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Best Way To Insulate a Summerhouse

Summerhouses are a great way to enjoy the summer months, but if they’re not properly insulated, they can become extremely hot and uncomfortable.

Despite their name, summerhouses can be used all year round. People often decide to use them as an office or a gym in the winter months. Since their walls are so thin, insulating them for use all year round is essential.

Like a home, if you don’t insulate your summerhouse, it can become expensive to heat. So the investment in insulation from the outset is more than worth it over time. It can also protect the summerhouse from the weather, and keep it looking in good condition for longer.

There are a few different ways to insulate a summerhouse, and you can insulate them from the inside or the outside. If you’re planning on using your summerhouse all year round, then it’s best to insulate it from the inside.


Before you install insulation you need to do some checks. Firstly you need to make sure the summerhouse doesn’t have any holes or cracks that will let in moisture, and secondly, make sure that the summerhouse is draught-free.

You’ll also need framing so the insulation can be properly installed. If there isn’t framing in the summerhouse already, then you can create it by nailing timber battens to the walls and roof. Always ensure you have adequate space and that you measure the depth of the battens as that will determine the thickness of insulation you’ll be able to use.

Finally, depending on the timber used for the summerhouse, it can be advised to treat the timber before installing the insulation. This will help to protect it from the weather and any insects that may want to take up residence.

Which Insulation Should I Use?

There are a few different types of insulation that could be used in a summerhouse, we’ll outline those options and what we think works best.

PIR Insulation Boards

PIR insulation boards are a great option for summerhouses as they’re lightweight, making them easy to install. They also have a good thermal conductivity value (0.022 W/mK), and don’t need any further treatments once installed. They can be used o the walls, floor, and ceilings of summerhouses, and are truly a multi-purpose product.

Celotex PIR insulation boards are a good option as they’re easy to work with, come in various thicknesses, and have a good thermal conductivity value. They are the most commonly used brand of PIR insulation, but EcoTherm, Recticel, Kingspan, and Xtratherm also do exactly the same job.

Insulation Rolls

Insulation rolls are a good option for summerhouses that have a flat roof. They’re made of glass mineral wool and come in various thicknesses and widths. The rolls can be fixed to the roof with an adhesive or using insulation nails which will help to hold them in place. They can be easily manoeuvred around tight spaces, so they’re a good option if your summerhouse is small.

Insulation Slabs

Insulation slabs can be used to insulate parts of the summerhouses, such as the floors and walls. They wouldn’t typically be used on the roof as they’re quite heavy.

The benefit of slabs is that they can provide good acoustic insulation, so if your priority is to cancel noise from outside, then they’re a good option.


If you want to fully insulate the floor, walls, and ceiling of a summerhouse, then our recommendation would be PIR insulation boards. They’re lightweight, easy to install and have a low thermal conductivity. They can be used on any surface and don’t require any treatment. If you’re going to use your summerhouse all year round, then this is the best option for you.

If you want to insulate a summerhouse and are still unsure of what is best for your construction, then you can speak to our friendly customer service team. They will be able to advise on what might be the best solution.

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