Basement Underpinning Permit Drawings in Ontario
Basement underpinning increases your basement ceiling height by lowering the floor — a common requirement for legal basement apartments in Ontario. Ontario Design Studio prepares BCIN-certified permit drawings coordinated with P.Eng structural designs for underpinning projects across Ontario.
When Is Underpinning Required?
If your existing basement ceiling height is below 1.95m (6'5"), underpinning or bench footing is typically required to achieve the minimum height for a legal dwelling unit under the Ontario Building Code. Many older Ontario homes have basement ceilings of 6'0" to 6'2" — requiring 3 to 5 inches of additional depth.
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- Foundation plan showing underpinning sequence and sections
- Structural details coordinated with P.Eng — footing dimensions, reinforcement, and sequence plan
- Cross-section showing existing and proposed floor levels
- Waterproofing and drainage details for the new deeper foundation
- Grading plan if exterior grade changes are required
Related Services
- Legal Basement Apartment Permits
- Basement Separate Entrance Permits
- Building Permit Drawing Cost Guide
Frequently Asked Questions
What is basement underpinning?
Basement underpinning is a construction process that increases your basement ceiling height by lowering the floor level. This involves excavating beneath your existing foundation in controlled sections and pouring new concrete footings at a deeper level. It's commonly required when converting a low-ceiling basement into a legal dwelling unit.
When is underpinning required for a basement apartment?
If your existing basement ceiling height is below 1.95 metres (6 feet 5 inches), underpinning or bench footing is typically required to achieve the minimum height for a legal dwelling unit under the Ontario Building Code.