Feasibility Check

Attached Garage Conversion



These are units built by converting an attached garage to a new unit. To legally register a unit there are some specific requirements you will need to meet. The checklist below is a good starting point to see if a garage is a candidate for this kind of suite. Remember to verify all code requirements with your local code, or hire a professional to do this for you!



Spatial Requirements


Can the garage accommodate a unit?


Most single-car garages are at least 2.7m by 8m. If the garage is this size you may be able to fit a micro studio but probably can’t fit a traditional studio which is often a minimum of 30mSq.

Most single-car garages will only be able to fit a small studio apartment, but large garages may be able to fit a one-bedroom.

You will need to add insulation to the garage - this is usually done from the interior. Subtract 10” from each dimension of the interior to get a more accurate idea of how big the space will be once it is insulated.

Measure the ceiling


Generally, a unit must have a ceiling height of 2300mm over 75% of the floor area in a living room or space, dining room or space, or kitchen space with a minimum clear height of 2100mm.

Measure the ceiling to see if it meets this minimum. Many garages have tall ceiling spaces which may allow you to put in a mezzanine.

Generally the minimum ceiling height is 2100mm (6’-10.5”) above and below a mezzanine.

Verify the ceiling height requirements with your local building code.


Are there windows?


Natural light is a necessity for housing. If the garage already has windows this is a plus!

The garage door can be removed and filled in with walls and windows to provide more light into the space, but you may want to consider adding a few more windows to make the space feel brighter.

The size of windows you will need for a unit depends on how big the unit is and what type of room you are in. Some windows may need to be used as an exit (more on this below!) The building code has minimum window sizes for different areas in your unit. These are generally:

  • Living room or dining room - 10% of floor area
  • Bedrooms - 5% of floor area
  • Laundry room, kitchen, bathroom - no windows required. 

If a window is used for exiting you may need a larger window. Verify the window size requirements with your local building code.



Getting in and out safely


Access/egress


There are two ways you can provide access to units within your house:

Option 1) You can provide direct exterior access.

This means each unit has its own fire-separated exit path from the main space of the unit to the exterior. In this case, each unit will have its own exterior ‘front door.’

Option 2) You can provide access to the exterior through a shared entryway.

This means units will share a ‘front door’ and have a small section of communal space from which they access each of their units.

Most garages can be retrofitted to have a direct exterior access. You may also need to provide a second exit through a window in your unit that is large enough for a person to get through and easily open without any tools.



Electric, Heating/Air, and Plumbing


Check your utilities


Check your electrical service

Step 1 - Check the existing electrical service on your electrical panel

Find the circuit box. Find the main cut-off switch—this is typically the biggest switch in the box. The cut-off switch often has the number of amps written on it. You will likely need a minimum of 100 amps.

Step 2 - Use the chart below to calculate the existing electrical capacity (Coming soon.)

Step 3 - Check how many units you can add based on the existing electrical capacity. (Coming soon.)

Verify the level of electrical service you will need with a licensed electrical engineer or electrician.







Health and safety

Working with your slab


You will need to level and seal your slab

The concrete floor in garages is not always level and often has oil leaks or other contaminations. You can seal the floor and add a new flat floor with insulation above the existing one.


Cost considerations


Whenever you are deciding what type of unit to add, it is important to understand what are the major cost considerations. For a garage conversion these include:

- retrofitting insulation
- new bathroom
- new kitchen
- connections to main home (plumbing/electrical/communications)
- new openings (windows/doors)


Case study:



This garage conversion case study involves creating a distinct living unit by adding to the existing structure of the garage to create a self-sufficient living unit. Existing walls are insulated from the inside and fire separated from the rest of the house. The project introduces a new kitchen and bathroom with very few additional partition walls. Plumbing is a major consideration as the existing garage has no connections for the required kitchen and bathroom.


Existing Floor Plans



Case Study Plans
               
         
 


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