Secondary-Suites-NeedtoKnowMortgage Helpers, Income Suites, Basement Suites, Secondary Suites, In-Law Suites, Nanny Suites, Garden Suites…So many names, so much confusion.

With high property prices, having a secondary accommodation that brings in rental income or allows multiple family members to live under one roof without living ‘with’ each other is very common.  A lot of people go house hunting for a place with a suite, or for the infamous ‘easily suitable’ gems.  There are however, a lot of rules and regulations around these suites, where they can be, how big they can be, and how they must be built to be ‘legal’.  So the big questions are: What is a suite?  What makes it legal?  And why does it have to be legal?

To answer one question simply – suites need to be legal to ensure that human safety is not compromised by the building.   When a house is built it has to pass inspections and needs to meet certain criteria in order to be considered habitable.  The same goes for a suite, even if it is built into an existing (already inspected) building.  By adding a suite you are changing the life safety and building usage, thus you must make sure it meets the codes.

There are many names for suites but they all fall into 1 of 2 categories within the BC building code.  To help clarify what kind of suite you have and what category it falls into we have made a simple yes or no diagram:


If you have a ‘Regular Suite’ you must meet the regular code requirements of any residential building.  For this post we are not going into detail about Regular Suites.

If you have a ‘Secondary Suite’ there is a special set of codes that you can use to make your suite legal.  Many of these secondary suite codes are relaxations or special allowances to assist in make suites (that are safe) in existing order buildings.  By older…we mean pre-90’s buildings.

We have developed a list of some notable allowances that are applicable to secondary suites.


From Section 9.36 BCBC 2012


  • maximum size – the lesser of 968.75 ft2 OR 40% of total living area of the residential building
  • example: If you have a 2000 ft2 house your secondary suite can only be 800 ft2 (40% of 2000). The suite square footage is calculate as all areas which are for the suite use only, this does not include shared facilities or storage as long as proper fire separate exists between these suite and these ares.

Ceiling Height

  • 6’6-3/4”
  • Some municipal bylaws state 6’6” some 6’7″.  By code it is 2m = 6’6-3/4” or 78.75”

Bulk Heads

  • one must be able to travel from one area to the next without a drop in ceiling height below 6’6-3/4”.
  • things to look for – structural beams, heating ducts and plumbing dropped below floor joists and crossing walking paths.
  • rule of thumb – if you have to walk under it to get from point A to point B and it is below 6’6-3/4” it must be changed or removed

Exit Stairs

  • minimum width 2’10”

Door Height

  • minimum 6’6”

Fire Separation

  • no min rating if sprinklers present in entire building;
  • 30min if hard wired (not battery operated) smoke alarms that are interconnected between the residential units (this means
  • when the alarm goes off in the suite it sets off the alarm in the main house and vice versa);
  • 45min without interconnected smoke alarms


  • can service both suites IF there is a fire damper in each duct to prevent smoke movement between suites
  • separate heating systems are preferred as a rule, some municipalities state this as a must



Each municipality has bylaws which further govern how we build and where.  Some municipalities don’t allow secondary suites, some call them by different names, some allow them but with further restrictions on how they can be built.

Because this is such a huge topic and the information varies so much by City we have put together a document to assist people in getting started with a legal Secondary Suite.

If you are house hunting with the intention of building a suite make sure you familiarize yourself with the document below or give us a call.  We actually house hunt with our clients (and their Realtors) regularly to ensure the dream of secondary suites become a reality after the keys exchange hands.


Download the Secondary Suites Overview created by Sitka Studios.  Inside there is information specific to the municipalities of the Lower Mainland of BC, building code references, municipal bylaw references and links to further information by City.


Our Secondary Suites Overview may not answer all of your questions or address your specific situation directly.  Contact us with your specific questions regarding your secondary suite project or to inquire about house hunting with a designer.