If you are a homeowner and you have questions, such as what types of home projects require a building permit, what by-laws to keep in mind before you build, and how to have your utilities hooked up - the Town of Ajax is here to help.

Construction that Requires a Building Permit

Before starting your project check if you require a building permit. If your project does not require a building permit, you must still comply with the requirements of the Zoning-By-law.

  • Adding a bedroom
  • Addition to a building
  • Attached garage, carport, shed or other roof structure of any size
  • Detached garage, carport or roof structure more than 10 square metres in building area
  • Detached shed that is:
    • more than 15 square metres in building area,
    • more than one storey,
    • constructed closer than 3 metres from other structures,
    • used for storage purposes that is not ancillary to the principle building on the lot, or
    • has plumbing in it
  • Additional dwelling unit
  • Decks or platforms more than 0.6 metre above grade or attached to another structure
  • Demolition of a structure greater than 10 square metres in building area
  • Excavating/underpinning a basement or crawl space
  • Basement finishing
  • Industrial, commercial, institutional and multi-residential construction, alterations, or changes of use
  • Increasing the size of an existing opening
  • Changing the heating system or altering ductwork
  • Plumbing additions and alterations
  • Reinsulating
  • Removal of a loadbearing wall
  • Residential dwelling unit
  • Retaining wall greater than 1 metre in height
  • Septic system installations and alterations (Requires a building permit through Durham Region)
  • Signs, permanent
  • Site servicing (water or sewer lines) for all building types
  • Solar panels that are mounted to a building or have an area of 5 square metres or greater
  • Tent or group of tents more than 60 square metres in aggregate ground area, attached to a building, or constructed within 3 metre of any structure
  • Retrofit an existing additional dwelling units under Section 9.8 of the Ontario Building Code.
    (This only applies to additional dwelling units built before July 14, 1994.)
  • Woodstove or wood-burning fireplace

Building Guides

We have created guides for the most common residential building permit applications to help residents understand the building permit application process. Each guide provides an application form, documents checklist and sample drawings. The sample drawings are intended to be used for reference only and cannot be submitted with your application.

Residential Building Permits

The following information is required when submitting a permit application for a new dwelling unit or addition.

Designer Requirements

All construction drawings for the permit application are to be prepared by the property owner, a qualified designer, architect or professional engineer, or a combination thereof. Designs outside the scope of Part 9, Division B of the Ontario Building Code (OBC) may require review by a professional engineer.

HVAC drawings are required to be prepared by a qualified designer, architect or professional engineer.

The OBC requires qualified and registered designers who review and take responsibility for design activities to include the following information on any documents submitted to the Chief Building Official:

  • The name and building code identification number (BCIN) of the registered firm.
  • A statement that the qualified person has reviewed and taken responsibility for the design activities.
  • The name and BCIN of the qualified person.
  • The signature of the qualified person.

Drawing Requirements

The following is a list of drawings and documents that may be required to accompany applications for permits according to the scope of work:

  • Lot grading plan
  • Foundation plan
  • Floor plans/framing plans
  • Roof plan
  • Roof truss layout and individual truss data sheets
  • Building Elevations
  • Sections and details
  • HVAC drawings and calculations
  • Manufactured products specifications and approvals (i.e. Exterior insulation and finish system, guards, etc.)

All documents and drawings are to be in PDF format, unsecured and not password protected. All drawings shall be fully dimensioned, drawn to scale. Note all sizes and types of construction materials to be used and their respective locations, finishes to all walls, ceilings and floor, and all existing and proposed fire separations.

Additional Information

The following is required for the building permit application process:

Driveway Widening, Curb Cuts and Boulevard Encroachments

The Town recently made several revisions to its policies for Driveway Widening, Curb Cuts and Boulevard Encroachments. These changes were introduced to provide property owners with more flexibility to alter their properties. If you have any questions, please send an email to PlanningServices@ajax.ca providing your municipal address and outlining the nature of your request.

Property owners looking to widen the depressed portion of their curb can submit a Curb Cut Application to the Town. All curb cut applications must be supported by a Curb Cut Concept Drawing that visually demonstrates all aspects of the proposal. 

For more information on driveway widening, visit ajax.ca/drivewaywidening

Locate Utilities - Call Before You Dig

Digging into an underground utility can be dangerous and have costly consequences. Even if you are just digging with a shovel, be sure to get locates in advance. Contact Ontario One Call for the location of buried pipes and cables prior to any excavation work.

Request your free locate online at ON 1 Call or call 1-800-400-2255.