Do You Need A Vapor Barrier For A Detached Garage?

Install or not install a vapor barrier in a detached garage is a concern for many homeowners.

Due to temperature differences, water vapor diffuses from a high-temperature zone to a low-temperature region.

Therefore, Do You Need A Vapor Barrier For A Detached Garage?

Generally, you should insulate your detached garage, especially if you live in cold climate areas. You should also insulate your detached garage if you plan to install a cooling or heating system in the building. However, most garages do not require vapor barriers. In most cases, the level of vapor that diffuses out of your garage is not enough to cause moisture damage to the walls.

Due to changing weather patterns, the temperature inside the garage is never constant.

For instance, the outdoor temperature is freezing during the winter while the indoors are warmer.

This temperature difference causes warm moist air in the garage to diffuse through the walls.

And when the warm moist air comes in contact with the cold wall sheathing, it is condensed to a liquid.

Continuous exposure of moisture to the wall sheathing leads to moisture damage. Molds and mildew will begin to form on the walls and thus reducing heat insulation efficiency.

Five Reasons To Install A Vapor Barrier In A Detached Garage

Although the vapor barrier may not be a big deal for some people, there are actually several instances that necessitate installing the vapor barrier in your detached garage.

So, let’s get into some of them.

1. Living In The Cold Climatic Areas

If you live in cold climate areas, it is worth installing vapor barriers.

Cold climate zones undergo a big temperate difference inside and outside the garage, especially during winter.

The inside air is humid and warm, while the outside air is dry and cold.

Therefore, a lot of vapor diffuses through the walls, which eventually causes moisture damage.

2. Repurposed Garage

Nowadays, a garage no longer houses vehicles alone.

Depending on your preferences, you can remodel your garage to serve other activities.

So, if you have repurposed your garage for laundry, bathroom, or kitchen, you should consider installing a vapor barrier to protect the walls and the ceilings from moisture damage.

3. Protection From Temperature Swings

It feels comfortable to work in a garage that is not frosty in the winter and very hot in the summer.

Adding insulation to your detached garage can help stabilize rapid temperature fluctuations in the building.

4. To Save Energy

Of course, an insulated garage experience minimal temperature swings.

So, if you insulate your detached garage, you will spend less on heating or cooling costs.

The inside temperature is kept at a reasonably constant range with slight loss to the surrounding.

Therefore you will spend less on energy costs.

5. To Safeguard Your Stuff From Extreme Temperature Fluctuations

Extreme cold weather can be harsh on some items and chemical-based products like paints.

If you have repurposed your garage for a temporary store, you need to insulate your garage to protect such items from the effects of temperature swings.

Insulation Types And Materials For Detached Garage

There are many insulation materials and styles available in the market for your consideration.

The level of insulation is measured in the R-value (resistance value), which measures the resistance to the conductive flow of heat in given insulation material.

A high R-value indicates better insulation.

Consider the following types of insulation for your detached garage:

1. Fiberglass roll insulation

It is made from tiny fibers of glass. Depending on its thickness, fiberglass is usually rated R-5 to R-30.

2. Mineral wool insulation

Mineral wool is similar to fiberglass, but it is stiffer. Therefore, it is usually sold on batts. Mineral wool insulation batts have ratings of R-15 to R-30.

3. Cotton Insulation Batts

They are made from recycled textiles. Although more expensive, cotton insulation batts are environmentally friendly and safe to install. Depending on the thickness, they are rated R-6.7 to R-30.

4. Loose-fill Insulation

They are famous for attic and ceiling insulation. Loose-fill is technical to install. You place bales of loose-fill materials into an insulation blower which then shreds and blow them into the wall to be Insulted. It is the best insulation for amorphous spaces.

5. Spray Foam Insulation

It is a popular choice for insulating both the interior and the exterior of a detached. Spray foam insulation is manufactured from latex and commonly from polyurethane.

6. Insulation Panels

Panels are versatile insulation types that you can virtually fit anywhere in your garage. You can use it to insulate your garage’s interior, exterior, attic, or basement. Additionally, they have a high R-value making them the best choice for insulating your detached garage.

7. Radiant Barriers

Radiant barriers prevent heat transfer through radiation. They are specifically designed to insulate cooled spaces against heat radiation from the sun.

How To Install Vapor Barrier To Your Detached Garage

So, if you’re looking for a simple way to insulate your detached garage, fiberglass batts insulation is your solution.

But before you settle on fiberglass, you should consider your climate zone, the level of skills required to install, costs, and whether you have time to get the job done.

The main aim is to prevent the warm moist air in your garage from entering the cold spaces inside the wall cavities.

The vapor will condense on cold cavities and cause deterioration of the building materials.

First, choose fiberglass batts depending on the stud size and the spacing in the garage.

The stud size determines the R-value of the insulation material. For example, it is recommended that a stud size of 2×4 walls should be insulated up to R-15.

You can then choose batts for attaching the insulation material to the joists.

You can choose faced batts or friction-fit batts. Now, cut insulation batts to fit the window spaces, outlets, and any other wall cavities you want to keep exposed.

Heat loss also occurs through the ceilings of your garage.

Since studs do not limit the ceiling, you can actually insulate it with a higher R-value insulation material than the walls.

First, cut the fiberglass batts to fit the spaces between rafters. And then push the faced batts into the ceiling space between the rafters and fasten them in place.

Another area you should insulate is your detached garage door.

Of course, the easiest way to insulate your garage door is to buy an insulated garage door.

But if you have already installed a non-insulated garage door, the best option is to retrofit the door with some insulation.

Proceed to a nearby home improvement store and buy a garage door insulation kit.

Lastly, should you install a vapor barrier on a garage floor?

Whether your detached garage flooring is concrete or wooden, there is not enough evidence to suggest that vapor diffusion occurs through the floor.

However, if for some reason you wish to install a vapor barrier on your garage floor, choose from the variety of flooring materials on the market.

Clean the floor and the perimeter walls and apply butyl tape.

Then unroll the vapor barrier sheet and trim the extra edges. Finally, apply the vapor barrier tape and fasten it to the walls.

Final Thoughts

Humid air is a significant cause of moisture damage in most garage walls.

Consequently, installing a vapor barrier in your detached garage is essential to prevent moisture damage on the walls.

Alternatively, you can consider installing a dehumidifier to augment the vapor barrier in your garage.