Insulation Considerations for Metal Building Projects

Posted on October 15, 2020 by MBCI

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.

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Energy Codes

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.

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://blog.mbci.com/coordinating-roof-insulation-with-metal-building-construction/

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