Start with Toronto’s underpinning permit guide
Toronto describes residential underpinning as extending the depth of an existing foundation by building new footings below existing footings. Its application guide requires foundation drawings that show the extent and sequence of underpinning work.
The City states that specific conditions involving neighbouring footings, soil or support height can trigger professional engineering design or review. Do not assume every project has the same engineering threshold.
- Get a site plan showing boundaries and adjacent structures.
- Ask how the proposed stages of underpinning will be documented.
- Discuss soil conditions, neighbouring foundations, temporary support and inspection sequencing with the appropriate professionals.
Check contractor and engineer credentials separately
Check relevant Toronto Building Renovator licence details and endorsements through the City lookup. Ask who performs the underpinning and who bears design and site-review responsibility.
If the business offers professional engineering services to the public, check the applicable PEO Certificate of Authorization and the responsible engineer. A contractor licence and an engineering authorization are different checks.
A quote should disclose major risks
Compare quotes that state scope, engineered drawings, underpinning sequence, shoring, excavation, waterproofing, inspections, unforeseen conditions and exclusions.
A very low fixed price without documented assumptions should not outweigh project-specific engineering and permit evidence.
Official sources and verification dates
These documents support the stated permit, qualification or data-methodology facts. They do not certify any directory company. Follow the original source before making a consequential decision.
Application drawings and conditions requiring professional review · Reviewed 2026-10-20
Building Renovator licensing · Reviewed 2026-10-20
Company-level check · Reviewed 2026-10-20
PEO individuals and firms · Reviewed 2026-10-20
Engineering services offered to the public · Reviewed 2026-10-20