Planning a home addition in Ontario? Use this checklist to ensure your permit application is complete and avoid delays. Incomplete applications are the #1 cause of permit processing delays.
Required Documents
- Completed permit application form (from your municipality)
- Site plan showing addition location and all setbacks to property lines
- Existing and proposed floor plans with room dimensions
- Exterior elevations (all sides affected by the addition)
- Building cross-sections showing floor-to-ceiling heights and structural assembly
- Foundation plan for the addition
- Structural details for connections to existing building
- Energy compliance form (SB-10 or SB-12)
- Schedule 1 - Designer Information form (with your BCIN designer's information)
- Lot survey or reference plan
Additional Requirements
Some municipalities may require a lot grading plan, tree preservation plan (arborist report), heritage review, or geotechnical report depending on your property's conditions and location.
Do You Need a Permit for a Home Addition?
Almost always, yes. Any addition that increases your home's footprint or adds habitable space - a rear or side addition, a second-storey addition, a sunroom, or an over-garage addition - requires a building permit with a full drawing set. The only work that usually skips a permit is cosmetic (paint, flooring, cabinets in the same footprint).
Zoning: Check This First
Before drawings, confirm your addition fits the zoning by-law: setbacks from property lines, lot coverage, building height, and floor-area limits. If the addition exceeds any of these, you will need a minor variance from the Committee of Adjustment, which adds two to four months - so it is worth checking early.
Structural Considerations
An addition has to tie into your existing foundation and framing, and the new loads have to travel safely to the ground. Depending on spans and how the addition connects, your permit may require P.Eng-stamped structural drawings. We coordinate the architectural and structural sets so the connection details satisfy the examiner.
Timeline & Cost
A complete addition drawing set is typically ready in 5–10 business days; municipal review then runs roughly 10–20 business days for a house. Designer fees usually range from about $2,000 for a small addition to $6,000+ for a large or two-storey addition. See our cost guide and timeline guide.
Avoid These Common Mistakes
- Skipping the zoning check and discovering a variance is needed after drawings are done
- Submitting without a current lot survey
- Undersized footings or missing structural connection details
- Leaving out energy compliance (SB-12) documentation
Ready to get started?
Call 416-558-9607 for a free consultation or request a quote online.