlooked, metal roofing is suitable for different roof slopes. Many metal roofs that use standing-seam systems are rated for use with a pitch as low as ½:12.

When considering which type of roofing material to use for a building project, there are a number of significant differences that illustrate why metal roofing is often the ideal choice.

Engineered For Superior Performance

Standing-seam metal roofing is made specifically for use on low-slope roofs as it meets a number of performance requirements:

Water resistance: Precipitation doesn’t penetrate through metal or through the standing seams where the metal panels join together. This is why they can tolerate such low slopes, allowing the water to drain away slowly and predictably without leakage.
Rigidity: The rigid nature of metal means that there is less opportunity for ponding (standing water). This is not always the case with asphalt/bituminous or membrane roofing systems.
Drainage: Metal roofs carry water to the building’s edge toward gutters and downspouts that carry it away from the building. Other roofing systems rely on drainage piped inside the building. This takes up space and has the potential to leak water inside the building and cause damage.
Wind Resistance: Standardized uplift testing shows that metal roofing performs as well or better in extreme weather than mechanically-fastened or fully-adhered membrane systems.
Durability: The most cited advantage of metal roofing is its long-term strength and durability. Engineered design and use of high-quality coatings ensures a longer lifespan—50 years or more. In contrast, other roofing types typically feature lifespan ratings of 20 or 30 years.
Puncture Resistance: Low-slope metal roofing is more puncture-resistant than asphalt/bituminous or membrane roofing. This makes it better able to tolerate foot traffic, hail and other puncture-inducing hazards.
Construction/ Installation Ease: Metal roofing panels are custom-made to suit specific building sizes and end uses. This customization typically means it takes less time to place and install metal roofing in the field. Further, metal panels can tolerate a wide range of temperatures and weather conditions and still install and perform as intended. Low-slope roofs are also safer to walk on with less risk of slips, falls and other hazards.

Cost-Effectiveness

Using metal roofing on low-slope roofing systems can be cost effective in a number of ways:

Fewer labor hours as a result of the ease of installation saves money during construction.
Competitive material costs, particularly if the metal roofing is part of a total metal building package from a single manufacturer.
Minimal maintenance requirements and aversion to rusting, mold growth and decay that save the building owner money over time.

This all adds up to a very favorable life-cycle cost.

The performance, cost-effectiveness and life-cycle benefits of metal roofing panels make them a viable option for low-slope roofing systems. Manufacturers like MBCI can help you select the right metal roofing products and provide information and resources to help ensure proper installation.

View examples of low-slope metal roofing projects and contact your local MBCI representative to start your project today.

Ordering Custom Products Online

Posted on January 22, 2019 by Shelby Shipman

In a prior blog post, we introduced the capability of ordering metal roof and wall panels, trim and building components online using the MBCI online ordering website. While most people are familiar with ordering products on the internet from a list of standard offerings, there is another exciting aspect to these sites–custom items can be ordered online too! That means instead of needing to call or meet in person to place a custom order with a sales rep during business hours, custom trim and structural products can be ordered online anytime. Here’s how it works.

When Standard Isn’t Enough

Most companies with online ordering websites offer products in standard shapes and lengths. Recognizing that not every job is standard, the MBCI online ordering website offers customers the ability to order custom trim and structural products online 24/7. Using the dedicated “Custom Trim” or “Custom Structural” product categories, you can select the type of trim or structural product you want and indicate all of the specifications desired. These include steel thickness, color, stretch-out (the width of the material before it’s bent), breaks needed in the trim, hems and other features.

Not every job is standard. To ensure you and your clients have exactly what’s needed, you can now create quotes and place orders for custom trim online at shop.MBCI.com.

Visualizing Custom Products Online

Even with the ability to set custom specifications, sometimes visuals are needed to ensure products are manufactured correctly. MBCI takes product customization a step further by enabling you to add hand-drawn or drafted drawings to show the complete layout of the product as a supplement to the selected specifications.

If drawings have already been prepared, they can be easily uploaded and linked to your MBCI order in any common electronic file format. If drawings aren’t already done, MBCI’s online ordering website provides an easy-to-use template that walks you through how to create simple hand-drawn or digital drawings.

A Time-Saving Process

Once all of the custom information is entered for your product(s) and you’ve reviewed for accuracy, simply add the item(s) to your cart. This process can be repeated for as many custom trim and structural products required. Additionally, you can save each custom item you create with it’s own product name to quickly add them to future orders.

Online ordering tools that offer a quick and seamless way to include custom trim and structural products in addition to standard items can save you time and help your business run more efficiently. The ability to customize products online makes it significantly easier to do business with the material supplier, particularly since most other online tools only allow standard products to be ordered.

To find out more about how to quote, order and build custom and standard products online, visit http://www.mbci.com/shop or contact your local MBCI representative to get signed up today. To be the first to know when we launch new time-saving enhancements to our online ordering tool, stay tuned to our blog, email and social media posts. Upcoming features include the ability to:

copy and merge items from multiple quotes onto one,
edit multiple items at one time,
add entire product packages (assemblies) based on building specifications,
and more!

Air Leakage and Water Penetration Testing of Metal Roof and Wall Panels

Posted on January 9, 2018 by Jason Allen

Metal roof and wall panels have many test standards they must meet under certain environmental conditions. Test standards that are specified for metal panels in our industry are ASTM E283 (air leakage) and ASTM E331 (water penetration) for wall panels, and ASTM E1680 (air leakage) and ASTM E1646 (water penetration) for roof panels. While the corresponding tests are similar, the orientation of the panels is a little different for the wall and roof panels. Here we’ll take a brief look at these testing protocols and what they mean for the integrity of the metal panel system at hand.

For air leakage tests, the protocol has been to test at a specified pressure. It should be noted that some manufacturers have changed it from the standard as many in the market are testing at a higher pressure. And while it’s true that you are going to have air pass through, you want the air to be minimized. Air leakage is tested in terms of cubic feet per minute, with a lower number indicating a better, more efficient product. For water penetration testing, water is sprayed and is tested for the water getting through the seam or side lap of the panel system.

The purpose of air leakage and water penetration testing is to establish air and water infiltration rates on the referenced test specimen in accordance with ASTM E283 and ASTM E331.

Metal Wall Testing Standards

As indicated above, the wall test standards are: ASTM E283 (Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen) and ASTM E331 (Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference).

The procedure for ASTM E283 is as follows: 1. Seal off test unit and measure air leakage (extraneous leakage); 2. Unseal test unit, then re-measure (total system); 3. Subtract extraneous air from total air = Performance.

According to ASTM, this test method is a “standard procedure for determining the air leakage characteristics under specified air pressure differences at ambient conditions.” Furthermore, the air pressure differences across a building envelope can have significant variation with numerous factors acting to affect air pressure differences relative to the particular building environment. For instance, the test method described is for tests with constant temperature and humidity across the specimen. These factors should be considered when specifying the test pressure differences to be used.

Additionally, rates of air leakage are sometimes used for comparison purposes but these comparisons would only be valid if the tested/compared components are of essentially the size, configuration, and design.

Using a Pass/Fail criteria, “Pass” results of this test indicated that water did not penetrate through control joints in the exterior wall envelope, joints at the perimeter of openings, or intersections of terminations.

The laboratory test procedure for ASTM E331 dictates that the test is conducted for a specified duration with water applied at 5.0 gal/ft 2 hr. at a specified pressure. The test has applied pressure and water spray for a period of 15 minutes.

According to ASTM, this test method is a “standard procedure for determining the resistance to water penetration under uniform static air pressure differences.” Furthermore, in applying the results of tests by this test method, ASTM points out that “the performance of a wall or its components, or both, may be a function of proper installation and adjustment. In service, the performance will also depend on the rigidity of supporting construction and on the resistance of components to deterioration by various causes, vibration, thermal expansion and contraction, etc.,” noting that exact simulation of real-world wetting conditions can be difficult (i.e., large wind-blown water drops, increasing water drop impact pressures with increasing wind velocity, and lateral or upward moving air and water) – and that it may depend to some degree on the design.

Metal Roof Test Standards

The Roof Test Standards are ASTM E1680 (Standard Test Method for Rate of Air Leakage Through Exterior Metal Roof Panel Systems) and ASTM E1646 (Standard Test Method for Water Penetration of Exterior Metal Roof Panel Systems by Uniform Static Air Pressure Difference).

According to ASTM, test method E1680 covers the determination of the resistance of exterior metal roof panel systems to air infiltration resulting from either positive or negative air pressure differences. The test method described is for tests with constant temperature and humidity across the specimen. (This test method is a specialized adaption of Test Method E283.)

ASTM literature explains that variables such as the slope of the roof and other factors can affect air pressure differences and, therefore, affect the implications of the resulting air leakage relative to the environment within buildings. Just as with wall panels discussed earlier, these factors need to be taken into consideration when specifying the test pressure difference to be used.

ASTM describes its E1646 test method as a “standard procedure for determining the resistance to water penetration under uniform positive static air pressure differences, and simulates win driven rain imposed on sidelaps and rain that is free to drain while building a water head as it flows.” For this test method, the slope of the roof is a significant factor.

According to ASTM, this test method covers the determination of the resistance of exterior metal roof panel systems to water penetration when water is applied to the outdoor face simultaneously with a static air pressure at the outdoor face higher than the pressure at the indoor face, that is, positive pressure. (This test method is a specialized adaption of Test Method E331.)

To learn more about MBCI wall and roof panels, please visit www.mbci.com.

Proper Cutting and Cleaning of Metal Building Panels

Posted on August 10, 2017 by Jason Allen

Metal building panels, whether for roofing or walls, are manufactured with a long-lasting and durable finish of different types and in many colors, allowing the panels to hold up and look great for decades. However, once they get to the building they may need to be cut to fit a field condition, or they may need to be cleaned either during or after installation for any number of reasons. Innocently doing either, without understanding that doing it the wrong way could compromise the integrity of the finish, can be disconcerting at best or warranty-buster at worst. Here are a few tips for the proper cutting and cleaning of metal panels.

Cutting Metal Panels:

Field cutting of panels is certainly allowed and acceptable to manufacturers and is common, particularly at framed openings. However, there are two things to pay attention to here:

Cutting Method: If field cutting is required, the panels must be cut with nibblers, snips or shears to prevent edge rusting. Do not cut the metal panels with saws, abrasive blades, grinders or torches. Abrasive saw blades, grinders and torches can leave irregular or rough edges that are no longer coated or finished, thus causing rust and corrosion.

Corrosion on this panel edge is due to an abrasive saw blade cut.

Cutting Location: All cutting of metal will produce fine particles, or swarf, that will fall from the cut. If this swarf falls on the roof, it can cause permanent staining and, if enough of it accumulates in one place, it could rust completely through the metal roof panel. Therefore, never cut metal panels on the roof or over other metal panels. It is best to cut the panel down on the ground where the swarf can be captured and disposed of.

Accumulated swarf from cutting is staining this metal panel.

Cleaning Metal Panels:

Metal panel manufacturers will usually provide information and directions for cleaning. A typical set of cleaning recommendation follows, based on a progression of cleaning levels—start with number 1 and work your way down the list for tougher jobs.

For simple cleaning, water and mild detergent will often be all that is needed. However, bleach should never be used, since it can change the finish color or interact disastrously with certain metals.
For water-soluble dirt or other deposits requiring more complete cleaning, a solution of hot or cold water mixed with detergent is appropriate. In a container of water, use a 5 percent solution of commonly used commercial (non-industrial, non-bleach) mild detergent, so as not to have any deleterious effect on the painted metal surface. Use a cloth or a soft-bristle brush for application of the cleaning solution, followed by an adequate rinse with clean water. Alternatively, pressure-washing with a 40° tip is also an option.
For non-water-soluble deposits such as tar, grease, oil and adhesives, a solvent or alcohol-based cleaner may be required. In this case, since most organic solvents are flammable and/or toxic, they must be handled accordingly. Generally, keep them away from open flames, sparks and electrical motors. Use adequate ventilation, protective clothing and goggles, and read the manufacturer’s Material Safety Data Sheet (MSDS) of any solvent used for any other specific safety details. The following are among the cleaners recognized by manufacturers for this type of non-water-soluble cleaning:
1. Alcohols
  1. Denatured alcohol (ethanol)
  2. Isopropyl (rubbing alcohol)
2. Solvents
  1. VM&P naptha
  2. Mineral Spirits
  3. Kerosene
  4. Turpentine (wood or gum spirits)

Regardless of the level of cleaning required, never use wire brushes, abrasives, or similar tools that will abrade the surface coating and leave scratches or other finish damage and lead to corrosion. Further, keep in mind that any misuse or abuse of any of the acceptable cleaning agents will automatically void any manufacturer’s warranty for the affected surfaces.

By using the tips above to properly cut and clean metal panels, installers can avoid the problems of corrosion, staining or other surface damage. Thus, the integrity and beauty of the finish is maintained without any impact on the warranty. To learn more about metal panel finishes, cutting, cleaning and warranties, contact your MBCI representative.

Reroofing and the Building Code

Posted on May 28, 2015 by Amy Crenan

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.