We Brits love our garden sheds. These outbuildings have grown from a simple storage to a home addition, often used as an office, granny annexe, or workshop.
However, using one year-round can be a challenge when the cold winter weather rolls in. The solution involves insulation, but many homeowners baulk at spending large sums of money on their shed.
But never fear, you can do it for free. All it takes is a bit of hard work, a few everyday materials, and ingenuity.
Key Insulation Points In A Shed
Before attempting to insulate the shed, you should understand where you need to insulate.
Floor
Floors, especially those of sheds without a concrete foundation, are prone to heat loss. You’ll want to plan on adding at least one layer of insulation to this area.
Walls
Wind and rain love coming in through the walls of a garden shed. When it comes to keeping the shed warm, having several layers of insulation in the walls is a must.
Ceiling
Heat rises, and naturally, an uninsulated ceiling will have plenty of heat escaping. Insulating the roof or ceiling is essential to keeping your garden shed warm throughout the year.
Critical Steps For Successful Insulation
Before insulating your shed, follow these steps to ensure a working (and warm) layer of insulation:
- Locate gaps in the wall. The crevices and cracks of the shed may have areas of poor sealing. Take a feather or a strip of paper on a windy day, hold it near the walls, and see if there’s a gust that moves it.
- Check for moisture problems. Most free or inexpensive insulation sources aren’t waterproof. Ensure that any leaking areas have a layer of plastic or waterproofing before adding insulation.
- Verify measurements. Insulation reduces the height and width of the shed. If you plan to add several layers of insulation to your annexe, ensure that you know your desired depth and how it will impact your shed’s measurements. Adjust your insulation amounts accordingly. For example, you may need to reduce your insulation if the ceiling threshold drastically reduces.
- Gather safety supplies. Whenever you work with insulation, nails, tools, or other handiwork equipment, wear a pair of safety glasses, a filtering mask, and work gloves to protect yourself from chemicals and debris stirred up during the project.
- Some of these insulation materials are even more flammable than the wood that sheds are made from. Think about that before you go and use a welding torch in your insulated workshop.
Once you have adequately prepared yourself for the installation, you can begin looking for the proper materials to insulate your shed.
Recycled Insulation Products
Styrofoam – walls and ceiling
Styrofoam is one of the best products to use for inexpensive insulation. You’ll often find it used to keep refrigerated materials or packages cold, but it works just as well for keeping an outdoor shed warm.
Reuse the styrofoam received in shipping materials to help insulate the shed. Simply apply sheets of foam to the walls of the shed using glue or tape for application and a utility knife to achieve the desired size for the wall or ceiling in question.
How much difference does styrofoam make?
Reused Styrofoam packaging can provide light insulation and some thermal resistance, but it is far less effective than purpose-made insulation boards. Thin packaging pieces offer only modest improvement.
You may notice the shed warms slightly faster when using a heater, yet it will still cool quickly once the heat source stops.
Cardboard – walls and ceiling
Those old shipping boxes bunched up in the shed can do more than take up storage space. Cardboard has poor thermal conductivity, making it ideal for inexpensive insulation.
Simply flatten the boxes to create cardboard sheets, and carefully stack them together into a thick layer of insulation. Slide the cardboard sheets between the walls or roof of the shed if accessible; if not, fix the sheets to the interior walls of the shed using glue or tape.
Cardboard is prone to water damage; therefore, waterproofing the walls first is a must.
Cardboard is also a highly attractive nesting material for mice and insects. If you use cardboard, lightly dust it with boric acid powder to deter pests.
What to expect from cardboard insulation?
Cardboard has very little insulation value compared with proper construction materials. Its main benefit comes from adding extra layers that slow airflow inside the wall space. In a dry shed, it can help reduce drafts and take the edge off temperature swings, but it shouldn’t be treated as a main insulation solution.
Bubble wrap – walls or ceiling
Bubble wrap works wonderfully as an inexpensive, temporary insulation source for a shed. The air bubbles do lose volume over time, so you’ll need to replace them every few months or so.
But, applying bubble wrap as an insulator takes only a few hours – just slide the wrap between the walls of the shed into a dense layer of overlapping wrap. For the ceiling, use double-sided tape or glue to adhere the bubble wrap to the surface.
What can bubble wrap do?
Bubble wrap can work as a temporary insulating layer and basic draught barrier. It can help cut some heat loss through thin shed panels and glazing. The difference is small, and you’ll notice it more when the shed is already being heated.
Plastic (stretch wrap) – windows
If windows make waterproofing the shed difficult, go to the kitchen and grab the plastic stretch wrap. Apply a layer or two of the plastic to cover the windows. This helps keep water and cold air out of the cracks in the window.
What stretch wraps help with?
Plastic film over windows won’t keep the shed warm on its own, but it stops cold air coming in through small gaps. It works as a simple secondary glazing, cutting drafts around window frames and helping the shed hold a little more heat when it’s already heated.
Rugs and blankets – floors
The floors of a shed can be quickly insulated with the addition of a rug or blanket. Consider lining the floor with plastic before placing the rug down to help prevent water damage.
What’s effect of rugs and blankets on floors?
Rugs and blankets make the floor feel warmer underfoot but don’t insulate the whole shed. They can cut some of the cold coming through timber floors and slow a little heat loss, but they won’t raise the overall air temperature much.
All Natural Insulation Products
Nature enthusiasts and all-natural product users can insulate their shed with products found on the farm or in the countryside:
Thatching – roof and walls
The English countryside is famous for its picturesque thatched cottages, which boast fantastic natural insulation. But there is a crucial secret to how they do it: they never use hay! Agricultural hay is full of nutritious seeds, making it an all-you-can-eat buffet for mice and rats. Instead, true thatching uses water reed or specially threshed straw with all the grain completely removed.
If you can get your hands on proper, dry, seedless straw, you can bundle it tightly and pack it between your shed’s wall framing. Because it is an organic material, you must ensure your shed’s exterior is completely watertight to prevent rot and mould. To keep it secure and pest-free, staple a layer of fine galvanised wire mesh over the wall cavities before putting up your interior boarding.
What happens when you use thatch as an insulating material?
When packed very densely, proper threshed straw or water reed provides excellent, breathable insulation that traps heat beautifully. However, if you simply stuff loose, regular hay into your walls, it will add very little warmth and instead create a luxury nesting hotel for local pests.
Wool – ceiling and walls
Sheep stay comfortable no matter the season thanks to their wool. If you have access to sheep’s wool, you can line the ceiling and walls of the shed with the material. Just stuff the wool into the walls, or gather it into bundles and tape them to the ceiling for additional warmth in the shed.
Commercial sheep’s wool insulation is treated with borax to repel insects and prevent mold. Don’t just get some from the local farm. It must also be thoroughly cleaned and kept bone-dry.
What to expect from wool insulation?
Sheep’s wool insulates effectively when packed densely between framing. Loose wool bundles stuck to surfaces will still add some warmth, but the effect is much smaller than properly fitted wool batts.
Inexpensive Insulation Upgrades
If you can spend a few pounds to upgrade your insulation, there are a few items that would significantly improve the use of the above mentioned free insulation materials. These insulation upgrades work well on their own, too.
Note: These inexpensive upgrades can make a noticeable difference, mostly by sealing gaps, reducing drafts, and adding extra layers of insulation. They won’t turn a standard shed into a fully insulated building, though.
Caulk and liquid weatherstripping
Caulk or liquid weatherstripping is the perfect inexpensive solution to close up the tiny gaps in your shed walls that allow water and cold wind into the space. Before adding any internal insulation, use a caulking gun to run a bead of acrylic or silicone sealant along the joints where the timber wall panels meet, as well as along the floorline. Additionally, you should apply it around the exterior and interior of your window and door frames to stop driving rain and drafts from entering those vulnerable areas.
Caulk won’t provide thermal insulation to the wooden panels themselves, but it is arguably the most cost-effective first step you can take. By eliminating the biting drafts and sealing out moisture, it drastically improves the effectiveness of whatever insulation material you choose to install over it.
Hardening foam
Hardening foam is an expanding sealant that works exceptionally well for sealing windows, door frames, and cracks. The foam hardens into a waterproof layer, and most variations are UV-resistant as well. Simply spray the foam on the targeted area and let it harden before adding additional insulation.
Reflective insulation
Reflective insulation serves as a radiant barrier and a vapour barrier in one product. It can easily slide between the walls of the shed and work with additional insulation to keep the space cool in the summer and warm during the winter. You can also staple or tape it to the ceiling for additional protection against temperature variation.
Fiberglass insulation
Rolls of fibreglass insulation are relatively inexpensive if you select a lower R-value (insulation ability) product. A roll or two will suffice to fill the walls of the smaller shed with insulation, and usually will only cost about a hundred pounds.
Insulating your home’s garden shed or summer house is a worthwhile project. Simply follow some of these DIY approaches for an inexpensive way to keep your shed comfortable year-round.
