Mon-Sat 9:00 AM - 5:00 PM
Increase basement ceiling height and strengthen foundations with professional underpinning services.
Basement underpinning is the process of deepening your existing foundation to increase basement ceiling height, creating usable living space from what was previously a low, cramped area. Many Toronto homes — particularly those built in the 1940s through 1970s — have basements with ceiling heights of only 5.5 to 6.5 feet, making them impractical for anything beyond storage. Underpinning lowers the basement floor by extending the foundation walls deeper into the soil, typically adding 2 to 4 feet of height to achieve the standard 8-foot ceiling that Ontario Building Code requires for habitable space.
Beyond ceiling height, underpinning also strengthens your foundation. The process creates a new, deeper footing that extends below the frost line and into stable soil — addressing settlement issues, structural cracks, and the shallow footings that were common in mid-century Toronto construction. It's both a space transformation and a structural upgrade.
Why Choose Us
Underpinning is the most complex residential foundation work we perform, and it requires engineering oversight, a building permit from the City of Toronto, and a methodical approach that maintains the structural integrity of your home throughout the process. The work proceeds in carefully planned sections — we never excavate more than one section at a time, ensuring the foundation is supported at all points during construction.
The standard approach in Toronto is the mass concrete method: we excavate beneath the existing footing in alternating sections (typically 3-4 feet wide), pour new concrete to the desired depth, and allow it to cure before moving to adjacent sections. This leapfrog pattern means the foundation is always supported by either the original footing or new cured concrete on both sides of the active work area. A typical Toronto home takes 4-8 weeks to underpin depending on the perimeter length and depth increase.
Don't Ignore the Signs
A structural engineer's design is required before any underpinning project begins. The engineer assesses your existing foundation, soil conditions, and the planned depth increase to produce drawings that specify the section sequence, reinforcement requirements, and concrete specifications. We work with experienced structural engineers who have designed hundreds of underpinning projects across the GTA and understand the specific soil conditions in different Toronto neighbourhoods — the clay soils in Scarborough behave differently than the sandy soils near the lakeshore.
The City of Toronto building permit process for underpinning typically takes 3-6 weeks from application to approval. We handle the permit application, coordinate with the engineer, and schedule inspections at each stage of the work. Multiple inspections are required: after excavation of each section, before concrete is poured, and a final inspection after all work is complete. This oversight ensures the work meets code and protects your home's structural integrity.
Underpinning is a significant investment, but it's also one of the highest-return renovations available for Toronto homes where adding above-ground square footage isn't practical. A properly underpinned and finished basement adds 600-1,200 square feet of living space to a typical Toronto home. At current GTA property values, that additional square footage can increase your home's value by $100,000-$200,000 or more — substantially exceeding the underpinning cost. Many homeowners combine underpinning with full waterproofing, creating a dry, comfortable living space with modern ceiling heights.
We recommend underpinning for homeowners who plan to stay in their home long-term and want to maximize living space, or for homeowners preparing to sell a home where the low basement ceiling is a significant drawback. The project is best done before finishing the basement — adding finishing materials to a freshly underpinned basement is straightforward, while underpinning a previously finished basement requires demolishing and rebuilding the finishes.
Materials & Methods
The traditional and most common method in Toronto: excavate beneath the existing footing in alternating sections, pour reinforced concrete to the designed depth, and cure before proceeding.
Steel rebar reinforcement is placed in each excavated section per the engineer's specifications before concrete is poured, ensuring the new deeper foundation can handle all structural loads.
During underpinning, waterproof membrane is applied to the newly exposed foundation walls and beneath the new floor slab, providing complete moisture protection for the deeper basement.
Our Process
A structural engineer assesses your foundation, soil conditions, and desired depth to produce detailed drawings specifying section sequence, reinforcement, and concrete specifications.
We submit the engineering drawings to the City of Toronto for building permit approval. This process typically takes 3-6 weeks.
Working in alternating 3-4 foot sections, we excavate beneath the existing footing to the designed depth while maintaining foundation support on both sides.
New reinforced concrete is poured in each excavated section and allowed to cure before adjacent sections are started. Inspections occur at each stage.
After all sections are complete and final inspection is passed, the new floor slab is poured and waterproofing is applied. The basement is ready for finishing.
Client Reviews
“Outstanding job! My basement is finally dry thanks to your team. No more musty smell or moisture problems. A+ service!”
“From the initial appointment to final inspection, service was exceptional. Prompt, professional, and results exceeded expectations.”
“Professional and friendly staff. They solved our leaky basement in no time. The results were fantastic. Basement has been leak-free since the work was done.”
Experience & Expertise
Related Solutions
Structural foundation reinforcement and waterproofing solution for basement expansion and strengthening.
Learn More →Complete foundation protection systems combining interior and exterior waterproofing methods.
Learn More →Comprehensive exterior foundation protection with membranes and drainage to prevent water from reaching your basement.
Learn More →Service Areas
We provide basement underpinning throughout Toronto and the Greater Toronto Area.
Common Questions
