Basement underpinning design in Toronto, coordinated with a Professional Engineer.

Yes. Toronto Building's Residential Underpinning guide covers a building permit for underpinning the foundation of an existing house. That means new footings beneath the existing ones to gain depth, reinforcing a foundation, or adding a below-grade or partly below-grade entrance. The application is filed as PDFs through Toronto Building's online Application Submission Tool. It carries a site plan on your survey, existing and proposed foundation plans, floor plans, sections, construction details and the forms. The City's fee is covered in the permit-cost question below.

Underpinning builds new footings beneath the existing ones. The work goes in numbered stages so the wall is never undermined all at once, and the new floor runs wall to wall at the lower level. Benching leaves the existing footing alone. The new slab is poured lower in the middle, and a sloped or stepped concrete bench is left along the walls. That bench keeps the soil under the old footing undisturbed within its angle of repose. You keep the footing, you lose floor width, and the deeper you go the wider the bench. For a few inches, benching can be the budget route. For a real change in ceiling height, underpinning is usual. The permit drawings show which, with the stages numbered.

Toronto Building's guide gives three triggers. First, a foundation built below the level of an adjacent building's footing, and within the soil's angle of repose, must be designed by a Professional Engineer. The engineer also reviews it on site, and the drawings carry the seal. Second and third come from the Commitment to General Reviews form. It applies where more than 1.2 m (about 4 ft) of the underpinned wall is left without soil or bracing to hold it from the side, or where the soil is clay or silt. On a semi or row house the party-wall footing is your neighbour's too, so the first trigger applies as soon as you go below it. And on every underpinning permit, whoever designed it, the City requires engineer testing and reports. They happen at the first and last stages at minimum, to pass inspections.

Toronto's Property Standards (Municipal Code Chapter 629, § 629-25) set a habitable room's minimum height at 1.95 m over at least half its floor area. Under § 629-4, no basement may be used as a habitable room or dwelling unit unless its way out (egress), light, ventilation and ceiling height all comply. A new secondary suite is also examined against the Ontario Building Code, and the City's Secondary Suites guide requires floor-to-ceiling heights on the sections. We design the lowered floor to the stricter figure that applies to your house and write it on the drawings. The ceiling planner on our underpinning page uses the 1.95 m Property Standards test.

In 2026, $12.37 per linear metre of underpinning, with a $214.79 minimum; 30 linear metres is $371.10. Finishing the basement under the same permit is $6.20 per square metre. If the lowered basement becomes a secondary suite, two more lines apply. The City's Secondary Suites guide lists interior alterations at $11.53 per square metre and a residential unit fee of $56.33 per new unit. Work started before the permit issues adds 50% of the fee or $214.79, whichever is greater, to a maximum of $29,456.99. These are paid to the City at submission and are separate from our fee and the engineer's.

Yes, and it is usually the right moment, because the stairs land at the new floor level. The City's Residential Basement Entrances guide asks for the underpinning extent next to the entrance, with the stages numbered. Sections must show the exterior landing at the base of the stairs, and the stair, guard and handrail details include their connections. The site plan carries setbacks to property lines and adjacent buildings, plus a summary of permitted and proposed zoning provisions. Where a below-grade entrance may sit on your lot is a zoning question, and we settle it in the zoning review before the drawings start.

Your contractor excavates and pours in the sequence numbered on the foundation plan, so the wall is only ever undermined in short lengths. The Professional Engineer tests and reports at the first and last stages at minimum, which Toronto Building requires to pass inspections. The engineer also carries out the general review committed to on the form. The City inspects against the drawings. That is why the stages, the linear metres and the depth are written on them rather than left to the crew.

Architalcan's office prepares the architectural drawings, and they are signed under BCIN 25897 – 41741 (House, Small Buildings, Large Buildings, HVAC-House). Toronto Building requires drawings by a qualified designer to show the designer's name, registration number, qualification number and signature, plus a statement accepting responsibility. Ours do. The underpinning design is sealed by the Professional Engineer and filed with the Assumption of Responsibility for Engineering Content form. The engineer signs the Commitment to General Reviews, and you complete its Part A.