Process · 6 min read · Last updated
Ontario's Building Code sets legal deadlines for permit review: 10 business days for a house, up to 30 for the most complex buildings — but the clock only starts once your application is complete. That one word explains why a "10-day" permit can take months, and it is the part you can actually control.
The legislated review windows
Division C of the Ontario Building Code requires the chief building official to issue the permit or refuse it (with reasons, in writing) within a set number of business days after receiving a complete application:
| Building type | Review deadline |
|---|---|
| Houses (detached, semis, townhouses) and most small residential work — decks, renos, additions | 10 business days |
| Other small buildings (generally up to 3 storeys / 600 m²) | 15 business days |
| Large buildings | 20 business days |
| Complex buildings (post-disaster, high hazard and similar) | 30 business days |
So for a typical homeowner project — a deck, a finished basement, an addition — the municipality has two working weeks to respond once everything required is in.
Why real-world timelines are longer
- Incomplete applications. Missing site plans, unsigned forms or drawings without the required details stop the legal clock from ever starting. This is the single biggest source of delay.
- Zoning problems. If the design breaks a setback or height limit, the application stalls until you redesign or obtain a minor variance — a process that adds weeks to months (our zoning guide explains how that works).
- Other approvals ("applicable law"). Conservation authority permissions, heritage approvals or tree permits must be in place before the building permit can be issued.
- Revision cycles. When the examiner finds code issues, they send comments; each round of "revise and resubmit" typically adds one to three weeks.
- Season and volume. Spring and summer submission spikes stretch practical response times in many municipalities.
Typical end-to-end timelines
Counting from "started preparing drawings" to "permit in hand," these are realistic planning ranges for straightforward projects with no variances:
| Project | Realistic total timeline |
|---|---|
| Deck | 2–6 weeks |
| Basement suite / major interior reno | 4–10 weeks |
| Addition | 2–4 months |
| New custom house or garden suite | 3–6+ months |
How to get your permit faster
- Submit complete. Use your municipality's application checklist line by line; a complete first submission is the closest thing to a fast lane.
- Check zoning first. Confirm setbacks, height and coverage before drawings are finalized — through the city's zoning map, a preliminary review service, or a tool like Permits2Go.
- Use qualified designers. BCIN-registered designers produce drawings examiners can approve without rounds of comments.
- Respond fast to examiner comments. Every day a comment letter sits unanswered is a day added to the schedule.
- Ask about e-permits. Most large Ontario municipalities, including Toronto and Mississauga, accept digital submissions — online applications avoid mail and counter queues entirely.
After the permit is issued
Construction must generally begin within six months of issuance or the municipality may revoke the permit. During the build you will book mandatory inspections at prescribed stages (footings, framing, insulation, final, and so on) — build those into your schedule too. And never start work before issuance: municipalities charge steep surcharges for work begun without a permit, as covered in our permit cost guide.
Skip the paperwork
Describe your project in plain English and Permits2Go finds, fills and assembles the exact municipal forms you need — for Toronto, Mississauga and municipalities across Ontario.
This guide is general information, not legal or professional advice. Permit requirements, by-laws and fees change and vary by municipality — always confirm the current rules with your local building department before you design or build.