Metal Building Insulation Basics

The following is a short explanation of the most basic insulation systems for metal buildings.  They are listed in the order of “ease-of-installation”.

MBI: Metal Building Insulation. 

This is the standard 3-inch (r-10), 4-inch (r-13) and 6-inch (r-19).  Other thickness are available.  The insulation installs over the purlins.

Sag and Bag

Sag and Bag includes 2 layers over the purlins.  Both layers are installed across the purlins.  You can accomplish r-values of r-7 to r-32.  There is no banding under the insulation.  The top layer is unfaced and the bottom layer is faced.  The insulation will be compressed if sag strapping or a queen’s truss is present.  Compressed insulation means less performance from the insulation.

Long Tab

Long tab is also 2-layers of insulation.  The long-tab (orange line in pictogram) on the bottom layer allows the bottom layer to fill the purlin cavity (less compression than Sag & Bag).  There is a single layer of steel strapping under the purlins that supports the bottom layer of insulation.  The bottom layer is installed between the purlins and the top layer is installed across the purlins.  Sag strapping and queen’s truss will compress the bottom layer just like the sag and bag.

Energy Saver

The Energy Saver system includes a fabric liner under the purlins, unfaced insulation between the purlins and unfaced insulation above the purlins.  You can cut the unfaced insulation around the sag strapping and queen’s truss, so no compressed insulation means more energy efficiency and more r-value for your money.  However, the fabric liner entirely covers the purlins so it is difficult for contractors to attach collateral items to the purlins (ceiling grid, HVAC, lights, etc).  There is also steel strapping 24-inches OC in two directions to support the fabric liner and the unfaced insulation.  Energy Saver will accomplish r-values from r-29 to r-43.  The additional strapping and the purlin-covering fabric liner makes this the most labor intensive, but also the most energy efficient.

For more details please contact your District Manager at 888-467-4443 today.

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