26-08-2026

During the autumn and winter months, our garden sheds come into their own. From storing gardening tools and equipment which won’t be used until spring, to keeping pots and even plants safe, outdoor storage can be crucial.

You may even want to spend time in your shed over winter, whether for work to transform it into a home office, or to carry out additional gardening work.

Without insulation, a shed can become damp and will be freezing in winter and excessively hot in summer. With insulation, temperature is regulated, and it will be warm in winter and cool in summer.

 

Why should I insulate my shed?

You may think that you don’t need to insulate your shed because you don’t spend time in there, but insulation can actually protect anything which is in there.

Damp can cause metal tools to rust and can affect electrical power tools. Excessive damp can cause mould and attract pests and will potentially damage any furnishings and materials such as chair covers and cushions.

Perishables, such as plant food and paint, can last longer in suitable, stabilised conditions. Huge adjustments in temperature and moisture levels can ruin liquids and other chemicals.

Insulation can reduce damp and ensure temperature and moisture levels remain consistent year-round.

What is the best shed insulation?

There are three different materials typically used to insulate a garden shed: rigid insulation boards, mineral wool, and multifoil. Each has its pros and cons, outlined below.

Insulation Boards

  • Excellent thermal performance.
  • Easy to cut and install.
  • Suitable for walls, roofs, and floors.

Mineral Wool

  • Good thermal and acoustic insulation.
  • Cost-effective.
  • Requires protection from moisture, as this can heavily impact its ability to trap air and insulate.

Multifoil

  • Lightweight and easy to handle.
  • More convenient in smaller sheds where space can be limited.

Out of these three options, we typically recommend using insulation boards. As they are rigid and easy to cut, they're much easier to install. Plus, with them being suitable for roofs, walls, and floors, you can buy a pack of them and get the whole shed insulated relatively easily.

Insulation boards also offer the best thermal performance, but are the most costly to purchase. A budget-friendly alternative is mineral wool, but you'll need to install a thicker layer of it to get comparable performance, and this can eat into your usable space within the shed itself. You also need to be more careful when it comes to installation of the mineral wool, as if it gets wet, its thermal performance will massively deteriorate.

For the purpose of this guide, we're explaining how to insulate your shed with insulation boards, as opposed to the inferior options.

Before You Start

While it can be easy to just want to jump straight into the job, it's important to complete some checks and preparatory work to ensure that your shed and the insulation you install stand the test of time and deliver the desired results.

  • Make sure you check for any leaks or water damage to your shed. If the timber has got wet over a prolonged period of time, or you have a leak, then the wood will likely rot (or be rotting) and will need replacing to maintain the structural rigidity of your shed. If a leak isn't fixed and you install insulation boards, prolonged exposure to water can reduce their thermal effectiveness.
  • Remove any mould. Use a fungicidal wash or diluted bleach solution to scrub the mouldy area and let it completely dry out. This is easiest to do in the summer as the warm, dry weather will naturally dry it out. Alternatively, you can hire a heater or dehumidifier to speed up the process.
  • Allow any damp areas to dry completely. 

How to insulate your shed: Step by Step

You will need:

Try to opt for a high-quality insulation plasterboard. This will be easier to cut to size and install and also offer better results in the long run.

When carrying out any DIY, wear gloves, eye protection, and a dust mask. Any PPE required can be purchased from Speedy online or in our depots.

Take precautions if there is any fibreglass or other old insulation material in the shed, and ensure your skin doesn’t come into contact with it or you don’t breathe any in.

 

  1. Empty the shed

The first thing to do is empty the shed completely. This gives you space to move around and also ensures all areas are covered.

Choose a dry day to insulate your shed. Ensure everything is dry and in good condition and get rid of anything which has been damaged. You don’t want to be putting damp items back into the shed once completed.

 

  1. Check everything is watertight

Check around the doors and any windows for any issues. Replace any doors which allow water through, and seal around windows and joints. Use an expanding spray foam if there are any large gaps.

 

  1. Measure & fit insulation

Measure the space between each stud, so you know how large the insulation sheets have to be. Cut the sheets to size using a sharp knife or scissors. Be careful when doing this and wear thick work gloves.

Put in place between each stud and try to tuck into the studs. Use a nail gun to attach to the walls if working with a wooden shed.

You may wish to instead use an adhesive to stick it to the walls if you’re working with a metal or plastic shed.

 

  1. Install plasterboard

While the insulation will give you the results required, covering walls with plasterboard gives you an additional layer of protection, as well as ensuring a professional-looking finish.

Attach the plasterboard to the studs, ensuring there are no gaps between the individual boards. If you need to cut the boards to size, use a circular saw or jigsaw. Attach using a nail gun, or screws if the boards are thick.

Seal any small gaps with sealant.

 

How to insulate a shed roof & floor

Insulating your shed roof follows a similar pattern to the walls, but you need to bear a few things in mind.

Step 1: Measure the space between the studs and fit a damp-proof membrane to each roof panel. However, you need to leave a 2-inch gap around each edge to ensure any moisture build-up can escape.

Step 2: Attach the insulation with a nail gun, and cover it with plasterboard to hide it, ensuring again that a small 2-inch gap is left around the edge of your roof.

Step 3: Check that there is roofing felt on the outside of the roof too, to minimise water damage.

Step 4: The floor is the same process, but you have to ensure that you won’t miss the lost internal height. As long as any shelving can still fit in the space, it is worthwhile doing, as a lot of heat can be lost through the floor.

Step 5: You should also purchase a thick, good-quality insulation board and plywood for the floor. It will need to hold plenty of weight and evenly distribute this.

Step 6: Use a nail gun to attach the insulation board to the existing floor, and then install the plywood over this. Check all sections are even in thickness, so the floor is level.

Step 7: To finish off, seal with sealant.

 

WANT SOME MORE PROJECT INSPIRATION?

We have plenty of tips, tricks, and guides available to help you through any home or garden project.

Browse through everything on our News & Guides section and find inspiration on our Gardening Projects page.

To start hiring, open a Speedy account online or on the app for all your tool hire needs.

Speedy has more than 200 local service centres across the nation, hire counters in selected B&Qs and nationwide 4-hour delivery.

 

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