Do You Need Insulation in a Shed?

Even a large property can feel small if you don’t have enough storage space. That’s why I constructed a 10- by 12-ft. shed with a loft some years ago.

Although I intended to fill the bays with insulation, I never got around to it. As it turns out, it hasn’t mattered much. And we ended up not actually storing things there! Instead, we use the shed as a workshop and living space. In California’s moderate climate, it never feels too cold in winter as long as there’s a heater on.

Bottom line: Insulation in a shed is optional. The decision to add it depends on your climate, the type of shed and how you use it. Keep in mind sheds often end up serving purposes that were unforeseen when built.

Consider these factors when deciding if you should insulate a shed.

Climate

If you live in a cold or wet climate, your shed will be more versatile if you insulate it. Insulation keeps the interior warm and dry, making it more comfortable for people and safer for garden equipment and valuables you store there.

If your winters are cold, insulate the shed right away. Adding insulation during construction is a lot easier than doing it later. The climate-controlled space will lower your heating bills and protect electrical wires and fixtures from corrosion.

If you live in a wet climate and plan to store lawnmowers, snowblowers and other gasoline-powered equipment in the shed, insulation will control moisture that can rust metal and contaminate gasoline. But it isn’t absolutely necessary.

If you’re diligent about emptying the gas tanks or adding stabilizer to the fuel, and you condition your shovels, saw blades and other hand tools regularly, they’ll do fine in an uninsulated shed. It’s more important to make sure the shed is well sealed and keeps out rain.

What Will Be Stored There?

Insulation is more important if you plan to store furniture, documents or other valuables vulnerable to moisture. Without insulation, wood furniture will warp in no time, metal will tarnish and documents will turn soggy and moldy. If these items are important enough to store, they should be in an insulated space that’s easier to keep dry.

Note that rodents and other pests are another concern. But by itself, fiberglass insulation won’t do much to control them. If you leave the insulation uncovered, you’re just inviting mice and cockroaches to make nests in it, and you may end up with more of them than if you didn’t insulate.

Cover fiberglass insulation with drywall to have a fighting chance against an infestation.

How the Shed Will Be Used

Insulation also provides soundproofing, a bonus for blocking out noise in your neighborhood for a quiet space. Another consideration: Controlling the noise from power tools if you use your shed as a workshop. An insulated shed may keep those activities from bothering your neighbors.

How to Insulate a Shed

The most efficient method depends on the shed’s construction. If it’s built with 2×4 framing, Kraft paper-faced fiberglass batts provide the easiest and cheapest method. Sized to fit standard framing spacing, you install them by simply stapling the paper to the stud faces.

The main drawback of fiberglass is that it attracts rodents. So if your shed, like ours, is in the middle of the forest, you might want to consider rigid foam sheets instead. They’re easy to cut to fit inside the framing bays. You can stick them to the walls with construction adhesive, and they don’t provide raw material for nests.

You can also use rigid foam sheets to insulate a shed with non-standard framing, like a store-bought model with 2x3s instead of 2x4s. (Note that some prefab steel or plastic sheds can’t be insulated.)

In a pinch, you could also use rigid sheets to insulate a steel or plastic prefab shed. But you’ll probably have a hard time covering the gaps along the seams where the walls and roof are bolted together.

If the shed is a permanent addition to your yard and you don’t intend to move it, you can cover these gaps with spray foam. It won’t look great. But the shed will be warmer in the winter and cooler in the summer because the insulation will deflect the heat that radiates through the walls.