How Much Does a Garage Conversion Cost?

Garage Conversion Cost Guide

Converting your garage can add some very useful space to your home. This guide goes through everything you need to know about garage conversion costs, from the price per square metre and what each type of conversion costs, to planning permission, building regulations and hidden costs.

In this cost guide we will talk about:

1. Average cost of a garage conversion
2. Single vs double garage conversion costs
3. Common garage conversion styles and costs
4. Planning permission and building regulations
5. Garage conversion cost breakdown
6. Avoid these hidden garage conversion costs
7. Find garage conversion specialists near you on MyBuilder
8. FAQ: Common questions about garage conversion costs

Average Cost of a Garage Conversion

Converting a garage into a new living space is a good way to expand your home’s living space without having to worry about moving, or taking up garden space with a full-on extension.

The cost of a garage conversion can vary depending on what you’re looking to use the area for.

Here’s a list of the average costs for a garage conversion:

Building stage	Cost
Design costs	£300–£800
Building control fees	£300–£900
Construction costs	£800–£1,500 per m²

The choice of materials for walls, insulation, flooring, and windows can also impact the final conversion cost.

For example, insulation costs can range from £10 to £30 per m². For a detailed breakdown, refer to our guide on the cost to insulate a garage.

Single vs Double Garage Conversion Costs

A single garage is usually around 12 to 18 m², while a double garage is around 30 to 36 m². Larger garages cost less per m², as fixed costs like building control fees are spread across more space. As a guide, most conversions cost £800 to £1,500 per m², with basic rooms at the lower end and bedrooms with an en-suite at the top.

Here’s what to expect for different garage sizes and specifications:

Type of conversion	Typical cost	Typical timeframe
Single garage, basic habitable room (office, gym, playroom)	£8,000–£15,000	2–4 weeks
Single garage, bedroom or fully finished room	£12,000–£22,000	3–6 weeks
Single garage with en-suite or kitchenette	£18,000–£30,000	4–8 weeks
Double garage	£18,000–£35,000+	6–10 weeks

London and the South East are usually 30–40% more expensive than the rest of the UK.

Common Garage Conversion Styles and Costs

There are a few different ways you can go with your garage conversion. Think stylish guest suite, productive home office, or dedicated gym. The cost varies depending on what you need, for example a bedroom may need more insulation than a gym.

Take a look at the cost of different garage conversion styles:

• Guest suite: On average, converting a garage into a guest suite with a bathroom costs between £18,000 and £30,000. This includes the installation of a bathroom, fitted with essential plumbing features.
• Home office: Establishing a home office generally ranges from £8,000 to £15,000. This conversion requires things like lighting and data connectivity.
• Gym: Transforming your garage into a gym can vary between £8,000 and £15,000. Costs depend on additional electrical outlets and specialised flooring installation.
• Utility room: This conversion type typically costs between £18,000 and £30,000. It often involves plumbing and storage solutions for functionality.

Now that you have a vague idea of how much your garage conversion costs, you might want to consider getting a quote from a professional. The easy and quick way to do this is by posting your job on MyBuilder today.

Then, garage conversion specialists near you can come to you, rather than you searching for them.

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Planning Permission and Building Regulations

You will almost always need building regulations approval to convert a garage into a living space, which covers structural stability, fire safety, insulation, ventilation, damp proofing and electrical safety. Fees typically cost £300 to £900 through your local authority’s building control team. Without a completion certificate, the room isn’t legally habitable. A detached garage under 30 m² that won’t include sleeping accommodation may be exempt, but check with building control first.

Most garage conversions don’t need planning permission, as the work is internal. You may need it if your property is listed or in a conservation area, if the work changes the outside of the building, if you’re converting a detached garage, or if your original planning permission requires you to keep the garage or parking.

Building and planning rules are set separately in England, Wales, Scotland and Northern Ireland (in Scotland, for example, you apply for a building warrant), so check with your local council before you start. Planning application fees also vary. In England, the householder application fee is £272.

Garage Conversion Cost Breakdown

Quotes are easier to compare when you know what’s included. Here’s a typical breakdown for converting a single garage:

Item	Typical cost
Design consultation and drawings	£300–£800
Structural engineer (if needed)	£300–£700
Building control fees	£300–£900
Garage door infill (wall, insulation and lintel)	£1,200–£3,000
Floor insulation, damp-proof membrane and screed	£1,200–£3,000
Wall insulation, dry-lining and plastering	£1,000–£3,000
Ceiling or roof insulation	£500–£1,500
New windows and external door	£800–£2,500
Fire door to the house	£400–£800
Electrics	£800–£2,500
Heating (radiator extension or underfloor)	£600–£2,000
Flooring	£500–£2,000
Decoration	£500–£2,000
En-suite (if included)	£3,000–£8,000

A few things are worth knowing about the biggest costs:

• Garage door infill: This is usually the biggest single cost, often 15% to 20% of the total. The door is removed and the opening filled with a new wall matched to your existing brickwork, with a structural lintel above.
• Windows and doors: New windows must meet building regulations for ventilation and, in a bedroom, escape. A fire-rated door is needed where the garage connects to your home.
• Electrics and heating: Electrical work must be carried out and certified by a registered electrician. You can extend your central heating with a radiator, or fit electric radiators or underfloor heating, which costs more.
• Insulation: Garages are rarely built to the standard of the rest of your home, so walls, floor and ceiling need upgrading to meet current regulations.
• Plumbing: A WC, shower or utility sink needs new plumbing and drainage.

Avoid These Hidden Garage Conversion Costs

When planning a garage conversion, it’s crucial to account for potential unforeseen expenses that could significantly impact your budget.

These hidden costs often arise due to the unique requirements of each project and can include modifications or additions that were not initially anticipated.

• Structural alterations: During conversion, you may uncover issues with the existing structure that need addressing, such as foundation repairs or the need for additional support beams, which can add significant costs.
• Utilities upgrades: Upgrading or extending utilities like plumbing, electricity, and gas can be expensive, especially if your existing systems don’t meet the demands of the new living space. For a better understanding of your home’s electrical setup, consider reading about understanding electric meters.
• Insulation and weatherproofing: Ensuring adequate insulation and protection from the elements is essential. Poor insulation can lead to higher energy bills and discomfort, so it’s a wise investment. Refer to our guide on the cost to insulate a garage for detailed information.

Find Garage Conversion Specialists Near You on MyBuilder

Whether you’re ready for the full conversion, or just have a few questions about turning your garage into a living space, just post your job on MyBuilder today.

Then, garage conversion specialists can respond to your post with their advice, services and quotes. It’s the easy and quick way to find a tradesperson near you.

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FAQ: Common Questions About Garage Conversion Costs

What factors influence the overall garage conversion cost?

The overall cost of a garage conversion depends on several factors, including the size and condition of the existing garage, the quality of materials used, and the complexity of the design. Insulation, plumbing, electrical work and building control fees can also increase costs. A professional assessment can provide a more accurate estimate based on your specific requirements.

What are the benefits of converting a garage into a living space?

Garage conversions can increase your home’s usable space, making them ideal for growing families or creating a home office. A well-planned conversion may also boost property value, although the effect depends on your local market. It allows for more functional use of underused areas.

What are some common challenges faced during a garage conversion project?

Common challenges include meeting building regulations, managing space constraints, and addressing damp or insulation issues. Structural changes may be needed to comply with regulations, especially if plumbing or built-in features are added. Getting the right approvals and avoiding breaches of planning conditions is also essential.

How do I calculate my final garage conversion cost?

Start with your garage size (for example, a single garage of around 16 m²). Multiply by £800–£1,500 per m², which gives roughly £12,800–£24,000 for 16 m². Then add 10–15% for contingency and extras like en-suites. Basic conversions on smaller garages can cost less. The best way is to get quotes from 3+ professionals using MyBuilder.