Garage Conversion Cost & Prices 2021

Garages are typically quite large, and whilst many households use them for their original purpose, a growing number of people are deciding to convert them into entirely new spaces. 

According to Virgin Money, garage conversions can add some 10% to 15% onto a home’s value, which is very significant given the initial outlay for such a project. This would make a garage conversion at least as good value as a loft conversion or extension. 

Furthermore, since garages are ground floor or may even be detached from the house entirely, the works are less disruptive than for loft conversions or other types of extensions. 

They’re also usually covered by Permitted Development, meaning only a small percentage of garage conversions require full Planning Permission.

This article will cover the costs involved in converting a garage in the UK, factors affecting the cost and other common questions around converting a garage.

Average Garage Conversion Cost

We’ve compiled price data from 8 garage converters and 13 secondary sources to generate the following average garage conversion prices. These are all-in costs that include VAT, but exclude Planning Permission.

The main cost factor is the type of garage. There are 3 main types of garage: 

  • Integral; where the garage is inside the house itself
  • Attached; where the garage is attached to the house, possibly divided by a corridor. It will have its own flat or pitched roof. 
  • Detached; where the garage is completely detached from the house

Costs are highest for detached double garage conversions with roof extensions and lowest for single-storey integrated garage conversions that are linked to the house. 

 Integral GarageAttached GarageDetached Garage
Single Garage (6m x 3m)£8,000 to £11,000£10,000 to £12,000£10,000 to £15,000
Single Garage High-End (6m x 3m)£12,000 to £13,500£14,000 to £20,000£20,000 to £25,000
Double Garage (6m x 6m)£15,000 to £18,000£22,000 to £28,000£30,00 to £35,000
Double Garage High-End (6m x 6m)£25,000+£35,000+£50,000+

The main costs include:

  • Structural integrity and foundational checks, upgrades may be required for attached or detached garages
  • Removing garage doors and replacing with walls, windows and doors
  • Insulation and heating 
  • Electricity, plumbing and gas
  • Architectural fees and admin costs
  • Some interior design costs (e.g. flooring, plastering, lighting, etc)
  • Knocking through a singular wall 

There are some additional costs for building specific types of garage conversions such as home gym garage conversions, kitchen garage conversions, bedroom garage conversions, home office conversions, etc.

Adding a pitched roof will also increase the cost (and may require Planning Permission). 

Additional CostsBudgetMid-RangeHigh-End
Kitchen (Open-Plan)£1,000£1,000 to £2,500£5,000+
Gym £500£1,000 to £2,000£2,000+
Spa/Bathroom£1,000£1,000 to £2,000£3,000+
Bedroom £500£1,000£2,000+ (with en-suite) 
Home Office£500£1,000£2,000+
Pitched Roof£1,000+£2,000+£3,000+

Why Build a Garage Conversion?

If you’re considering an extension, it’s wise to firstly consider what space you already leave unused in your home. Garages often instantly spring to mind. 

Whilst some do use garages for parking, storage, workshops or other miscellaneous uses, they’re a prime candidate for a more fully-featured extension. 

Garages are popular amongst homeowners and can already boost the value of a home, but for homes with a decent array of parking options, they are absolutely ideal for converting into extra usable interior space. 

The average garage in the UK is typically at least 3m x 6m with a 2.5m tall ceiling, but double garages are considerably bigger. It’s also possible to install a pitched roof to extend the ceiling to some 3.5m. This is enough space to accommodate a very large bedroom with en-suite, a sizable home office and work area, a gym, kitchen, spa, etc. 

It’s worth mentioning that garage conversions don’t necessarily need to be self-contained with their own doors, they can form an open-plan part of your ground floor, allowing you to extend the rooms adjacent to the garage. You can even reconfigure your entire ground floor, adding significant extra space via a garage conversion. 

Real Homes provides some awesome ideas for garage conversions that go above and beyond the basics. Unlocking that extra space for your home allows you to make major changes if you so desire, or you can keep things simple if you prefer. 

Pros of Garage Conversions

  • Garages are already generally structurally sound (in the case of brick or concrete garages). Very little building work is required to repurpose a garage into a general residential space. 
  • Many garages already carry some level of insulation, electrics and even plumbing. This reduces the workload. 
  • Garage conversions don’t take up garden space like other extensions. 
  • Planning Permission is not usually required for garage conversions, more details on this below.
  • Unlocks space for open-plan configurations or more grandiose redesigns of your groundfloor space. 
  • Can form a platform for a second-storey extension to create a larger annex-type space. 

Cons of Garage Conversions

  • Garage conversions are obviously at the expense of the garage itself. 
  • You’ll need to trade away your garage parking space, which could come at considerable cost if you don’t also have a driveway space. If you do have a driveway or other form of safe parking then this is rarely an issue. 
  • Garage conversions are subject to rigorous Building Regulation approval seeing as they’re designed to be occupied and lived in. 

Garage Conversions Guide to Planning Permission and Building Regulations

Prior to undergoing any garage conversion work whatsoever, there are two crucial considerations: Planning Permission and Building Regulations. Let’s start off with Planning Permission. 

Do I Need Planning Permission for Garage Conversions?

Resi estimates that only 10% of garage conversions require Planning Permission, the rest fall under Permitted Development Rights. Permitted Development Rights (PDRs) provide certain rights for property owners to modify their property legally without Planning Permission.

There are certain areas where Permitted Development Rights do not apply or are limited, such as:

  • Conservation Areas
  • Areas of Outstanding Natural Beauty
  • World Heritage Sites
  • National Parks

In any of these locations, it’s imperative you contact your Local Planning Authority prior to carrying out any work. 

Garage conversions may also be specifically limited in:

  • Flats/maisonettes
  • Listed buildings (you will need Listed Building Consent)
  • Some new developments or leasehold property where you’ll have to look for restrictive clauses in your lease 

Otherwise, garage conversions will rarely need Planning Permission so long as:

  • The garage uses similar building materials to the rest of the home.
  • The conversion does not otherwise enlarge the building. This may still be covered by PDRs, but will fall under rules for an extension or outhouse modification. We have covered these rules in detail in this article.  
  • All works are internal. If you plan on extending the roof then this is usually possible under PDRs up to a maximum height of 4m, but you must contact the Planning Authority first and meet other criteria for extending.  

In the case of detached garages, conversions may require full Planning Permission (though this is still rare and likely only concerns larger garages). 

It’s always highly recommended that you contact your Local Planning Authority to discuss your plans and obtain a Lawful Development Certificate prior to undertaking work.

Some contractors and architects will require this prior to undertaking work. You will be able to discuss Planning Permission and PDRs with your contractor and/or architect or surveyor. 

Building Regulations for Garage Conversions 

You’ll need to alert your local Building Control department about your garage conversion. 

They will likely send around a building inspector during and after the building is complete and will issue you with certification once the work is finished and fully authorised. Your builders/agency should organise this, always ask if you have any queries. 

The following must meet specific criteria to adhere to Building Regulations:

  • Fire safety; the conversion must have adequate fireproofing and escape routes.
  • Acoustics; the conversion must be adequately soundproofed.
  • Structural; the garage should have sufficient foundations. These may have to be strengthened. 
  • Electrics; must be safely installed by a qualified electrician. 
  • Plumbing and heating; as above but by a plumber. 
  • Insulation; the building must be well-insulated for energy performance. 
  • Ventilation; to prevent moisture buildup. 

If building work involves a neighbour’s wall then you’ll also have to consider the Party Wall Act. Your architect and/or builder will be able to advise you on this. 

Garage Conversion Cost Breakdown 

Foundations, Walls and Windows

Most substantial garages won’t require much work on the foundations, if any, but this really depends on the age of the garage. Most garages built in the last 40 to 50 years won’t require foundational work. 

The garage door will need to be removed and walled up with windows and maybe a door. You may also need to knock through an interior wall, particularly if you want to create an extended open-plan space. This could cost an additional £1,000 or so depending on the size of your wall. 

Flooring and Plastering

New floors will need to be laid, and this can be one of the more expensive elements of a garage conversion, particularly as floor insulation of some sort is usually required for Building Regulations. Tiled or wooden floors can come at a significant cost and would probably push your garage towards the higher end of the spectrum. 

Insulation, Heating and Utilities 

Some garages are already well-insulated, but additional insulation is often required in the roof at least. Thermal performance is a requirement to meet Building Regulations. 

Heating can be provided via radiators connected to your central heating system, electric heating or underfloor heating. Underfloor heating is a popular option and may add some £500 to the cost of a standard garage conversion. 

Plumbing and heating will be cheaper for integrated garages, whereas the job will likely be much more complex for external garages if they’re a fair distance from the home. 

Electricity 

Garage conversions need to be safely wired by a qualified electrician to meet Building Regulations. Again, this is a simpler job if your garage is integrated into the house. 

Architectural and Interior Design Fees 

Most garage conversion builders work with architects, or are architectural agencies themselves. The architectural fees will usually be included in the total project cost.

The same goes for interior designers, you could choose to work with a separate designer or choose one that works with your building firm. 

Choosing a Builder or Architectural Agency 

There are many reputable garage conversion specialists around the UK. You can look for some of the following accreditations when choosing one. Make sure that the firm has a proven track record and a portfolio of successful projects to look at. 

Other professionals collaborating on the project may also ideally be part of the following organisations and schemes:

Get Prices on a Garage Conversion Near You

We’ve done our best to give you a good idea of what you can expect to pay for converting a garage.

However, our guides are not a substitute for a fixed quote specifically for you.

We work with all the best garage converters ready to price your job. Get free, no-obligation quotes in your local area and compare prices using the form below.

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