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This chapter of the "Foundation Crack Bible" discusses in detail How to Evaluate and Diagnose Vertical Foundation Movement - Foundation Settlement Cracks, Foundation Leans, Vertical or "up and down" Shifts in Foundation Walls.

Vertical foundation movement may be foundation settlement, frost heaves, movement caused by expansive clay soils, footing settlement, or severe damage from earthquakes or other more sudden forces. Diagnosing the type of foundation movement and its cause are essential in deciding on the appropriate measures to repair a damaged foundation wall and to prevent future foundation damage.

Leaning buildings: Our photo, courtesy of Tom Smith, shows the Leaning Tower of Pisa - whose foundation has moved both laterally and vertically as the structure began tipping even during construction.

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.

Also see FOUNDATION CRACK EVALUATION for a discussion of the diagnosis of specific crack patterns in masonry foundations, and see FOUNDATION BULGE or LEAN MEASUREMENTS which explains a simple method for determining how much bulge or lean is present in a foundation or wall, then see FOUNDATION MOVEMENT ACTIVE vs. STATIC which helps determine if the foundation movement is ongoing, and see FOUNDATION DAMAGE SEVERITY for a discussion of just how much foundation movement is likely to be a concern.

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.

Vertical Movement in Foundations & Walls

• Soil Characteristics: the presence of a footing at all, and footing width and thickness and reinforcement requirements may vary depending on the soil characteristics - different soils have different load bearing capacities, as shown in the sketch provided above by Carson Dunlop.
• Settlement or differential settlement of the supporting soils below the footings or foundation walls
• Frost heave (in areas of freezing climate) can push up (or in) buried foundation components
• Frost lensing (in areas of freezsing climate) can lift a foundation wall or post or pier even if the bottom of the structure is below the frost line
• Inadequate or even absent footings

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.

Here are some classes of vertical foundation or building wall movement which we illustrate and discuss in more detail below

Vertical Frost Pressure, Frost Heaving, & Lensing Movement of Foundations

• Frost lensing: Masonry walls, masonry columns, or even wooden posts, pilings, or piers can also be heaved upwards by frost, even when the bottom of the post is below the frost line. Lensing describes this phenomenon: wet soil adheres to the vertical surface of the masonry wall, or post or pier, sticking to it, and lifting this structural component as the soil itself heaves upwards during freezing.

A Common Source of Vertical Frost Heave - Un-heated Homes

Frost and soil pressure can also cause horizontal movement of the building foundation or piers, as we discuss further at HORIZONTAL MOVEMENT IN FOUNDATIONS.

Uniform Building Settlement

• Uniform building settlement: an entire building moves up or down together, causing little or no foundation cracking or damage, though there could be important damage to mechanical connections to the building and even dangerous gas line leaks. [See below]

Non-Uniform Building Settlement - Leaning or Tipping Buildings

• Building tipping or leaning: a foundation wall, post, pier, or an entire building tips or leans out of level. While we consider this primarily a lateral or horizontal structural movement, in fact one end of a building can move substantially higher or lower than its opposite end - a vertical dislocation as well. For a detailed discussion of the diagnosis of specific crack patterns caused by wall bulging and leaning in masonry foundations, and see FOUNDATION BULGE or LEAN MEASUREMENTS

Other Building Movement Causes & Cracks

• Earthquake or Storm Damage to Buildings: can cause complex building movement in multiple directions, as we illustrate at Foundation Movement due to Earthquake.
• Vertical shrinkage cracks in foundation walls: If a vertical crack is fairly uniform in width we pose that it was produced either by a non-sloping vertical settlement of one section of the footing or foundation wall, or the crack was produced by shrinkage (in some wall materials like concrete) not by vertical movement at all. We discuss the types of crack or movement patterns produced by shrinkage, expansion, and settlement further at SHRINKAGE vs EXPANSION vs SETTLEMENT.

Differential Settlement vs. Uniform Settlement in a Foundation Wall

Differential settlement in a foundation or wall:: We use the term "differential settlement" to describe a condition in which one portion of a building foundation is moving down, (or up and down) at a different rate or in a different amount from other portions of the foundation or wall. Differential settlement will damage the foundation or wall by producing (usually vertical, possibly diagonal or stair stepped) cracks and other symptoms of wall movement. The large foundation crack in this poured concrete wall was caused by differential settlement in a new foundation wall. All of this movement occurred during the first 13 months after the home was built.

Uniform settlement in a foundation or wall: Some buildings may settle so uniformly that the entire building moves down without producing cracking in the building's foundation or walls. For example, while it has a few settlement cracks, the Empress Hotel in Victoria BC, a very large masonry structure built on pilings on what was originally a marsh, has settled rather uniformly down over many decades, so that now visitors enter the hotel's "lobby" on what was originally its second floor.

Vertical Crack Patterns Caused by Vertical Foundation Wall Movement

Vertical movement between different sections of a masonry foundation wall, whether it is constructed of concrete, concrete block, brick, or stone, tends to produce vertical cracks or a combination of vertical and step cracks through the wall, though there are definitely exceptions to this rule, as we will point out.

Uniform Width vs. Tapered Width Foundation Cracks

We like to look at variations in the width of a vertical crack to try to understand further what's happening to the foundation wall. In general we pose that if a crack is wider at its top than its bottom, differential settlement may be allowing one section of the wall to slope downwards away from its neighbor. Or in less common cases, for example a footing which was placed mostly on soft fill but which passes over a boulder, might break over the boulder and slope downwards on both sides of the boulder, producing a crack wider at its top than its bottom. If a vertical crack is fairly uniform in width we pose that it was produced either by a non-sloping vertical settlement of one section of the footing or foundation wall, or the crack was produced by shrinkage (in some wall materials like concrete) not by vertical movement at all.

But unfortunately this "rule" has exceptions. When a masonry wall is "shrinking" such as curing concrete (and some experts pose also drying concrete block), it is not held uniformly in place across its length.

The top of a poured concrete wall is generally unrestrained during the first portion of it's initial 28 days of curing, since nothing has been built atop the wall, or even if someone has started floor framing, the floor framing system does not secure the top of the wall against shrinkage movement.

On the other hand, the bottom of the wall is pinned (or should be) to its previously poured and cured footing. The bottom of the newly poured concrete wall is more secured against horizontal movment along its length than its top.

This might therefore produce some vertical shrinkage cracks that are wider at top than bottom. Why don't we always see this in concrete walls? As a concrete wall shrinks, the stresses produced in the wall are not concentrated at one single point, say the center of the wall; rather, shrinkage cracks may appear in various locations in the wall, not just at its center. Shrinkage cracks may be distributed rather than concentrated. However shrinkage cracks do tend to appear at local stress points in a wall such as at discontinuities in its form caused by windows, doors, or holes left for mechanicals and pipes.

We discuss the types of crack or movement patterns produced by shrinkage, expansion, and settlement further at SHRINKAGE vs EXPANSION vs SETTLEMENT.

Diagonal Cracks in Poured Concrete Foundations

Concrete walls tend to display vertical cracks but settlement or frost heaving at a corner of a concrete wall can produce diagnoal cracksor breaks in that location. Steep diagonal cracks may also appear in concrete foundations due to unusual point loads that exceed the compressive strength of the concrete (maybe it was weak concrete not high loading), and we've seen steep diagonal cracks in poured concrete and other high-rise masonry buildings exposed to frost damage. Steep diagonal shrinkage cracks: But in this photograph of a diagonal crack in a poured concrete foundation, we are almost certainly looking at a large shrinkage crack. Notice that discontinuity in the crack pattern?

Diagonal Step Cracking in Concrete block or Brick Walls Caused by Vertical Movement

Vertical movement in a concrete block or brick wall might appear as either vertical cracks but more often as step cracks in which the crack pattern follows the mortar joints between the masonry units in a stair stepping pattern. In this photograph, major vertical dislocation, foundation settlement, has caused large step-cracking in the concrete block foundation wall. In addition to diagnosing and correcting the reason for this settlement or foundation movement, this section of wall will probably have to be rebuilt. Where step cracks are present, if you draw an imaginary line at right angles (orthogonal) to the diagonal formed by the stairstepped cracking, the downwards direction of the line will generally point to the center of the point of downwards (or up and down) movement in the structure. But unfortunately even this "rule" has exceptions. In Florida we observed a concrete block home with step cracking high in some of its walls. The cracks were traced to settlement at the other end of the building which was responding to soil subsidence over a sinkhole.

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FOUNDATION CRACKS & DAMAGE GUIDE - how to inspect and diagnose foundation problems, in-depth diagnosis, and evaluation of all types of structural and non-structural cracks in residential foundations [Brick, Concrete, Masonry Block, Stone]
EARTHQUAKE DAMAGED FOUNDATIONS - examples of earthquake-damaged building foundations
FOUNDATION CONSTRUCTION TYPES - identify different foundation types, construction materials, effects of sequence of construction
FOUNDATION INSPECTION METHODS - what to look for when inspecting any building foundation
FAILURES by FOUNDATION TYPE & MATERIAL- unique failure characteristics of each foundation material
  Block Foundation & Wall Defects
  Brick Foundation & Wall Defects
  Brick Thermal Expansion Cracking
  Concrete Poured Foundation Wall & Slab Defects
  Concrete Pre-cast Foundation Defects
  Stone Foundation Defects
  Wood Foundation Defects
FAILURES by FOUNDATION MOVEMENT TYPE -recognize & diagnose types of foundation damage by the nature of foundation movement
  BULGED vs. LEANING FOUNDATIONS - distinction of foundation bulging from foundation leaning has important implications for stability
  COMBINATIONS OF FOUNDATION MOVEMENT - the real world of foundation cracks and movement: often more than one force is at work
    Bulge & step cracks
    Earthquake Damage to Foundations
    Flood Damage to Foundations
    Foundation Movement During Collapse
    Other Foundation Step cracks
  HORIZONTAL MOVEMENT IN FOUNDATIONS - detection, causes, effects, evaluation of horizontal or lateral foundation movement; hillsides
    Bulging, Leaning & Sliding Wall
    Horizontal Foundation Creep
    Horizontal Movement & step cracks in brick
    Impact Damage to Foundations
    Thermal Expansion Cracking in Brick
  VERTICAL MOVEMENT IN FOUNDATIONS - detection, causes, effects, evaluation of vertical foundation movement, differential settlement
    Diagonal Cracks in Concrete Foundations
    Diagonal Step Cracking in Masonry
    Differential vs. Uniform Settlement Cracks
    Leaning or Tipping Buildings
    Uniform Width vs. Tapered Foundation Cracks
    Vertical Cracks
FLOOD DAMAGE TO FOUNDATIONS - examples of flood damaged foundations, flood damage case analysis: were these cracks due to flooding?
FOUNDATION DEFECTS OF OMISSION - recognize things that were left out, like footings, reinforcement, soil compaction, during foundation construction
FOUNDATION CRACK EVALUATION- recognize & diagnose types of foundation cracks, movement, damage, by the size, shape, location, pattern of cracks
  DIAGONAL FOUNDATION CRACKS - causes and significance of diagonal foundation cracks, varies by foundation type & material
  HORIZONTAL FOUNDATION CRACKS - causes and significance of horizontal foundation cracks, varies by foundation type & material
  SHRINKAGE vs EXPANSION vs SETTLEMENT - which foundation materials shrink, which expand, & their characteristic crack patterns
  Sinkholes & Building Damage - sinkhole recognition, significance, cause, underlying geology, areas where sinkholes are worst
  VERTICAL FOUNDATION CRACKS - - causes and significance of vertical foundation cracks, varies by foundation type & material
FOUNDATION BULGE or LEAN MEASUREMENTS - procedure for documenting the amount of lean or bulge in a foundation or other building wall
FOUNDATION DAMAGE SEVERITY - rules of thumb for deciding how much foundation movement requires further action
FOUNDATION DAMAGE REPORTS - how to report foundation inspection results and damage
FOUNDATION INSPECTION STANDARDS - definition of scope of what a foundation inspector
FOUNDATION MOVEMENT ACTIVE vs. STATIC - determine if foundation movement was a one-time event or an ongoing problem
FOUNDATION REPAIR METHODS - catalog of methods used to repair damaged foundations and masonry building walls
  Bulged foundation Repairs
  Crack Repair Methods
  Horizontal Movement Repairs
  Shrinkage Crack Repairs
  Vertical Movement Repairs
SITE FACTORS AFFECTING FOUNDATIONS - drainage, rock, soil compaction, slope or grading, bedrock, sloping bedrock, proximity to roads
SLAB CRACK EVALUATION - recognize and diagnose different types of slab or concrete floor cracks and movement
  Control Joint Cracks in Concrete - what are control joints, why they are needed, what happens when they're omitted; are they structural?
  Freezing & Water Damage - recognize frost and water damage to concrete slabs, distinguish from other crack types
  Frost Heave/Expansive Soil Cracks in Slabs - distinguish between frost damage and expansive clay soil damage to slabs
  Seal Cracks by Polyurethane Foam Injection - stop basement or crawl space leakage
  Seal Cracks in Concrete, How To - products and methods used to seal or repair cracks in poured concrete walls, foundations, floors, & slabs.
  Settlement Cracks in Slabs - recognize slab settlement, assess risk, assess potential impact on structure
  Settlement Cracks vs. Frost Heaves - how to tell the difference between frost heaves and foundation settlement; does it matter?
  Settlement Cracks vs. Shrinkage Cracks - critical identification of shrinkage cracks (non-structural) compared with foundation movement
  Shrinkage Cracks in Slabs - causes, prevention, assessment of concrete slab shrinkage cracks
  Shrinkage Cracks Along Foundation Walls - why do we see a gap between a poured concrete slab and its abutting foundation wall?
  Standards for Repair of Cracks in Floors - when does a floor or slab crack need to be repaired? why?
WATER ENTRY in BUILDINGS
  SUMP PUMPS GUIDE - how a sump pump can avoid foundation damage and reduce building water entry
ADDITIONAL READING

• "Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
• Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• "Concrete Slab Finishes and the Use of the F-number System", Matthew Stuart, P.E., S.E., F.ASCE, online course at www.pdhonline.org/courses/s130/s130.htm
• 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
• Terry Carson - ASHI
• Mark Cramer - ASHI
• JD Grewell, ASHI
• Duncan Hannay - ASHI, P.E. *
• Bob Klewitz, M.S.C.E., P.E. - ASHI
• Ken Kruger, P.E., AIA - ASHI
• Aaron Kuertz aaronk@appliedtechnologies.com, with Applied Technologies regarding polyurethane foam sealant as other foundation crack repair product - 05/30/2007
• Bob Peterson, Magnum Piering - 800-771-7437 - FL*
• 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

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