Step-by-Step Guide: How to Insulate Your Garden Room for Year-Round Use

DIY vs Professional Insulation: Which is the Right Choice for Your Garden Room or Office?

A question I often get regarding garden rooms is whether they need insulation. This is a perfectly reasonable question, as structures like garden sheds are not insulated. However, garden rooms and offices are much more than sheds—they are fully functional structures that can be used all year round.

In this article, I explain the benefits of insulating your garden office and give tips on how to insulate a garden room if you already have a structure and are feeling the cold!

Does a Garden Room Office Need to be Insulated?

Yes. If you want a quick answer, a garden office should be insulated if you intend to use it during the winter. Can you imagine sitting inside your garden shed and working 8 hours a day when the temperature outside is 2 degrees?

Of course not! This is what it could feel like without proper insulation for your garden room or garden office. The timber structure won’t be warm enough during the autumn and winter, and heat will be lost easily. This is why insulation is essential.

How Do You Insulate an Outside Office?

Insulated garden rooms typically have insulation in four key areas:

• Floor
• Roof
• Walls
• Windows

The floor is typically insulated using foam insulation boards, an underlay, and thick floorboards. The 100mm foam insulation board acts as a fantastic barrier between the ground and internal space; the only downside is that it reduces vertical space a little.

The roof and walls are usually insulated using a timber frame fitted to the external walls/roof, to which you fix various insulation items such as breathable membrane, insulation board, and acoustic insulation board. This leaves an ugly wooden frame on the inside of your garden office, but this is addressed with plasterboard, plastering, and painting as you would inside a house.

Insulation for windows and doors is simple—you need double-glazed glass instead of cheaper single-pane fixtures. Rope caulk can seal gaps in the doorframe and window frame fittings where heat can be lost.

How Thick Should Garden Office Insulation Be?

In addition to the insulation method, you must also consider the thickness. If your insulation is too thin, it won’t be effective, and you could still feel the cold.

As a rule of thumb, I recommend 50mm for the walls and 100mm for the floor. This should give plenty of insulation without cramping the interior of your garden office too much.

You can opt for 50mm on the floor when insulating a garden office, too, but I advise going thicker. Plenty of cold can seep through the floor if the office is on a concrete base, for example. The floor is where you can afford to have thicker insulation, too, as you are only losing vertical space.

What is the Best Way to Insulate Exterior Walls?

The exterior walls cover the largest surface area of your garden cabin, so they’re the area where the most heat is lost. As a result, the insulation here needs to be top-notch.

The best way to insulate exterior walls is to attach a timber frame to them. On top of this, you create layers of insulation, including a moisture barrier, breathable membrane, and insulation boards (typically 50mm).

Acoustic insulation can also be included, but it is optional. On the inner layer, you have plasterboard sheets, which you finish with plaster and paint.

What is the Cheapest Way to Insulate a Garden Room or Office?

If you have a tight budget, you can create cheap insulation for your garden room, but the method might seem a little bizarre!

You can’t avoid having a timber frame and plasterboard connected to your external garden room walls. Therefore, you can’t save much cost here by choosing cheaper timber and plasterboard.

The cost-saving exercise is filling the space between the boards and the external wall with insulation boards! In the method above, we used various traditional insulation techniques, such as breathable membranes and insulation boards.

However, these cost money, so what’s the alternative? Wait for it…. Old clothes and packing material! This might seem unconventional, but old or recycled clothing and packing materials like polystyrene work fantastically. You can even take a peak in your loft and see if there is any spare insulation to steal!

Insulate to Regulate – Make Sure Your Garden Room is Insulated to Year-Round Use

If you choose to buy a garden room, you can often pay a little extra to have it insulated. This eliminates the hassle and stress of buying the insulation materials and trying to install them yourself. Either way, your garden office should be insulated so that it is comfortable to use year-round.