Garage Insulation: How to Insulate a Garage in the UK

Garage insulation is a crucial step in making your space more functional and energy-efficient. With over 11 million homes in the UK featuring garages, many of these spaces are often left underutilised due to poor temperature control. 

Insulating your garage can significantly reduce heat loss in winter, keep it cooler in summer, and even provide soundproofing benefits. Whether you use your garage for storage, as a workspace, or a home gym, proper insulation can make it more comfortable and usable throughout the year. 

In this guide, we’ll explore how to effectively insulate your garage, from selecting the best materials to installing insulation in walls, floors, doors and ceilings. Understanding this process can help you make informed decisions that could lower energy bills and enhance your home’s overall comfort. 

Is garage insulation right for your home? Finding the right specialist can be time-consuming, but GreenMatch makes it simple. Just fill out our 30-second form, and we’ll connect you with up to four quotes—completely free, with no hidden costs or obligations. Let us make garage insulation easy and stress-free. Click below to get started!

Garage conversion insulation provides numerous benefits that enhance your garage's functionality and improve your home's overall thermal efficiency. Garage insulation helps regulate temperature, preventing heat loss in winter and keeping the space cooler in summer. Here are some of the key benefits of garage insulation:

Garage insulation in the UK is often simpler than insulating a home. Still, whether you choose a DIY approach or hire professionals, knowing how to insulate each part of your garage correctly is essential. Here's a step-by-step guide to help you insulate the areas of your garage effectively.

Garage wall insulation is one of the most effective ways to boost thermal efficiency, as uninsulated walls can account for up to 33% of heat loss. Many garages in the UK are made from single-skin brick or block, which lacks a cavity wall for insulation. If your garage has double skin or cavity walls, it may already be insulated, but it's always best to consult a professional to confirm. For uninsulated double-skin walls, blown-in polystyrene insulation can be added.

Internal wall insulation (IWI) is often more affordable and straightforward for garage insulation, especially those attached to your home. There are several methods of IWI to consider when insulating a single skin garage:

Each method offers its benefits, making it essential to choose the one that best suits your garage’s structure and needs.

External wall insulation (EWI) is a highly effective method of insulating a single skin garage without sacrificing interior space. The process involves several layers:

EWI offers superior thermal efficiency compared to internal wall insulation (IWI) while also protecting against weather and saving interior space. However, it is typically more expensive than IWI. In some cases, especially in conservation areas or listed buildings, planning permission may be required. 

Additionally, proper ventilation is crucial to prevent moisture build up, as EWI can reduce natural air exchange within the garage. Despite the higher cost, EWI is an excellent long-term investment in energy savings and comfort.

To find the best insulation method for your garage walls, it's important to consult with an insulation expert who can guide you in making the right decision based on your needs and budget. At GreenMatch UK, we can connect you with top insulation professionals in your area. Fill out our quick 30-second form to receive up to four free quotes—no hidden costs, no obligations. Click below to get started.

Garage roof insulation can be applied to both pitched and flat roofs, depending on the structure of your garage. For a pitched roof, the insulation process mirrors that of a typical house. Insulation is installed between the rafters to prevent heat loss and maintain a comfortable environment. Various insulation materials can be used, including rigid foam boards, fibreglass, spray foam, or even sheep's wool. Each material has its benefits, with rigid foam offering excellent thermal resistance and fibreglass providing a cost-effective option.

For a flat roof insulation, there are two primary methods: warm deck and cold deck insulation. A warm deck roof is the most common choice due to its superior thermal efficiency. This system's insulation is placed above the roof's structural deck, directly beneath the waterproof layer. The structure typically consists of a solid insulation board, timber decking, wooden joists, and a plasterboard ceiling. This setup keeps the entire roof structure warm, reducing the risk of condensation and heat loss.

In contrast, a cold deck roof places insulation between or beneath the roof joists, leaving an air gap between the insulation and the roof deck. While this method is more cost-effective, it requires proper ventilation to prevent moisture buildup and condensation, which can lead to long-term damage.

Garage floor insulation is an effective way to make the space more comfortable, especially during colder months when uninsulated floors can feel extremely cold. Garage insulation improves warmth and makes the garage more appealing if you plan to use it as a living space.

One of the best methods is to install rigid insulation boards, which provide excellent thermal resistance while minimally raising the floor height. Thin insulation boards are available to help maintain the original floor height. Still, in many attached garages, there’s often a step down to the floor, giving you extra height to work with.

In addition to thermal benefits, floor insulation can enhance the garage’s appearance. After installing the insulation, you can finish the floor with underlay, carpet, or even a timber deck for a polished look. If noise reduction is a concern, you can add acoustic matting over the insulation to reduce echoes, particularly in large or high-ceiling garages. Alternatively, insulation boards with built-in acoustic properties can minimise airborne noise and echo, making the space more comfortable and functional.

The garage door is often a significant source of heat loss, affecting the overall warmth of your garage, even if the rest of it is well insulated. If you're insulating a room above a garage, the most cost-effective starting point is to insulate the garage door. Draughts from an uninsulated garage door can easily escape through the ceiling and into the room above, reducing the effectiveness of insulation in both areas. By insulating the garage door first, you can significantly improve the thermal efficiency of both the garage and the room above it.

The most common method for garage door insulation is using reflective foil, which can be easily glued to the inside of the door. This is a cost-effective, DIY-friendly option that improves thermal efficiency. Another effective approach is attaching rigid foam boards to the inside of the door for added insulation.

Additionally, sealing gaps around the door frame is crucial for preventing drafts, even though it may be slightly less effective on its own. When combined with proper insulation, it can greatly improve overall thermal performance. Even if you don't plan to insulate the entire garage, insulating and sealing the garage door will make the space warmer and more inviting at a minimal cost.

When selecting the best materials for garage insulation, it’s essential to consider three key factors: R-values, cost-effectiveness, and sustainability. The R-value measures thermal resistance—the higher the R-value, the better the insulation. Here’s a breakdown of the R-values for common insulation materials:

It’s important to note that spray foam and rigid foam boards come in different types, which can impact their R-values. When choosing insulation, weigh the R-value for energy efficiency, the cost based on your budget, and sustainability if environmental impact matters to you.

Rigid foam boards and spray foam offer the highest R-values, providing superior thermal efficiency. While sheep wool is more eco-friendly, its thermal performance is lower. Fibreglass is the most affordable option, but it has a lower R-value compared to other materials.

Working with a professional can help you choose the best insulation material for your needs and budget. However, finding the right specialist can be time-consuming, and comparing multiple quotes may lead to dead ends. GreenMatch UK simplifies this process by providing up to four free quotes—just fill out our 30-second form, with no hidden costs or obligations. Click below to learn more. 

The cost of garage insulation depends on several factors including the size, materials used, and whether you choose to do it yourself or hire a professional. Typically, the cost to insulate a garage will range between  £35 to £45 per m2. Here are the average costs for insulating different areas of your garage:

The cheapest way to insulate a garage roof or anywhere in the garage is by using fibreglass insulation, which is both cost-effective and easy to install, making it ideal for DIY projects. While fibreglass provides decent insulation at a low cost, it's important to choose materials based on your specific needs. Below are the average costs of common garage insulation materials:

Insulating a garage in the UK is worth it, especially with the country’s varying climate. Proper insulation improves the comfort and usability of your garage. It helps reduce energy costs by preventing heat loss in winter and keeping the space cooler in summer. Insulation can make it more functional year-round, whether you use your garage for storage, as a workshop, or even as an additional living space.

Additionally, insulating a garage attached to your home can help regulate temperatures in adjacent rooms, enhancing overall energy efficiency and comfort. It also offers benefits like noise reduction, moisture control, and protection of stored items from extreme temperatures.

While DIY insulation is possible, professional installation ensures the job is done correctly, maximising energy savings and preventing issues like dampness or air leaks. Finding the right specialist can be challenging, but GreenMatch makes it easy. Fill out our 30-second form to receive up to four free quotes from trusted insulation professionals in your area—no hidden costs or obligations. Click below to learn more!