Extend Shallow Footings with Foundation Underpinning
Older homes, additions, and basement deepening projects often expose a footing that was never sized for what it carries. Laval Concrete extends those footings downward or outward in a controlled sequence of numbered bays, keeping the structure supported throughout. The work is engineered, the process is proven, and your free assessment starts the conversation.
Load always supported, never the whole footing open
Written quote with firm timeline included
Footing problems demand footing solutions
Why Underpinning Fixes What Repair Cannot
A cracked foundation wall can be reinforced, injected, or braced. But if the crack exists because the footing beneath it is too shallow or too narrow for the load, reinforcing the wall above solves nothing. The footing is still undersized. Underpinning addresses the root, extending the footing to the depth and width the structure actually needs.
Basement deepening is another common trigger. When you lower the floor to gain headroom, the existing footing now sits above the new slab elevation. That footing must be extended downward in bays so the new floor can be poured below it. Similarly, when an addition loads an existing footing beyond its original design, the footing is extended to carry the new load.
The method is always the same: the existing footing is supported in numbered bays while a deeper or wider section is poured beneath or beside it. Load transfers cleanly, the building never settles during the work, and the result is a footing that matches the structure it carries. We integrate underpinning with basement renovation, crack sealing, and waterproofing as needed.
Recent work
The underpinning sequence
How Footing Extension Happens in Laval
Structural engineer designs the sequence
The engineer specifies footing depth, width, materials, and the exact order of bays so the building remains supported at every stage. This engineered sequence is the foundation of safe underpinning.
Excavate one bay at a time
Following the sequence, a single bay is dug out to the new footing depth. Adjacent bays stay intact, so the building is always supported on both sides of the open section.
Form and pour the new footing
The bay is formed and concrete is poured to the engineered depth and width. The new footing is tied to the existing footing above with rebar and mechanical anchors so load transfers without gaps.
Cure and move to the next bay
The concrete cures to full strength before the next bay is excavated. This cycle repeats until the entire footing has been extended to the new depth or width.
Why bays are non-negotiable
The Bay Sequence Is What Makes Underpinning Safe
Underpinning could theoretically be done by excavating the entire footing at once and pouring a new one. That would collapse the building. Bays prevent that. At any moment, only a small section of footing is unsupported, and the rest is bearing the full load of the structure above. The building never settles, never moves, never cracks during the work.
The engineered sequence also prevents mistakes. Skipping ahead, doing two adjacent bays simultaneously, or filling before proper curing all risk settlement during construction. We follow the sequence exactly as designed, and we pair the work with proper footing installation details and foundation waterproofing on newly exposed wall sections before backfill.
Bay sequences, basement deepening, additions, and when underpinning is the right choice.
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 Laval Homeowners Say About Their Underpinning Work
We added a second storey and the engineer said underpin. Laval Concrete did the sequence by the book, addition went on top, no settlement since. Done right.
T. J.
Laval
★★★★★
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.
Montreal
★★★★★
Basement deepening project, underpinning first, then the new lower slab. Headroom we wanted, structure stronger than before. Worth every cent.
U. O.
Repentigny
★★★★★
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.
Longueuil
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Describe what is happening with the foundation, whether it is ongoing settlement, a planned addition, or basement deepening, and we will assess it at no cost and provide a written quote with timeline.
