Insulated Metal Panels (IMPs) have become the choice material for the construction of roofs and walls because they can be tailored to fit your needs. That being said, this degree of customization comes with a caveat; it makes the design and installation of IMPs a little trickier.
Today, we’ll be taking a closer look at some of the most important design parameters you need to keep in mind when it comes to the installation of IMPs.
1. Thermal Effects:
It’s a well-known fact that when metals are heated, they expand (thermal expansion). This means that we can’t use bare metal surfaces in extreme temperature. This is where an IMP comes into the picture.
If there’s one aspect that IMPs have become renowned for then it is their ability to withstand high temperature differentials. Due to their impeccable design, IMPs accommodate thermal expansion by using thermal bow and thermal stress. Confused? Allow us to elaborate.
Think of IMPs as a composite sandwich that has two sides (the interior and the exterior) bonded to the core. This minimizes the effects of linear expansion and ensures that we only have to contend with thermal bow.
Now, instead of stretching the insulated panel to the verge of its mechanical limit, design engineers install IMPs in a bow configuration (as shown above). This negates the need for using slotted clips in installation and doesn’t adversely affect the performance of these panels. So, any way you look at it, it’s a win-win.
Fun fact: Owing to long exposure to the sun, a dark-colored IMP can reach a service temperature of about 180°F. However, this temperature can be reduced to 120°F to 160°F by using lighter colors.
2. Metal Roof End Laps:
It’s a little known fact that shipping constraints and handling limitations dictate the maximum size of an IMP. Owing to these limitations, design engineers often provide an end lap joint for IMPs (particularly for those panels used in roofing).
Generally speaking, this is achieved by cutting the inner layer and the foam core to make room for an extension (which will accommodate the end lap joint) on the lower panel. As for the length of the extension, this will be determined by the slope of the roof.
3. Metal Roof Slope
Speaking of the slope of the roof, it is also an important design parameter in the design of an IMP. Just like any other metal roofing option, IMPs too are installed at a minimum slope (which varies from manufacturer to manufacturer).
Although more accurate information can be found by talking to your manufacturer, a common rule of thumb for IMP design is:
- For single length panels: a quarter inch for a 1-ft slope
- For panels with a lap joint: half an inch for a 1-ft slope
To reiterate, these are approximations and you should always consult your panel manufacturer before making any significant decision.
4. Metal Roof Penetrations
To ensure the structural integrity of your IMP, we highly recommend minimizing roof penetrations as much as possible. However, when penetrations are absolutely crucial, follow this rule of thumb;
- For small penetrations, seal the exterior layer of the IMP with boots (i.e. stack flashings).
- For large penetrations, seal the exterior layer of the IMP with a factory-welded curb (complemented by additional structural support).
Allied Steel Buildings provides impeccable IMP roofing solutions to its clients in the United States and Canada. We offer comprehensive design, engineering, and fabrication services and can tailor the end product to meet your needs. Ensure that your design is of the highest caliber by either getting in touch or opting for a free quote!
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Read more about Insulated Metal Panels:
- Everything You Need To Know About Insulated Metal Panels
- Why You Should Choose Insulated Metal Wall and Roof Systems for Your Construction Project
- Everything You Need To Know About Performance Testing of IMPs
- Insulated Metal Panels: What They Are and Where to Use Them
- Selection Guide: How To Select The Right IMPs For Your Construction Project
- How Insulated Metal Panels Are Produced
- Quality Testing: How Insulated Metal Panels Are Tested
- Installation of Insulated Metal Panels: How It’s Done
- What You Should Know About the R-Value of Insulated Metal Panels
- Why Panel Thickness Matters in the Selection of IMPs
- Comparing Insulated Metal Panels to Other Options
- Insulated Metal Panels: All the Benefits and Features They Offer
- Construction 101: How IMPs Improve the Thermal Performance and Aesthetics of a Building
- Comparing Thermal Resistance of IMPs to Other Materials