11 Cheap Ways To Insulate A Shed (Money Saving Options)

Photo: Brett and Sue Coulstock / Flickr / CC BY 2.0

Many people already spend a lot of time in their outdoor sheds.

Perhaps you have a hobby that needs a separate working area, or you might use it as a home office. Moreover, you might use the space as a home gym or playroom to get the kids out of the house.

Alternatively, electronic equipment doesn’t store well in temperature extremes, and you might need somewhere to keep a range of appliances.

Finally, many people who don’t have much indoor space use a shed to keep an additional food freezer or beer chiller. But, these won’t operate well during a hot summer. 

Whatever your shed’s purpose, insulating it to prevent temperature extremes is a good plan to get more use out of your outbuildings. But, how do we go about insulating a shed, so it’s affordable and safe?

This guide will steer you through the reasons for insulating, the best materials to use, which are the cheapest, and the factors affecting shed insulation.

Why Insulate A Shed?

Lining your shed gives many benefits that aren’t always obvious. 

Insulating allows the space to be more comfortable during hot summers and cold winters. The additional layers between the warm and cold sides prevent drafts, but you should seal gaps before installing the insulation.

Furthermore, the task doesn’t take long, usually less than a day. And the low-cost (often free) materials mean you can line the shed without worrying about the price. 

If you want the best materials to insulate your shed but can’t afford them, temporarily use the free materials listed here while saving up the required funds.

This is especially important if your shed is made from iron or aluminum, as metal conducts heat faster than any other material, so it needs good quality insulation.

However, most insulation needs studs for fixing in your shed, which adds to the overall price. Therefore, choosing a cheap way to insulate a metal shed is even more critical than a wooden one with studs. 


Cheapest Ways To Insulate Your Shed

Before going any further, let’s consider where the building loses its heat.

Hot air rises, so most warmth within your shed disappears through the roof. Next, the walls lose a lot of heat because of their large surface area. So, it’s these two areas that need the most insulation.

Finally, although the floor doesn’t lose much heat compared to the other outdoor surfaces, your feet are always in direct contact with the floor. This situation means you lose body heat, making your feet cold. So, insulate this too.

Let’s look at the various inexpensive methods to reduce heat loss from your shed during winter and increase cooling effects during the summer.

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Remember, not every material is suitable for long-term use, especially those that might decompose, absorb moisture or burn.

1. Rugs And Carpets

Let’s begin with the floor. Heat loss through the floor is minimal unless you’re in direct contact. Then, your feet feel cold through conduction.

The easiest and cheapest way to prevent heat loss here is by using an old rug or carpet. You might already have an offcut from your new living room carpet.

Alternatively, keep an eye on social media or garage sales for unwanted rugs. Some carpet stores have discounted clearance sales, too, if you can’t get carpet anywhere else.

Another affordable method is to ask carpet stores for discontinued carpet samples. Unfortunately, the colors and textures won’t be consistent, but you’ll stay warm for a small outlay.

Furthermore, if you can place some underlay beneath the carpet, then all the better. But first, lay a waterproof membrane onto the shed floor to protect the rug from dampness and rot. 

2. Straw And Hay

Some farm buildings and old rural cottages use bunches of straw called “thatch” as a roofing material. It’s fixed outside the roof structure for waterproofing and heat insulation.

Furthermore, many farm outbuildings also use straw bales as wall insulation for their livestock. If your shed is large enough, use straw or hay bales as an insulating material.

However, there are two main reasons not to do so.

  1. Dry straw is flammable. So, don’t use it if there’s a chance of fire. Surprisingly, this also applies to damp straws. Organic materials rot very quickly and turn into compost. And as every gardener knows, composting vegetation gets hot enough to smolder, which is also a fire hazard.
  2. Dry straw is an inviting nesting material for bugs and rodents. Therefore, be aware of what might be living in your shed.

3. Fiberglass And Mineral Wool Slab

This is probably the most affordable material for your shed. Most store-bought sheds incorporate frames made with 1-2 inch wide lengths of wood.

Furthermore, the structure is usually a regular distance apart, making it easy to friction-fit (pushed between the vertical frame to fit its width) insulation slabs between them.

However, this method needs ventilation between the slabs and the outside wall. So, install a breather membrane, used in constructing timber-frame buildings, followed by the insulation slabs.

Finally, hide the insulation with plywood to prevent dust. Mineral wool also comes in rolls and is available in different lengths and thicknesses.

4. Foam Board

Another low-cost insulation material is foam board. The foam can be various types of material, but the most popular are polyurethane or polystyrene.

These foams are lightweight and easily cut to size, after which friction-fit rigid slabs between the frames. Alternatively, cut and staple a roll into place. Cut both types using a utility knife. 

Some rigid foam boards have a foil backing to add to the insulation properties. Also, some have foil on both faces with the foam sandwiched between them. However, foil-faced boards are more expensive than others.

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Once again, fit a vapor barrier first, then install the foam, followed by plywood or drywall covering.

5. Spray Foam

Spray foam is applied from a spray gun as a liquid and allowed to expand and set into a solid form.

This foam is usually polyurethane and will adhere to any surface. However, if you choose this method, ensure plenty of ventilation as the fumes are toxic if inhaled.

You can buy spray foam in two general types:

  1. Open-cell foam is the less expensive of the two. But, it doesn’t provide as much heat insulation.
  2. Closed-cell foam is more expensive. But, it’s much more effective as insulation.

Once you’ve applied the foam, cover it with plywood or drywall as protection.

6. Draftproof Doors And Windows

There’s no point insulating the shed if you’ve gaps around doors and windows, allowing the cold air to enter. Therefore, seal all holes and cracks first and ensure the windows and doors fit properly.

If possible, replace single-glazed windows with double-glazed for extra warmth. However, if you can’t afford double-glazing, use shrink-to-fit plastic wrap over the window glass.

It’s a simple job, with plenty of YouTube instructional videos available. Here’s one of them:

 

7. Bubble Wrap

Bubble wrap is gas bubbles trapped between two layers of flexible plastic. It’s mainly a packaging material, preventing damage to goods in transit. But, it can also be used as an insulation material.

Many people save Amazon packaging bubble wrap, thereby recycling an insulation material that costs nothing. However, if this isn’t feasible, buy rolls of bubble wrap online or at DIY stores.

Furthermore, foil-lined bubble wrap is available but is more expensive. Bubble wrap is easily cut to size using a utility knife and should then be stapled into position. Once in place, cover with plywood or drywall as protection. 

Bubble wrap may be cheap but doesn’t last long and needs regular replacement.


Can You Insulate A Shed For Free?

We’ve already mentioned saving bubble-wrap packaging from your Amazon deliveries, but this isn’t the only available free insulation.

The following are just a few:

8. Used Cardboard

Yet another material supplied by Amazon and other online retailers is the cardboard box.

Corrugated cardboard is a good insulator; you can use multiple sheets between the shed’s wall and ceiling studs. But, use aluminum tape to seal the edges to prevent dampness from entering the corrugations.

9. Polystyrene (Styrofoam)

Like bubble wrap, companies use styrofoam as packaging.

Save up enough pieces and stick them to the shed wall with adhesive. But remember to use glue suitable for polystyrene. Otherwise, the foam will melt.

Styrofoam is easy to cut using a utility knife. But it’s flammable and gives off toxic smoke when burned, so take care.

10. Fabric

Textiles such as old curtains, unusable clothes, cotton waste, old rugs, and carpet pieces keep the cold out. So, if you have nothing else, these items will help keep your shed warm.

However, old fabric is usually flammable and makes a great nesting place for pests. So, ensure it’s clean and properly treated first.

11. Egg Boxes And Trays

You buy eggs from the grocery store or farm in plastic or cardboard boxes or trays with egg shape indentations. Believe it or not, egg boxes make excellent free insulation when fixed to a wall because of the trapped air pockets.

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So, hoard your egg boxes and ask friends and family to do the same. Then, you’ll have enough to line your shed against the winter cold before long.


Factors Affecting Shed Insulation

Photo: Nevada Department of Agriculture / Flickr / CC BY NC 2.0

Several factors affect the insulation used when protecting against extreme temperatures. 

R-Value

All materials have an R-Value, which measures the material’s ability to resist heat flow.

In other words, it indicates how good your insulation is, and a substance with a high R-Value is a good insulator. Therefore, a high R-Value material needs less thickness to perform as well as a low R-Value. 

Various insulators have different R-Values, which must match your region’s climate (we’ll discuss this later). If you want to calculate R-Value for your circumstances, read this guide before having a go.

Insulation Quality

Some insulation is good, while other types are not. All purchased insulation has been certified by an independent certification body recognized by the US Environmental Protection Agency (EPA).

The Energy Star certification ensures the insulation performs as expected while meeting stringent safety standards. 

Climate

You must understand your climate before choosing a suitable insulator. Therefore, before deciding on the insulation’s type and thickness, look on this map to see where you live and what the necessary R-Value for your region should be.

Insulation Thickness

It goes without saying that thick insulation keeps you warmer than thin insulation. However, there is a maximum thickness when the heat transfer is minimal, and it won’t improve anymore.

The R-Value determines the maximum thickness, which we’ve discussed elsewhere. Generally, store-bought foam boards, fiberglass rolls, and slabs come in various thicknesses and R-Values to suit your circumstances.

Different Parts Of The Shed

As previously discussed, sheds lose most heat through the roof and walls, with the floor losing the least. Therefore, using an old carpet on the floor is okay while using store-bought insulation on the other parts.

Also, don’t forget to insulate the door.


Summary

If you intend to spend a lot of time in the shed, using it as a playroom, hobby room, or home office, it makes sense to insulate it so that you can use the building in the depths of winter and on sweltering days in the summer.

Many types of insulation are available, each with its R-Value for a specific thickness. And you must match the required R-Value necessary for your climate region with that of the insulation. 

You might want to hire a handyman or contractor to insulate the shed. But, the job is simple enough for anyone with basic DIY skills. Thus, saving a lot of money.