How to Detect, Diagnose, & Evaluate Horizontal Foundation Movement, Cracks, Damage InspectAPedia® -
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
Our site offers impartial, unbiased advice without conflicts of interest.
We will block advertisements which we discover or readers inform us are associated with bad business practices,
false-advertising, or junk science. Our contact info is at
InspectAPedia.com/appointment.htm.
This chapter of the "Foundation Crack Bible" discusses in detail 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.
Our "Foundation Crack Bible" document, of which this web page is a chapter, 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.
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.
Photographs of types of foundation cracks and other foundation damage: we have a large library of photographs which
we're in process of adding to this document. Pending completion of that work, contact the author if assistance is required.
Horizontal Movement in Foundations & Masonry Building Walls
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:
Frost pressure (in freezing climates) can be both vertical (frost lensing or frost heaves) and horizontal (wet, then frozen earth pressure).
Foundation walls or building piers can be lifted vertically by frost heaving, by frost lensing, as well as bulged or pushed inwards by horizontal pressure from frozen soils. See BUCKLED FOUNDATIONS due to INSULATION? for additional details about these phenomena.
Soil pressure (depending on the amount of backfill & soil characteristics)
Soil pressure + water pressure caused by extra weight from water (rain, surface runoff, or flood conditions)
Soil pressure + live loading caused by extra weight from vehicles driven near the foundation wall
Impact pressure caused by a vehicle or a storm-driven object like a tree
Earthquake/Storm movement: Horizontal shift during earthquake or storm damage
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.
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 houseat right, the sketch depicts soil which is so well drained that it does not retain water, making frost heaving unliklely.
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:
Bulging foundation wall movement: the wall may bend or "bulge", tending to bulge away from the force (usually inwards into the building from earth, water, or frost
pressure), with the greatest amount of inwards movement at or near the point of greatest pressure or force being applied.
If the wall
is constructed of concrete block, for example, it may bulge inwards and crack or break horizontally along its mortar joints high on the
wall if the damage is due to pressure from a heavy vehicle driving close to the wall, or it may crack in the top 1/3 of the wall
if the damage is due to pressure from frost. As you can see in our soil pressure sketch above on this page, a break lower in a foundation wall (assuming it is buried to near the wall top) suggests earth pressure or wet earth pressure more than frost pressure problems. See BUCKLED FOUNDATIONS due to INSULATION? for additional details about these phenomena.
Heavy or heavy and wet soils may also produce inwards movement and crackng lower on a
wall when pressure is primarily due to earth pressure rather than frost. Of course the height of such bending or cracking depends on
the height of the entire wall, how much of the wall is below ground level, and where the force is being applied.
Leaning foundation wall movement: the wall may lean away from the force being applied (usually into the building from the same forces listed above).
A reinforced concrete wall or a vertically-reinforced concrete block wall may tend to lean rather than break in response to the
same forces we've listed. When force is closer to the top of such a wall, the top will lean inwards. When the forces are closer
to or greatest at the bottom of the wall, the bottom may tend to lean inwards and the top of the wall lean "outwards".
Shifting or creeping foundation wall movement: a foundation wall, or portions of it, may remain close to vertical, without leaning or bulging, but forces
applied to the wall may cause the entire wall (or a portin of it) to move horizontally.
We see horizontal shift or creep
occuring in several cases: The wall may be sliding off of its footing, or an entire footing and wall may be sliding downhill
over rock or clay soils; in this case vertical cracks may appear where the moving wall is or was joined to its neighboring side walls.
Forces applied to a wall may cause a portion of it to break and slide horizontally over another portion.
For example a masonry
wall may become pushed inwards from soil or frost, but where the first course of blocks is held in place by a concrete floor slab,
that course may remain un-moving. Depending on where the wall breaks from outside forces, upper courses of the masonry block
wall will slide horizontally over and "hang over" the lower course(s) of block.
Complex foundation wall movement: most of the drawings we see at seminars on foundation damage or used by companies
offering foundation repair products are clear and helpful for understanding the concept of foundation damage and movement,
but often they do not describe what we actually find in the field. Very often the forces that are causing a building foundation
to move will cause a combination of bulging, cracking, leaning, and shifting of foundation or wall components.
We illustrate horizontal foundation wall movement patterns below.
Bulging or Leaning and Sliding Horizontal Wall Movement - Masonry Block "Overhang"
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.
In this case you'll see both that some masonry wall
blocks will overhang or protrude past others in the wall (usually upper inwards pushed blocks hang over lower more stable
blocks closer to the floor), and there may be bulging and cracking at another elevation of the wall.
This is a photograph of frost push and horizontal overhang or sliding between horizontal courses of a masonry block wall.
Impact Damage to Foundation Walls - horizontal movement
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.
Horizontal Foundation Wall Movement, Creep, non-leaning Lateral Shift
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.
Horizontal wall movement and step cracking in brick walls due to thermal expansion
Horizontal movement occurs in brick masonry walls due to thermal expansion, producing step cracking and potentially also
verticl cracks through structural brick or brick veneer walls.
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
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
Sal Alfano - Editor, Journal of Light Construction*
Thanks to Alan Carson, Carson Dunlop, Associates, Toronto, for technical critique and some of the foundation inspection photographs cited in these articles.
Arlene Puentes, ASHI, October Home Inspections - (845) 216-7833 - Kingston NY
Greg Robi, Magnum Piering - 800-822-7437 - National*
Dave Rathbun, P.E. - Geotech Engineering - 904-622-2424 FL*
Ed Seaquist, P.E., SIE Assoc. - 301-269-1450 - National
Dave Wickersheimer, P.E. R.A. - IL*
*These reviewers have not returned comment 6/95
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
More Information on Building Diagnostic Inspections and Repairs
...
InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.
InspectAPedia ® Home & Site Map 
InspectAPedia® Home & Site Map
