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This article explains How to identify types of foundation construction, methods, materials as an aid to diagnosing foundation damage. This document 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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FOUNDATION CONSTRUCTION - How to Identify Foundation Construction Type, Materials, Sequence
StructAPedia ^®

The photo above shows a concrete block foundation wall which had been damaged by water and frost, exacerbated by construction very close to bedrock which sloped to the foundation wall from the surface, trapping roof runoff against the building. A thick concrete laminate wall has been added inside to stabilize the wall (but no proper steps had been taken outdoors to redirect water away.) At this website we explain how it is sometimes possible to be confident about the cause of foundation damage which in turn helps assess the risk presented to the building.

Photographs of types of foundation cracks and other foundation damage: we have a large library of photographs which continually add to this website. Pending completion of that work, contact the author if assistance is required.

Foundation Construction Types

The type of foundation construction affects how a foundation may be damaged, cracked, settled, or moved.

Slab-on-grade - (Sketch at left courtesy Carson Dunlop Associates) Definition of slab on grade foundation: concrete is placed directly onto a prepared soil surface. Modern slab on grade construction usually provides for solid foam insulation below the slab and may use steel reinforcement (re-bar) or fiber-reinforced concrete to resist cracking.= Control joints are important to avoid other foundation cracks. Slab on grade foundations and floors are vulnerable to shrinkage cracks (often not significant), settlement on poorly-prepared sites.

Photos of slab on grade foundations are included in the following articles:
  SLAB CRACK EVALUATION
    Control Joint Cracks in Concrete
    Freezing & Water Damage
    Frost Heave/Expansive Soil Cracks in Slabs
    Settlement Cracks in Slabs
    Settlement Cracks vs. Frost Heaves
    Settlement Cracks vs. Shrinkage Cracks
    Shrinkage Cracks in Slabs
    Shrinkage Cracks Along Foundation Walls
  SLAB CRACK REPAIR
    Control Joint Cracks in Concrete
    Seal Cracks by Polyurethane Foam Injection
    Seal Cracks in Concrete, How To
    Standards for Repair of Cracks in Floors

Monolithic slabs - (shown at left slab on grade construction, sketch courtesy of Carson Dunlop Associates.) Definition of monolithic slab foundation: poured concrete footings and the concrete floor are poured simultaneously as one continuous system. Excavation and concrete forms are used to form the footing and foundation wall portions of the structure. Monolithic slab foundations are resistant to problems over sink holes / clay Supported slabs - (see slab on grade illustration above) Definition of a supported slab foundation: a poured concrete slab is supported on footing/foundation/pins. Vulnerable to hairline step cracks in block walls that rest on the slab; (FL per Mark Cramer). Cracks that are hairline to 3/16 common at the top of slab elevation (in FL-Cramer)

Floating slabs - (shown at left floating slab construction, sketch courtesy of Carson Dunlop Associates.) Definition of a floating slab: a flat concrete slab, typically reinforced with steel re-bar or steel wire mesh is poured on (hopefully) prepared soil and is not supported by a surrounding foundation. Floating slabs may be used inside of concrete, block or other foundation walls, for example in garages. Some poured slabs are pinned to a surrounding foundation wall to prevent tipping or settlement - and thus are no longer technically free-floating. In sum the slab is not connected to a separate building foundation wall. The slab is reinforced and "floats" on supporting soil.

• Crawl spaces, foundations - wall height is a key factor in predicting crawl space failures. Special crawl space wall and knee-wall reinforcement is required in earthquake areas. Also see CRAWL SPACES.
• Basement - wall height vs block width/reinforcement: taller basement walls may require additional reinforcement to resist buckling and bulging. See FOUNDATION BULGE or LEAN MEASUREMENTS.
• Building Additions, foundations - connection to original, varying materials, varying footing depths. Watch for differential settlement cracks and foundation leaks where old and addition foundations meet.
• Actual footing/foundation type is usually not visible, that is, the poured footing, or gravel, or other details that are below ground may be inferred, known from photographs taken during construction, supposed from building plans and drawings, but the actual details are buried unless excavation is performed to permit an inspection.

Also see Three Types of Poured Concrete Slab Floors - Different Implications of Cracks & Movement found at SLAB CRACK EVALUATION.

Foundation Construction Materials

Foundation Construction Sequence Considerations

Below we list site factors to be considered when evaluating foundation damage of this type. See FOUNDATION INSPECTION METHODS for details.

• Site preparation, construction on fill
• Excavation-errors
• Forms and Footing errors
• Foundation errors
• Backfill errors
• Site Drainage errors
• Modular construction concerns
• Site blasting
• Adjacent Site Blasting

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FOUNDATION BULGE or LEAN MEASUREMENTS
  How to Measure Foundation Movement
  Example of Measuring Foundation Bulge
FOUNDATION CONSTRUCTION TYPES
FOUNDATION CONTRACTORS, ENGINEERS
FOOTING & FOUNDATION DRAINS
FOOTINGS EXPOSED, Repair Methods

FOUNDATION CRACKS & DAMAGE GUIDE
  BRICK FOUNDATIONS & WALLS
  BUCKLED FOUNDATIONS due to INSULATION?
  CRAWL SPACES
  EARTHQUAKE DAMAGED FOUNDATIONS
  FOUNDATION CONSTRUCTION TYPES
  FOUNDATION INSPECTION METHODS
  FOUNDATION FAILURES by TYPE & MATERIAL
  FOUNDATION FAILURES by MOVEMENT TYPE
  FLOOD DAMAGE TO FOUNDATIONS
  FOUNDATION DEFECTS OF OMISSION
  FOUNDATION CRACK EVALUATION
    CRACK MONITORING Methods
    DIAGONAL FOUNDATION CRACKS
    HORIZONTAL FOUNDATION CRACKS
    SHRINKAGE vs EXPANSION vs SETTLEMENT
    Sinkholes & Building Damage
    Thermal Expansion Cracking of Brick
    VERTICAL FOUNDATION CRACKS
  FOUNDATION BULGE or LEAN MEASUREMENTS
  FOUNDATION DAMAGE REPORTS
  FOUNDATION DAMAGE SEVERITY
  FOUNDATION INSPECTION STANDARDS
  FOUNDATION MOVEMENT ACTIVE vs. STATIC
  FOUNDATION REPAIR METHODS
  PIER or PILE FOUNDATIONS
  SITE FACTORS AFFECTING FOUNDATIONS
  SLAB CRACK EVALUATION
  SLAB CRACK REPAIR

FOUNDATION DEFECTS OF OMISSION - MISSING

FOUNDATION FAILURES by TYPE & MATERIAL
  BLOCK FOUNDATION & WALL DEFECTS
  BRICK FOUNDATION & WALL DEFECTS
  BRICK STRUCTURAL WALLS Loose, Bulged
  Brick Thermal Expansion Cracking
  BRICK VENEER WALL Loose, Bulged
  BRICK WALL DRAINAGE WEEP HOLES
  CONCRETE POURED FOUNDATION WALL, SLAB DEFECTS
    Cold Pour Joints
    Shrinkage Cracks in Concrete
    Holes & Penetrations
    Settlement Cracks
    Form Tie Marks & Leak Points
    Other Concrete Wall or Floor Damage
  CONCRETE PRE-CAST FOUNDATION DEFECTS
  STONE FOUNDATION DEFECTS
  WOOD FOUNDATION DEFECTS

FOUNDATION FAILURES by MOVEMENT TYPE
  BRICK FOUNDATIONS & WALLS
  BUCKLED FOUNDATIONS due to INSULATION?
  BULGED vs. LEANING FOUNDATIONS
  COMBINATIONS OF FOUNDATION MOVEMENT
    Bulge & step cracks
    Earthquake Damage to Foundations
    Flood Damage to Foundations
    Foundation Movement During Collapse
    Other Foundation Step cracks
  HORIZONTAL MOVEMENT IN FOUNDATIONS
    Bulging, Leaning & Sliding Wall
    Horizontal Foundation Creep
    Horizontal Movement & step cracks in brick
    Impact Damage to Foundations
    Thermal Expansion Cracking in Brick
  SETTLEMENT IN FOUNDATIONS
  SHRINKAGE CRACKS in CONCRETE
  VERTICAL MOVEMENT IN FOUNDATIONS
    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

FOUNDATION INSPECTION METHODS
FOUNDATION INSULATION OPTIONS
FOUNDATION MATERIALS, Age, Types

FOUNDATION REPAIR METHODS
  Bulged foundation Repairs
    Pilasters for Repair of Bulge, Cracks
    Reinforcing Steel I-Beams for Wall Bulge
    Foundation Anchors for Foundation Movement
    Reinforcing Sister Walls for Foundations
    Cables for Repair of Foundations
    Reconstruction of Bulged Cracked Foundations
  Crack Repair Methods
  FOOTINGS EXPOSED, Repair Methods
  Horizontal Movement Repairs
  Seal Cracks by Polyurethane Foam Injection
  Seal Cracks in Concrete, How To
  Shrinkage Crack Repairs
    How to Seal Cracks in Concrete
    Polyurethane Foam Injection
  SLAB CRACK REPAIR
  Vertical Foundation Movement Repairs

FOUNDATION SETTLEMENT
FOUNDATION WATERPROOFING

SINKHOLES, WARNING SIGNS
SINKING BUILDINGS

SLAB CRACK EVALUATION
  Control Joint Cracks in Concrete
  Freezing & Water Damage
  Frost Heave/Expansive Soil Cracks in Slabs
  Settlement Cracks in Slabs
  Settlement Cracks vs. Frost Heaves
  Settlement Cracks vs. Shrinkage Cracks
  Shrinkage Cracks in Slabs
  Shrinkage Cracks Along Foundation Walls

SLAB CRACK REPAIR
  Control Joint Cracks in Concrete
  Seal Cracks by Polyurethane Foam Injection
  Seal Cracks in Concrete, How To
  Standards for Repair of Cracks in Floors

• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, 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, 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)
• *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.

• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
• Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
• The Journal of Light Construction has generously given reprint permission to InspectAPedia.com for certain articles found at this website. All rights and contents to those materials are ©Journal of Light Construction and may not be reproduced in any form.
• Appliances and Home Electronics, - energy savings, U.S. Department of Energy
• Avongard foundation crack progress chart for structural crack monitoring
• Basement Moisture Control, U.S. Department of Energy
• Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 ISBN-13: 978-0471331728
• Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
• The Circular Staircase, Mary Roberts Rinehart
• Construction Drawings and Details, Rosemary Kilmer
• Crawl Space Moisture Control, U.S. Department of Energy
• 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.
• Building Failures, Diagnosis & Avoidance, 2d Ed., W.H. Ransom, E.& F. Spon, New York, 1987 ISBN 0-419-14270-3
• Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon.com
• 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.
• Guide to Domestic Building Surveys, Jack Bower, Butterworth Architecture, London, 1988, ISBN 0-408-50000 X
• "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
• Energy Recover Ventilation Systems for Buildings, U.S. Department of Energy
• Energy Savings Methods: Whole House Systems Approach, U.S. Department of Energy
• Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008) ISBN-10: 0471788368 ISBN-13: 978-0471788362
• Log Homes: Minimizing Air Leakage in Log Homes, U.S. Department of Energy
• Log Homes: Controlling Moisture in Log Homes, U.S. Department of Energy
• Log Homes: Log Home Design, U.S. Department of Energy
• Moisture Control in Buildings, U.S. Department of Energy
• Moisture Control in Walls, U.S. Department of Energy
• Quality Standards for the Professional Remodeling Industry, National Association of Home Builders Remodelers Council, NAHB Research Foundation, 1987.
• Quality Standards for the Professional Remodeler, N.U. Ahmed, # Home Builder Pr (February 1991), ISBN-10: 0867183594, ISBN-13: 978-0867183597
• Natural Ventilation for Buildings, U.S. Department of Energy
• R-Value of Wood, U.S. Department of Energy
• Spot Ventilation for houses, U.S. Department of Energy
• Slab on Grade Foundation Moisture and Air Leakage, U.S. Department of Energy
• Straw Bale Home Design, U.S. Department of Energy provides information on strawbale home construction - original source at http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10350
• More Straw Bale Building: A Complete Guide to Designing and Building with Straw (Mother Earth News Wiser Living Series), Chris Magwood, Peter Mack, New Society Publishers (February 1, 2005), ISBN-10: 0865715181 ISBN-13: 978-0865715189 - Quoting:
  Straw bale houses are easy to build, affordable, super energy efficient, environmentally friendly, attractive, and can be designed to match the builder’s personal space needs, esthetics and budget. Despite mushrooming interest in the technique, however, most straw bale books focus on “selling” the dream of straw bale building, but don’t adequately address the most critical issues faced by bale house builders. Moreover, since many developments in this field are recent, few books are completely up to date with the latest techniques.
  More Straw Bale Building is designed to fill this gap. A completely rewritten edition of the 20,000-copy best--selling original, it leads the potential builder through the entire process of building a bale structure, tackling all the practical issues: finding and choosing bales; developing sound building plans; roofing; electrical, plumbing, and heating systems; building code compliance; and special concerns for builders in northern climates.
• "Vapor Barriers or Vapor Diffusion Retarders", U.S. DOE: how vapor barriers work, types of vapor diffusion barriers, installing vapor barrier
• Ventilation for energy efficient buildings, Purpose, Strategies, etc.,