Cornerstone Foundation Repair Services

Wall Deflection

The inward movement of basement walls due to increasing hydrostatic pressure.

There are 3 different types of foundations that are commonly found in KansasCity:


Stone:

Stone, the oldest form of foundation, was commonly installed in the early construction of Kansas City until the 1940's.

Cinderblock:

Cinderblock is usually built with hollow building blocks made with concrete and coal cinders. This foundation is typically found in homes built in the 1940's and 1950's.

Poured Concrete:

Poured Concrete is usually 6-10 inches thick and joint-free, unlike cinderblock walls. As a result they are considered to produce stronger and drier foundation walls, which is critical for the building of basement walls. Poured concrete is commonly found in homes built from the 1960's to present day construction.

Causes of Wall Deflection:

  • Lack of maintenance
  • Negative grading
  • Inadequate gutters and Downspouts
  • Hydrostatic (water) pressure due to a failing foundation drain system causes a buildup of moisture in the soil creating enough weight to exceed the wall’s design capacity resulting in wall deflection. This pressure can also be caused by poor surface grading and drainage. As the repetition of wet cycles continues so does the reduction of the structural integrity of the wall causing an inward wall movement to occur.
  • Soil expansion due to frost, large tree root systems, and surcharge loads from the foundations of adjacent structures
  • Heavy storage items placed immediately adjacent to basement walls

Symptoms of Wall Deflection:

  • Horizontal cracks
  • Diagonal cracks
  • Water leakage
  • Bowed and leaning foundation walls
  • Stair step cracking appearance (more severe cases)
  • Horizontal shearing
  • Vertical shearing
  • Buckling of ceiling panels and drywall

Solutions - There are several options available for repairing wall deflection:


Deadman Anchor System:

Heavy duty steel earth anchors are securely embedded in a concrete trench. The earth anchors are connected to steel wall plates positioned on the foundation wall with long, threaded steel rods. This system relies on the passive resistance of the concrete buttress created 10 feet out from the foundation wall. No reliance on the home itself for support.

Bracing options for steel I beams and other wall restraints:

  • S4x7.7 I beam
  • S4x9.5 I beam
  • W4x13 I beam
  • C8x11 Channel Steel
  • 4x4x3/16 Square Tube Steel
  • Deadman Anchors
  • Wall Stiffners

Installation of Wall Restraints:

The floor is brought up with a jackhammer, then a beam is set in a beam pocket and bolted with a 3x5 L bracket to the floor joists. New concrete is poured around the new beam relieving all pressure from the existing walls keeping them from contracting further movement.

Concrete: I beams need to be spaced every 6 feet on center on a poured concrete wall.

Stone and Cinderblock: I beams need to be spaced every 4 feet on center.

Total removal and replacement of a home’s foundation walls:

All concrete slabs and landscaping are removed and all surrounding soil is excavated. The home is lifted and alternatively supported while foundation is replaced. Walls are then torn down to footing or bottom course of block. Stone foundation tear outs typically will need a new footing poured before walls are constructed.

What to do in case your deflection is more than 3 inches:

Concrete: Walls can be excavated and pushed back to plumb.

Stone: The walls would need to be torn down completely and replaced with the material necessary to suit the structure.

Cinderblock: The walls would need to be torn down completely and replaced with the material necessary to suit the structure.

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