The Ultimate Guide to Metal Building Insulation

Written By Nick Rodriguez

Insulation improves the comfort in your building year-round, regardless of whether or not your building will be climate controlled. Building insulation is typically much more affordable when done at the time of initial construction. Insulating your building also helps prevent condensation in northern climates, which can wreak havoc on your metal building by leading to mold growth, foul odors, and related issues.

There are 5 common options available for metal building insulation:

  • Bubble Foil (Radiant Barrier)

  • Vinyl-backed Fiberglass (Blanket)

  • Filled Cavity Fiberglass (Energy/Simple Saver)

  • Spray Foam

  • Insulated Metal Panels

Bubble Foil

Reflective insulation can work in the right situation. They are often more effective in warmer climates.

Pros

  • Reflective insulation provides a radiant barrier that reflects heat

  • Very Affordable

Cons

  • Often require air space between paneling and insulation which is difficult to achieve in field installations

Vinyl-backed Fiberglass (Blanket)

Fiberglass insulation is often the most cost-effective way to insulate metal buildings. The faced fiberglass insulation is installed between the girts/purlins and the exterior metal wall panel. 3” R-11 is the most common offering. Typically, 4” is the thickest recommendation when the insulation will be sandwiched between purlins/girts and the wall paneling to prevent oil canning.

If higher insulation values are desired or required, see the filled cavity systems described below.

Pros

  • Built in vapor retarder helps prevent condensation

  • Simple install

Cons

  • Unlikely to meet modern energy code requirements

  • Thermal bridging at each girt/purlin reduces the effective R-Value

    • Insulation is compressed in these areas

FILLED CAVITY SYSTEMS

Girt/Purlin cavity completely filled with insulation. The installer applies thermal break tape to the outside face of the girts/purlins prior to installing the wall panels to reduce heat transfer between the panels and girt/purlins.

Wall Install

  • Unfaced insulation is held up by insulation hangers

  • Fabric liner system is placed over the girts and the insulation

Roof Install

  • Metal banding installed to bottom of roof purlins to support fabric liner

  • Fabric liner installed

  • 1st layer of unfaced fiberglass insulation is installed between the purlins.

  • 2nd layer of unfaced fiberglass insulation is installed perpendicular to and over top of the roof purlins

  • Metal roof installed over 2nd layer of insulation

Pros

  • Works well in new and retrofit solutions

  • Meets or exceeds building energy codes

  • Most liner systems do provide fall protection for workers once installed

  • Improved vapor/air barrier vs backed fiberglass

  • Provides “finished” interior wall/ceiling finish with white and black options available

Cons

  • Installation process is more complex

  • More difficult to access girts/purlins for electrical, maintenance, and HVAC services

  • Requires coordination between the insulation provider and the building manufacturer to ensure girt/purlin spacing will accommodate standing insulation roll widths

Spray-foam

Spray foam is created by mixing two chemicals which react with each other and expand up to 30-60x after it is sprayed in place. This expansion produces a high thermal insulating value with virtually no air infiltration. Spray foam is installed directly to the inside of metal wall panels. Closed cell spray foam is typically used, but open cell can be used in depending on the application. A fire rated coating needs to be installed to the spray foam if left exposed in a commercial structure.

Spray foam insulation can be used with screw down roofs, but it is not recommended for standing seam roofs. Standing seam roof systems are designed to expand and contract in order to work properly and spray foam does not allow for proper expansion/contraction.

Pros

  • Increases rigidity of building by “gluing” components together

  • Higher R-values per inch of insulation

Cons

  • Spray foam is typically 2x-4x more expensive than fiberglass insulation

  • Spray foam will void your panel warranty

    • Any water that leaks past screw gaskets will be trapped between the panel and foam, significantly increasing panel degradation

  • When mixed improperly:

    • Insulation can release dangerous fumes into your building

    • Insulation may begin to delaminate from your building

  • Reduces repairability of building

    • Significantly more difficult to replace building panels in the future as they are “glued” to the framing

INSULATED METAL PANELS

Insulated metal panels “sandwich” spray foam insulation between two layers of metal panels. The metal panels provide a finished surface on both the interior and exterior of the buildings. Insulation thicknesses from 2” to 6” are typically available. Insulation values are typically R5 to R-7 per inch. Coordination with the building manufacturer is critical due to loading (weight) and trim conditions.

Pros

  • Provides finished interior surface via steel sheeting

  • Provide most effective water, air, and vapor barrier on metal buildings

Cons

  • Most expensive option

  • Expertise is required by installation crew for proper performance

Nick Rodriguez
Next

Cold Formed vs Red Iron Buildings