The Foundation Damage & Repair Bible
Foundation Cracks, Leans, Bulges, Settlement: Inspecting Foundations for Structural Defects - Detection, Diagnosis, Cause, Repair
FOUNDATION DAMAGE & REPAIR GUIDE - home - CONTENTS: Guide to foundation inspection, troubleshooting & repair. Visual inspection of foundations, Types of foundation damage, Extent of foundation damage. Concrete foundation cracks, damage, Masonry block foundation cracks, damage, Stone foundation bulges & movement. Photographs of foundation crack patterns
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This article series describes in detail how to recognize, diagnose & repair various types of foundation failure or damage, such as
foundation cracks, masonry foundation crack patterns, and moving, leaning, bulging, or bowing building foundation walls.
Types of foundation cracks, crack patterns, differences in the meaning of cracks in different foundation materials, site conditions, building history,
and other evidence of building movement and damage are described to
assist in recognizing foundation defects and to help the inspector separate cosmetic or low-risk conditions from
those likely to be important and potentially costly to repair.
Methods & Procedures for Evaluating Residential Structural Foundation Cracks, Movement, & Condition
This article series explaining how to recognize, diagnose and repair foundation cracks & damage is for building owners, professional or licensed home inspectors, foundation repair companies, foundation engineers, architects,
and other building professionals concerned with residential property
masonry foundation failure detection, diagnosis, and repair.
Watch out: 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.
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
are constantly adding this website.
The photo above shows a cracked, bulged, leaning stone foundation wall at the edge of an embankment - a condition we discuss further
at this website.
Strategy for Building Foundation or Floor or Slab Crack, Damage, or Movement Assessment
To understand the cause, effect, and remedy for all types of building foundation or masonry wall damage or movement we have categorized foundation damage into these broad categories:
The photo at page top shows a bowed masonry block foundation wall with horizontal cracking that occurred due to earth loading at the time
of construction, probably by vehicles driving too close to the foundation wall shortly after it was constructed.
Foundation Inspection Objectives
Home inspectors, building code compliance inspectors, and general building contractors are often able
to recognize possible foundation or other building problems which may be costly or dangerous,
thus requiring the intervention of an expert
foundation repair company or foundation design engineer.
These early visitors to a building site, most often the home inspector,
see a very large number of in-service field conditions leading to building failures.
Foundation inspectors can,
without performing any engineering calculations or analysis,
learn to recognize signs of important foundation or other structural problems developing well before
forensic engineers and foundation experts are asked to
design a repair and almost always well before the actual occurrence of a catastrophic building failure.
This breadth of field inspection experience and education, combined
with an informed and careful building inspection, provide a valuable
first line of defense for building owners and occupants who may be facing previously unrecognized costly or
dangerous foundation damage.
Foundation inspections are conducted to identify & document potential costly or dangerous conditions. The inspection
must consider many factors beyond the obviously visible condition of the foundation, such as attending to site conditions,
evidence of the history of building movement, and the type, location, and extent of cracking and movement.
This data, combined
with education and experience, permit a knowledgeable foundation inspector to advise the client about the urgency of
foundation repair and the type of repair that may be needed.
Accountability: the inspector is accountable for visible portions of the foundation
and for recognizing signs of defects. In some circumstances this may include
invisible or hard-to-see conditions for which there are nonetheless adequate clues: contextual, historical,
or other visible secondary evidence.
Action: If appropriate, the inspector may suggest further evaluation/repair including invasive methods such as removing finish
materials that cover the foundation, outside excavation, the employment of a foundation engineer, foundation repair company,
a test firm to make soil borings, or other investigative measures.
Watch out: Danger: Since certain masonry structure defects, such as bulged above ground brick masonry walls, can lead to sudden
precipitous and catastrophic collapse, dangerous conditions may be present at some properties.
While there are often
hidden conditions which can disguise building conditions, the ability to
recognize those potentially urgent or dangerous conditions which can be detected is important in a foundation inspection.
In-service field conditions refers to the state of repair of a building or its components
while the building is in-use. Building construction standards, engineering and architectural design, and building
code compliance have traditionally dealt either with advance specifications for a building which is
to be constructed, or with the forensic examination of a building or component after it has failed.
The science and practice of in-service building inspections and building conditions provide
an important but different base of experience about the way in which
buildings and building components fail, the causes of building failures, and the detection of
clues indicating that failures are developing.
In-service building inspections provide an opportunity to detect
evidence of developing construction failures which (usually) have not yet reached such dire conditions as to
be obvious to the lay person.
The home inspection profession (contrasted with the "home inspection industry")
focuses on in-service field conditions and as such has developed its own unique education, standards, ethics,
and practices. Yet it also requires an understanding
of design, codes, and building standards as well as traditional failure analysis.
Development of Foundation Damage Assessment Criteria: When is a Foundation Expert Needed?
Our series of articles on the topic begins at FOUNDATION CRACKS & DAMAGE GUIDE - for which I'd welcome any questions, critique, suggestions, or content contributions. There you might find some material of use in your classes.
In the 1980's ASHI was desperate for an education chairman - so desperate that I [DJF] was given the job even though I was a neophyte; I used that position to organize conferences around the U.S. on topics that I wanted to know more about - of which this foundation damage assessment & repair topic was at the top of the list. Both for professionals like PE's and RA,s as well as general and less rigorous bread-truck-drivers who became home inspectors, learning to recognize trouble at the foundation and figuring out criteria for deciding when the owner/buyer needed to call in an expert, and figuring out who, really, WAS an expert, was difficult and had not been stated clearly by anyone.
At a conference I organized for ASHI I asked Ed Seaquist, PE and Dave Wickersheimer, PE, RA, to teach some seminars on recognizing foundation damage and diagnosing it. Seaquist had written a useful but incomplete book on the topic; Wickersheimer was a true in-depth expert analyst. At the conference Ed told us that he thought that it was the contractor/building-inspector population who were first in line to decide if a foundation needed action or expert assessment or not. His reasoning was that we see thousands more conditions than he did. He and Dave were only called when there was already a catastrophe.
Wickersheimer told a heart-stopping story about looking at a tall structural brick school building's bulged wall, calling off a basketball game on the court below, and learning that right at the time of the scheduled game the building collapsed into the court.
Anyhow we spent a lot of time trying to figure out "how bad is 'bad'" - e.g. how much lean, bend, bow, or how big a crack forms a call to action. We learned that to some PEs & RAs, since the foundation is "not supposed to crack" then ANY crack was something they called a "failure" - but that was not helpful, the experts agreed.
The answer ultimately has to be made on-site and in the context of a number of observations: type of construction, foundation materials, presence/absence of reinforcement, location of cracks, size, shape, type, pattern, lateral dislocation, history of movement, diagnosis of the cause of the movement or cracking, leaning, etc., and its extent. But a few rules of thumb emerged, such as the 1-inch lean or bulge rule for concrete block residential foundation walls.
A topic that's missing from my exposition, and a bit beyond building inspection and diagnosis, is the recurrent and terrible problem of buildings that collapse when some idiot undermines or damages the foundation while working next-door - it happens about once a year in the U.S. alone. The news just had a similar story of a NY building that collapsed onto its neighbor during demolition, killing several people.
Starting with Seaquist, expanding with Wickersheimer, and having had the material reviewed by about 20 experts the topic was improved but remains forever incomplete. All of these criteria are reflected in the article series I cite. I continue to welcome any questions, suggestions, etc. Together we are smarter than any individual.
Really? Beginning in the 1980's or even before, a couple of PE's in NY
, fellows who were apparently more interested in inspections than in performing actual engineering work, decided they wanted all of the home inspection business in the state. They took a public position that only a licensed PE could make any statement whatsoever about the condition of a foundation.
This was absurd as thousands of contractors, owners, and general hoi-polloi look at building foundations all the time and have to decide if there is a problem that needs an expert .. or not. It was also absurd given that a vocal member of this movement held a license in aerospace engineering - having nothing to do with structures and foundations.
By this reasoning, rather than make an actual inspection of property condition, a building inspector would have to simply refer a building owner or buyer to a roofer, electrician, plumber, framer, heating contractor, A/C contractor or other specialist for every system in the building. Happily saner (and more principled) voices prevailed, and the position of the obstructionists was held to be improper and untenable by the state department of engineering and its licensing board. 
Building Codes & Standards on Foundation Damage Assessment?
Reader Question: is there a building code that describes "foundation damage assessment"?
I was reading your article on foundation damage. Is there a building code in PA or the USA that sets forth these criteria? I see you base it on surveys of inspectors, but is there a criteria in a code somewhere that mandates whether repair is required or what monitoring is required? - D.M. 8/5/2014
One might infer a fundamental error in the form of your question: the presumption that indications of or measurements of building foundation failures have been or can be codified into building performance codes, structural codes, or standards.
I have had an abiding interest in the assessment of residential building foundations for decades, have met with engineering experts, forensic architects and educators as well as several thousand home inspectors to discuss this topic at conferences and individually.
The original question was how might a building inspector recognize signs of foundation trouble and how should that be reported, including its seriousness.
I organized a national conference on the topic. One of the speakers was an expert and author, Ed Seaquist (Diagnosing House Foundation Problems). The predictable arguments included
How much building foundation damage or movement constitutes a serious risk?
Technically some foundation engineers call any crack a failure since the foundation was not supposed to crack. But some cracks are of no import while others may indicate an imminent life-threatening disaster. The more salient question is how to sort these out.
How should evidence of building structural damage, including foundation damage, be reported?
The boundaries between visual inspection of building components and systems and the practice of structural engineering or forensic engineering
Other construction inspectors and all of the trades have to encounter and report on site conditions but must take care that they don't practice engineering without a license. Similarly, even within the field of engineering, engineers should practice within their specialty. For example electrical engineers should not claim structural expertise any more than civil engineers claim expertise in circuit design.
Ultimately, suggested by Seaquist, and Wickersheimer, we concluded that in-field inspectors see thousands more buildings in more conditions than engineers and architects who are called to the scene when the signs of trouble are severe, and that that larger body of inspections was the most valuable resource in writing guidelines for foundation inspections.
Building codes, excepting the Residential Maintenance Code that has not been widely used, address the "front end" of a building's existence: its safe and proper construction. Reflected in those codes are anticipated usage, loads, and environmental exposures of the building, ultimately expressed as construction standards and codes.
Research on building failures informs those code and standard writers.
But building code and standard writers have pretty much avoided the very difficult companion topic of attempts to codify damage by type, severity, causation, and repair requirements.
Because steps to codify damage by type, severity, causation, and repair requirements for a building demand very careful, experienced, expert and thoughtful on-site investigation of many factors that vary considerably from case to case.
So we instead find these discussions in forensic engineering courses, forensic architecture courses, and at a less quantitative level in home inspection classes in damage recognition and reporting.
These factors are cataloged and listed in the foundation damage article series found here.
I have not found building codes or standards attempting to codify or quantify such damage beyond some very simple comments in the Residential Maintenance Code on repair requirements for cracked concrete floor slabs - those are included in our information at InspectApedia.com
Instead we have drawn on the experience and opinion of architects, engineers, and home inspectors and their field experience to describe both foundation damage analysis procedures for field use by non-engineers/architects - the first people on the scene in 90% of cases - and by the more expert people as well.
The building inspection generalist is expected to be competent to recognize possible or probable serious conditions across a wide range of building construction and mechanical system topics and is expected to report the need for further action accordingly.
If you have contributions or suggestions for this topic we'd welcome hearing from you.
Reader Question: are these horizontal foundation cracks "cosmetic" or "damage" ?
2016/05/11 Jing said:
I am buying a house (built in 1965) that has several horizontal cracks (2-3, about 6 feet long) in the concrete foundation in the crawl space. I asked a foundation consultant to do an inspection on the house. He checked the leveling of each room with his tool and also went into the crawl space to look at these cracks. After that I was told that the house is in good shape and the cracks are hairline like and thus no concern. When I asked whether I need to fix the cracks, he told me no.
But I am still concerned about these cracks since I saw many people say horizontal cracks can be problematic because moisture can go in and then the steel can have corrosion and expansion and finally the concrete foundation can collapse. I have no knowledge on house structure and thus would like to get a second opinion on this. The inspection contingency is expiring soon and I do not have time to ask another guy to do another round of inspection.
[Here] are several images. It seems to me these cracks are not hairline like.
Reply: Cold pour joints are not damage, but if cold pour joints + poor concrete mix yield an un-stable wall there could be leaks, movement, or other problems with the foundation
Jing, your images of "concrete cracks" look to me like cold-pour joints rather than cracks caused by bending, sagging, settling or other forces on concrete.
The concrete work looks a bit sloppy and possibly the concrete mix was poorly made. One image included a discontinuous horizontal crack that looks like a shrinkage crack (photo above) but is probably one that occurred as the cold pour joint cured.
If the cold pour joints in a concrete foundation wall are unusually open you may find water leaking through the wall (fix that problem outside first) and if earth or other forces from outside the foundation wall are significant, a concrete foundation wall might bend or buckle along the cold pour joint - though that's something I've never seen myself in 40 years of foundation inspections.
It would make sense to make a more careful measurement of leaning or bending in this foundation wall. See BULGE or LEAN MEASUREMENTS (found by searching InspectApedia for FOUNDATION LEAN MEASUREMENT).
Just below on this page you'll see a list of articles on foundation damage assessment. Also in the ARTICLE INDEX to BUILDING STRUCTURESS (live link below) you'll find a complete index to types of foundations and foundation damage, including this article that is a "must read" considering the photos you submitted: CONCRETE COLD POUR JOINTS.
Reader follow-up: cold pour joints are not horizontal foundation cracks
Dan, thank you very much for your reply, you are so fast!
So if I understand you correctly, these (relatively bigger) cracks are cold pour joints but not real horizontal cracks. And it seems to me like if no leaking issue is present here, probably there is nothing to fix, which is consistent w/ what our inspector says. One suggestion I got from him is to keep the crawl space dry. I think this should be true for all houses.
I have posted a few more pictures in the following link. Would you please have a look at them? In case you see anything unusual please do let me know.
I really like this website, a lot of useful info and also very quick reply! Thank you so much!
Take a look at our discussion in the article above where you see your photos, Jing and you'll see a link to COLD POUR JOINTS - be sure to take a look there if you haven't done so. Your photos are (mostly) sharp up-close images; stand back and look at the concrete pattern and you may recognize cold pour joints.
However your picture #6 looks a bit like an open crack in an old concrete wall. I can't tell from this perspective if I'm looking at just an open cold pour joint or, as I suspect, someone's prior patch attempt on the wall.
Have your home inspector or other building experts look further as I advised for leaning, bowing, bulging, water entry. If none of those are observed, and if they confirm that these are cold pour joints, then the foundation isn't moving and there has been no foundation issue demonstrated by these clues.
Reader follow-up: so are these cracks indicating structral problems or not?
Thanks again for your quick response. That's very helpful. We need to decide tomorrow, so we don't have time to have a profession come to the site. You mentioned that leaning, bowing or bulging will be a big concern along with the cracks. My foundation consultant gave us a chart showing the leveling of the house, please see the picture I provided. Is it able to tell from this chart that, the house doesn't have settlement movement, and these cracks are not structural problems? Thank you very much!
I've said as much as I can speculate based on just your photos. That is enormously less information than one would see at an on-site inspection.
Watch out: The most-upset home buyers I ever find are those who are forced by circumstance to run towards a property screaming I WANT IT and throwing their wallet and checkbook ahead of themselves.
That's because in the rush to close people do hasty work, make mistakes, or fail to understand the building they are buying. Sometimes they're upset later by what are described as "big surprises".
While nobody should make up hazards to the detriment of a property seller, the buyer should exercise all due diligence - that's standard advice in real estate transactions.
You should not and cannot rely on brief e-text to a stranger or a website to make multi-thousand purchase decision on a home. You need an on-site expert whom you can trust completely, who has true expertise and experience where needed, and who has no conflicts of interest regarding the transaction, seller, realtor, or buyer.
I have said as much as I can see from your photos; I certainly cannot tell from your posted photos what is the overall condition of the home, its foundation, nor the rest of its structure.
I do not agree that simply determining that the floors in a home are level means there has been no foundation movement. There could be prior repairs that are or are not adequate, additoinal leveling and shimming that have been done that are ok or not ok, ongoing or not -ongoing foundation movement. I can't see that nor answer those questions from your photos. But those questions can be answered by an on-site expert. Enormously more information is available to a competent home inspector or other on-site building professional.
Building Foundation Damage Texts, Research, Codes
Please see the principal texts and citations for this article series found at REFERENCES. Additional research of interest is listed next.
Allen, David E. "Tornado Damage in the Barrie/Orangeville Area, Ontario, May 1985." Building Research Note 240 (1986): 23.
Ayscue, Jon K. Hurricane damage to residential structures: risk and mitigation. National Hazards Research and Applications Information Center, Institute of Behavioral Science, University of Colorado, 1996.
Blong, Russell. "Residential building damage and natural perils: Australian examples and issues." Building Research & Information 32, no. 5 (2004): 379-390.
Bondy, Kenneth B. "Performance evaluation of residential concrete foundations." PTI Technical Notes 9 (2000): 1-6.
Bruneau, Michel. "Building damage from the Marmara, Turkey earthquake of August 17, 1999." Journal of Seismology 6, no. 3 (2002): 357-377.
Cameron, D. A., and P. F. Walsh. "Inspection and treatment of residential foundation failures." In First National Local Government Engineering Conference 1981: Reprints of Papers, p. 186. Institution of Engineers, Australia, 1981.
Carpinteri, Alberto, Stefano Invernizzi, and Giuseppe Lacidogna. "In situ damage assessment and nonlinear modelling of a historical masonry tower." Engineering Structures 27, no. 3 (2005): 387-395.
Cope, Anne D. "Predicting the vulnerability of typical residential buildings to hurricane damage." PhD diss., University of Florida, 2004.
Cornell, C. Allin, Fatemeh Jalayer, Ronald O. Hamburger, and Douglas A. Foutch. "Probabilistic basis for 2000 SAC federal emergency management agency steel moment frame guidelines." Journal of Structural Engineering 128, no. 4 (2002): 526-533.
Day, Robert. Geotechnical Earthquake Engineering. McGraw Hill Professional, 2012.
Ellingwood, Bruce R. "Probability-based codified design: past accomplishments and future challenges." Structural Safety 13, no. 3 (1994): 159-176.
Faccioli, E., V. Pessina, G. M. Calvi, and B. Borzi. "A study on damage scenarios for residential buildings in Catania city." Journal of seismology 3, no. 3 (1999): 327-343.
Finno, Richard J., Frank T. Voss Jr, Edwin Rossow, and J. Tanner Blackburn. "Evaluating damage potential in buildings affected by excavations." Journal of geotechnical and geoenvironmental engineering 131, no. 10 (2005): 1199-1210.
Friedland, Carol J. "Residential building damage from hurricane storm surge: proposed methodologies to describe, assess and model building damage." PhD diss., Louisiana State University, 2009.
Gibbons, Gerald R. "Residential Landlord-Tenant Law: A Survey of Modern Problems with Reference to the Proposed Model Code." Hastings LJ 21 (1969): 369.
Gurley, K. R., and F. J. Masters. "Post-2004 hurricane field survey of residential building performance." Natural Hazards Review 12, no. 4 (2010): 177-183.
Gurley, Kurtis, R. Davis, Sean-Paul Ferrera, Jeff Burton, Forrest Masters, Tim Reinhold, and Makola Abdullah. "Post 2004 Hurricane Field Survey–an Evaluation of the Relative Performance of the Standard Building Code and the Florida Building Code." In 2006 ASCE Structures Congress, St. Louis. 2006.
Kropp, Alan. "Survey of residential foundation design practice on expansive soils in the San Francisco Bay Area." Journal of Performance of Constructed Facilities 25, no. 1 (2010): 24-30.
Nadolski, Michael E. "Architectural damage to residential structures from seismic disturbances." Bulletin of the Seismological Society of America 59, no. 2 (1969): 487-502.
Yilmaz, Işık, and Atilla Bagci. "Soil liquefaction susceptibility and hazard mapping in the residential area of Kütahya (Turkey)." Environmental geology 49, no. 5 (2006): 708-719.
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after a foundation company installed a foundation the back door won't shut correctly and the concrete blocks are cracking all around the house
My mother decided after 3 yrs it was wise to install block foundation. A company installed her foundation with block. then she noticed her back door was shutting correctly and the block all around the house was cracked.
She called this company back and he proceeded to fix it saying his concrete was probably bad and reported it to his insurance. After a couple of weeks after he so called fix it the home has bad cracks again and the door never fixed correctly. I feel there taking advantage of my mothers no knowledge.
Can you help with advise or what is the correct procedure thx.
I apologize correction: kitchen door was NOT shutting correctly..
- Elsa Lopez
Elsa, take a look at the types of foundation cracking, causes, repairs, beginning at FOUNDATION CRACKS & DAMAGE GUIDE. With so little information I cannot guess accurately about what went wrong. We'd need a lot of information about what was already there, what problem was being solved, and what work was done.
In other words, before we can begin even thinking about a foundation repair (other than perhaps emergency support in dire cases), we need to know
- the extent of building movement and damage
- the effects of those events on the structure
- the cause(s) of the movement
But in any case I agree that foundation cracking all around a house sounds like a serious mistake that needs to be diagnosed accurately before any further amateur repair work is undertaken.
You might find a foundation expert in our EXPERTS DIRECTORY or among local foundation repair companies or from an engineering firm PROVIDED the engineer actually has personal experience with residential building foundation inspection, diagnsosis, and repair.
Keep us posted.
(Aug 20, 2011) Basement flooding said:
Research shows that almost 100% of all basements will suffer some form of basement flooding at some point in their existence. “Almost 100%” translates into “it’s certain”. It makes sense, too, because basements are the single lowest location in any structure, and excess water is always going to flow downhill. Put the two together and you have an unwelcome flooded basement.
(Nov 5, 2011) Anonymous said:
My home is not on ground and it has concrete walls everytime earth movement accures I get cracks on walls what can I do to prevent this from happening?
(Nov 15, 2011) jan said:
my 3 bed loft conversion (which was already done,when I moved in)needs some strengthening works done to the floor and walls, please could I have a ball park figure of what this could cost me ?
(Jan 5, 2012) Sheryl said:
I own a very large manufactured home. Since I moved in a year ago I've noticed some cracking around the ceiling area where some of the sections were joined together; especially after I had new roofing put on. Could all the banging and thumping caused some of this?
Sheryl, in my OPINION, the answer is a definite "maybe" -
Depending on the home's roof framing and covering, the roof and ceiling might indeed flex during work above, moreso if the contractor piled a heavy weight of roof covering materials in one spot.
(Mar 7, 2012) Colleen said:
Unlicensed roofing company, shoddy repair, holes in roof, tore off gutters and plucked out all insulation in attic plus electricity. Foundation has been weakened. Walls cracking, floors shifting and dropping. HELP!
Colleen: from your note it sounds as if you need an onsite expert who is professional, thorough, expert, and unbiased, and who can inspect and document what conditions you face and recommend what repair steps are needed. This is not something you should handle by webmail. The EPERTS DIRECTORY at page top may help you find someone, or check with your local better business bureau.
That said, frankly I can't imagine wat a roofer could have done that would cause foundation damage and cracking shifting walls - it sounds as if something more basic is going on.
Finally, if there is significant movement or if you have any reason whatsoever to be worried about a possible building collapse, you should go outside, get others out of the building, and call your local fire department for help.
(Oct 4, 2012) Richard Brummell said:
We are somewhat disappointed with hair line crack in foundation 1 week after pouring.
See our article about shrinkage cracking and perhaps that will assist you.
6/16/14 David said:
I live an 3-floor apartment building, bottom floor, and have begun to notice quite a few cracks in the concrete walls of my apartment. The walls are not cement all the way through but hollow, that's all I know I'm afraid. Most cracks are quite narrow and they are found mostly near doors or other openings, except for one which runs from the ceiling to the floor. The majority of them are vertical or diagonal. There might have been an addition to the building last year, a metal roof I believe. There is a door that has started to act oddly, sort of opening itself if pushed beyond a certain point. The landlord isn't the type who's gonna do more than fill or paint over the cracks if informed. Is it safe for me to stay in this apartment? Is the building going to collapse? Or can I wait and see?
If a building is moving or settling enough that doors stop working I'm concerned that it may be unsafe. Even if there were no imminent risk of collapse, a stuck door is a fire-exit hazard that should not be ignored.
I can't assess collapse risk from just your note;
Notify the landlord in writing of your concerns that include both building structure and fire safety.
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 New York State Department of Engineering, correspondence. D. Hasbrouck, P.E. to DJF.
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: firstname.lastname@example.org
"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. *
Superior Walls of America Builder Guideline Booklet MAN 42-9000 booklet, [local copy] web-search 09/01/2010 original source (indirect link): http://www.superiorwalls.com/faq.php?&answers=1&details=53
FOUNDATION DAMAGE SEVERITY - How to Evaluate the Significance or Amount of Foundation Movement when a foundation is leaning, bulging, bowing, or settling
See FOUNDATION DAMAGE SEVERITY for our discussion of how to evaluate and report the severity of building foundation damage. A few examples are provided just below.
Historical data is a key observation or data that needs to be collected to assess the significance of any evidence of foundation movement
New or sudden foundation movement: If foundation cracking or movement is new, recent, or sudden: serious, prompt action is needed and you should consult an expert, in particular
if the amount is more than trivial. Trivial movement would be the discovery of a hairline crack (less than 1/16" in width) or a shrinkage crack
in a building foundation wall or floor slab. A word of caution: sometimes a crack has been present for a long time at a building but has simply
not been noticed by the building owner or occupants. The first time such a crack is seen it may be mistaken for "new" and "sudden" when that is
not the case. See our discussion of SHRINKAGE vs EXPANSION vs SETTLEMENT.
Recurrent foundation cracking or movement: action is probably needed since recurrent movement can lead to cumulative damage to some structures
even if the amount of movement is not great. In particular, if you have made cosmetic repairs to a foundation or to plaster or drywall finished
areas above and supported by such a foundation you may see that the cracks you repaired have simply recurred.
Long term, continuing, but slow foundation movement: action may be needed, particularly if the effects of long term foundation
movement are cumulative.
Initial foundation cracking or other limited damage occurring at time of construction such as foundation
cracks in a masonry block wall which occurred during backfill may not need other than cosmetic repairs, in particular if there is no
evidence of subsequent foundation movement and still more likely if the initial damage and amount of movement was minor (say less than 1/2"
of inwards foundation wall bulge in the cracked areas.)
Foundation damage due to being struck: in this case the foundation will certainly need repair if the damage
to it was extensive with collapsed or severely dislocated components. Trivial foundation damage, say cracking a masonry block
on the corner of a garage with no basement below, is less likely to be significant.
Initial foundation settlement may not require additional repair. A hairline to 1/16" vertical crack in a concrete wall or
similar dimension step cracking in a masonry block wall may need cosmetic and sealant repair (to reduce leakage through the wall,
but if the initial amount of settlement was very small and is not ongoing, repair is unlikely to be needed.
These examples of foundation damage are almost always very important and need expert attention
Dislocated gas, plumbing, or electrical wiring or piping: NOTE: ANY foundation damage or crack associated with significant displacement of original structural or mechanical (gas/sewer lines) components is
likely to be significant. Even slight displacement is significant if mechanical systems may be unsafe (earthquake). Dislocated gas lines means
gas leaks are likely and there is serious damage of catastrophic explosion. Vacate the property, and immediately call the gas company from a telephone that is
not exposed to gas fumes.
Dislocated or broken structural connections such as a building which has shifted off of its foundation or has broken sill bolts or straps
connecting the foundation to the building framing needs expert investigation and repair.
Bulging foundation walls in response to area flooding are at risk of collapse; temporary support of the building and other measures
to relieve stress on the foundation may be needed. Do not delay in seeking expert advice in this situation.
This list is not complete. Suggestions welcomed.
Foundation Inspection Standards - ASHI Standards of Practice (American Society of Home Inspectors)
Arlene Puentes, 845-339-7984, is an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees as well as HVASHI Chapter President. Ms. Puentes can be contacted at email@example.com.
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
Technical Edits, Changes, Amendments to This Document
09/01/2010 technical edits
09/23/2008 adding crawl space safety warnings and crawl space dyrout procedures
06/09/2010 adding flood damage to foundations - a flood damage investigation case suggests pre-existing cracks
08/03/2007 adding text, illustrations, content, organization changes, citations to authority
06/07/2007 adding text, illustrations, content
5/30/2007 editing to add content on foundation crack repair
9/23/2006 editing to clarify text and add content; Technical review (partial) by Arlene Puentes.
4/17/2006 editing to clarify text in several sections.
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.
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.
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.
Masonry structures: The Masonry House, Home Inspection of a Masonry Building & Systems, Stephen Showalter (director, actor), DVD, Quoting: Movie Guide Experienced home inspectors and new home inspectors alike are sure to learn invaluable tips in this release designed to take viewers step-by-step through the home inspection process. In addition to being the former president of the National Association of Home Inspectors (NAHI), a longstanding member of the NAHI, the American Society of Home Inspectors (ASHI), and the Environmental Standard Organization (IESO), host Stephen Showalter has performed over 8000 building inspections - including environmental assessments. Now, the founder of a national home inspection school and inspection training curriculum shares his extensive experience in the inspection industry with everyday viewers looking to learn more about the process of evaluating homes. Topics covered in this release include: evaluation of masonry walls; detection of spalling from rebar failure; inspection of air conditioning systems; grounds and landscaping; electric systems and panel; plumbing supply and distribution; plumbing fixtures; electric furnaces; appliances; evaluation of electric water heaters; and safety techniques. Jason Buchanan --Jason Buchanan, All Movie Review
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.
Sinkholes and Sudden Land Subsidence References, Products, Consultants
"A Hole in the Ground Erupts, to Estonia's Delight", New York Times, 9 December 2008 p. 10.
History of water usage in Estonia: (5.7 MB PDF) jaagupi.parnu.ee/freshwater/doc/the_history_of_water_usage_systems_in_estonia.pdf
"Quebec Family Dies as Home Vanishes Into Crater, in Reminder of Hidden Menace", Ian Austen, New York Times, 13 May 2010 p. A8. See http://www.nytimes.com/
"Quick Clay", Wikipedia search 5/13/2010 - http://en.wikipedia.org/wiki/Quick_clay
Florida DEP - Department of Environmental Protection, & Florida Geological survey (http://www.dep.state.fl.us/geology/default.htm) on Florida sinkholes: Effects of Sinkholes on Water Conditions Hernando County, Florida, Brett Buff, GIS in Water Resources, 2008, Dr. David R. Maidment, Photos - Tom Scott, Florida Geographic Survey - Web Search 06/09/2010 - http://www.dep.state.fl.us/geology/geologictopics/jacksonsink.htm
and - http://www.dep.state.fl.us/geology/geologictopics/sinkhole.htm
Lane, Ed, 1986, Karst in Florida: Florida Geological Survey Special Publication 29, 100 p.
Foundation Engineering Problems and Hazards in Karst Terranes, James P. Reger, Maryland Geological Survey, web search 06/05/2010, original source: http://www.mgs.md.gov/esic/fs/fs11.html Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD 21218
"Frost Heaving Forces in Leda Clay", Penner, E., Division of Building Research, National Research Council of Canada, Canadian Geotechnical Journal, NRC Research Press, 1970-2, Vol 7, No 1, PP 8-16, National Research Council of Canada, Accession number 1970-023601, Quoting from original source
The frost heaving forces developed under a 1 ft. (30.5 cm) diameter steel plate were measured in the field throughout one winter. The steel plate was fixed at the ground surface with a rock-anchored reaction frame. heave gauges and thermocouples were installed at various depths to determine the position and temperature of the active heaving zone. The general trend was for the surface force to increase as the winter progressed. when the frost line approached the maximum depth the force was in excess of 30,000 lb (13,608 KG). Estimates of the heaving pressure at the frost line ranged from 7 to 12 psi (0.49 to 0.84 KG/cm) square during this period. The variation of surface heaving force was closely associated with weather conditions. Warming trends resulting in a temperature increase of the frozen layer caused the forces to decline.
Leda clay slopes in the Ottawa valley are vulnerable to catastrophic landslides. More than 250 landslides, historical and ancient, large and small, have been identified within 60 km of Ottawa. Some of these landslides caused deaths, injuries, and property damage, and their impact extended far beyond the site of the original failure. In spectacular flowslides, the sediment underlying large areas of flat land adjacent to unstable slopes liquefies. The debris may flow up to several kilometres, damming rivers and causing flooding, siltation, and water-quality problems or damaging infrastructure. Geologists and geotechnical engineers can identify potential landslide areas, and appropriate land-use zoning and protective engineering works can reduce the risk to property and people.
Deposits of Leda clay, a potentially unstable material, underlie extensive areas of the Ottawa-Gatineau region. Leda clay is composed of clay- and silt-sized particles of bedrock that were finely ground by glaciers and washed into the Champlain Sea. As the particles settled through the salty water, they were attracted to one another and formed loose clusters that fell to the seafloor. The resulting sediment had a loose but strong framework that was capable of retaining a large amount of water. Following the retreat of the sea, the salts that originally contributed to the bonding of the particles were slowly removed (leached) by fresh water filtering through the ground. If sufficiently disturbed, the leached Leda clay, a weak but water-rich sediment, may liquefy and become a 'quick clay'. Trigger disturbances include river erosion, increases in pore-water pressure (especially during periods of high rainfall or rapid snowmelt), earthquakes, and human activities such as excavation
After an initial failure removes the stiffer, weathered crust, the sensitive clay liquefies and collapses, flowing away from the scar. Failures continue in a domino-like fashion, rapidly eating back into the flat land lying behind the failed slope. The flowing mud may raft intact pieces of the stiffer surface material for great distances.
Kochanov, W. E., 1999, Sinkholes in Pennsylvania: Pennsylvania
Geological Survey, 4th ser., Educational Series 11,
33 p., 3rd printing April 2005, Pennsylvania Department of Conservation and Natural Resources / Bureau of Topographic and Geologic Survey, DCNR Educational Series 11, Pennsylvania Geological Survey, Fourth Series, Harrisburg,
1999 - web search 06/05/2010, original source: http://www.dcnr.state.pa.us/topogeo/hazards/es11.pdf - Quoting from the document introduction: The first 18 pages of this booklet contain an explanation of how sinkholes
develop. In order to tell the sinkhole story, it is important to discuss
a number of related geologic disciplines. The words used to describe sinkholes
and these disciplines may be a bit unfamiliar. However, general explanations
are given throughout the booklet to help clarify their meanings.
Key words are printed in bold type for emphasis. The more important
ones are defined in a Glossary that begins on page 29.
The remaining sections, starting with “Sinkholes in the Urban Environment”
(page 18), deal with sinkholes and their impact on our environment.
This includes recognition of subsidence features and sinkhole repair.
 Sarah Cervone, [web page] data from the APIRS database, Graphics by Ann Murray, Sara Reinhart and Vic Ramey, Vic Ramey is
the editor. DEP review by Jeff Schardt and Judy Ludlow. The web page is a
collaboration of the Center for Aquatic and Invasive Plants, University of Florida, and the Bureau of Invasive
Plant Management, Florida Department of Environmental Protection contact: firstname.lastname@example.org [A primary resource for this article
 Center for Cave and Karst Studies or the
Center, both at
Vanity Fair - web search 06/04/2010 http://www.vanityfair.com/online/daily/2010/06/what-caused-the-guatemala-sinkhole-and-why-is-it-so-round.html
Sinkholes, Virginia Division of Mineral Resources,
Virginia Department of Mines, Minerals and Energy, www.dmme.virginia.gov Virginia Department of Mines, Minerals and Energy
Division of Mineral Resources
900 Natural Resources Drive, Suite 500
Charlottesville, VA 22903
Sales Office: (434) 951-6341 FAX : (434) 951-6365
Geologic Information: (434) 951-6342
divisionmineralresources.shtml - Web search 06/09/2010
Sink Hole & Related Engineering References
Newton, J. G., 1987, Development of sinkholes resulting from man's activities in the eastern United States: US Geological Survey Circular 968, 54 p.
Sinclair, W. C., 1982, Sinkhole development resulting from ground-water withdrawal in the Tampa Area, Florida: U.S. Geological Survey Water-Resources Investigations 81-50, 19 p.
White, W. B., 1988, Geomorphology and Hydrology of Karst Terrains: Oxford University Press, New York, 464 p.
Williams, J. H. and Vineyard, J. D., 1976, Geologic indicators of subsidence and collapse in karst terrain in Missouri: Presentation at the 55th Annual Meeting, Transportation Research Board, Washington, D.C.
Barry F. Beck, A. J. (1999). Hydrogeology and Engineering Geology of Sinkholes and Karst. Rotterdam, Netherlands: A. A. Balkema.
Beck, B. F. (2003). Sinkholes and the Engineering and Environmental Impacts of Karst. Huntsville, Alabama: The American Society of Civil Engineers.
Beck, B. F. (2005). Sinkholes and the Engineering and Envrionmental Impacts of Karst. San Antonio, Texas: The American Society of Civil Engineers.
Tony Waltham, F. B. (2005). Sinkholes and Subsidence, Karst and Cavernous Rocks in Engineering and Construction. Chichester, United Kingdom: Praxis Publishing.
Whitman D., G. T. (1999). Spatial Interrelationships Between Lake Elevations, Water Tables, and Sinkhole Occurence in Central Florida: A GIS Approach. Photogrammetric Engineering and Remote Sensing , 1169-1178.
Sinkholes in Guatemala, Guatemala City, Wikipedia - web search 06/04/2010 - http://en.wikipedia.org/wiki/Guatemala_City
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, 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. Field inspection worksheets are included at the back of the volume.
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