Fiberglass Insulation Resource Guide

Learn installation practices, R-Values, Specifications, Descriptions, and a lot more

Basic Fiberglass Insulation

The definition of fiberglass 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.  

Most people are familiar with fiberglass insulation. It has been the most popular insulation type for over 100 years, though its facings have improved dramatically.

Rolls of Fiberglass Insulation

One of the primary purposes of fiberglass insulation in the summer months is to reduce the heat transfer between the outside of your metal building or pole barn and the inside. The purpose is the opposite in the winter: to minimize the cold transfer from the outside to the inside. The insulation’s effectiveness is measured based on R-values. The higher the R-value, the more apt to protect your structure.

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). 

Should I insulate my steel building

Understanding R – Value of Fiberglass Insulation

R-Value is based on measuring the amount of heat loss or the ability to retard the loss of heat flow. Understanding the 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- 8







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Our Fiberglass Insulation meets or exceeds these standards

Fiberglass Insulation Standard Specifications and Features

  • A 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′. 
  • Factory Steel Overstock standard quotes include a stronger VR-R “PLUS” facing instead of the industry-standard VR-R. 
unfaced metal building insulation
Fiberglass Insulation Descriptions and Facings
  • VR
  • VRR+ (Standard Offer)
  • WMP-10
  • WMP – 30
  • WMP-50′
  • Unfaced

Your 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
  • Delivered cost

Pdf of More Detailed Recommendations for installing Fiberglass Insulation

Single Layer Fiberglass Insulation Installation Instructions

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  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

Double Layer Fiberglass Insulation Installation Instructions: 

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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.
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Choosing a Right Insulation

There are many factors to consider when choosing an insulation type. Let me begin by saying that insulation is imperative for making your metal building kit more energy-efficient. Insulation will undoubtedly save you on heating and cooling costs, give you comfort, and protect your structure from the effects of condensation. By the way, condensation can damage building members through rot and rust and cause mildew, leading to illness.   However, with many insulation types available, the challenge is effectively selecting the ideal insulation for you. This article aims to simplify that process.

The Climate Condition

The #1 condition to factor in is the climate condition in which the building will reside. The climate you live in significantly impacts your insulation choice. For instance, higher R-value insulation is essential in colder climates to guard against these harsher environmental conditions. If you choose fiberglass metal building insulation, consider selecting R-19 or more.

The Existing Building Situation

The design of the structure and whether the structure is a new construction will play a role in the type of insulation chosen.

Decide The Insulation Purpose or Specific Need

For instance, are you insulating primarily to protect your metal building kit from sound, condensation, or energy efficiency? Though most insulation types offer multiple benefits, each one has its niche or primary benefit.

 5 Popular types of Insulation

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Fiberglass Insulation (Batts and Rolls).

Fiberglass Insulation rolls are often selected where there are standard spaces between members. The rolls can easily be ordered to particular standard widths to fit in between steel or wood members; therefore making roll insulation the easiest DIY project.”

The one key drawback to roll insulation, it requires price dimensions to fit within spacing. Consequently, precise cutting is required for it to fit around obstacles.

Spray Foam Insulation

Spray Foam Insulation

Quite often, Spray Foam insulation is selected when sealing cracks and gaps is a key. It has a high R-value per inch. One of its drawbacks is the required professional installation, which makes it expensive.

Foam Board Insulation

Rigid Foam Board

This insulation type is good for under slabs and on exterior walls under siding. It is a vapor barrier and insulates well to its thickness. A negative is that it is more expensive than blanket insulation. It is also easier to install, avoiding gaps.

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Blown-in Insulation (loose fill)

If you have hard-to-reach areas, Blown-in insulation may be the way to go. It is often installed in attics. The negative aspect of blown-in, is requires professional installation; therefore, can be quite expensive.

Reflective Insulation

Reflective Insulation

People tend to order reflective insulation in hot climates because it is a great radiant barrier.  This means it will reduce cooling costs by reflecting heat away. It is considered less effective in very cold climates

As you can see, there are pros and cons to all insulation types. Factory Steel Overstock offers two types of insulation. Fiberglass Blanket (rolls) and Reflective insulation because it feels for the cost it is the best insulation options for pole barns and metal buildings where there is standard spacing available. Also, when cost considerations are important, it is often the choice.

Why our Fiberglass Insulation?

1. Originates from Owen Corning

2. Fiberglass Insulation is Naima 202-96 compliance

3. Comcheck- Energy Compliance Certificate

4. Fabric and Banding

5. Quick Delivery

6. Secure Price and Quick Delivery

1. 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 profit-fee AFTER (same day) quoted savings.

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2. Fiberglass Insulation is Naima 202-96 compliance

This is an independent test performed by Home Innovations.  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 hits the field from these manufacturers which is less than performance.  With NAIMA 202-96 fiberglass guarantee you get the R-value you ask for.

An additional standards met or exceeded:

  • ASTM C991-08, Standard Specification for Flexible
    Fibrous Glass Insulation for Metal Buildings; Type II.
Certification Tage

3. Comcheck- Energy Compliance Certificate

Is a program put out by the department of energy.  This program models buildings in compliance software to verify government energy code performance.  The certificate will specify a percentage equal to or better than code requirements.  Our company will provide this certificate for a building with any order. COMCheck certificates are available on request for full building orders to guarantee energy code compliance

4. 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.  Factory Steel Overstock is committed to offering the correct amount of banding and screws per order request.

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5. Quick Delivery

Our Fiberglass insulation is delivered within 7-14 days, and the customer is called within 48 hours of delivery. Most firms double this time frame.

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6. Promised Savings

With Factory Steel Overstock’s cost-plus program, the general public is informed of the wholesale delivered cost for their fiberglass insulation. Whether the cost is $2,000 or $25,000, the public pays only $350 above cost. Factory Steel Overstock’s guarantees saving below market quotes of equal specifications.

In addition, when there are insulation shortages, some firms will indicate that they can 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 deliver their insulation if they don’t accept the price increase.  With Factory Steel Overstock, there are no surprises. There is never a possibility of a price increase after the initial order! The price and savings are guaranteed!

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Additional Resources

Options for Vinyl Vapor Barrier Facings
Facing WMP VR R Plus

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!

Facing AreanaSheild Ice Arena
Facing Blackwmp vrwmp vr rplus wmp 10wmp 50

Facing GymGuardFacing
Facing Radiant Ice
Facing WMP 50
Facing WMP 30 Heavy Duty

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Buy fiberglass insulation online. Profit amount is $350.

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Profit amount for Insulation Wholesale Quote is $350-$500. Steel Buildings is $1,000.

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We promise to return all calls, emails, and text sent during a work week within 24 hours.

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You are guaranteed a net savings below market quotes of equal specifications.