Footings that were adequate decades ago may no longer support what sits on them now. Oshawa Concrete extends shallow or narrow footings downward and outward in engineered bays, keeping the building supported throughout the work. Whether you are settling, adding a second storey, or deepening the basement, underpinning is the structural solution. Free assessment and written quote.
Why Underpinning Solves Footing Issues That Repair Cannot
A cracked foundation wall can often be fixed by reinforcing the wall itself. But when the root cause is a footing that is too shallow, too narrow, or sitting on poor soil, wall repair alone will not stop the movement. The footing must be extended deeper or wider to reach better bearing soil or to distribute the load across more area.
Underpinning also enables two major renovations: basement deepening (where the floor is lowered and the footing must be extended downward to stay below the new slab) and second-storey additions (where the existing footing must be widened to carry the new load). In both cases, the structural engineer specifies the new footing depth and width, and we execute it in numbered bays.
The bay method is the key to safety. Each bay is excavated and poured one at a time in the engineered sequence, so the building is always supported on the sections that are not being worked on. This is why foundation installation and basement work must be coordinated with underpinning. If the problem is only in the wall and not the footing, foundation repair is the faster and less costly option.
Recent work
The underpinning sequence
Step-by-Step: How Foundation Underpinning Gets Done
Structural engineer designs the sequence
The engineer determines footing depth, width, bay size, and the exact order in which bays are excavated and poured so the building stays supported through every cycle.
Excavate the first bay
The first bay in the sequence is dug out to the engineered depth, exposing the existing footing. The rest of the footing remains intact and bearing the load.
Form and pour the new footing section
The new, deeper or wider footing is formed and poured in that bay, then allowed to cure fully before any load is transferred to it.
Move to the next bay in sequence
Once the first bay is cured and pinned to the existing footing, the next bay is excavated and poured. The cycle repeats until the entire footing is extended.
The bay principle
Why Numbered Bays Are Essential to Safe Underpinning
Underpinning the entire footing at once would collapse the building. Bays solve this by ensuring only a small section of footing is unsupported at any time, while the rest continues to carry the load. The engineered sequence is not optional; it is the structural requirement that makes underpinning safe.
Skipping bays, working on adjacent sections simultaneously, or pouring without proper curing time all risk settlement during the work. We follow the sequence exactly as engineered, and we coordinate foundation waterproofing on newly exposed walls before backfill. The written estimate includes the full timeline so you can plan around the work schedule.
Bay sequence, basement deepening, additions and when underpinning is the right tool.
If settlement keeps happening after repair attempts, if the cracking is at the footing rather than just in the wall, if the soil bearing capacity has changed, or if you are adding load or lowering the basement floor. The assessment will tell us which is right.
Yes. The bay sequence means only a small section of footing is unsupported at any time, and the rest is bearing the load. Most homeowners stay in their homes through underpinning; we let you know if your situation is the exception.
Yes, that is one of the main uses. Lowering a basement floor below the existing footing requires the footing to be extended downward in bays; once underpinned, the floor can be excavated to the new depth and a new slab poured.
Only when the new load on the existing footing exceeds what the footing was sized for. The structural engineer for the addition determines that; we underpin the existing footing to the engineered detail when required.
Several weeks for a typical residential underpinning, because each bay has to be excavated, formed, poured and cured before the next bay starts. The full schedule is in the written quote so you can plan around it.
Homeowner reviews
What Oshawa Homeowners Say About Their Underpinning Projects
We added a second storey and the engineer said underpin. Oshawa Concrete did the sequence by the book, addition went on top, no settlement since. Done right.
T. J.
Oshawa
★★★★★
Settlement that two other contractors had tried to fix as wall cracks was actually a footing problem. Underpinning solved it. Cracks haven't moved since.
N. K.
Toronto
★★★★★
Basement deepening project, underpinning first, then the new lower slab. Headroom we wanted, structure stronger than before. Worth every cent.
U. O.
Durham
★★★★★
Engineered, sequenced, communicated every step. Lived in the house through the whole project, never felt unsafe. Underpinning is a craft and these guys know it.
G. H.
Mississauga
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Describe what is happening with your foundation, whether it is ongoing settlement, a planned addition, or a basement deepening project, and we will assess it at no charge and provide a written quote with a firm timeline.
