How to Insulate a Shed

A garden shed is a British tradition, but British weather can often make them unusable for long periods of the year. A shed can be used as a relaxation space, a home gym, or even a home office, but our famously brutal winters can often render them uninhabitable.

A great solution to this is to fully insulate your shed, conserving heat throughout the room and allowing it to remain usable throughout the winter. You can insulate your shed whether it is made of wood or metal, installing high-quality insulation within its walls, floor, and roof, offering stellar thermal support for your outside space.

In this guide from Building Materials Nationwide, we’ll talk you through your options in terms of shed insulation, and the methods used to install insulation within your shed. We’ll cover both wooden and metal sheds, showcasing the different insulation types suited to each.

With an insulated garden shed, your garden space can be usable all year round.

What Are the Best Options for Shed Insulation?

You will have a variety of insulation options available to you. At the cheaper end, bubble wrap can be used as a method of shed insulation, with cost-effective, foil-backed bubble wrap available. In wooden sheds, insulation slabs or rolls are a great choice, with an easy fitting process.

These will both need to be covered with plywood or MDF boards to secure them in place and maintain the look of your shed. Sheep's Wool insulation slabs can offer both great thermal insulation and regulate air moisture, avoiding dampness within your shed. Breathable insulation sheets can also be used, offering both thermal insulation and vapour control.

Insulation boards, like those made by Celotex, can also be used as shed insulation. This will be a more expensive option but can offer higher levels of thermal insulation.

Looking For Quality Insulation?

View Our Range

Precautions to Take Before Insulating Your Shed

The first thing you must take into account is the amount of insulation needed. To fully protect your shed from heat loss, you will need to install insulation in the roof, walls, and floor. While bubble wrap tends to come in large rolls, when buying insulation slabs or boards, as well as plywood boards to cover them, you will need to carefully measure and calculate the amount needed beforehand.

Especially in a wooden shed, it is important to check the quality of your shed. Make sure that the windows, door, and roof are intact and secure, and not causing heat to escape. If you identify issues, such as leaks around windows or loose roof felt, it may be worth either fixing the issues or if that is not possible investing in a new shed. There is no point in fitting high-quality insulation within a shed that has severe structural issues.

Before you start work, make sure to empty your shed, lay out a dust sheet, and wear appropriate safety equipment, like safety goggles or a mask depending on what material you are using. If using mineral wool insulation, a full gas mask should be used during fitting.

How to Insulate a Wooden Shed Wall

The vast majority of wooden sheds in the UK are built with joists, which insulation should be fitted within. If you are using foil-backed bubble wrap you should cut it into strips that will fit within your shed walls, before stapling it to the framing. This will create an air gap to limit dampness from getting through.

Once you have installed the bubble wrap, it should be covered with a thin layer of plywood or MDF to hide it from view. This can be cut and fitted to the joists to easily create a cohesive, clean look to your shed interior, without sacrificing much space. 

Breathable insulation sheets should be fitted directly to the cladding of your shed, tacked or stapled in place. Sheet insulation will offer better levels of insulation than bubble wrap, and can similarly be obscured through the use of plywood or MDF boards secured to the wall joists.

For Insulation slabs, you can friction fit them within the joists, by simply pushing them in. You can cut slabs to size, making sure that you fully cover the entirety of the wall. Once installed, you can then cover them with plywood or MDF boards.

Insulation boards, like Celotex General Application Boards, should be cut to size and fixed within a wall joist. If you need to cut an insulation board, tape the edges with foil tape for a stronger seal. Insulation boards can be attached to the cladding using plasterboard nails or screws.

How to Insulate a Wooden Shed Floor

An insulated garden shed floor can save as much as 40% of the heat that would have been lost. When looking to insulate a shed floor you have two options, to install insulation within the foundations of your shed, or to create a false floor in your shed.

It is much easier to install insulation within the foundations during the building process, as doing so within an existing shed is likely to be a painful process as it involves removing all flooring in your shed. For an existing shed, making a false floor offers good thermal insulation, with a much easier installation process.

When installing within foundations, using a solid board like a Celotex insulation board is the best underfloor insulation for a shed. You can nail smaller wooden pieces near the top of a foundation joist, onto which insulation boards can be affixed.

If there are any small gaps you can fill them in with expanding insulation foam, and you can seal all boards with foil-based tape. Your traditional shed floor can then be installed over this, greatly minimising heat loss within your shed.

To create a false floor, your first option is to install a thin layer of insulation board across your shed floor and cover it with plywood or MDF boards. An alternative option is to cover your shed floor with an insulation sheet, which can offer water-resistant benefits.

This can either be topped with plywood boards or a carpet. When considering whether to opt for underfloor insulation or a false floor, it is worth considering that you will lose height within your shed by adding a false floor.

How to Insulate a Wooden Shed Roof

The roof of a wooden shed can be insulated via the same methods used on a wall, installing your choice of insulation material between the joists, and covering with plywood or MDF boards. If installing within an older shed, you should check the quality of the roof felt beforehand, if it is damaged you will need to either repair or replace it. For shed roof insulation, you will want to use a product with moisture resistance, such as insulation sheets with breathable membranes, sheep's wool rolls, or Celotex insulation boards.

How to Insulate a Metal Shed

A metal shed offers stronger thermal insulation than a wooden one, but this can bring its issues. On a hot summer day, a metal shed may become unusable warm, and this can cause condensation to form, over time rusting your shed and causing dampness.

Spray foam insulation is a popular choice for metal buildings, covering the walls and ceilings of your shed in layers of foam. This offers a high level of thermal insulation but is difficult to install effectively. When looking for spray foam insulation, opt for closed-cell, a two-canister option, which helps provide a vapour barrier within your metal shed.

Foam insulation boards are also available, which can be attached to walls with adhesive (either silicone adhesive or subfloor adhesive, applied with a caulk gun). You should then use foil tape to seal the joints. These are an easier choice for DIY metal shed insulation, as foam boards can be easily cut to size and attached.