Faced or Unfaced Insulation in Garages: Which is Right?

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When I insulated my garage, one of the first decisions I had to make was between faced vs. unfaced garage insulation.

Although it was easy to tell the difference between them, I had no idea which to use. 

Then, if you choose faced insulation, which way should the insulation face in a garage?

So I did some research to find the differences to help choose the proper insulation. Each has its pros and cons, but depending on your situation, it might not be an obvious choice.

Generally, you should use faced insulation for your garage to comply with your local building codes, especially if you live in a very cold or humid climate. The vapor barrier side of the insulation should always face toward the room’s interior. However, use unfaced insulation when adding an additional insulation layer to your garage. 

This article will explain what faced insulation is, why you might want it, and whether it is better than unfaced insulation for your garage. 


Faced or Unfaced Insulation in Garages

Faced insulation adds a vapor barrier to protect exterior walls against excessive moisture damage. This barrier is usually made out of Kraft paper and is sometimes called a vapor retarder. 

It helps prevent moisture from moving from one space to another and usually faces the inside of the room. Depending on your local codes, you may be required to cover the Kraft paper with other materials

By contrast, unfaced insulation is plain insulation that doesn’t have a vapor retarder.

Usually, when insulating a room or house for the first time, you will use a vapor retarder. However, facing is not suitable for adding additional insulation to existing applications. 

Fiberglass insulation and mineral wool insulation, the two most popular insulation materials, are available in both faced and unfaced. Loose-fill insulation cannot be faced.

Types of Faced Insulation

Faced insulation is typically made from regular paper, aluminum foil, or Kraft paper. 

Aluminum foil is an upgrade to plain-paper insulation facing. Many vapor barriers are made from aluminum, making them great for thermal insulation.

Kraft faced insulation has an insulating barrier made of thin but strong cardboard made from wood pulp. 

By itself, Kraft paper is not a good insulator. It’s often used for paper shopping bags which can quickly get wet. However, when soaked in transformer varnish, it turns into an excellent insulator. 

When to Use Faced Vs. Unfaced Insulation in Your Garage

This section will highlight the situations you might want to use faced insulation. We will also explain some benefits of faced insulation instead of unfaced insulation.

Faced Insulation: In Cold or Rainy Climates

If you live somewhere with really harsh winters, consider getting faced insulation.

Moisture from snow, ice, and rain can lead to mold and mildew. Faced insulation will help keep the garage warm during the winter and help prevent moisture from getting in and ruining the frame of your wall.

Additionally, it’s worth getting faced insulation if you plan on converting your garage into an office, gym, or bedroom. It’ll help keep your garage dry and warm.

Faced Insulation: In Hot and Humid Climates

On the flip side, if you live in a hot and humid climate, faced insulation can help fight mold and mildew.

Many areas have a mix of hot and cold climates with both cold, harsh winters and hot, humid summers. If that sounds like where you live, that’s an extra reason to use faced insulation.

Faced Insulation: When Your Local Codes Require It

Depending on your local building codes, you may be required to install a vapor barrier when building your house.

If that is the case, you should get faced insulation to fulfill those requirements. Every place is different, so check local building codes in your county.

It’s important to note that using Kraft paper is not the only way to create a vapor barrier. We’ll cover this in more detail in a later section. However, there are quite a few ways to create vapor barriers.

Faced Insulation: On New Insulation Projects

As I mentioned earlier, faced insulation is generally used on first-time applications. So if you already have insulation and are simply adding another layer of insulation over the first layer, you should not use faced insulation. 

The additional vapor barrier can trap moisture where you don’t want it to be trapped. 

No matter which insulation you choose, it is vital to ensure that the existing insulation is not wet. Instead of adding additional insulation to fix a moisture problem, it’s better to find the root cause of that moisture. Find the leak and waterproof your garage walls first?   

When to Use Un-Faced Insulation

Although faced insulation should generally be used when insulating your garage for the first time, there are a few cases where you want to avoid using it. 

Typically, you don’t need to use faced insulation on interior walls. There aren’t enough temperature or moisture variations to warrant the additional cost.

Keep in mind that all this is not considering local building codes. You must comply with all local laws if required to install a vapor barrier. It’s always a good idea to check with your local building planners to see if you need a permit for your garage project

As we mentioned, do not add faced insulation over existing insulation. If you already have an insulated garage and adding additional insulation over an existing layer, use unfaced insulation. 

One of the problems with faced insulation using a paper vapor barrier is that it can be highly flammable. 

For example, if you plan on using your garage for your welding projects, you risk having a welding fire. If you use faced insulation, you must take extra precautions to avoid a fire. 

Vapor Barriers vs. Vapor Retarders

Is there a difference between a vapor barrier and a vapor retarder? Or are they the same? 

These terms are often used interchangeably, but they are different.

As mentioned earlier in this article, a vapor barrier is often referred to as a vapor retarder. 

A vapor barrier is “a type of vapor retarder with a permeance rating of 0.01 perms.” 

Perms are short for permeability, a rating system used to determine how effectively a vapor retarder stops moisture from getting through. 

The more moisture that can permeate the material, the lower the rating. 

The intricacies of this rating are beyond the scope of this article. However, this article discusses permeability ratings and the differences between vapor barriers and vapor retardants in depth. 

Installing a Vapor Barrier Correctly

Whether you use Kraft paper or aluminum foil for your facing, you must ensure that it is not damaged.

Often, a facing is ineffective because it was not installed correctly, not because of the material itself.

For example, aluminum foil can easily get torn, especially when installed around light sockets. If you’re unsure how to install faced insulation, it is best to get a professional to do it.

Wrapping It Up

For most people insulating their garages, faced insulation is the better option. When installing faced insulation, it should always face the room’s interior.

Check your local building codes to determine if you need a vapor barrier.

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Tim Wells

Tim Wells, the founder of Garage Transformed, has been featured in dozens of home renovation publications, including BobVila.com, Home Stratosphere, House Digest, Livingetc, and SFGate. Since 2018, he has helped over two million people transform their everyday garages into something they can be proud of. He lives in Central Florida with his wife and bulldog.

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