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BRICK FOUNDATIONS & WALLS
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BUCKLED FOUNDATIONS due to INSULATION?
CHIMNEY INSPECTION DIAGNOSIS REPAIR
COLD POUR JOINTS, CONCRETE
COLUMNS & POSTS, DEFECTS
CONCRETE FOUNDATIONS, PRE-CAST
DISASTER BUILDING INSPECTION & REPAIR
EARTHQUAKE DAMAGED FOUNDATIONS
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FLOOD DAMAGE TO FOUNDATIONS
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FOOTINGS EXPOSED, Repair Methods
FOUNDATION BULGE or LEAN MEASUREMENTS
FOUNDATION CONSTRUCTION TYPES
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FOUNDATION CRACKS & DAMAGE GUIDE
FOUNDATION DEFECTS OF OMISSION - MISSING
FOUNDATION FAILURES by TYPE & MATERIAL
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FOUNDATION INSPECTION METHODS
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FOUNDATION MATERIALS, Age, Types
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FRAMING DAMAGE, INSPECTION, REPAIR
FROST HEAVES, FOUNDATION, SLAB
GRADING, DRAINAGE & SITE WORK
GUTTERS & DOWNSPOUTS
INSECT INFESTATION / DAMAGE
MOBILE HOMES, DOUBLEWIDES, TRAILERS
MODULAR HOME CONSTRUCTION
MOISTURE CONTROL in BUILDINGS
RETAINING WALL DESIGNS, TYPES, DAMAGE
RETAINING WALL GUARD RAILINGS
SINKHOLES, WARNING SIGNS
CONCRETE SLAB CRACK EVALUATION
CONCRETE SLAB CRACK REPAIR
STRAW BALE CONSTRUCTION
STRUCTURAL DAMAGE PROBING
STRUCTURAL WOOD ASSESSMENT
THERMAL EXPANSION of MATERIALS
TIMBER FRAMING, ROT
WATER BARRIERS, EXTERIOR BUILDING
WATER ENTRY in BUILDINGS
WINTERIZE A BUILDING
WOOD STRUCTURE ASSESSMENT
How to Evaluate and Diagnose Horizontal Foundation Movement by Type & Location of Cracks or Shift in Foundation Walls. Horizontal foundation wall movement may be caused by earth pressure, vehicles driving too close to a building wall, water and frost, and even footing movement or foundation wall creep on hillsides.
We distinguish among vertical movement, horizontal movement, leaning, tipping, bending, differential and uniform settlement, earthquake and storm damage, and other foundation damage patterns. This article series describes how to recognize and diagnose various types of foundation failure or damage, such as foundation cracks, masonry foundation crack patterns, and moving, leaning, bulging, or bowing building foundation walls.
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Horizontal foundation wall movement includes leaning, tipping, or bulging foundation walls as well as movement of an entire wall in a single direction such as hillside slippage or creep. Knowing just how a foundation wall is moving and just what is causing damage are important in deciding on how to repair the damaged foundation wall and how to prevent further foundation movement. Typical causes of horizontal foundation movement include:
How Soil Pressure vs. Frost & Water Pressure Cause Different Damage to a Foundation Wall
Horizontal frost pressure on a foundation wall: Our sketch at left shows how earth pressure (or wet or freezing earth pressure, or earth pressure combined with vehicle weight if you drive a truck along the foundation wall) can cause both vertical and horizontal foundation movement.
Drawing courtesy Carson Dunlop Associates. [Click to enlarge any image]
This is a nice sketch because it also shows that the location of horizontal cracking in a foundation wall can help diagnose the root cause of the pressure that caused the wall to crack or break.
The sketch also helps us understand why the top of the wall resists inwards movement: in good construction the top of the foundation wall is secured to the floor framing which in turn resists horizontal movement at the wall top by transferring some of that inwards pressure across the floor to the opposite foundation wall.
Two Cases Where Frost Heave is Unlikely - Foundations on Bedrock & Well-drained Soils
As these two Carson Dunlop drawings show, in certain circumstances frost heave is an unlikely cause of foundation movement or damage.
In the house at left, if a foundation is sitting pinned to bedrock there is no volume of wet soil to expand and push the foundation up even if wet, then freezing conditions occur. However we often find water leaking under the foundations pinned to rock in this situation.
And omitting mechanical connections between the foundation or footing and the bedrock can lead to sliding movement over the rock.
In the house at right, the sketch depicts soil which is so well drained that it does not retain water, making frost heaving unlikely.
How Lateral or Horizontal Foundation Pressure Shows Up as Damage
Horizontal movement in building foundations or walls is generally caused by an external lateral or "sideways" force applied to some portion of the wall. Depending on the construction materials used and the strength of a foundation wall, a force applied to the wall can cause it to move in any of several ways:
We illustrate horizontal foundation wall movement patterns below.
Inspectors or building owners may also encounter a foundation wall which has moved inwards in a combination of forms, both bulging at its most-pushed-in
point (with horizontal cracks in the foundation wall) and the wall may have also been pushed inwards sliding some of
the masonry blocks inwards past others which have remained in place.
This is a photograph of frost push and horizontal overhang or sliding between horizontal courses of a masonry block wall.
Impact damage from a vehicle or from unusual weather such as a hurricane which lifts and tosses large objects, can lead to severe foundation or masonry wall damage and may even render the wall unstable and unsafe.
In the photograph shown here the cause of damage to the foundation wall is pretty obvious.
Almost certainly a delivery truck has backed into this concrete block wall, perhaps even more than once.
The damage to this wall was extensive, extending nearly to the top of the structure. The wall needs extensive repairs, probably reconstruction.
On less frequent occasions we've found that an entire masonry block wall (or portions of it) were pushed horizontally inwards by some outside force, without causing the wall to lean or bulge.
In the photograph here we suspect that the cracks in this masonry block wall occurred as a defective wall footing began to creep down a steep hill behind the building.
In a pure example of horizontal creep or movement without leaning in a masonry wall or foundation, all of the differential movement measured (wall to string) between the wall bottom point (held in place by the floor slab) and the inwards-pushed wall section, will be a horizontal movement of that portion of the wall, and if it's masonry block, you'll see that the inwards-moved blocks are "hanging over" or projecting past the surface of the masonry blocks that did not move.
Other vertical or near vertical cracks in concrete block can occur in foundation wall without leaning or bulging if the entire wall is moving due to footing settlement or frost or, as we showed here, possible tipping or leaning of the footing itself.
If the bottom of a wall is not pinned in place by a secure footing or a concrete slab, or if the entire footing itself begins to move, the entire wall, from top to bottom may move horizontally with no leaning and with no "overhang" of one portion of the wall over another.
In this case we'd expect to see cracking or evidence of separation of this section of wall from its neighboring sides - as you can see in the upper vertical cracking at the left side of the masonry block wall in the photograph above.\
If you are considering a brick masonry building, or a building carrying a brick veneer exterior, we discuss and illustrate thermal cracking in brick masonry in detail at Thermal Expansion Cracking of Brick
See SHRINKAGE vs EXPANSION vs SETTLEMENT for aid in distinguishing between these different conditions.
These articles explain How to Evaluate and Diagnose Horizontal Foundation Movement by Type & Location of Cracks, Bends, Leans, or Shift in Foundation Walls: How to recognize foundation impact damage; How to recognize foundation creep or footing movement
To be used properly, this information must be combined with specific on-site observations at the particular building in order to form a reliable opinion about the condition of that building's foundation. Anyone having concern regarding the structural stability, safety, or damage of a building, foundation or other components, should consult a qualified expert.
For more guidance on evaluating the seriousness of foundation cracks & movement see FOUNDATION DAMAGE SEVERITY for a discussion of just how much foundation movement is likely to be a concern.
Continue reading at BULGED vs. LEANING FOUNDATIONS or select a topic from the More Reading links shown below.
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