Fiberglass Resources Guide

The highest-rated fiberglass insulation at the lowest industry prices.

Simple Installation Procedure for Single Layer Blanket

Pdf of More Detailed Recommendations for installing Fiberglass Insulation

  1. You simply place the insulation roll over the top of the roof purlins and / or wall girts. This is done prior to the exterior metal panels being installed.
  2. The fiberglass rolls are essentially sandwiched between the interior metal and the exterior sheeting.
  3. The vapor barrier (usually white finish) is faced towards the inside of the building, giving the building a clean finished look. We always Re-enforce this facing so that our customers have the sturdiest backing. With a single layer application, you can achieve R-Values up to R-19, but not higher.
  4. The 3” tabs are to be rolled over and stapled. Orders come with double-sided tape for easy adherence to building, and a small supply of patch tape to assist with minor tears if needed

Simple Installation Procedure for Double Layer Insulation System: 

The great thing about fiberglass insulation is you can just add an additional layer and increase your R-value. The highest R-value you can have with a single layer of insulation is R-19 which is 6”.  Your purlin depth determines the thickness of your bottom layer.

  1. Faced fiberglass (we always include a reinforced faced backing) rolls are installed between the purlins and/or girts, filling the cavity. This cavity is important, for it allows the insulation to maximize its efficiency.
  2. This insulation is secured by banding that is screwed to the underside of the purlins. An additional layer of unfaced insulation is then placed over the top of purlins or girts, creating a double-layer high R-Value system.

Our Fiberglass Insulation originates from Owen Corning

Factory Steel Overstock’s source of fiberglass insulation – before lamination -comes from the highest-rated insulation company in the industry – Owen Corning. You can order R-value 8 to 30 with multiple facing options. To review delivered estimates, click INSULATION DYI ESTIMATOR.  Since Factory Steel Overstock has already posted delivered estimates and guarantees a quoted savings, quotes are exclusively completed for those willing to pay a $500 profit-fee AFTER (same day) quoted savings. Everyone is guaranteed a minimum of $200 net savings below market quotes. The average savings is 10%.

Insulation 101

Most people are familiar with fiberglass insulation.  It is what was in their attic when growing up–though there have been improvements on its facings.

Steel building insulation is blankets of woven long-strand fiberglass that are laminated on one side to a vapor-barrier facing.  Facing materials are applied to fiberglass insulation blankets to serve as a vapor retarder as well as a protected cover over the fiberglass. This vinyl-reinforced backing is far more durable than vinyl alone.  

Not all Fiberglass Insulations are the same

  • Fabric and Banding: Be aware there are insulation systems that are of low quality. Some sellers utilize fabric that is thin and cheap, as well as use plastic nylon strapping in place of traditional metal banding.  Most erectors will complain about this kind of banding twisting up on the screw as they try to attach the strapping. 
  • Naima 202-96 compliance. This is an independent test performed by Home Innovations.  This test is the gold Standard for Flexible Fiberglass Insulation to be Laminated for Use in Metal Buildings. When the facing is laminated to the fiberglass it crushes the fiberglass.  The test ensures that after manufacturing the product unrolls to the specified R-value.   Some manufacturers do not want to pay for this test and say they do in-house testing.  In these cases, the product often arrives from these manufacturers with less than claimed performance.  Simply put, it means other insulation outlets, R-19 (6″) insulation may show up at the job site as 4″ or 5″ with a lower R-Value!  Our NAIMA 202-96 compliance guarantees you get the R-value you ask for.
  • Comcheck- Energy Compliance Certificate  COMcheck is a program put out by the department of energy.  This program models buildings in a compliance software to verify government energy code performance as it relates to insulation.  The certificate will specify a percentage equal to or better than code requirements.   COMCheck certificates available on request
  • Secure Price: Some firms will indicate that they have the option to increase the price based on insulation availability. This means these firms can process the order and then hit the customer with an increase at the last minute before shipping. At that point, the customer is stuck and may have to wait several weeks to get their insulation delivered if they don’t accept the price increase. A few steel building outlets are doing this same tactic.

With Factory Steel Overstock, there are no surprises. There is never a possibility of a price increase after the initial order! Insulation is normally delivered within 3 weeks and the customer is called within 48 hours of delivery. If an apple-to-apple price and feature comparison is made, it will be self-evident the better choice! 


  • VR
  • VRR+ (Standard Offer)
  • WMP-10
  • WMP – 30
  • WMP-50′
  • Unfaced


  • Black
  • White

Standard Features

  • Factory Steel Overstock standard quotes include a stronger VR-R “PLUS” facing instead of the industry-standard VR-R. 
  • 2 – 3″ tab runs along the length of both sides of rolled-out insulation for easier handling during installation.
  • Double face tape and patch is a standard inclusion on insulation quoted by building measurements. Quotes of a specific square ft or number of rolls, patch, and double-face tapes are added upon request.
  • Customers can indicate the cut length of their rolls.
  • Standard insulation width: 3′, 4′, 5′, and 6′.

Comprehensive Fiberglass Insulation Invoice will indicate:

  • Type of insulation (example- VR-R +)
  • Number of rolls
  • Width of rolls
  • Length of rolls
  • Total square ft of insulation
  • Estimated Weight
  • Volume in cu ft
  • Thickness of insulation
  • R-Value
  • Tax rate
  • A delivered cost – that is guaranteed $200 below market quotes of equal specification standards.

Understanding R – Value

R-Value is based on measuring the amount of heat loss, or ability to retard the loss of heat flow. Understanding R-value with fiberglass insulation is easy: The R-value is directly related to the fiberglass thickness. The thicker the fiberglass blanket you have, the higher the R-value. Factory Steel Overstock quotes R-Value 8 to 30.

Approximate Thickness             R-Value

2.75″                                                       R – 8

3″                                                            R – 10

3.5″                                                         R – 11

4″                                                            R – 13

6″                                                            R – 19

8″                                                            R – 25

9.5″                                                         R – 30


Pdf of More Detailed Information on Specifications

Pdf of More Detailed Information on Air Barrier System

Pdf of More Detailed Information on Rigid Envelope System

Pdf of More Detailed Information on Banded Liner System

  • ASTM C991-08, Standard Specification for Flexible
    Fibrous Glass Insulation for Metal Buildings; Type II.
  • NAIMA 202-96 (Rev. 2000) Standard for Flexible
    Fiberglass Insulation to be Laminated for Use in
    Metal Buildings.

Why do I need insulation?

An insulation R-value is the measurement of a material’s ability to stop heat and cold transfer.  No matter what a metal building’s usage, insulating it will be of value.  Because of the unique nature of a steel building, it requires a vapor barrier and radiant barrier. 

  • The summer heat (sun’s rays) on a steel surface will create extreme heat temperatures inside the building.
  • In addition, the cold winter temperatures are exaggerated by the metal roof and wall sheeting making it frigid inside.  Warm temperatures coming in contact with cool metal roofs or walls create sweating (condensation). 

Options for Vinyl Vapor Barrier Facings

For most standard uses of your metal building, this is sufficiently strong and adequate for being tear resistant.  We simply wouldn’t settle for less, nor expect you to pay more than the wholesale pricing we pass on to you!

Average savings is 10% below market quotes of equal specification standard. Guaranteed savings is a net of $1,000 on steel buildings and $200 on insulation below market quotes.

1. Review Building or Insulation delivered estimates.

2. Ready buyers, fill out a Quote – Order Form

3. Must pay profit-fee amount AFTER (same day) quoted savings!

Wholesale Building Costs + Profit 
$0 to $100,000 | Profit $1,000

Wholesale Insulation Cost + Profit 
$0 to $25,000 | Profit $500

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