How to Recognize Foundation Defects of Omission - things left out InspectAPedia® -
How to Recognize Foundation Defects of Omission - things that were omitted that later lead to foundation damage, cracks, settlement, movement, leaks
Missing foundation footings & piers
Missing columns: Lally columns that were removed during remodeling
Visual inspection of foundations and structures to locate missing elements
Photographs of foundation, footing, pier and column mistakes
Questions & answers about missing or incomplete building foundations
This article explains how to notice missing foundation footings, missing structural columns, and other foul ups - How to Recognize Foundation Defects of Omission - things that were omitted that later lead to foundation damage, cracks, settlement, movement, leaks and
other problems.
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Our page top photo shows a pre-fab concrete and wood foundation which has been installed over no footing and no backfill (yet). Is this a problem?
Detecting omissions, such as leaving out a foundation footing is an important step in learning 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 COLUMNS & POSTS, DEFECTS
FOUNDATION DEFECTS OF OMISSION - Identify Foundation Defects of Omission, things that were left out or forgotten during foundation construction
Construction defects of omission refers to leaving out or removing necessary structural
components.
It is considerably more difficult for a building inspector to learn to observe
the absence of a component than to notice defects involving a component which is present.
This brick veneer wall was constructed over a masonry block structural wall; the veneer contained no expansion joints though some of its sections were nearly 100' in length.
The cracks visible in this photograph had that omission as their root cause.
Northridge Earthquake Building Collapse - Check out These Supporting Columns
Here are examples of types of omission that contributed to a structural collapse. During our work at the Northridge Earthquake site in California in 1994 we noticed that some of the supporting Lally columns were hollow rather than concrete filled.
Perhaps due to material shortages or rush during construction, these hollow, and weaker supporting columns were wrapped with a fire-barrier just as were the "real" supporting columns used elsewhere.
Our photos show a section of Northridge Meadows which collapsed during the earthquake. At left you can see that this column was hollow.
Our opinion was that these were defective columns and that they were a factor in the structural collapse during the Northridge earthquake. Other areas of the same complex moved, columns even leaned, but they did not collapse where the columns were of the proper type and were properly connected to the structure.
Other factors in the collapse appeared to include how exterior sheathing had been nailed across or not across certain sections of the building supporting walls. Our list of examples of defects of omission during foundation construction continues below.
Missing footings (may or may not be a defect depending on design and soil conditions)
Missing supporting columns such as a basement Lally column, where an owner has removed the column
to open up a basement space being remodeled for use as living area. Our photo, below left, illustrates one way you can spot a missing column: a Lally column top plate remains tacked in place on the under-side of a built-up beam in a basement. Sometimes you can spot the imprint of this Lally column top plate as a rectangular impression on the underside of a beam even though the steel plate itself was removed. See COLUMNS & POSTS, DEFECTS for details.
Omitted steel reinforcement - footings missing re-bar or other required steel rods (not visibly detectable after construction)
Omitted steel reinforcement - walls missing steel reinforcing wire or re-bar (possibly visibly detectable after construction if cracks permit view into wall structure)
Missing piers beneath interior or exterior posts (may be visible as post settlement)
Missing control joints in poured concrete slabs, concrete floors where random shrinkage cracks appear - see Control Joint Cracks in Concrete
Missing expansion joints in large or long brick masonry walls both in structural brick walls and in brick veneer walls, where thermal expansion cracking occurs (see photograph above). See Brick Thermal Expansion Cracking, and see BRICK VENEER WALL INSULATION.
Missing expansion joints/materials around windows or doors in poured concrete or brick masonry walls may appear as damaged or inoperable windows or doors.
Failure to compact the soil under a foundation footing or under a poured concrete slab which has been placed on backfill
Questions & answers about missing or incomplete building foundations
Question: what is the best way to fill in missing soil around the footings in my crawl space?
Water table in my area is high. During winter and rainy season, I get water
under my crawl space. I have installed two sump pumps, which takes care of
that. But since the original owner had done nothing to it for 40 years or
so, now I have spots around the permitter of the crawl space that dirt has
been gone and my foundation is exposed. It is still OK but I need to dump
dirt on the entire permitter. But I do not know how.
I need close to
6 to 7 yards of dirt to be dumped there. I either have to hire 6 or 7
people to pass bucket of dirt under the house or open up my brand new floor
at couple of locations to dump dirt from top.
Any suggestions? - S.E.
Reply: temporary foundation openings may make interior backfill easier: three different methods
1. emporary Foundation Openings for Foundation Footing Backfill and Repair
Where foundation or backfill repairs are needed due to inadequate backfill inside of a crawl space, or where as in your case the soil has settled or been washed away by water entry and years of sump pump operation, you will want to consider the following steps:
Assure that the foundation footings themselves rest on compacted fill or virgin soil and that the footings have not been undermined by soil loss. If footings are undermined then you'll need to either pour new lowered footings or your backfill will need to include some soil compacting steps to reduce the risk of future footing settlement or tipping and subsequent movement in and damage to the foundation wall. Start with a visual inspection of the exposed foundation and footings in the whole crawl area.
Make one or more temporary openings through the foundation walls to provide an access opening through which soil can be brought into the crawl space to fill to the desired level. If the crawl area has sufficient ceiling height to make working and moving about in the crawl space practical, one opening at just one end of the building may be sufficient. This is the approach I'd take for cases in which we do not want to pull up the flooring and subflooring over the crawl space.
Finish the crawl space grade and put down a moisture barrier: When enough soil has been placed into the crawl space to provide a relatively smooth floor you might want to add a layer of 6-mil poly to hold down soil moisture, keeping it out of the building and reducing the risk of future mold and humidity problems. See CRAWL SPACE GROUND COVERS and also CRAWL SPACE VAPOR BARRIER.
Some contractors place rounded river-stone gravel atop the poly moisture barrier to protect the plastic and to provide a walking surface that is less slippery. A down-side of the gravel-on-top-of-plastic approach is that if you didn't keep the ground surface smooth below the plastic, there is a risk of hidden puddles that may form atop the plastic in the future. I like to slope crawl space soils (and surface covering of plastic) to a low point where one or more sump pumps are installed (or can be added) should they be needed in the future.
2. The Bill Tsukamoto Conveyor Belt Method of Foundation Excavation and Repiar
And a friend of ours in Honolulu addressed an under-house excavation and construction problem by building a chain-driven bucket conveyer that moved dirt from where it was to where he needed it. But for smaller under-home foundation excavation or backfill, other means may be more appropriate.
3. Complete Under-Home Excavation and Repair
Eric Galow described to us a major under-home foundation repair project that involved temporarily jacking up the entire structure and using a Bobcat to dig first a ramp to the bottom of the building foundation and then to excavate the entire space below the home in order to install both a full basement and properly-constructed footings and foundation walls. When the foundation walls were complete and a slab had been poured below, the house was lowered back onto its new foundation walls.
Keep Water out of the Crawl Space
Watch out: regardless of the method you may choose to add fill around exposed crawl space footings, make sure that you have taken the proper steps to keep water out of the crawl area. It is far better for the building to prevent crawl space water entry in the first place than to let water enter the space and then pump it away. See CRAWL SPACE DRYOUT PROCEDURES
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Additional technical contributors & reference sources for this article are listed below.
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"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
"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)
*These reviewers have not returned comment 6/95
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: ericgalow@gmail.com or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
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
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.
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