Some foundations were never built for what sits on them now, a footing too shallow, too narrow, or never extended below the right bearing soil. Oshawa Concrete underpins those foundations one bay at a time, deepening or widening the footing in numbered sequence so the building is always supported. Every project is engineered and the assessment is free.
Foundation repair fixes walls. Underpinning fixes footings. When the cause of settlement, cracking or bowing is that the footing itself is not deep enough or wide enough for the load, no amount of wall reinforcement is going to stop it; the footing has to be extended or rebuilt.
Underpinning is also how we handle basement deepening, where the floor is lowered to gain headroom and the existing footing now sits above the new finished elevation, and additions where the new load on the existing footing is more than it was sized for.
Either way, the principle is the same, the existing footing is supported in numbered bays while a deeper or wider section is poured beneath or beside it, engineered so the building is supported through every step. The work integrates with our other foundation services and the basement that sits on top. Where the cracking is in the wall only, foundation repair is the right call instead.
Recent work
How it works
How We Underpin a Foundation in Oshawa
Engineer underpinning sequence
A structural engineer designs the underpinning, footing depth and width, bay sequence, materials and the order each bay is excavated and poured so the building stays supported through every step.
Excavate in numbered bays
Bays are excavated one at a time in the engineered sequence, never adjacent ones simultaneously, so the building always has supported footing on either side of an open bay.
Pour underpinning pier
The deeper or wider footing section is formed and poured in that bay, allowed to cure, and pinned tight to the existing footing above with the engineered detail so load transfers cleanly.
Sequence cycle to next bay
With one bay cured and load-bearing, the next bay in the sequence is excavated and poured, and the cycle continues until every section of the footing has been extended to the new depth or width.
Why the sequence matters
Underpinning Is Done in Bays for a Reason
It is tempting to think of underpinning as digging out the whole footing and putting a new one in. That would collapse the building. Bays are why underpinning works, only a small percentage of the footing is unsupported at any time, and the rest is holding the load while that bay cures.
The engineered sequence is also why underpinning has to be planned, not improvised. Skipping ahead, doing two adjacent bays at once, or filling without proper curing time risks settlement during the work. We follow the sequence exactly, and we pair the work with waterproofing on the newly exposed wall before backfill.
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
From the blog
Concrete Guides & Articles
Practical reading on planning, finishes and caring for concrete in Oshawa.
Tell us what is happening with the foundation, whether it is settlement, an addition or basement deepening, and we will assess it free and put the underpinning work into a written quote.
