What is Foundation Underpinning?

Foundation underpinning is a construction technique used by Alliance Inc. to strengthen and stabilize the foundation of a building or structure. It involves adding support or reinforcing the existing foundation to prevent settling, sinking, or structural damage. 

When would you use underpinning? 

Underpinning is typically used in the following situations:

• Foundation Settlement: When a foundation settles unevenly, causing cracks or structural issues in the building.
• Foundation Damage: If the foundation has been damaged due to soil movement, water damage, or other factors.
• Increasing Load-Bearing Capacity: To increase the load-bearing capacity of the foundation for additional stories or heavier structures.
• Changing Foundation Design: When modifying or adding to an existing building’s foundation design.

When does a building need foundation underpinning?

Signs that a building may require underpinning include:

• Cracks in Walls: Vertical or diagonal cracks in walls, especially near corners or windows.
• Uneven Floors: Floors that slope or feel uneven.
• Doors and Windows Sticking: Difficulty opening or closing doors and windows.
• Sagging or Uneven Ceilings: Visible changes in ceiling height or sagging.
• Foundation Cracks: Visible cracks in the foundation itself.
• Bowing or Leaning Walls: Walls that appear to be leaning or bowing outward.

How is foundation underpinning done?

At Alliance Inc. we use helical piers (also known as helical piles) for foundation underpinning.

Helical piers consist of a shaft or helix-shaped blade that resembles a large screw or drill bit. These piers are typically made of steel and are installed into the ground to transfer the load of a structure to more stable soil or bedrock layers beneath the surface. The helical shape allows them to be “screwed” into the ground with minimal soil disturbance.

The process of underpinning involves excavating sections of the foundation in a controlled manner and then reinforcing or extending it to a deeper and more stable soil layer.