01. Assessment and measurement
A site visit records existing clear height, wall condition, footing depth where visible, drainage, access routes and anything already showing movement. This is what determines whether underpinning, benching or neither is the right answer. It is also the foundation of an honest quote.
02. Engineering and drawings
A structural engineer designs the sequence, pin widths, depths and any temporary support. The drawings are what the City reviews, and they are also what protects you if a question arises later from a buyer, an insurer or a neighbour.
03. Permits and approvals
A building permit is applied for through the City of Toronto. Plumbing, secondary-suite or walkout work adds its own review. Timelines depend on the City's queue and on how complete the submission is. Permit guide.
04. Sequential excavation and pinning
The foundation is lowered in short, alternating sections. Each pin is excavated, formed, poured and allowed to cure before adjacent sections are opened. Soil leaves the basement by hand or conveyor to a bin at grade. The sequence is the safety mechanism. It is never a continuous dig.
Ask any contractor to show you the pin sequence on the drawings. If they can't, keep looking.
05. Drainage, waterproofing and slab
With the perimeter lowered, interior drainage, any sump, plumbing rough-in, insulation and the new slab are installed. This is the cheapest moment in the project's life to get water management right.
06. Inspection and handover
City inspections are called at the stages the permit requires. You should finish with drawings, permit records and inspection sign-offs in hand. If The Foundation Kings are finishing the space, you should also have a basement that is ready to live in.
Want the whole picture, including costs, permits and choosing a contractor? Read Underpinning Toronto: the complete homeowner's guide.
