How to Inspect, Diagnose, & Repair Concrete Foundation Cracks, Movement, Settlement, Leaks InspectAPedia® -
Poured Concrete Foundation Defects listed, described & explained
How to identify and evaluate cold pour joints, shrinkage cracks, holes, settlement cracks in foundations
How to identify and diagnose Poured Concrete Foundation Wall & Slab Cracks, Movement, Settlement, Foundation Leaks, & Leans, Bulges, & Other Foundation Defects
Photographs of foundation damage patterns and types
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This article explains How to identify and diagnose Poured Concrete Foundation Wall & Slab Cracks, Movement, Settlement, Leaks, & Other Defects
involving reinforced concrete foundations and concrete walls, such as damage due to shrinkage, impact, settlement, frost or water damage, and other causes.
See our starting point for foundation damage assessment: FOUNDATION CRACKS & DAMAGE GUIDE. Also see this close companion article: SLAB CRACK EVALUATION which discusses in detail the process of evaluating cracks, settlement, leaks, shrinkage, or other damage
in poured concrete slabs, monolithic slab foundations, and concrete floors, and see FOUNDATION CRACK EVALUATION which
discusses evaluating foundation damage by examining concrete crack size, shape, pattern, and location.
Examples of structural & other failures in Poured Concrete Foundations: Cracks, Leaks, Movement, & Other Defects
How to Identify Cold Pour Joints in Concrete Foundation Walls
Cold Pour Joints in concrete foundations which leave visible lines in the concrete foundation wall are not usually a structural problem but may in some cases form a dry joint which permits water leakage through the foundation wall.
Cold pour joints occur because of the time delay between subsequent "pours" into the foundation forms.
An astute inspector, by
noting the position, pattern, and slope of the cold pour joint, can probably determine the position from which the concrete
was poured into the forms (the high end of the sloping lines) and the extent of delay between pours (evidence of water leaks
through the joints indicates that enough time passed for the lower pour to solidify).
Our photo (left) provides a closeup of a distinct cold pour joint in a concrete foundation wall of a 1980's home in New York.
Reader Wade Mariage has pointed out that cold pour joints may also occur due to the accumulation of form-release oil on top of a pour into oiled aluminum concrete forms. As Mr. Wade noted and we agree, even when the concrete crew "chuck" the "mud" (concrete) between pours to improve bonding of the subsequent pour and to reduce pour marks, these marks still often appear in the cured concrete. If the aluminum concrete forms are heavily oiled the cold pour mark may be still more visible.
Mariage asserts and we agree that normally a cold pour line is not a structural concern. Exceptions are wall leaks or failure of subsequent pours to bond well if the concrete actually sets between pours - unusual events in normal concrete construction.
Visual clues of cold pour joints give a history of construction sequence and timing: In the photograph above one can just
make out the lines of boards used to construct the forms used to pour this foundation wall. The visual clues combine
to suggest how this foundation wall was constructed and what happened later. The use of boards and somewhat rough
workmanship suggest a "do it yourself" project, perhaps by a small builder or the homeowners themselves. Small contractors
or homeowners might rent a cement mixer and mix small batches of concrete, perhaps not even a cubic yard at a time.
Because a fair amount of manual labor would be involved in mixing each small batch of concrete, it's possible that so much
time elapsed between concrete pours that the lower pours had cured and hardened so much that subsequent concrete pours
did not bond with their predecessors. This (speculative) history might explain why we see horizontal cracks in this
concrete wall in a pattern which tracks, almost exactly, the cold pour joint lines in the wall. If the builder also
skimped on reinforcing steel or wire in the wall that might be another factor in the development of these cracks in
response to earth or frost pressure from outside after the wall was cured.
Where was the concrete truck, how full was it during pouring of the foundation?
The cold pour joints in this concrete foundation wall show us that the concrete truck made the first pour from the corner of this foundation wall. Concrete spread roughly evenly away (and sloping down) from each side of the foundation corner as the concrete was poured into the forms. The truck was probably nearly empty when it started this pour as we don't see much height of concrete below the cold pour joint.
A full concrete truck probably made the second pour as we see no other cold pour joints up to the top of the foundation wall.
This interesting cold pour joint tells us that this wall was poured from its two opposite corners, leaving a vee-shaped cold pour joint in the center of the wall.
Although we can see the dark line between the two concrete pours that formed this wall section, as there was no evidence of an actual crack and no water leakage in the wall, this cold pour joint, like the one above, is not a structural concern - it's cosmetic. Sometimes we can learn something subtle about how a home was constructed and how organized was the builder or mason contractor by observing these clues.
How to Identify Concrete Shrinkage Cracks in Concrete Foundation Walls
Concrete shrinkage cracks are not usually a structural problem but may permit water leaks through
the foundation wall. Shrinkage cracks are often mistaken by owners and inspectors who, failing to observe
the characteristic discontinuous path of the crack and its meandering path, mistake shrinkage cracks for structural damage.
How to Identify Recognize and Repair Holes and Penetrations in Concrete Foundation Walls
Holes and penetrations in concrete foundations such as poorly-sealed openings left for piping for water or electrical lines
or where form ties were broken off may form points of water entry into the structure but are not normally
a structural concern.
The "patched" holes shown in this photograph had been a source of chronic leakage and basement
water entry since this home had been constructed about two years before this photograph was taken. While several
unsuccessful attempts had been made to seal and patch this leak point in the concrete foundation wall, none of the
repairs had tried using a suitable product sold for that purpose and the wall was still leaking.
Of course the
root problem was that surface water was not being directed away from the building outside. These holes were high
enough on the foundation wall that it would be reasonable (and perhaps preferable) to seal the wall from outside
before also re-grading to drain surface water away from the building.
How to Identify Settlement Cracks in Concrete Foundation Walls
Concrete foundation settlement cracking such as from footing settlement, absence of or poorly prepared footings,
water leading to settlement or actual loss of soils, thus undermining the footings (this can occur and can damage most foundation
types), or movement of the foundation due to nearby blasting or excavation work.
Shrinkage cracks in concrete occur only during curing and will appear mostly in the first 28 days after a wall or
floor is poured. If cracks noted and documented after this time continue to increase in length or width, some other
cause is at work and further investigation is needed.
The concrete settlement crack shown here appeared initially
in this wall as a hairline fracture of less than 1/16" in width. The homeowner monitored the crack and watched
it increase in width to nearly 1/2" over the following 12 months, leading to the correct inference that there was
structural movement going on.
In this case we traced the movement to uneven footing settlement which was aggravated
by the combination of having placed the footing partly on bedrock, water from roof and surface
spillage and runoff causing soil settlement (the contractor had not compacted the backfill under
the footings), and by ongoing foundation blasting at a neighboring lot.
Concrete foundation damage from horizontal loading, vehicles, frost is less commonly seen than with unit-construction
materials such as brick or masonry block but might occur under unusual conditions.
Concrete foundation damage from unusual point loads
How to Identify Form Tie Marks and Leak Points in Concrete Foundation Walls
Concrete Foundation Form Tie leaks: Leaks at the location of concrete form ties used during construction of a poured concrete foundation are not normally a
structural problem but they can be blamed for basement water entry.
Form tie leaks occur in a poured concrete foundation wall
where the form ties used to construct the foundation have left penetrations in the concrete walls.
Form ties are wire or steel
connections between the two vertical sides of the wood or steel concrete form. Concrete form ties are needed to prevent
the forms from separating and bulging from the weight of the concrete poured into the form. The best
solution to concrete wall form tie leaks is to keep water away from the foundation from outside.
Other Types of Foundation Damage to Concrete Walls or Floors
Leaning concrete foundation walls or structural walls due to: water, frost, or earth loading, vehicle passage too close to the wall, inadequate footings, soil undermining
Concrete foundation wall cracks*: settlement, shrinkage, cold joints
Concrete foundation spalling due to poor concrete mix, too much water, excessive working of the surface, pouring during cold weather without
proper additives, roof runoff rain-splash erosion of the wall surface.
Articles on Repair of Foundations
For detailed information about foundation repair methods, including repairs to various kinds of cracks in concrete, see:
FOUNDATION REPAIR METHODS for our catalog of Foundation Repair Methods - Examples of Typical Foundation Repairs for various types of foundation cracks, leaks, settlement, movement, or other failures
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.
"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
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, professor, school of structures division, UIUC - University of Illinois at Urbana-Champaign School of Architecture. Professor Wickersheimer specializes in structural failure investigation and repair for wood and masonry construction. * Mr. Wickersheimer's engineering consulting service can be contacted at HDC Wickersheimer Engineering Services. (3/2010)
Wade Mariage, Project Coordinator,
K-Wall Poured Walls, Inc.,Traverse City, MI - 231.943.4727-Office
213.943.4679-Fax
www.k-wall.com
*These reviewers have not returned comment 6/95
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop, and from the InspectAPedia bookstore. The 2010 edition of the Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
Design of Wood Structures - ASD, Donald E. Breyer, Kenneth Fridley, Kelly Cobeen, David Pollock, McGraw Hill, 2003, ISBN-10: 0071379320, ISBN-13: 978-0071379328 This book is an update of a long-established text dating from at least 1988 (DJF); Quoting: This book is gives a good grasp of seismic design for wood structures. Many of the examples especially near the end are good practice for the California PE Special Seismic Exam design questions. It gives a good grasp of how seismic forces move through a building and how to calculate those forces at various locations.THE CLASSIC TEXT ON WOOD DESIGN UPDATED TO INCLUDE THE LATEST CODES AND DATA. Reflects the most recent provisions of the 2003 International Building Code and 2001 National Design Specification for Wood Construction. Continuing the sterling standard set by earlier editions, this indispensable reference clearly explains the best wood design techniques for the safe handling of gravity and lateral loads. Carefully revised and updated to include the new 2003 International Building Code, ASCE 7-02 Minimum Design Loads for Buildings and Other Structures, the 2001 National Design Specification for Wood Construction, and the most recent Allowable Stress Design.
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting: A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
"Avoiding Foundation Failures," Robert Marshall, Journal of Light Construction, July, 1996 (Highly recommend this article-DF)
"A Foundation for Unstable Soils," Harris Hyman, P.E., Journal of Light Construction, May 1995
"Backfilling Basics," Buck Bartley, Journal of Light Construction, October 1994
"Inspecting Block Foundations," Donald V. Cohen, P.E., ASHI Reporter, December 1998. This article in turn cites the Fine Homebuilding article noted below.
"When Block Foundations go Bad," Fine Homebuilding, June/July 1998
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