Cheapest Way to Insulate a Metal Building

If you want to use your metal shed as a workspace or even for sleeping, you have to insulate it. You can insulate it for very little cost with the right materials. What is the cheapest way to insulate a metal building?

Fiberglass is the cheapest way to insulate a metal building. Other insulating materials such as spray foam costs 3 times as much in many areas.

Fiberglass is not the most durable insulating material, but its price per square foot is the least expensive of all. 

There are many options you can use to insulate your metal shed. They include ISO Rigid Foam, Blown-in Cellulose, and many others. But if you consider all their costs per square foot, you will find that fiberglass is the cheapest of them all per square foot. 

Read on to learn more about the cheapest method of insulating a metal building, and tips on insulating a metal building.

Cheapest Way to Insulate a Metal Building

cheapest way to insulate a metal building

The cheapest way to insulate a metal building is by using fiberglass. Other insulating materials are also available such as spray foam. But this is 3X the price of fiberglass.

When talking about the cheapest way of insulating a metal building, you have to consider the different brands of insulating materials, the quality of these materials, and by using an average of R-13 per square foot.

R-13 is the R-Value of the insulating material. It defines the insulation level that the material can provide. This is the measure of the ability of the material to resist heat transfer. The higher the R-Value of an insulating material, the better is the thermal performance of the insulation.

If we compare all the options for insulating materials available in the market today, the cheapest of them all is fiberglass.

Consider this table, which lists all these materials from the cheapest to the most expensive:

Insulating MaterialPrice per square foot
Fiberglass batts$0.40 per sq. ft.
Blown-In Cellulose$0.45 per sq. ft.
Mineral Fiber$0.55 per sq. ft.
ISO Rigid Foam$1.20 per sq. ft.
Polyurethane Closed-Cell Spray Foam$7.50 per sq. ft.

As you can see from the table above, the price of the most expensive insulating material, spray foam, is considerably much higher than the cheapest material, fiberglass.

Why Insulate a Metal Building?

Why is there a need to insulate a metal building?

There are many reasons for doing so because the metal is an excellent conductor of temperature.

Whatever the temperature outside, be it hot or cold, metal will absorb it and transfer it indoors very efficiently. This is bad news if you want your building always to stay dry.

1. Control the Temperature Inside

A comfortable indoor temperature is essential for good health. If you want to use your metal shed as a working space or even as an extra sleeping area for your guests, making its indoor temperature comfortable is very important.

Insulating the metal structure is the most effective way to ensure its comfort level. With proper insulation coupled with good ventilation, the metal building’s indoor temperature will be very comfortable, whether it is summer or winter.

2. Prevent Condensation

In summer, an un-insulated metal building will heat up terribly during the day. At night, that huge amount of heat will try to escape as the temperature goes down. Since the building’s metal structure conducts temperature efficiently, it will allow the heat to escape outside.

However, moisture will be left behind inside the building. Thus condensation forms inside the building, particularly on the ceiling and the walls. Corrosion of the metal structure will result if this is unresolved.

If the condensates are in the ceiling, they will eventually fall to the floor. If the floor is made of wood, this will lead to rotting. Eventually, it will compromise the integrity of the whole metal structure.

3. Minimize Noise

If the working shed is made of metal, insulating it will minimize the noise you create inside. The noise you are producing while working will be deadened enough to bother your neighbors.

The insulation will also isolate you from the noise outside. If you are using your metal shed as your own little music or recording studio, you will prevent outside noise from contaminating the sounds you are recording inside. Insulating it is a straightforward soundproofing option.

Options for Insulating a Metal Building

As have been already mentioned, there are many kinds of insulating materials that you can use for metal buildings. What is the best option for your metal structure?

Here is a list of the options available, from the cheapest to the most expensive:

1. Fiberglass Batts

cheap way to insulate a metal building

These are the materials that are mostly used for insulating metal sheds and buildings. In fact, prefabricated metal sheds already come with pre-installed insulation made of fiberglass batts.

One good thing about fiberglass is that it has a good R-value, which is about R-13 for its 4-inch type, and yet it is still cheap.

There are fiberglass batts that are entirely covered by vinyl, plastic, or other composite vapor barriers. They are more expensive than those that are covered with paper. But they offer more resistance to moisture. They are easier to install and are very durable.

Fiberglass batts are available in rolls. Whether plastic, vinyl, or paper, the faced part of the rolls is ideal for metal sheds. The faced part ensures that no moisture from outside the structure will penetrate the fiberglass and affect its R-value. Its average cost is only $0.40 per square foot.

2. Blown-In Cellulose

This insulating material is typically made of sawdust, old newspapers, and other waste paper products. These materials are combined and infused with fire-retardant chemicals. Its R-value is higher than that of fiberglass batts but is similar to Mineral Wood.

Blown-in cellulose is basically made of paper; therefore, it is not fire-resistant. Since it is made of paper, it does not fare well with moisture. They are not very resistant to mold and moisture, and the R-value is not that high.

Before you can install blown-in cellulose in a wall or a ceiling, you must first affix a moisture barrier to the surface where it can be attached to.

There must also be a vapor barrier with an opening or sheathing on the ceiling that will enable you to fill it with cellulose. The average cost of blown-in cellulose is $0.45 per sq. ft.

3. Mineral Wood (Fiber)

A cheap way to insulate a metal building is by using mineral wood. They also come in batts of 4 inches and 6 inches wall stud applications. These insulating materials have high moisture resistance but will shrink and lose their R-value if they directly contact moisture.

They are made with different ingredients, including crushed stone. These components make them easier to handle than fiberglass. Being made of molten rock, they are completely fireproof.

They are supplied in foil-faced packages, which is ideal for metal building use. But being more rigid compared to fiberglass, installing them is more difficult. They can be installed in metal sheds that don’t have studs, but it will be more difficult. The average cost of Mineral fiber is $0.55 per sq. feet.

4. Rigid Foam Boards

An inexpensive way to insulate a metal building is to use rigid foam boards. If your metal shed has flat inner walls and surfaces, this material can be used. However, you can’t use it on curved walls and ceilings because they are flat-shaped.

Rigid foam boards are ideal for metal structures that have no studs. If you have a prefabricated metal shed, you can use this insulating material. They can be cut to size so they will fit the height of the structure. These boards can be taped one on top of the other to cover a wall.

They are best in covering the floor of a metal structure. The foam can rest between the wood joists. If the floor is made of metal, the foam can be placed below the entire shed.

Rigid foam boards are highly resistant to moisture, making them ideal for insulating shed floors. Their average cost is $1.20 per sq. ft.

5. Spray Foam

The advantage of spray foam over the others is that its moisture blocking capacity is higher, and its R-value rating per inch is very high. Spray foams can completely seal your metal building’s inner surfaces from the moisture and thermal conduction outside.

Its high resistance to thermal conduction makes it effective in keeping heat inside the room during the winter. When using spray foam, it is important to keep your shed properly ventilated.

The ventilation will remove excess moisture and keep the spray foam from getting condensed on the ceiling and the walls.

You can buy kits of spray foam, but they are costly. If you want to economize, you can DIY by buying it in cans and spraying it directly onto the walls and ceilings in 1-inch layers. The average cost of spray foam is $7.50 per sq. ft.

Tips on Choosing the Right Insulation

Aside from the cost and the insulating material’s quality, it would help if you also considered the ease or difficulty of its installation.

While there is no clear method of determining whether this material is easier to install than the other, it is safe to assume that the more rigid the material is, the easier it is to install.

Considering their installation mode, the insulating materials can be ranked from the most difficult to the easiest in the following manner:

1. Blown-In Cellulose

inexpensive way to insulate a metal building

While loose cellulose is easy to apply, you need first to install a barrier to ensure that the loose-fill will not spill onto the floor of your metal shed.

2. Mineral Fiber or Wood

This insulating material is installed between studs. Without any studs in your structure, the installation of this material will be difficult.

3. Fiberglass Batts

Whether you use faced or unfaced batts, they should be installed between the studs. As with mineral wood, if there are no studs, they will be difficult to install. You will need fasteners to attach them to the ceiling and walls.

4. Closed-Cell Spray Foam

While installing this material is labor-intensive, you can apply it quickly and easily once you start. But it would be best if you had special safety gear like a mask and a suit.

5. ISO Rigid Foam

It is straightforward to cut the rigid foam into the required sizes. It only gets difficult when you are installing it in a tight fit.

How to Insulate a Metal Building Using Foam Spray?

The typical process of insulating a metal building is not that difficult. It is the same process used whether you are using the cheapest or the most expensive insulating material. But there is one thing that you can’t change: it takes time to insulate a metal building.

If you are using foam spray as your insulating material, you will need to follow this process:

  1. Measure the floor area, the walls, and the ceiling of the metal building;
  2. Remove all wall sheathing, if required;
  3. Use closed-cell spray foam to coat the walls with a 2-inch layer;
  4. Allow the insulating material to dry between layers;
  5. Apply closed-cell spray foam to the ceiling in the same way as steps 3 and 4;
  6. Allow the foam to dry;
  7. Remove the floor and replace it with rigid foam panels between joists;
  8. Another option is to lift the structure to install the rigid foam panels underneath the floor; and
  9. Re-install the flooring and wall sheathing if they were removed before the installation of the insulating material.

Conclusion: Cheapest Way to Insulate a Metal Building

Fiberglass is the cheapest material you can use to insulate a metal building. There are other insulating materials, such as spray foam, that costs 3 times as much.

While fiberglass is not the most durable, it is a good option for insulating metal structures because its price per square foot is low. 

Other materials you can use include mineral wood, ISO rigid foam, blown-in cellulose, among others.