Secondary Dwelling Unit (SDU)

In 2025, as part of the Government of Canada’s Housing Accelerator Fund, the City of Fredericton agreed to permit four units on more parcels across the city. Fredericton's approach was unique, focusing on maintaining existing homes and increasing the number of units through Secondary Dwelling Units (SDU) appropriate to lot size and frontage. This gentle, homeowner-friendly approach will help Fredericton continue to grow in a way that offers a broad range of solutions to address the housing crisis. The following page provides answers to some commonly asked questions for homeowners curious about the changes and how they might develop Secondary Dwelling Units.

General Questions

What is a secondary dwelling unit?

A Secondary Dwelling Unit (SDU) is defined as a dwelling unit which is secondary to the main residential dwelling on the lot. There are four types of secondary dwelling units:

Accessory Apartment: a secondary dwelling unit that is attached to the side or rear of or within the main residential dwelling.	Image
Basement Apartment: a secondary dwelling unit contained in the basement of the main residential dwelling.	Image
Garden Apartment: a secondary dwelling unit that is detached and located at grade to the rear of the main residential dwelling.	Image
Garage Apartment: a secondary dwelling unit located above a detached garage to the side or rear of the main residential dwelling.	Image

While these can be used in combination, you cannot have both a garden and a garage apartment on the same lot.

Am I required to add four units to my property?

Can my neighbour tear down their home to build a four-unit building?

What exactly was changed in the zoning bylaw?

The following changes were made to the zoning bylaw as part of By-law Z-5.328 and By-law Z-6.8:

Combined zones to increase flexibility and reduce redundancy (R-1, R-1N and R-2 combine to form a new R-1 zone; TP-2 and TP-3 combine to form a new TP-2 zone)
Allowing up to 3 SDU on a lot in all low-rise residential zones, subject to minimum lot area and frontage standards;
Adding the garage apartment as a new SDU type (unit over detached garage) with associated development standards to address privacy as well as massing and height of the upper level;
Reducing minimum lot area and frontage standards;
Revising parking rules specifically for SDUs to provide more flexibility, including tandem parking (one car parking behind another) and parking in the required front yard (on a driveway only), among others;
Reducing driveway and parking aisle widths for all developments up to 4 units for more flexibility;
Reducing the number of parking spaces required for new development up to 4 units.

I want to add additional units to my property

The following section provides responses to common questions for owners who would like to add additional units to their property. You must apply for a building permit before constructing any additional units.

Do I have to own the property?

Do I need to know the Zone I live in?

How many units can I add?

Depending on the zone, you will have different lot area and frontage requirements that limit the number of additional units.

For example:

Say I have lived at 123 Sesame Street for 3 years. The property, which is zoned R-1, has a lot area of 500m2 and a frontage of 16m. If this is compared to the zoning regulation below, I can see that I can build two additional units.

Secondary Dwelling Units
Number of Secondary Dwelling Units (MAX)	Lot Area (MIN)	Lot Frontage (MIN)
1 Unit	345 m²	11.5 m
2 Unit	450 m²	15 m
3 Unit	540 m²	18 m

You must meet the minimum standards in both "Lot Area" and "Lot Frontage" to build the associated max number of secondary units. For instance, if the example lot above at 123 Sesame Street only had a frontage of 14m, I could only build 1 secondary unit despite the 500m²area.

Please consult the zoning bylaw here to determine what you are permitted to do on your property or reach out to planning@fredericton.ca.

What kind of SDU should I build?

Another key aspect of building new units is determining what form they will take. As mentioned in the preceding section, Secondary Dwelling Units can take the form of either:

Basement Apartments
Accessory Apartments
Garden Apartments
Garage Apartments

While these can be used in combination, you cannot have both a garden and a garage apartment on the same lot. For example;

Basement Apartment + Garage Apartment = permitted
Accessory Apartment + Garden Apartment = permitted
Garden Apartment + Garage Apartment = not permitted

This prevents three separate structures containing a dwelling unit on a single lot.

What should my SDU look like?

The zoning bylaw provides specific directions for the required setbacks and design of secondary dwelling units depending on the form you choose. Please consult the zoning bylaw for more specific information. The building will also need to conform to Canada's National Building Code.

The Canada Mortgage and Housing Corporation (CMHC) also provides a housing design catalogue with potential floor plans for inspiration. Please refer to Atlantic Accessory Dwelling Unit 01 as an example. If you proceed with these plans, it is your responsibility to ensure that they still conform to setbacks and other requirements of the zone.

How much parking do I need to provide?

In the Central Business District (CBD) and Area 1 (see map), you do not need to provide any additional parking spaces. In Area 2, you require one space per unit; however, parking may be:

Provided in tandem
Located within the front yard setback, but only on the driveway (max two spaces)
One parking space for a garage apartment or garden apartment may encroach into the required rear yard setback up to 2m from the rear property line.

What are the servicing requirements?

How does the addition of new units affect property or income taxes?

Any additional information should I consider?

Is there any funding available?