Which Way Should Insulation Face In A Garage?

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Insulating a garage creates a more comfortable environment that allows you to use the space for other functions besides vehicle storage. Although, it is advisable to consult an insulation professional to insulate your garage, you might also embark on this as a DIY task. If you decide to insulate the garage yourself, one of the details you will need to figure out is which way the insulation should face. We researched this topic, and here are our findings.

You can either use faced or unfaced insulation when insulating your garage. If you use faced insulation, the paper side should face the inside of the garage. Alternatively, when using unfaced insulation, it is recommended that you add a vapor barrier over the garage walls after installing the insulation.

Now that you already know which way the insulation should face in a garage, keep reading as we will discuss how to install insulation in a garage wall and whether you need to cover the insulation. We will also discuss if a garage ceiling needs to be insulated.

White and spacious garage with white walls painted concrete flooring and a light on the garage mechanism, Which Way Should Insulation Face In A Garage?

How do you install insulation in a garage wall?

A garage is primarily built to protect your vehicle from precipitation, vandalism, and theft. However, the garage can also be multi-functional. It can be used for purposes besides parking your cars, such as a storage area, a workstation, or a fitness area.

It is advisable to insulate the garage if your house's heating system is located there or if you have adapted the garage to serve roles that require a certain degree of comfort.

To insulate the garage, you can install faced or unfaced insulation. While faced insulation has a pre-attached moisture barrier, it is advisable to add a vapor barrier if you use unfaced insulation.

A spacious garage with beige painted walls, granite tiled flooring and a white garage door

Insulation Thickness

The size of the studs used to frame your garage will determine the thickness of the insulation you should use. Often, it is advisable to use R-19 insulation with two-inch by six-inch lumber since it is slightly over six inches thick. These insulation rolls fit tightly in the wall and prevent air from flowing through gaps on the walls.

You can also use R-21 insulation rolls instead of the R-19 ones, as they are designed to fit into the same space. However, the R-21 rolls tend to be thinner than the R-19 due to higher density.

Although the R-21 rolls are more expensive per square foot, they are also more efficient at preventing heat transfer and may guarantee more savings on energy bills in the long term.

If your garage has lumber that measures two inches by four inches, it is recommended that you use R-13 or R-15 kraft-faced insulation rolls. These rolls are ideal as they are designed to fit 3 1/2 inches deep spaces.

Step-by-step Installation Guide

Fiberglass insulation is often used when insulating a garage since it is DIY-friendly and relatively affordable. The insulation comes in pre-cut rolls and batts that fit the width of the studs.

Determine how much insulation you will need by measuring the entire length of the garage and multiplying that by its height to calculate the square footage.

Gather the necessary tools and materials. You will need a staple gun, staples, a sharp utility knife, and a piece of wood to guide you in cutting the right size of insulation.

To insulate the garage wall:

  1. Clean the garage walls before installing the insulation. Thoroughly inspect for mold and remove them.
  2. Fill in any gaps and cracks in the walls. If left unattended, these gaps will reduce the efficiency of your insulation by allowing outdoor air to your garage. It is advisable to use spray foam insulation to fill the gaps and holes.
  3. Install the rolls and batts between the wall framing. If you are using faced insulation, staple the paper face of the insulation to the side of the studs. Using the wood and utility knife, cut the appropriate insulation sizes and tuck them to make them easier to staple.
  4. Cover the insulation with drywall to minimize the potential for a fire hazard since the vapor barrier is flammable.

What happens if insulation is installed backward?

It is advisable to install the insulation correctly since you are susceptible to any of the following issues if installed backward:

  • The vapor barrier can trap moisture inside the insulation, creating a favorable environment for mold to build up. If inhaled, mold can cause allergic reactions such as running nose, congestion, and lung irritation. Mold can also cause skin irritation.
  • Trapped moisture also damages the insulation material making it inefficient. You, therefore, use a lot of energy to regulate the temperature in your garage.
  • As trapped moisture accumulates, wood may rot, causing structural deterioration. Consequently, you will need a hefty budget for repairs.
  • Trapped moisture can also cause paint to peel, chip, or crack. In older homes built before 1978, this may contribute to higher lead levels in the house from lead-based paints. If left unmonitored, it can eventually cause lead poisoning, which could be fatal.
  • Installing the insulation backward also increases the potential for a fire hazard since the vapor barrier is flammable.

Which way should the vapor barrier face?

Whether you are using faced insulation with a pre-fixed vapor barrier or adding a moisture barrier over the garage walls after insulation, it is recommended that the vapor barrier should face the garage's interior.

Typically, an insulated garage is warmer than the surrounding environment. Since warm air carries more moisture, the relative humidity inside the garage is higher than outside. So, it is advised for the vapor barrier to face the inside of the garage. This will minimize exposure to moisture from inside the garage.

The vapor barrier should be air-and-water resistant but also vapor-permeable. Permeability keeps moisture from accumulating in the wall structure, which may cause mold build-up. Additionally, moisture can also cause rotting that may compromise the structural integrity of your home.

Do you have to cover insulation in a garage?

An insulation contractor removing old fiberglass insulation of a house

It is advisable to cover insulation in a garage to avoid irritation from coming into contact with the exposed insulation. Fiberglass particles can cause lung irritation if inhaled. Additionally, these particles can also irritate the skin and eyes.

Using a permeable barrier that won't trap moisture to cover the insulation is best. While you want to avoid the side effects of exposed insulation, you also want to prevent moisture problems, which would harm the usability of the garage.

Covering insulation in a garage also reduces the risk of a potential fire outbreak since, as previously mentioned, the vapor barrier is highly flammable.

Does a garage ceiling need to be insulated?

A gorgeous tiled garage painted in yellow with white painted walls and cabinets with bicycles hanged on the wall

It is advisable to insulate the garage ceiling to reduce heat loss during the cold months. Because hot air rises if the ceiling is left uninsulated, heat would be lost through the gaps and cracks in the ceiling, raising your energy bills.

Insulating the garage ceiling also reduces air conditioning costs during the hot months since insulating controls the heat passing into your home. It is recommended to use R-30 or R-38 insulation for the garage, depending on the thickness of the ceiling joists.

Insulating the ceiling also aids with sound control. The insulation absorbs sound, reducing unwanted noise from appliances and other equipment that may be running in the garage.

It is recommended that you include baffles for ventilation before fixing the insulation to curb moisture build-up and allow proper air circulation. The baffles should be near the edge of the roof.

You may be interested in reading this article as it discusses in greater depth "How To Insulate Garage Ceiling Rafters."

In conclusion

White and spacious garage with white walls painted concrete flooring and a light on the garage mechanism

Insulating a garage makes it more comfortable for functions besides parking your automobile. Ensure that the vapor barrier faces the garage's interior to avoid moisture problems. Also, ensure that you use the correct R-value when insulating the garage.

It is easier to install faced fiberglass insulation as you would only need to staple the paper side of the insulation to the side of the studs. It is also cheaper than the alternative forms of insulation on the market. We hope that the information provided in this article will guide you as you insulate your garage.

Ensure that you comply with your local building codes when installing the insulation. Further, regularly check the insulation condition in your garage to ensure that it is in perfect condition to serve you efficiently. Remove any worn insulation and replace it.

Be sure to check out this post as well:

Should You Air Condition Your Garage? [Pros, Cons And How To]

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