A Comprehensive Guide to Garden Room Insulation

Whether you use it as a calm personal retreat, office space, or an extension to give you more living space, incorporating high specification insulation into the build means that garden rooms from Make Room Outside are ideal for year-round use, ensuring a comfortable environment for every season.

Keeping a garden building warm in winter and cool in summer can be a challenge. Insulating every aspect of the garden rooms, including roof, walls and floor, means a consistent temperature can be achieved whatever the weather.

An additional benefit is that efficient insulation also acts as a sound barrier, particularly useful where garden rooms are subject to ambient noise, or used as a music room or other application which could disturb neighbours.

Considering garden room insulation is an important step when choosing the design, styling and component products of your new garden room project. A well-insulated garden room will yield energy savings and give you the thermal performance to make it a worthwhile investment.

In this post, we’ll look at how different types of insulation work and how the Make Room Outside solution means their insulated garden rooms provide elegant and functional extra space, from a quality garden office, studio, salon or gym, with the right ambient temperature providing a comfortable space, whatever the weather.  

Why your garden room should be insulated

Building effective insulation into garden rooms makes sense at every level. Firstly, it makes the entire build more energy-efficient, regulating the temperature effectively and meaning you’ll spend less on keeping it warm in the winter months and cool in the summer months - ideal year-round and especially important for office space.

Insulation also plays an important role in reducing the risk of condensation and the growth of mould, which can occur in spaces subject to rapid temperature changes and will detract from your enjoyment of the garden rooms. It acts as a good sound insulation barrier too.

For people who use their garden rooms as an office, or even run a small business from the space, thermal efficiency is vital, and your customers will appreciate the benefits of a pleasant, well-regulated and healthy environment too. Garden room insulation should be an important consideration when choosing your space to reduce energy costs.

Types of garden room insulation

Choosing the right insulation provides a range of practical and energy-efficient benefits for garden rooms.

Fibreglass insulation

Fibreglass insulation, usually made from recycled glass, is a popular choice and provides a range of benefits for garden rooms.

• Fibreglass is essentially flexible and fits into different spaces and corners.

• Fibreglass is also inexpensive and can offer good thermal properties for garden rooms.

• However, it can be aggressive to work with, does not provide a complete air seal and where high humidity is present, may not repel moisture effectively.

Recommended thicknesses of fibreglass required for garden room insulation will depend upon the R-value of the material, indicating how well it resists the conductive flow of heat.

Cellulose insulation

Cellulose insulation is produced from recycled paper products, which makes it a sustainable choice.

• Cellulose insulation provides good acoustic and thermal properties.

• It can be particularly useful for more awkward corners and cavities, where it can be packed to optimise the effectiveness of insulation.

• It provides a match for green building practices in garden rooms.

• However, it can be susceptible to moisture damage and may settle over time, meaning the insulation values of garden rooms can reduce.

It is generally recommended that cellulose insulation be installed at a layer thickness of 220mm, which means it can take up a significant amount of space in garden rooms' footprints. Garden rooms insulated this way will reduce interior space.

Foam board or rigid insulation boards

By contrast, rigid foam board, also known as rigid foam insulation, is an extremely effective insulation material at minimal thickness, saving space and providing effective levels of performance.

• Rigid foam has a closed-cell structure, which means it is impermeable to air.

• It is lightweight, easy to install and provides excellent thermal resistance.

• For garden rooms, it’s a great choice, saving space and keeping the area comfortable and dry.

Rigid foam insulation boards or structural insulated panels, also known as PIR insulation, are the preferred choice of insulation for garden rooms from Make Room Outside, where they optimise space and thermal efficiency with an effective layer just 50mm thick.  

Spray foam insulation

Spray foam insulation is a liquid insulation material made up of expanding foam, effectively filling corners, cracks and crevices.

• Spray foam insulation provides good air and heat sealing properties and thermal performance.

• It also provides good acoustic properties and R values for energy efficiency in garden rooms.

• However, it is made from unsustainable materials and is known to exacerbate certain health issues - garden rooms insulated this way may not be suitable for everyone.

The thickness required to achieve optimum R values will depend upon the type of foam being used, but this is typically between 3.5 inches to 5.5 inches, so the spatial requirements are an important consideration for proper insulation in garden room kits.

Understanding R values and U values

So, what is the best choice for garden room insulation? Let’s look at what is meant by R values and U values.

R values indicate the thermal resistance of each insulation material, demonstrating how well the material resists thermal transfer or conduction of heat. Higher R-value numbers mean better insulation performance.

Knowing the R value of your insulation material is important not just when considering reducing heating costs in the winter, but also for general comfort in the warmer summer months in garden rooms.

By contrast, U values indicate how elements of a build conduct heat per unit of area, expressed across a temperature gradient. Here, the higher the U value, the less the material can resist heat transfer. So low U values and high R values indicate improved levels of garden room insulation.

U values are the measure used by building control, and manufacturers of garden rooms will be given a target to attain.

How Make Room Outside insulates garden rooms

Garden rooms designed, manufactured and installed by Make Room Outside feature Celotec multi-purpose rigid insulation boards using polyisocyanurate foam (PIR) and low emissivity aluminium foil facing. These super-thin boards optimise usable space and guarantee premium efficiency, with low thermal conductivity to minimise heat transfer.

Incorporating the ideal insulation boards is just one element of our garden room's wall make-up. Make Room Outside multi-layer garden room walls (inside to out) include:-

The image below shows the typical wall make up of a garden room and all the various layers, including insulation. You can also see an interactive 3D diagram about the construction of our ceilings, walls and floors on the process and quality page.

Layers include

• Skim-coated plasterboard

• Vapour barrier/air barrier

• OSB engineered wood

• Wall frames

• 50mm rigid insulation

• Breather membrane

• Horizontal battens

• Selected garden rooms cladding

Celotec R Value: 2.25 M²K/W

Celotec Thermal Conductivity (U value): 0.022 W/mK

Local building regulations

Building regulations may have an impact on the materials and specifications for garden room insulation, as they may have minimum insulation standards requiring compliance.

Different regions, areas of the country and indeed countries in mainland UK may require manufacturers to achieve specific high R values to ensure thermal resistance in line with energy efficiency and conservation requirements. Where these regulations exist, it is important to comply with them, which will also be a factor when selecting garden room insulation materials.

We have a mainly temperate climate in the UK, but choosing garden rooms which demonstrate a high insulation value will ensure you have the opportunity to use the space all year round, providing the perfect solution. 

Get a fully insulated garden room from Make Room Outside

When you're considering the purchase and installation of garden rooms and insulated garden buildings, it's vital to choose a product which is designed and built using premium quality products and energy-efficient insulation materials.

Visit the Make Room Ouside show village to see the range of designs on offer to enhance your outdoor space, and rest assured that when you choose insulated garden rooms or modular extensions from Make Room Outside you'll be able to enjoy year round use in a building which is as energy efficient as your home, if not more so!