Small Residential or Commercial Additions

Service Description

A building permit is required for an addition to a small residential building such as a detached house, a semi-detached house, or a townhouse, and for small additions to commercial buildings.

Service Outcome

Building Permit

General Information

All drawings are to be drawn on standardized sized sheets, drawn to scale, fully dimensioned, signed and dated.

If drawings were prepared by a qualified designer (as defined under Div. C, Part 3, Section 3.2 of the Ontario Building Code), drawings must include the designer's name, registration number, qualification identification number, signature, and stamp/statement that the person has reviewed and taken responsibility for the design activities.

Required Documentation

Site Plan (Site Plan Checklist below)

  • Survey or site plan showing property lines, lot area, right-of-way or easements (referenced to a current survey) 
  • Location of existing/proposed buildings with overall dimensions and include setback dimensions to property lines and adjacent buildings. 
  • Summary of permitted and proposed zoning provisions to include lot area, building area (GFA), coverage, and grade elevations to confirm height.
  • Indicate dimensioned parking areas, driveways, hard & soft landscape treatments, accessory structures (sheds, decks, detached garages, etc).

Floor Plans

  • Fully dimensioned, for each level showing existing & proposed uses of all spaces, including location of smoke alarms & carbon monoxide detectors and all plumbing fixtures. 
  • Provide existing/proposed construction with foundation & exterior wall information, showing interior partitions and structural framing above.

Roof Plan

  • Existing/proposed roof layout showing roof structure, skylights, roof slopes, hips/valleys/peaks and ventilation.


  • Exterior finishes with roof slopes, window/door type, locations & sizes including height of sills above floor level. 
  • Provide area of exposed building face, percentage/area of unprotected openings and required limiting distance(s). 
  • Show exterior decks/landings, stairs, guards/handrails. 
  • Provide overall building height dimension.


  • Cross section(s) to show existing/proposed building construction and specifications of all floor, wall, & roof assemblies. 
  • Provide footing & foundation wall details including height of exterior grade above basement floor. 
  • Show floor to floor, floor to ceiling and overall building heights. 
  • Detail stairs, landings, guards & handrails.

Residential Garages or Accessory Structures

Garage or Accessory Structure to be shown on Site Plan, showing the 

  • Location of all existing and proposed buildings on the lot, setbacks to property lines, distance between proposed structure and other buildings on the lot.
  • Dimensions and locations of all required vehicle parking spaces and the driveway used to access the spaces(s).
  • Floor Plans, Elevations, Sections, Construction Details of the structure, including the details of the concrete floor slab, such as the concrete strength and re-enforcement proposed.

Decks and Verandahs

Plans for decks and verandahs must show the following:

  • Details of footings, including footing size, spacing, depth, height above grade and frost protection details. 
  • Sizes and Locations of all Columns; sizes, locations and spans of all beams.
  • Stair Construction Details, including height and depth of stair treads and headroom above stairs (where applicable).
  • Guard Construction Details, including information about openings and climbability, and the location of the guards with respect to stairways, landings, and edges of the proposed platform.

Mechanical and Plumbing Requirements (If Applicable)

If your project includes a Mechanical (HVAC) please submit the Energy Efficiency Design Summary Form and Mechanical Ventalation Design Summary (below) with your building permit application.

Plumbing and Drain Permits

If your project includes a plumbing or drain and water service elements please submit a Plumbing Application (below) with your building permit application. No plans required unless the project includes a reverse sloped driveway. If the project includes a reverse sloped driveway then drawings must be submitted showing details of reverse sloped driveway and drain plan

Required Forms

Site Plan Checklist
Plumbing Permit Application
Mechanical Ventilation Design Summary
Energy Efficiency Design Summary
Application for a Permit
Optional:  Cross-section of a House