Home Additions · Ontario Building Code
Home addition permit drawings — zoning checked first.
BCIN #511123. Rear and side additions, second storeys, sunrooms and covered porches. We confirm what the by-law allows before a line gets drawn.
- Zoning first — coverage, setbacks and height confirmed before design.
- Structural load path worked out from the new roof down to new footings.
- Spatial separation checked at every wall facing a lot line.
- We file the application with your municipality for you.
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Tell us the municipality and what you're planning — same-day reply on weekdays.
What It Is
What are home addition permit drawings?
An addition permit set covers everything involved in adding floor area to an existing house — a rear or side bump-out, a second storey over an existing single-storey, a sunroom, or a covered porch. It documents what's there now, what's being added, and how the two are structurally and thermally joined.
Additions are the scope where zoning does the most damage to a plan, and it does it early. Lot coverage, setbacks, building height and — in some municipalities — angular plane rules decide how big the addition can actually be. That check happens before design, not after.
Code & By-Laws
What the Code and by-laws generally require
An addition is reviewed as new construction joined to an existing building, so both sets of rules apply. Typically:
- Zoning — lot coverage, setbacks, building height, and angular plane or overlook rules in some municipalities.
- Foundation — new footings below frost, or underpinning where the addition ties into what's there.
- Structural — beams, lintels and a continuous load path to the foundation; a P.Eng where the loads warrant it.
- Spatial separation — limiting distance and the permitted area of unprotected openings on walls facing a lot line.
- Energy compliance — an SB-12 package covering the new heated area.
- Heating and ventilation — whether the existing furnace can serve the added area, and a new HVAC design if it can't.
- Egress, headroom and stairs in any new or altered space.
- Land survey — most municipalities require a current survey for an addition.
- Grading and drainage — a lot grading plan in many municipalities.
- Tree protection where the work is near a protected or municipally owned tree.
This is a general guide, not a code review. What applies to your project depends on the scope, the municipality and the age of the building — tell us what you're planning and we'll confirm what's actually needed.
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