Method reference / existing foundations
What does foundation underpinning include?
Underpinning is the work of strengthening or extending support below an existing structure. It describes the objective, not one universal product.
Enlarge or deepen support
New concrete may extend or replace part of an existing footing in staged sections. Excavation sequence, temporary support, soil, connection, and cure all belong in the design.
Add piers or piles
Deep elements can transfer load below weak or disturbed near-surface soil. The system, bracket or cap, capacity criteria, installation record, and structure connection must be identified.
Add beams and support points
A beam can collect load from an existing wall or framing system and deliver it to new supports. The beam, bearing points, connections, and foundation below each support are one load path.
Improve or replace supporting material
Grouting or ground improvement may belong to a particular design, but the method name alone does not establish which soil volume is treated or how capacity and movement will be verified.
Design record
Six questions every underpinning proposal should answer.
Temporary works and permanent works need separate descriptions. The house has to remain supported while the new load path is built.
- 01
What condition requires underpinning?
Document movement, damaged material, inadequate bearing, excavation risk, altered loads, or another observed reason. A crack by itself does not prove the method.
- 02
Who owns the design?
Name the design professional where required and identify the site information, loads, soil assumptions, existing-foundation findings, and code basis used.
- 03
How is the structure supported during work?
Show shoring, jacking points, excavation sequence, access limits, utilities, weather protection, and the conditions that pause the work.
- 04
How does load reach the ground?
Trace the structure, existing wall or footing, bracket or beam, new support, and soil or rock. A named pier without the connection is an incomplete explanation.
- 05
Is the goal stabilization or movement?
Stopping further movement and attempting a lift are different outcomes. State the target, tolerances, monitoring points, and risks to finishes and utilities.
- 06
What closes the record?
Require permits and inspections where applicable, installed locations and depths, load or torque records, concrete records, photographs, lift readings, and the written warranty.
Shallow underpinning
Sequence is part of the structure.
The HUD foundation rehabilitation guide describes shoring and underpinning as existing-building work, where access and support cannot be separated from the permanent repair. Excavating every support point at once can change the load path before the new work is ready.
Deep systems
An evaluation report is only the starting document.
ICC-ES criteria and evaluation reports can define recognized uses, components, design conditions, and installation requirements for named systems. They do not select a product for the property or replace the site-specific design.
Safety boundary
Do not disturb an existing support without a support plan.
Excavation beside a footing, removal of a post or beam, and lifting a structure can change the load path immediately. Restrict access when support is unstable, masonry is falling, or movement is active, and have the responsible building professional establish the temporary-work sequence.
Regional application note / contractor-owned source
603 publishes two deep-foundation methods.
603 Basement Solutions publishes helical and push piers for settling foundations. Its pages distinguish how the systems enter the ground and say the repair goal may be stabilization rather than a guaranteed return to original position.
That establishes contractor-owned service scope, not independent proof that either system fits a property. The proposal still needs the design, connection, installation record, and outcome terms above.
Technical sources / checked September 11, 2026