Garage conversions: the ultimate guide to budgeting, planning and designing a garage conversion

Garage conversions are a great solution for anyone who wants more space but doesn't want to add-on. Find out how to successfully convert a garage into extra living space

Garage conversions: by OB Architecture
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(Image credit: Martin Gardner)

Before you begin planning a garage conversion, first consult a real estate agent about whether converting your garage could have a negative impact on your property's price. If you'll be living in your home for years to come, it may well be worth proceeding regardless of what they say, but if garages are highly sought after in your area, think carefully before converting yours.

Before you start work on the conversion, consider what you’ll do with everything currently kept in the garage. If you store a lot of garden tools or lawn equipment in it, you may need to factor a shed into your plans; if it’s where you keep your chest freezer, you’ll need to work out where it can be moved to – or whether you can live without it. 

If you really have no room anywhere else for these things, perhaps a partial garage conversion (or a conversion that has lots of storage space set aside within it) will work better for you.

Do you need insurance to convert a garage?

In a word, yes. While some homeowners insurance policies will cover the work done during a garage conversion, not all will, so it pays to contact your insurance provider to double check. If you fail to insure yourself properly, and there is any loss or damage caused during the works, it's unlikely that your home insurer will cover you while your home is undergoing modification or renovation.

It's also crucial to check that anyone you engage to work on the property has their own insurance that covers both themselves and their subcontractors, too. 

Planning a garage conversion: can you DIY convert a garage?

Planning a garage conversion on a budget? Some people choose to come up with a design themselves and carry out all the work they can on a DIY basis – a good option for those with limited funds and the spare time.

You can do most of the garage conversion yourself, which is ideal if you’re on a tight budget, but your work will still need to be regularly inspected and anything that's not up to code will have to be redone at your own expense. 

spare bedroom in a garage conversion


Garage conversion structural essentials

When planning a garage conversion, there are some important structural considerations that you need to tackle early on.

Replacing the garage door

The garage door will have to be replaced with a new wall and/or window. This may mean new a new foundation for the portion where the door once sat. Note that you'll need at least one window to meet building codes. Expect to pay, including a small window, around $1,300 for this.

Garage converted into a home office seen from the exterior by Bliss Interiors

(Image credit: Bliss Interiors)

Upgrading the garage roof

Unless it is below another level of your home, the garage roof will almost certainly need to be upgraded to ensure it is water-tight. Use new shingles and materials that match those of the main roof. If you can swap a flat roof for a pitched one it will make the conversion less obvious from outside, and the new raised pitch may have space for skylights, which will again help to camouflage the space's former life as a garage.

Internal wall work in a garage conversion

An internal structure of stud walls built inside your garage will need to have insulation added to increase energy efficiency. Expect to pay around $1-$2 per square foot for insulation.

Ventilating, heating and insulating a garage conversion

Ventilation: If you plan to use your garage as a bathroom or kitchen, you'll need a form of ventilation. Typically, that's either via an exhaust fan or window, but codes vary by location. 

Insulation: Building regulations require walls, windows, the floor and roof to be insulated to a certain level. It’s important to get this right — poorly done, it will result in a cold, damp room. 

Heating and cooling:  If your boiler can't cope with another radiator, or it’s not practical to run new ductwork, consider a ductless mini-split, which functions as both heating and AC, and is mounted to the wall. 

Electric and plumbing in a garage conversion

Plumbing: If you're planning on installing a toilet or shower, double check the location of the existing water and waste pipes – doing so may help you keep garage conversion costs down, if you can arrange the fixtures in a convenient place. 

Electrical: Ask your electrician or builder if rewiring the garage for lights and electric sockets will mean that your electrical service will be put under strain, too. They may suggest increasing your home's electrical load.

If yours is a detached garage conversion, wiring can be run through an underground conduit, although a new connection may be needed if it is to be a separate dwelling. A good electrician will always be able to advise.

Expect to pay around $150-$200 to have a new electrical outlet installed; this price will be negotiable the more electrical work you are having done.

Kitchen in a garage conversion

This garage conversion is now a spacious kitchen

(Image credit: Clear Architects)

Garage conversion build schedule

  • Check structure is suitable for conversion
  • Produce design drawings
  • Confirm permits needed for garage conversion
  • Apply for permits
  • Produce detailed design and building regulations drawings
  • Check if your homeowners insurance covers the work being done to your garage
  • Strip garage to studs and rectify any moisture issues
  • Make any structural alterations, including knocking through to the rest of the house
  • Add a moisture barrier/insulation for the floor, if necessary
  • Add moisture barrier/insulation to the walls
  • Install new windows and door frames
  • Tackle joinery, wiring and plumbing
  • Plaster and drywall
  • Paint walls
  • Install moldings, flooring and light fittings
  • Decorate

Designing a garage conversion >>