Beauty is More Than Skin-Deep
The most basic requirement of any building is to keep the elements out – while keeping comfortable conditions in. Those elements can be relentless – from bitterly cold wind, snow, sleet and ice to ferocious heat and torrential rain. It’s no wonder buildings have historically been clad in multiple layers to combat these different forces. For centuries, those multiple layers have done the job adequately. But advances in manufacturing, materials and technology have completely changed the game, and you can take advantage of all of it with backup wall systems from MBCI.
A Package Deal
Like insulated metal panels (IMPs), backup walls combine air barrier, vapor barrier, moisture control and insulation into an all-in-one product. The key difference between IMPs and backup walls is that while IMPs function as the rainscreen or façade, MBCI’s backup walls are designed to work with the rainscreen or façade of your choice.
Instead of relying on three or four different contractors to install insulation, Zs, sub girts, air/vapor barriers and sheathing, one worker can install backup walls in one simple step. This has shifted construction standards in cost savings, sustainability and design integrity in ways with which traditional walls simply can’t compete. It’s hard to justify the scheduling and liability hassles of traditional backup wall construction when you could more quickly and reliably weather-in a building with a backup wall system.
Backup walls eliminate a number of common headaches from the jobsite. There’s no longer a need for multiple crews to work in turn on the cladding, and likewise no need for conventional batt or board insulation, exterior gypsum, air barriers, vapor retarders or building wraps. That’s a sizeable amount of material, subcontractors and coordination suddenly off your plate. Better yet, the expedited close-in/dry-in times mean interior trades can move in and get started sooner.
Backup walls are a virtually unbeatable solution for all building types in all climates. MBCI’s Backup Walls are made of foamed-in-place polyisocyanurate with two steel skins, offering strength, durability and a superior drain plane – all in one foolproof, easily installed product. Once the backup walls are installed, you can choose nearly any type of rainscreen or façade you like, from brick and metal to terracotta, ACM and stucco. A popular design choice is an aesthetically pleasing combination of facades. For instance, a public-facing part of a building might be clad in handsome brick or stone, while the obscured sides and rear are clad in IMP’s or something more economical.
Traditional multi-component walls with continuous insulation require supplemental Z steel framing to convey wind load from the rainscreen to the supports, causing a loss in thermal performance and condensation potential in the cavity. The all-in-one structural construction and enclosed system of backup walls eliminates this problem and makes for better thermal performance. Another often-overlooked concern, air infiltration is addressed in MBCI’s Backup Wall Systems by providing a continuous air barrier via a formed metal liner with a combination of field- and factory-applied sealants. In fact, MBCI’s Backup Walls achieve U-Factors that exceed the International Energy Conservation Code (IECC) energy performance requirements based on tests in accordance with ASTM C1363. They also offer outstanding fire resistance, meeting requirements of the NFPA 285 multi-story fire test.
Making the Right Choice
Depending on your ultimate end-goals for design and practicality, either the BW Universal System™ or the BW Stretch System™ will suit your needs best. BW Universal covers two-foot spans, is installed horizontally, and can accommodate nearly any rainscreen or façade with horizontal or vertical rainscreen rails, panel clips or brick ties. BW Universal is often chosen for more architecturally driven projects due to its compatibility with any façade. The BW Stretch System’s primary differentiating characteristic is its ability to cover up to six-foot spans. BW Stretch is compatible with several rainscreens, though it’s not a good match for masonry.
Though BW Stretch is installed vertically, and BW Universal is installed horizontally, MBCI product manager Jennifer Franz clarified that “Some people think that means the facade can only be installed horizontally or vertically. That is not the case. Either one can have horizontal or vertical facades.” Franz also pointed out that rainscreens and facades often have their own span requirements, which designers should be aware of before making final decisions. “The BW Stretch System can span up to six feet,” she said, “but that doesn’t necessarily mean the rainscreen or façade you put in front of it can. The façade may still dictate a lot of the capabilities of the wall. You need to understand the capabilities of the facade as well as the BW panels.”
Whichever system you choose, you’ll receive a weathertight 10-year warranty. But you’ll also receive so much more in terms of time and money saved, hassles avoided, and peace of mind gained. When you’re ready to learn more about MBCI Backup Wall Systems, simply get in touch with your representative. We’ll be happy to help – and you’ll be happy you reached out.
Insulated metal panels (IMPs) are ideal for many roofing and wall applications. They are considered a top-of-the-line choice known for their superior insulation value, high performance air barrier, design flexibility, and fast installation. The simplicity of installation creates a high-performance building envelope. The many design options provide a versatile building solution for commercial, industrial, and institutional projects.
Sounds great, doesn’t it? What’s the catch? Well, those benefits won’t mean much if proper care is not taken during the installation process to ensure you’re getting what you paid for. Potential consequences can span the gamut—from minor aesthetic headaches to extremely costly errors such as leaks and structural issues.
Here are some ways to avoid common pitfalls when installing IMP panels on your next metal wall or roof project.
1. Pay attention to the manufacturer’s product installation manuals.
Installation manuals are not just for show! Even the most experienced installer should read, review and understand the installation guide before installing IMPs, and the panels should always be installed in accordance with the project’s installation drawings.
Don’t simply rely on the “what-you’ve-done-before” mindset. Take the time to review the specifics for every individual project. In addition to providing the information needed to execute a successful install, it can also give installers an opportunity to build upon their own knowledge base. One of the most common errors is related to proper receipt and handling of the panels. Investing a few minutes before the project starts and at the start of each day to review key topics helps avoid costly errors and improves production.
If you have a question or something does not seem right stop and call the manufacturer. It is always best to address a problem up front than try and fix a problem after the building is in operation.
2. Equipment check. Do you have what you need?
To keep your IMP installation on track, it’s imperative to ensure you have the equipment you’ll need for the job. Does your project need one or two forklifts, is a crane a better option? Will your project include longer-length IMPs being installed in a vertical orientation? If so, you may need special lifting equipment so as not to damage the panels. Whatever the details, crews need to be prepared to receive a project’s specific materials on site. A little advance planning will ultimately save you time and money by reducing labor and avoiding costly mistakes.
3. Don’t assume every IMP application is the same.
All buildings are not created equal. Just because a construction crew has had experience installing insulated metal panels on past jobs, doesn’t mean they can assume the process will be exactly the same every time. There will always be specific conditions and variables that need to be taken into consideration. Techniques used for vertical industrial panels will be different for horizontal architectural panels.
The vapor barrier (a key function of an IMP) is a great example of how a miscalculation can be problematic. Depending on the panel, the vapor barrier may be applied either at the factory or at the jobsite. If the project calls for a cold storage environment, the “warm” side of the vapor barrier will be on the exterior. Alternatively, a commercial or industrial application generally calls for the vapor seal to be on the opposite side of the panel. Confuse placement of the seal and you’re bound to run into problems down the road.
4. Be on the lookout for creases, buckles and framing alignment.
A crease or buckle on the face of a panel might seem like no big deal, but that couldn’t be further from the truth. In fact, framing alignment is one of the most critical aspects to ensure a proper fit-up of the construction as a whole. In terms of the panels themselves, not only will a framing misalignment not LOOK right but can also cause numerous efficiency and performance issues. Installing inexpensive shims can avoid panels needing to be replaced.
Additionally, make sure the first panel is plum and square, if you start right it is much easier to finish right.
Purlins must be level and square and all framing and bracing should be installed before installing panels. (The IMP manufacturer should specify the amount of tolerances allowed.) Also, take care with caulking and taping, foam-to-foam connections (in order to mitigate potential vapor leaks), seaming, and lap joints.
Attention to detail will avoid costly mistakes.
5. Always think ahead.
Being proactive may be the most important piece of advice construction crews need to hear.
For one, be sure to have a panel surplus on hand. You may be of the mindset that ordering extra panels is at worst a waste or at best, not worth the effort. This is a common judgement error that often leads to installation delays. If a crew has only ordered the exact number of panels needed for a job and there is any damage to the product, whether prior to delivery, on-site or during the installation, there a risk to the project schedule. Waiting on replacement panels can wreak havoc on schedules, especially with panels that may need special manufacturing due to custom components, finishes or colors. What do you do with extra panels you don’t need on the initial installation? Building owners can hold on to any surplus panels to be used as replacements, as needed, over the lifecycle of the building. A little preparation today can go a long way.
Other best practices include understanding the project’s site conditions and ensuring crews remain crews up to date on proper installation techniques—including staying current with training and certifications.
By taking this advice to heart, you can exponentially increase your ability to enjoy the many benefits of IMPs and be confident in your investment. For more information on MBCI’s insulated metal panels and proper installation guidelines, we encourage you to contact your local MBCI representative or visit our website.
Once you’ve set your sights on metal panels for your next building project, insulation will be one of the first, and most important, considerations. There are so many variables, though, so how do you know what’s best?
When you’re trying to make a determination of the insulation type, you should first identify what’s driving your decision making. Are your insulation requirements based on external parameters, such as job specs or established code requirements, or is there some other self-proposed condition at play like the end-use function of your building? Do you require upfront cost savings or is long-term value what you’re after?
Here we’ll take a look at some of the most common determining factors and how they might affect your insulation choices.
Depending on whether you’re building in the commercial or residential arena, and what the physical location of your project is, you may have to adhere to strict energy/building codes that will be an unmovable goal post in your decision making.
Are there any local code or project-specific stipulations as far as minimum R-values for the roof or for the walls? What must you be in compliance with? There can be many different aspects of an energy or building code that you will need to research. For example, there may be an envelope solution where the whole building nets out “X” R-value. Or, a prescribed method could be mandated, where each individual component (i.e., windows, doors, walls, etc.) going into that building cannot exceed (or must meet) a particular requirement.
Let’s say, as an example, you have a code that requires you to have a continuous R-value at your structural attachment point. Depending on what that requirement is, it may be harder to achieve that by using a rolled or batt fiberglass systems. You might be able to achieve it much more easily with a componentized system using metal decking/liner and rigid board insulation, or perhaps an insulated metal panel (IMP) may be better suited. In that case, you could be looking at spending more money for that panel system while saving money on the labor … which brings us to the next variable: upfront costs.
Another critical factor is the cost associated with materials and labor of the system you’re going to install. Let’s say, for instance, your needs require a higher-end type installation in order to reach higher R-values or a code-prescribed method. How are you planning to achieve that?
In some instances, you may be looking toward an insulated panel system, which can readily give you those higher installed R-values. While these are extremely efficient systems, there can be a notable bump in the panel material price to get to that same level than if you choose a single-skin approach with a fiberglass or rigid board insulation system. You would, therefore, need to accurately compare the installed costs of the two systems versus just the material alone. Which will be less expensive/more efficient: the multiple components with lower individual costs plus more labor time and expense to assemble OR the potentially higher individual IMP panel price but with less time and expense to install? You will need to look at the project holistically to determine which is more cost-efficient for the specific situation.
Long-term costs, value and end-use functionality
Oftentimes, upfront material and labor costs need to be evaluated in terms of potential long-term savings and value. Some things to consider here are what your big picture needs are for the structure, including an assessment of how it will be used now and in the future. Unlike with dictated codes and regulations, here it may be more a question of wants vs. needs or owner-occupying vs. vendor leasing.
While you might want an R-30 building, for instance, is it economically beneficial for your end use of the building? Let’s use this example: If you’re a homeowner using a metal structure to store relatively non-valuable belongings, how well does it have to be insulated? Is it worth a high price point? In this case, perhaps single layer roof and wall insulation will be adequate for your needs.
If on the other hand, you’re a builder contracted to construct a structure for which interior climate control is critical for the end use—either because of the production to occur inside or perhaps due to food storage or other temperature-sensitive contents—then you might lean more toward an insulated panel system. In another example, if there’s going to be the potential for an abundance of heat or moisture in the building, as with paper products production or wastewater treatment, then you’ll want to be certain that the insulation system you use best resists such an interior climate and doesn’t permit condensation to form. In this example, it is critical that the structure is significantly protected so that moisture cannot become trapped in the roof or wall assemblies leading to reduced building efficiency or even formation of mold.
You should also consider how long it will take to recoup your initial investment. Obviously, for instance, you may spend less money upfront by only putting 4-inch blanket in your single layer metal walls as opposed to choosing to install an insulated metal panel (IMP) system, but long-term, is the money you save by going with the lesser insulation system going to be more than what the energy savings would be over the time that you’re the occupant of the building?
If you’re only going to be in the building for one or two years, or you’re not even occupying the building, you might be tempted to install a lesser expensive system, but then you might be risking not being able to retain tenants or impacting future resale value.
What Are the Insulation Options?
Once you’ve identified what the driving factors are for your insulation system choice, you can match up your needs with most popular options, which are:
Fiberglass insulation solutions, including over-the-purlin systems; cavity fill insulation systems; batt insulation; rigid board insulation via a composite system with metal decking and vapor barrier; or spray-on insulation systems. Alternatively, if a foam core insulation is preferred, it may be worth considering the use of insulated metal panels (IMPs) that are designed, engineered, and fabricated to be compatible with metal building construction as an envelope building solution.
For more specifics on the types of insulation systems that are available, check out this MBCI blog article: https://www.mbci.com/coordinating-roof-insulation-with-metal-building-construction/
Insulated metal panels (IMPs) are “lightweight, composite exterior wall and roof panels with metal skins and an insulating foam core” as defined by the Metal Construction Association (MCA). The outer skin serves as either metal wall siding or metal roofing using standard profiles, while the inner face serves as a metal interior finish or liner. The rigid insulation between the metal skins gives the panels their superior energy conservation properties and also provides a rigid core for extensive spanning capabilities across structural members.
With this basic make-up in mind, here are a few things you should know about using IMPs in a metal building project:
Virtually any building being designed as a metal building should consider the use of IMPs. This includes all types of commercial, industrial, institutional, recreational and government buildings. More specifically, IMPs have been used very successfully on manufacturing facilities, schools, retail centers, offices, warehouses, power plants and many other building types.
Insulated Roofing and Walls Assemblies
IMPs serve as a complete wall or roof assembly. That means they can provide cladding, insulation, a water-resistant barrier, an air barrier, and finished surfaces all in one panelized product – essentially everything but the building structure upon which they are installed. These characteristics are true for conventional buildings as well as for specialty construction types such as the climate controlled processing, storage, or distribution of perishable food or other items. With panel thicknesses commonly available from 3 inches to 6 inches, walls and roofs can be designed to meet the specific thermal performance requirements of virtually any building need.
IMPs are available in a wide variety of colors, widths, profiles and finishes, enabling virtually any aesthetic desired for walls and roofs. Further, architectural IMPs provide the freedom to address building-specific or unique circumstances with options such as custom shapes and widths, special custom colors and finishes, custom fabrication including, but not limited to bent corners, curved panels, and trimless ends. Architectural IMPs also offer options to integrate with windows, louvers, sunshades or other similar products to offer total building envelope solutions.
Most IMPs are fabricated with the intention of working together as a complete system. That means attention has been paid to the design of the edges so the panels can interlock and be sealed to form a continuous joint that is water tight and air tight. In some cases panels may need to overlap, such as on long roof runs over 50 feet, but manufacturers have worked out those details to help assure the roof or wall performs as intended. Based on this, properly-installed IMP systems generally come with a very long warranty period.
Ease of Installation
The fact that IMPs are a single, finished, rigid panel, makes them quicker to install than other multi-product and multi-step assemblies. This translates to obvious labor savings and some material cost savings compared to other systems. Further, the simplified installation process has been shown to limit exposure to accidents, helping create a safer, more efficient work flow. It can also mean that construction time schedules are easier to meet or even beat.
Energy codes and increasing energy costs have prompted the installation of more roof insulation into metal buildings in recent years to make them more energy efficient. That is fundamentally a good thing and metal building manufacturers have developed ways to accommodate a variety of building enclosure packages that increase energy performance while still being engineered to meet the structural requirements of the building. This allows the whole building envelope to be designed and fabricated so it works as a complete, coordinated system.
The metal roofing or metal building suppliers typically don’t design the insulation systems. However, it is important to include them in the discussions or make them aware of what type of system is to be installed. It is not uncommon for a metal building to be ordered with the design stipulation of “insulation by others.” In that case, coordination is needed between the person ordering/designing the insulation system and the metal building manufacturer or roofing supplier. Since there are a great many variables in the way that insulation can be provided, it is not appropriate to think that the design of structural systems (purlins and roof bracing) and cladding systems (clips, fasteners, and metal roofing profiles) will necessarily accommodate all the same insulation in all conditions. Rather, unless the specific details of the insulation system being used in the building are communicated effectively at the time of the order, the manufacturer can not assure compatibility of the systems used with the insulation system that is to be installed.
In order to understand some of the variability in the options, let’s look at some of the common ways that metal buildings are or are not insulated.
Buildings that do not have any heat or air conditioning in them may not need for an insulated roof. This could be true for outdoor shelters, some agricultural buildings, or vehicle storage buildings. However, uninsulated metal roofs have the potential for “roof rumble” as they move due to thermal expansion and contraction, wind, or weather as there is no insulation to mask or deaden this noise. Absence of insulation can also lead to condensation during certain times of the year if temporary heat is added to the building. This condensation builds up and can drop or fall onto whatever is below. Many times condensation issues are mistaken for roof leaks when in fact it’s a mechanical design issue of the building envelope that’s not been properly addressed. If neither sound nor potential condensation are a concern, then there’s no problem. But if either or both need to be avoided, then some basic level of insulation may be prudent.
Over the Purlin Systems:
One of the most common insulation systems for metal buildings and/or open framing systems is to simply install rolls of blanket insulation. In this case, fiberglass insulation with a reinforced liner is draped over structural beams and purlins. The rolls are supplied to length by the insulation supplier based upon the roof structural layout and the required “R” value necessary for the building envelope in thicknesses that can vary from 3″ to 12″. Is is this thickness to be installed over open framing that the metal building/roofing supplier must be made aware of. Based on this thickness, the panel profile can be verified to determine if it can be used as well as confirmation of the correct clip heights and screw lengths for installation. Keep in mind that the supplier will offer a guide to the installer based upon insulation thickness. As insulation can vary by manufacturer, it will be up to the installer to make adjustments as needed in the field to ensure proper placement and hold modularity of the steel system. (See Respect the Module: Metal Roofing Panels are Modular for Good Reason)
Cavity Fill Insulation Systems:
When higher “R” values are required for roof insulation, a single layer over the open framing system may not be sufficient. When that occurs, the designers of the building envelope may need to employ the framing cavity to add more insulation. There are also variation on the cavity fill approach.
One means is to simply introduce a second layer of unfaced blanket on top of the faced insulation. Sometimes referred to as a “sag and bag” approach, here the first layer of insulation over the purlins is ordered to accommodate larger amounts of drape between the roof structure to permit another layer of unfaced insulation to be added on top. This increases the insulation thickness between the purlins but keeps it thin enough to be compressed to accommodate the roof panel installation. For coordination purposes, the thickness of this upper insulation over the purlins needs to be known by the building manufacturer so the clips and fasteners can be properly sized. Likewise, the amount of insulation draping between the purlins needs to be known to determine if purling bracing or other accessories may potentially interfere with the insulation installation.
Other types of cavity fill system may include a faced batt or face roll insulation with long tabs, which are secured to the tops of roof purlins and nest fully into the purlin cavity to fill the space more effectively. This helps in eliminating greater compression of multiple layers of insulation on top of the purlins and permits an additional layer of unfaced insulation on top of the roof structures and/or a thermal spacer block. This system may also require some intermediate banding to support the insulation between the primary supports.
A liner system may be installed that employs a continuous vapor retardent material. This liner is secured to the bottom of the roof structure and additionally supported with metal banding allowing the cavity to then be filled with unfaced insulation between the purlins. More unfaced insulation can also be added on top of the purlins as well. In all of the cases where cavity fill systems are used, it is important to advise the building manufacturer/roof supplier which type is being used to ensure proper panel clip heights and screw lengths. This is important because these systems can and will interfere with the roof structural bracing making them more difficult to install. The metal building supplier may be able to offer bracing alternatives or remedies to eliminate some or all of the bracing that would otherwise be in the way when installing the roof insulation. There may also be suggestions on how to avoid impeding or penetrating the vapor barriers which could lead to condensation issues. Overall, it is best to discuss and coordinate all of these items ahead of time.
Rigid Board/ Composite Systems:
In this insulation approach, rigid foam insulation board is used to achieve the sought after energy performance. Commonly, these use metal deck panels over the roof structure thus supporting the insulation and a vapor retardant material on top of the deck. The insulation and the metal roofing can then be secured to the framing substructure or to the metal deck itself, which means the details of attachment need to be reviewed and engineered to avoid adverse affects on the roofing system.
All of the above systems typically require attention to providing additional air and vapor barriers and proper cutting and fitting during installation so as not to cause unwanted infiltration or to prevent condensation from occurring. For these reasons and more, some people will consider the use of closed cell spray-on foam insulation, which can continuously provide all of these features in one product. It can also be installed after the roof is completed and structure is weathertight.
In the case of metal buildings, spray-on insulation is typically applied in the field onto the inside face of installed roof panels and sometimes wall panels too. There are, however, a few concerns with this approach in metal buildings. First, if conditions are not right and the panels are not properly prepared, then the spray foam can, in fact, trap moisture between the insulation and the metal components it is sprayed onto. That can lead to corrosion of the metal or deterioration of the insulation. Secondly, not all spray foams on the market are intended for this type of use so they don’t always adhere well to some metal panels, meaning it could become loose and fall away. Finally, continuous spray foam in this application will not always be able to expand and contract at the same rate that metal does. In some cases, that could mean that the foam suffers from differential movement causing it to break or lose adhesion.
For all of these reasons, be certain to research all options before considering or selecting a foam spray-on insulation that will not negatively impact your roof performance. If a foam insulation is preferred, it may be worth considering the use of insulated metal panels (IMPs) that are designed, engineered, and fabricated to be compatible with metal building construction.
Recognizing all of the above variations and options, the key point to remember about insulating metal buildings is the importance of communication between those designing and ordering an insulated metal building and those who are manufacturing and fabricating it. To find out more about the best ways to do that, contact your local MBCI representative.
Insulated metal panels (IMPs) used for building envelopes offer great simplicity in terms of enclosing a building in an attractive, energy-conscious manner. However, they require somewhat different thinking in terms of design and installation compared to conventional single skin panels on metal building with separately installed fiberglass insulation and vapor liners. That’s because, while the insulation aspect of IMPs is well controlled in the factory, the air and vapor sealing aspects are entirely in the hands of the installers in the field.
Why is vapor sealing a concern? Because it can make or break a building envelope. Airborne moisture that travels through seams, joints, or gaps between IMPs or between the panels and the structural steel can condense and wreak havoc on the integrity of the wall system. If that condensed moisture makes its way to unprotected edges of metal, then rusting, staining, and deterioration can occur. If it collects and drains out the bottom of the panel, then a building owner may mistakenly think that the IMPs are leaking water. If the moisture works its way inside a panel and becomes trapped it could freeze in cold climates or applications, and push panels enough to make unsightly or fail to perform as intended.
How does an installer of insulated metal panels avoid these issues? By properly using sealants as recommended by the IMP manufacturer to close the gaps and assure a vapor-tight installation. Here are the key things that installers need to pay attention to:
In most cases, butyl caulking is the recommended sealant for panel joints and perimeter attachments, although urethane sealant may be called for in some cases. For fire-rated panels, silicone sealants are usually required. The important caveat for all of these sealants is that they are most successfully installed when they’ve been stored within acceptable temperature ranges. In cold weather, they may need to be kept in a warming bin; in warm weather they must be kept out of direct sunlight.
Tools to Use
Applying any of the needed sealants will require using the proper tools. Manual caulking guns don’t provide the consistent quality of application needed, so electric or pneumatically operated applicators are required.
For typical building applications (non-freezer/coolers), the vapor sealant is placed in the interior panel joints when IMPs are installed vertically. For refrigerated spaces, the sealant is commonly placed on the exterior. If the IMPs are installed horizontally, then it usually is sealed on both the interior and the exterior panel joints to help with weather sealing as well. Note that the final placement of the sealant, as well as type and location, is actually the responsibility of the mechanical contractor/architect and not the panel supplier as it is to be based also on the mechanical design of the building envelope. In addition, the entire perimeter of the panels where they meet the building structure needs to be sealed. This includes the base flashing, interior corner trim, and eave struts. Further, marriage beads of butyl sealant must be placed at all panel terminations.
In order to be effective, all sealant and caulking must be fully continuous. That means that the thickness of the sealant bead must be consistent and thick enough to fully close all gaps between or around IMPs. It should not be overdone, however, since too much sealant will ooze out between panels that are pressed together, causing a bit of a mess on one side of the other. Sealant continuity also means that it can not be interrupted due to poor adhesion. Therefore, before any sealant is installed, the application surfaces must be cleaned and dry to be sure that full adhesion is achieved. Always check with the panel suppliers details for minimum bead size and critical locations.
Factory-Installed Option for IMP
Some IMP manufacturers offer the option of having sealant pre-installed along the edges of the IMPs. Since the panels are wrapped and sealed for shipping, the sealant is protected and should be ready for use onsite. However, in this case, it is incumbent on the installers to handle the panels quite carefully, since the inadvertent placement of a hand over the sealant can damage it or deform it enough to render it ineffective. This factory-installed option offers a labor saving in the field but must be checked during installation and can be impacted by time climate depending on the time of year. Field application, while requiring more labor, does provide greater onsite flexibility for installers. Nonetheless, in all instances, the installer must ensure the sealants are properly located.
By paying attention to the details of sealing and caulking, a metal building constructed with IMPs will be a quality installation that will hold up quite well over time. To find out more about IMP metal products and systems that can help your next building be more vapor- and weathertight, contact your local MBCI representative.
When metal roofing and wall systems of insulated metal panels, or IMPs, are combined with integrated daylighting and electrical lighting systems (such as with skylights, windows and translucent panels) it can improve occupant wellness and overall building performance. Are you curious if the return would be worth your investment? Uncover the recent advancements in daylighting technologies, the benefits and how to measure your building’s success.
Advancements in Daylighting Technologies and IMPs
In recent years, IMP assemblies have seen significant improvements, including more effective seals and thermal breaks as well as better thermal performance.
A range of novel daylighting products and technologies have been introduced in recent years that aid in the deployment of natural illumination for a multitude of occupancies—maximizing daylighting effectiveness while also maintaining the envelope’s barrier and thermal performance. These tools include pre-engineered, integrated metal envelope and roof solutions with compatible curbless skylights, light tubes, pan-type prismatic skylights, automated dimming controls for lighting, motorized shades and other components.
One example of how new tools are replacing more traditional products is the use of domed and pan-type units with prismatic embossing, which refracts and directs two to four times as much illumination into the indoor spaces when solar incidence angles are more acute, such as in the early morning and late in the day. These prismatic elements also help eliminate “hot spots” and reduce glare and ultraviolet (UV) deterioration from daylighting.
Benefits of Investing in Daylighting
Overall, using the current crop of novel skylight products in combination with a highly thermally efficient base system of metal panel walls and roofing will reduce excessive solar heat gain as they reduce the electrical base load for lighting. Highly diffusing acrylic and polycarbonate lenses and spectrally selective glass openings are very effective for maximizing functional visible light indoors while inhibiting unwanted heat gain. Many of the skylight aperture designs block 85% of infrared (IR) and 99.9% of UV light, which also reduces the unwanted degradation of products and materials inside the buildings. Additionally, the new generation of skylights also optimizes solar harvesting because many of the lenses have a minimal effect on VT.
In this way, the use of skylights with metal roofing and IMPs can be an effective way to meet the requirements of IECC 2012 and state energy codes. The skylights reduce overall electrical loads without adding unacceptable levels of solar heat gain, and their small relative area means the overall roof U-values remain low.
How to Measure the Success of Daylighting
Building teams will encounter a number of key variables that help measure the effectiveness of proposed daylighting designs. The most common (and valuable) daylighting performance metrics in use today include the following:
• Daylight factor
• Window-to-wall ratio, or WWR
• Effective aperture, or ea.
• Daylighting depth
• Solar heat-gain coefficient, or ShgC
• Haze factor
Using the above tools and terminology, building teams can better assess the benefits of daylighting strategies with skylights, prismatic pan-type products and solar light pipes, among others. In particular, these are important for meeting the widely used 2012 International Energy Conservation Codes (IECC) and ASHRAE 90.1 as well as state energy codes and “reach targets” such as green building certifications, the Passive House standard and others.
How to Learn More
The use of building systems combining metal roofing with skylights and integrated lighting provide significant life-cycle performance. Much of this is due to the research and development behind the individual products and materials used for these applications.
For a more in-depth look at daylighting within the context of metal roof and wall systems, please refer to MBCI’s whitepaper, Shining Light on Daylighting with Metal Roofs, which showcases the strong rates of return of using integrated daylighting systems with novel prismatic optics and high-efficiency lighting on metal envelopes with good thermal and barrier performance.
Panelized metal exteriors have joints. It’s just a rule of best-practice design. Yet these joints are seen by some as interruptions in the façade or roof, when in fact they are connections — the opposite, one can argue, of the word “interruption” that suggests a discontinuity.
In fact, engineered metal panel systems offer arguably the best possible continuous exterior system. Not only are they properly applied exterior to the building structure—outboard of columns, joists and girts—but they are also designed to ensure an unbroken chain of thermal control and barrier protection. Combined with controlled penetration assemblies as well as windows, doors and skylights that are engineered as part of the façade and roof system, the insulated metal panel (IMP) products provide unequaled performance.
That’s the main reason that specialized facilities designed for maximum environmental barrier control are made of IMPs: refrigerated warehouses, R&D laboratories, air traffic control towers and MRI clinics, to name a few.
But any facility should benefit from the best performance possible with metal roofing and wall panels. Consider insulation shorthand for the code-mandated thermal barrier required for opaque wall areas in ASHRAE 90.1 and the International Energy Conservation Code (IECC). For a given climate zone, says Robert A. Zabcik, P.E., director of R&D with NCI Group, the project team can calculate the functional amount of insulation needed by using either the “Minimum Rated R-values” method or the “Maximum U-factor Assembly” calculation. For IMPs, teams use the Maximum U-factor Assembly, which can be tested using ASTM C1363.
With IMPs, the test shows thermal performance values up to R-8.515 and better per inch of panel thickness, meaning that a 2.5-inch-deep panel would easily meet the IECC and ASHRAE minimums.
With metal roofing panels and wall panels, a building team can achieve needed energy performance levels with this single-source enclosure, providing a continuous blanket of protection.
The same is true for air and moisture control. In a July 2015 paper by Building Science Corp., principal John Straube wrote, “Insulated metal panels can provide an exceptionally rigid, strong and air impermeable component of an air barrier system.” He noted that, “Air leakage condensation cannot occur within the body of the insulated metal panel, even if one of the metal skins is breached, because all materials are completely air impermeable and there are no voids to allow air flow.”
In terms of water control, Straube writes that IMPs have a continuous steel face that is a “high-performance, durable water control layer: water simply will not leak through steel, and cracks and holes will not form over time. The exterior location of the water barrier,” he adds, “offers some real advantages.”
Connecting the panels at transitions, penetrations and panel joints is the key, of course. Straube notes that sealant, sheet metal, and sheet membranes are effective and commonly used to protect joints.
In my experience, these joint details are incredibly effective. They often outlast most other components of the building. Even more important, they help make IMPs better barriers that meet thermal, air and moisture performance needs. They help make metal panels one of the best choices of all.