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By Amy Hanlon on 04 May 2023

Should I insulate a summerhouse?

Should you insulate your summerhouse?

I’ll admit, I worried when I found out that my office was a summerhouse. I’m a cauld tattie at the best of times, and I was pretty sure that I’d spend most of my time in here wearing twenty layers of clothing and a couple of blankets. 

But Cara pointed out that this wasn’t just any summerhouse. It’s a fully insulated and lined summerhouse. She assured me that an infrared heater would be enough to keep me cosy, and she was absolutely right!

Because of the insulation and lining, once the building is heated it stays warm. In fact, when the sun comes out it’s well and truly toasty in here! 

This is one major benefit of insulating a summerhouse. But what else do you need to know? Let’s take a look.

How do you insulate a summerhouse?

Here is the interior of The Deuchny summerhouse. You can see it in our show area demonstrating what a great craft cabin it would make. 

Notice the vertical pieces of wood at regular intervals on the wall. This is the frame of the summerhouse. If you can see the frame, the summerhouse is unlined. The timber that you see between the framing is the weatherboard. It’s exposed to the elements outside. 

To insulate a summerhouse you place insulating material in between the vertical timbers of the frame. Then, to cover the insulation you line the walls with your lining material of choice. 

Now take a look at this timber vision. Here you can see what a summerhouse looks like when it’s insulated and lined with weatherboard. There are now two layers of timber, with a layer of insulation board in between. 

If you want to line your summerhouse with timber, you will need some serious skills. Or, if you pay an expert to do it, the cost will be around 70-80% of the summerhouse itself. This is because you’re essentially getting TWO summerhouses – one built inside the other, with a layer of insulation in between. 

Of course, a summerhouse doesn’t have to be lined with timber. Other options include plasterboard, plywood, or OSB sheeting. If you pay someone to install these lining materials on top of your insulation material the cost will depend on which you choose and on the size of your summerhouse. 

You can also insulate the floor of your summerhouse, but this can only be done when the summerhouse is installed. The walls and roof can be insulated and lined on installation, or this can be done at a later date.

While you may not need mad joiner skills to install plasterboard or sheet lining, it’s not really a job for a novice either. 

Disadvantages to insulating a summerhouse

Let’s not pretend otherwise: this is a big old job. You’ll either have to pay an expert to do it or muster up the skills and time to do it yourself. 


The main disadvantage is the cost. The cost of insulating a summerhouse varies. There are different qualities and types of insulating materials, different qualities and types of lining materials, and the cost of the labour involved. Of course, if you do it yourself you save on labour costs.

Additional Costs

The other thing to consider is heating. Insulation will help keep heat in a summerhouse, but in the colder months, there won’t be much heat in there to start with. My summerhouse office has an infrared heater which does the trick, but there are other options. 

A wood-burning stove will keep your summerhouse warm and doesn’t need an electrical supply. If you want to use an electric heater you’ll either need a really long extension cable or you’ll have to install electricity in your summerhouse. These options do involve spending yet more money. 

Will a summerhouse lose heat from the windows?

And what about the windows?

By their nature, summerhouses have more windows than the average building. Since double glazing in a summerhouse isn’t a feasible option, your building will lose some heat from the windows. However, a decent low-cost heater will take care of this.

Advantages to insulating a summerhouse

The biggest advantage of insulating and lining a summerhouse is the difference this makes to temperature control.

Will insulation keep a summerhouse cool?

I know we’re hardly in the air-conditioning country around here, but there are a few days (weeks 🤞) in summer when the idea of sitting in a roasting hot summerhouse seems unbearable. Lining and insulation keep both warm air and cool air inside your building. 

You could even add blinds or curtains to your windows to keep the sun out on those warmer days, then enjoy the cool interior while the rest of the garden bakes in the sun. 

Whether you’re keeping warm or keeping cool, the insulation and lining mean that you can use your summerhouse all year round. The last thing anyone wants is to invest in a summerhouse only to find it can only be used the first two weeks of July. Lining and insulation give you a better return on your investment, because you’ll get more use from the building whether it’s scorchio or not.

Does insulation and lining give more decorating options?

Another advantage of lining and insulation is the greater range of decorating options. We recommend that unlined summerhouses should only be painted with thinned Sadolin to prevent water ingress. A lined summerhouse can be painted with any kind of paint or varnish you like. 

Hanging shelves or heavy objects on an unlined summerhouse wall is also limited. You can only really attach anything heavy to the frame of the summerhouse, as the weatherboard isn’t thick enough to hold excess weight. With a lined and insulated summerhouse, you can hang shelves or heavy pictures, or whatever you want on your walls.

Is Summerhouse Insulation Worth It?

Do you want to use your summerhouse all year round and be comfortable in there whatever the weather? If these are your priorities it’s well worth your while to insulate and line your summerhouse. With an electrical supply and a heater, you’ll have extra room to enjoy in comfort.

Is a lined and insulated summerhouse the same as a garden room?

If you’re looking for true home-from-home comfort, it’s worth checking out our range of garden rooms. Garden rooms are even more versatile than a lined and insulated summerhouse. 

You can use them as an office or an art studio, but also as an extra bedroom or AirBnB. But be warned – this is reflected in the cost. Garden rooms require a bigger budget than an insulated summerhouse. 

Should I line and insulate my summerhouse?

If you only want to use your summerhouse in summer, or you don’t mind bundling up with blankets to use it on chillier days, insulation probably isn’t a priority for you. 

But on the cold Spring days, I’ve really appreciate the sweet-smelling timber lining and insulation of my summerhouse office, safe in the knowledge that I’ll be cosy all day – no thermals required!

As always, you can find out more about any aspect of #shedlife in our Learning Centre.

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