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11 Minute Read

How to Insulate a Metal Shed & What Insulation Material to Use

Learn the essential steps and best materials for insulating your metal shed, turning it into a comfortable, energy-efficient space for all seasons.

A smaller sized shed from Alan's Factor Outlet

Insulating your metal shed transforms it from a simple storage space into a comfortable, year-round, usable area. Proper insulation regulates the internal temperature, prevents condensation—which can lead to rust and damage—and reduces heating or cooling costs. 

This guide will help you understand the different insulation materials you can use, including Double Bubble, Woven R17, foam spray, fiberglass, and foam boards. You’ll learn the advantages, disadvantages, and costs of each. By the end, you’ll know precisely how to choose and install the right insulation for your shed’s needs.

Why Insulate Your Metal Shed? 

A few reasons to insulate your metal shed are to regulate its temperature, prevent condensation, and save on energy costs.

Regulate temperature: The temperature in a metal shed can change drastically. In the summer, it can be like an oven, and in the winter, it can be like an ice box. While the temperature does change in a metal shed, with insulation, the temperature change is less extreme.

Prevent condensation: Insulation helps prevent condensation, a common issue in metal sheds. In more humid weather, condensation can occur, leading to metal rusting and structural damage. Insulation acts as a barrier in your shed, keeping the internal temperature consistent and reducing humidity. 

Save on energy costs: Because insulation reduces extreme temperatures, it costs less to cool or heat your shed, saving you money.

Types of Insulation Materials

The different types of metal shed insulation are Double Bubble, Woven R17, foam spray, fiberglass, and foam boards. At Alan’s Factory Outlet, we recommend Double Bubble and Woven R17 because of its price and overall quality. However, spray foam may be a wise choice if your shed is rounded or has areas that are challenging to reach.

Insulation R-value

One insulation feature you’ll learn about below is the R-value. The R-value measures insulation’s ability to resist heat and cold airflow. For metal sheds, a higher R-value means better insulation against temperature changes. This consideration is essential because the higher the R-value, the more comfortable and energy-efficient your shed will be. 

Let’s discuss each insulation more in-depth.

Double Bubble Insulation (Reflective Radiant Barrier)

Double Bubble insulation in a building purchased from Alan’s Factory Outlet
Double Bubble insulation in a building purchased from Alan’s Factory Outlet

Description: A reflective radiant barrier, such as Double Bubble, has a silver backing that goes against the wall of the shed. The other side of the insulation, the side you see, is white.

Advantages: Double Bubble insulation primarily controls moisture. The insulation prevents condensation from forming inside the shed.

Disadvantages: The Double Bubble R-value is 1, which is very low and will do little to protect the shed from temperature changes.

Cost: Around $1.50 per square foot. To fully insulate the roof and sides of a 12 x 20 shed, Double Bubble will cost around $1,356.

Woven R17 Insulation

Woven R17 insulation in a larger shed purchased from Alan’s Factory Outlet.
Woven R17 insulation in a larger shed purchased from Alan’s Factory Outlet.

Description: Woven R17 is made from a combination of foil, bubble material, and woven material. The insulation color inside the shed is typically white.

Advantages: Woven R17 has an R-value of 17, which means it’s very good at regulating temperature changes. Similar to Double Bubble, it will also prevent moisture buildup inside the shed.

Disadvantages: The main disadvantage of Woven R17 is its cost. It’s typically twice as expensive as Double Bubble and two to four times as expensive as fiberglass batt.

Cost: Around $3 per square foot. To fully insulate the roof and sides of a 12 x 20 shed, Woven R17 will cost around $2,712.

In this video, you can see an example of Woven R17 insulation:

Fiberglass Batt Insulation

Example of a fiberglass batt
Example of a fiberglass batt | Source

Description: Fiberglass batt is made of tightly woven glass fibers formed into blanket-like sheets. A batt is an insulation cut into pieces, whereas a roll isn’t pre-cut. Fiberglass batt is designed to fit between the studs of a shed’s roof and walls. The insulation works by trapping air in its fibers, slowing heat transfer. The R-value for fiberglass batt insulation is around 3 to 4.

Advantages: Fiberglass batt insulation is inexpensive and is typically the cheapest installation for a large metal shed. You can often buy this insulation at your local hardware store.

Disadvantages: When installing, you must ensure you fill every opening thoroughly. Any opening can lead to a drastic reduction in temperature efficiency. Fiberglass batt is more challenging to install in metal sheds than wood sheds because of the larger surface area between frames.

Cost: $.88 to $1.64 per square foot 

Spray Foam Insulation

Foam spray added to a building purchased from Alan’s Factory Outlet.
Foam spray added to a building purchased from Alan’s Factory Outlet.

Description: Spray foam is an insulation material that is applied as a liquid, then it expands to fill gaps and cracks. This insulation comes in open cell or closed cell. The closed cell insulation is significantly more expensive because it is water resistant, and you can apply it in places with likely water contact. The R-value for open cell is 3.8. For closed cell, the R-value is 7.

Advantages: Spray foam is an excellent option if your shed has tight spaces or an odd shape. The spray foam will cover every nook and cranny in your shed. Additionally, this insulation can be applied at almost any thickness.

Disadvantages: We don’t recommend open cell spray foam for sheds in hot or humid climates. This recommendation is because foam spray can allow moisture from inside the building to pass through and contact the metal walls, causing corrosion. Closed cell is typically the most expensive insulation option.

Cost: $2.70 to $7.20 per square foot

In this video, you can see a customer who added spray foam to their metal building:

Foam Board Insulation

Example of foam board insulation
Example of foam board insulation | Source

Description: Foam board insulation is a rigid panel. These panels are cut and installed on a shed’s walls, roof, or floor. R-values depend on the thickness of the board and can range from R-2 to R-20 for very thick, 3-inch panels.

Advantages: Foam boards are lightweight and generally easy to install. The boards are also durable and long-lasting, requiring minimal maintenance.

Disadvantages: The main disadvantage of a foam board insulation is that it isn’t compatible with certain types of sheds, such as the curved walls in a rounded shed.

Cost: $.50 to $3 per square foot—can be more expensive for higher density 

What’s the Best Insulation for a Metal Shed?

At Alan’s, we recommend Woven R17 as the best insulation option for a metal shed. While more expensive than Double Bubble and Fiberglass, the high R-value provides the shed with better temperature control and a more comfortable environment.

If you have a shed that is an odd shape or has difficult-to-reach areas, we recommend spray foam. Alan’s Factory Outlet doesn’t sell sheds with spray foam as an insulation option, so you will need to apply it yourself or hire someone to do so.

Tip: Don’t Use Loose-fill Insulation For Your Shed

Loose-fill insulation is made up of loose debris that fills the empty spaces in your wall. It usually consists of newspaper, fiberglass, or rock wool. This type of insulation is designed for attics and basements, not sheds.

How to Insulate Your Metal Shed in 4 Steps

Here’s a step-by-step guide to properly insulate your metal shed’s walls, roof, and floor.

1. Prepare the metal shed

Before beginning the insulation process, you should clean the interior completely. Remove dust, debris, or existing materials. When installing the insulation,it should have a clean and smooth interior.

While cleaning, also check for any damages to your metal shed that may need a repair. Check the shed for any moisture issues like leaks or condensation. Moisture can cause damage to the insulation and potentially the shed’s structure. 

Next, you should seal any gaps and cracks. Use caulking, foam sealant, or insulation tape to seal these areas. Any areas where air can leak in or out of your shed will make the insulation less effective.

If you’re using a do-it-yourself spray foam insulation kit, prepare the shed using tape and pieces of plastic to mark off any areas you don’t want the foam to get on. 

Once you clean and inspect the shed, gather the proper tools and materials. Depending on your type of insulation, you may need the following:

  • Insulation 
  • Tape measure
  • Utility knife
  • Stapler or adhesive
  • Plastic sheets
  • Safety gear such as gloves, mask, and goggles

2. Measure and cut insulation

Measuring the insulation should be easy for you to do. One cutting tip is to ensure you account for any obstacles to the insulation, such as an electrical outlet.

If you’re installing fiberglass batt, cut about an extra inch thick so the pieces fit snugly into place and keep the insulation effective.

If installing a foam board, consider using a straight hedge with the knife for a cleaner cut.

To cut the insulation, use a utility knife or insulation cutter. Ensure the blade is sharp; this will ensure that the cutting goes smoothly and quickly. 

An organization tip to save you a potential headache is to label each piece’s location after you cut it. That way, once you finish the cutting, you won’t get pieces mixed up. You’ll know exactly where each piece should fit.

3. Install and seal the insulation

Here are a few installation tips for different types of insulation:

Reflective barrier: Ensure you orient the reflective barrier insulation with the shiny side facing the shed interior. You will typically fasten the reflective insulation to the framing studs. You also should leave an air gap of at least an inch between the shed and the insulation.

Fiberglass batt: It’s important to wear safety gear when installing fiberglass batt, including long sleeves, gloves, eye protection, and a mask. If you don’t, the fiberglass particles can cause severe irritation. When installing fiberglass batts, make sure not to press too hard on the insulation, which can compress the fibers and make them less effective.

Spray foam: Often, spray foam is applied by a professional, however, if you’re using a do-it-yourself kit, ensure your shed is well-ventilated. It’s best to start with the outer edges and work your way towards the middle. The foam will expand to fill all nooks and crannies in the shed.

Foam board: When installing foam boards, use either special insulation adhesive or mechanical fasteners such as nails or screws. To seal the foam boards effectively, tape all joints between boards to create a continuous thermal barrier. 

4. Inspect your insulation and adjust

After installing your insulation, one step you should take, no matter your type of insulation, is to check for any air leaks. On a windy day, hold your hand around the shed to check for any air coming into the shed or any areas that may be more cold or hot. You could also use a smoke pencil or incense stick to track where the smoke moves within the shed.

Here are a few post-installation tips depending on your insulation:

Fiberglass batt: Gently press on the fiberglass in different spots to ensure it’s not overly compressed. The batt should spring back to its original thickness.

Spray foam: After around 24 hours of application, remove excess foam.

Foam board: Check that all nails and screws you used to install the boards are secured and haven’t punctured the shed. Punctures could create holes where hot or cold air could enter the shed.

Common Shed Insulation Mistakes to Avoid

Common mistakes to avoid when installing insulation include: 

  • Ignoring air leaks
  • Compressing fiberglass insulation
  • Choosing incorrect insulation

Ignoring Air Leaks

Air leaks will cause warm and cold air to sneak into your shed, making it difficult to heat your shed or cool it. It’s important when preparing your shed to ensure that you seal it properly. After you install the insulation, you always want to check to ensure you fully seal the insulation. 

Compressing Fiberglass Insulation

While it may seem like a good idea to compress the fiberglass insulation against the wall of your shed, you are likely making it less effective. Fiberglass insulation is designed to trap pockets of air. These pockets create a barrier that resists the passage of heat. If it’s compressed, fewer pockets are available to resist heat and cold flow.

Choosing Incorrect Insulation

If you live in a humid or an extreme weather environment, ensure you choose the insulation right for you. If you live in a humid area, you will need insulation that keeps moisture from reaching your shed, such as Double Bubble or Woven R17. 

If you live in an extreme weather environment, while more expensive, consider purchasing insulation with a higher r-value to protect your items and make the shed more comfortable to work in. 


You are now ready to insulate your metal shed! You know about different types of insulations, their advantages and disadvantages, and their costs. You’re also equipped with the steps to make your shed a comfortable and energy-efficient space for years to come.

Profile picture of Alan Bernau Jr

Alan Bernau Jr

Alan Bernau Jr. is the founder and owner of Alan’s Factory Outlet. He has helped more than 75,000 homeowners design and install custom carports and garages over the last 20 years.

Alan Bernau Jr. is the founder and owner of Alan’s Factory Outlet. He has helped more than 75,000 homeowners design and install custom carports and garages over the last 20 years.

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