Garage & Workshop Insulation: Why It Matters and How to Do It
How Do You Insulate a Garage or Workshop?
The best results come from treating the garage as a whole rather than insulating just one area.
The walls, roof, floor and doors need to work together to create a warm, dry and comfortable space.
At a Glance
To insulate a garage or workshop:
- Choose insulation that suits how you'll use the garage or workshop
- Insulate the walls, roof and, where possible, the floor
- Seal draughts around doors and windows
- Add heating if you plan to use the space throughout the winter
- Allow enough ventilation to help control condensation.
How Much Does It Cost to Insulate a Garage?
The cost of insulating a garage depends on several factors, including:
- The size of the garage
- The type of insulation you choose
- Whether you install it yourself or hire a professional
- Whether you're insulating a new garage or retrofitting an existing one
As a rough guide, according to Checkatrade:
- DIY insulation materials: £500–£1,500
- Professionally insulating a single garage: £1,500–£4,000+
- Professionally insulating a double garage: £2,500–£6,000+.
Retrofitting an existing garage often costs more than insulating a new one because the walls and ceiling usually need to be opened up before insulation can be fitted.
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Is It Worth Insulating a Garage?
In many cases, yes. Here are five reasons why it's worth doing.
1) Protect Your Car
Cold, damp conditions aren't ideal for vehicles. Condensation can encourage rust over time, while freezing temperatures can affect your battery, thicken fluids and make rubber parts, such as windscreen wipers, less effective.
Insulation helps keep the building drier and temperatures more consistent, creating a better environment for your vehicle. You'll also be less likely to scrape ice off the windscreen on frosty mornings.
2) Make Your Garage or Workshop More Comfortable
Whether you use the space as a workshop, home gym, hobby room or home office, insulation helps create a more comfortable environment throughout the year.
If you plan to spend long periods in the garage, adding heating alongside insulation will make an even bigger difference.
3) Make Your Garage Quieter
Insulation can also help reduce noise from outside and stop sound travelling as easily out of the building.
If you use your garage as a workshop, office or hobby space, a quieter environment can make it easier to concentrate and more enjoyable to use.
4) Protect Tools and Stored Belongings
If your garage doubles as a storage space, insulation can help protect tools, bikes, garden equipment and other belongings from damp conditions and temperature changes.
5) Save on Heating Costs
If you plan to heat the building, insulation helps keep the warmth inside for longer. That means your heater doesn't have to work as hard to maintain a comfortable temperature, helping reduce energy use and running costs.
If you’re thinking of adding a heater to your garage or workshop, read our article about the best ways to heat a timber garage.
How to Insulate Your Garage or Workshop
- Choose the right insulation for how you'll use the garage or workshop
- Insulate the walls, roof, doors and floor where possible
- Seal draughts around doors and windows
- Make sure the building stays ventilated to help prevent moisture build-up.
What Is the Cheapest Way to Insulate a Garage?
You don't need to insulate every part of the garage at once. If your budget is limited, start with the roof, walls and garage door; you can improve the floor later.
Some of the most common options include:
- Mineral wool: A popular choice that's affordable, easy to install and ideal for walls and roofs
- Rockwool: A denser mineral wool that provides better thermal and sound insulation, making it a good choice for workshops, home gyms and offices
- PIR insulation boards, such as Celotex: Thin, rigid boards that provide excellent insulation without taking up too much space.
Once the insulation is in place, it's usually covered with internal boarding. This protects the insulation, gives the garage a neater finish and can help reduce draughts.
If you're insulating during construction, it's much easier to fit ceiling insulation before the internal lining is installed.
Don't forget about draught-proofing:
- Seal gaps around doors, windows and other openings
- Fit brush strips to the bottom of the garage door
- Add weather seals around personnel doors to help keep warm air in and cold air out.
Can You Insulate a Garage Yourself?
Yes. Many homeowners choose to insulate their own garage, especially if they're fitting mineral wool or rigid insulation boards between wall studs or roof rafters.
However, if you're installing new electrics, heating or making structural alterations, it's worth using a qualified professional. They'll make sure the work is completed safely and complies with any relevant Building Regulations.
Do You Need Building Regulations to Insulate a Garage?
Not always. Simply adding insulation doesn't usually require Building Regulations approval.
However, Building Regulations may apply if the work forms part of a larger garage conversion, involves structural alterations or includes new electrical installations.
If you're unsure, check with your Local Authority Building Control department before work begins. You can also find more information in the Government's guidance on Approved Document L: Conservation of Fuel and Power.
Why Build Insulation in From the Start?
Retrofitting insulation usually means removing the internal lining before insulating the walls and roof, then reboarding and redecorating the interior.
If insulation is included during construction, it's installed as the building is assembled. This creates a neater finish, reduces disruption and avoids the extra work involved in upgrading an existing building later.
Build a Garage That's Comfortable Year-Round
At Olson Timber Buildings, our timber garages and workshops can be insulated from the outset, with insulated walls, roofs and floors designed as part of the building rather than added afterwards. The result is a comfortable, energy-efficient space that's ready to use throughout the year.
Take a look at our range of timber garages, or get in touch.
Frequently Asked Questions
How much difference does garage insulation make?
A well-insulated garage is easier to heat, more comfortable to use and less affected by outside temperatures. It can also help reduce condensation, protect stored items and lower heating costs.
Will insulation keep my garage cool in summer?
Yes. Insulation slows heat transfer, helping keep the garage cooler in summer and warmer in winter. It also helps create a more stable temperature throughout the year.
Is it worth insulating a garage if you only park a car?
It can be. Insulation helps reduce condensation and creates a more stable environment, which can help protect your car from damp and make frosty mornings a little easier.
Is it worth insulating a workshop?
Yes. If you spend time working in your garage, insulation makes the space more comfortable, helps reduce condensation and makes heating much more effective. For more information about how insulation improves energy efficiency and reduces heat loss, see the guidance from Energy Saving Trust.
What's the best insulation for a garage?
That depends on your budget and how you use the space. Mineral wool is a popular, cost-effective option, while higher-performance products such as Rockwool or rigid PIR insulation boards offer improved thermal performance. At Olson Timber Buildings, we recommend Rockwool for its excellent thermal and acoustic insulation.
Can you insulate an existing garage?
Yes. Although it's usually easier to install insulation during construction, most existing timber garages can be insulated later. Walls, roofs and garage doors can all be upgraded, although some work may be needed to remove the internal lining first.
Should I insulate my garage door?
Yes. The garage door is often one of the biggest sources of heat loss, so insulating it can help the garage stay warmer and reduce draughts. Many people use rigid insulation boards or purpose-made insulation kits, depending on the type of door.
Should I insulate the garage ceiling?
Yes. Heat naturally rises, so insulating the roof or ceiling can make a noticeable difference to how well your garage holds heat. Mineral wool and rigid insulation boards are both popular options.
Should I insulate the garage floor?
If you can, yes. Floor insulation helps reduce heat loss and can make the space much more comfortable if you use it as a workshop, home gym or hobby room. It's usually much easier to install during construction than retrofit later.
Do I need to insulate the whole garage?
Not necessarily. If your budget is limited, start with the biggest areas of heat loss, such as the roof, walls and garage door. You can always add more insulation later.
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