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Q&A on damaged masonry block foundations & walls:
Frequently-asked questions about the diagnosis & repair of damaged masonry block foundations & walls.
This article series explains the 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.
Types of foundation 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.
Questions & Answers on Masonry Block (concrete & "cinder block") Foundation & Wall Damage
Recently-posted questions & answers about masonry block foundation wall defects
On 2017-02-16 by (mod): how to repair tree root damage to a concrete block foundation
You will want to hire a foundation contractor with experience in foundation repair. Unlike the great Carno I can't quite see, from here in Mexico, the condition of your foundation nor how your home is constructed.
But in general the contractor will install one or more horizontal beams supported by posts to support the structure from below over a sufficient expanse that the damaged foundation section can be removed and re-built.
Jacking up the building is kept to an absolute minimum, lest you break other building components. -
I have an older home build In 1910 that has a cement block foundation that has collapsed severely on one side due to a tree root. Any suggestion on how to go about jacking it up and fixing the wall?
Tony: if the foundation is sound and the damage is to isolated blocks I'd consider removing loose material, applying a bonding agent, then repairing with a masonry patch concrete that you can stain or color to match the original.
On 2017-02-06 by Tony
I have a 15 foot high block wallmade with the red designer blocks. A couple are crumbling and I don't know how to fix them. Help?
On 2016-11-10 by (mod) - foundation coatings using Hydro-Seal 75 waterproofing
Thanks Rick for the clandestine ad along with installation tips for this waterproof coating product.
Warning to readers: some, perhaps many coatings will be pushed off of the interior wall surface if you do not also get water away from the building exterior.
On 2016-11-10 by Rick Bernard
When applying Hydro-Seal 75 waterproof coating to basement walls and floors we run into cracked and spalling concrete surfaces all the time.
1. Remover all loose concrete with wire brush and chisel.
2. Apply coat of Hydro-Seal 75 with paint brush to act as a bonding agent for patching mortar
3. Apply Hydro-Seal 75 Mortar made from Hydro-Seal 75 Portland Cement & Sand applied with putty knife or trowel on large resurfacing areas.
4. Apply Hydro-Seal 75 over entire surface with brushes and rollers
On 2016-09-14 by (mod)
Why not invite your neighbor to stand there and watch your wall. Start with a clean dry wall and then have an accomplice pour water on the neighbors side.
Let your neighbor watch the water coming through the wall. At that point your neighbor can see what any normal fair-minded person would acknowledge that if you pour water on one side of a concrete block wall it's going to come through on the other side.
Use the page Bottom CONTACT link to send me some sharp photos and we can comment further.
On 2016-09-14 by S Danahy
My cinder blocks(1976) on the one corner of my house seems to be flaking or scaling in planes, professionals are trying to sell me a foundation kit however there is no symptoms in the frames, Windows & doors showing any signs, as well as the exterior & interior walls.
They want just over $18000.please your input would be more knowledge. S.Danahy
On 2016-09-09 by Bill
I have a common cinder block wall,shared with a neighbor. He has a planter on his side, with 8-10 inches of soil against the wall. when he waters the planter the water LEACHES into the wall and is causing damage.
He denies any responsibily. Need literature or help with proving my case
On 2016-09-08 by (mod)
I could use some of that physical persuasion power - to improve communications with a couple of fellows who steal our website traffic by swiping our content and images, thus carrying off the pittance of an income that permits InspectApedia to give away information to anybody who wants it.
On 2016-09-08 by Anonymous
Cheers moderator, I will check the search description you have recommended.
Still I might tell people it's caused by my punching power :)
On 2016-09-07 by (mod) Pounding a punching bag causes foundation wall damage?
I'm not sure what's meant by breeze block walls; vertical cracks in masonry walls often mean that there has been settlement in the wall footing.
You may be a heck of a guy who packs a whale of a punch, but I'd be surprised if hitting a punching bag would cause foundation settlement or cracking.
Search InspectApedia for VERTICAL MOVEMENT IN FOUNDATIONS to read details.
Just covering a crack with cement won't stop the cracks from recurring if there is settlement going on.
On 2016-09-07 by Mick Fenton
Hi I have cracks running vertically through the cemented corners to the breeze block walls in my garage, not sure if these are serious and what caused them.
I do have a punching bag hanging from the timbered roof of the garage and was wondering if this has caused the cracking and whether just covering with more cement would cure it?
Any help would be gratefully received.
On 2016-07-29 by (mod) chipping falling concrete block, with stairstep cracks
Connie, I cannot guess how serious is chipping or cracking block from your e-text; It depends on the size, location, cause of cracking, the amount of movement and thus its impact on the structure.
Certainly I'd be surprised if installing a starter strip for siding would cause structural damage to a building;
Similarly I'd be surprised if drilling a 1/4" hole to pass a cable into a building could cause structural damage. More likely something else is going on.
On 2016-07-28 by Connie c
Hi, we just moved into a well built brick house with a block basement. We had a tv satellite company to hook us up to a dish and they drilled a hole through our block foundation for the cable. We now have several cracks in our block. Some are stair stepped and some go through the block.
And there is some chipping and falling pieces of block. How serious is this? Thanks. Connie
On 2016-07-27 by Bill Coulter
Seven years ago my Townhome Association replaced our siding. They attached a 6" cedar strip as a starting point for applying the siding.
Over time alot of my neighbors have noticed the foundation block where the board was attached show signs of the concrete block deteriorating, I have found indications that in attaching these strips nails were driven into the concrete blocks. Could this be a contributing factor to the block deteriorating?
On 2016-07-26 by (mod) water-main flood damaged foundation wall - is there a collapse risk?
I can't buy enough insurance to promise, based on a mere e-text question, that someone's house is safe from collapse nor much else.
Your lawyer, being a lawyer, would enjoy litigation, so is willing to do research for you that more properly, and more sensibly, would be decided by an on-site expert who knows foundations, old types of masonry block, and structural failures.
This might be a licensed professional engineer IF she/he has experience in these specific areas.
Some masons and even some home inspectors might also have the right experience and background to assess your foundation.
I can offer a general remark that if the block has retained its hardness, position, surface texture, then it's likely to not be showing signs of structural failure. If it's crushing, crumbling, leaning, bending, bowing, bulging, or if you can poke a hole in it with your finger or a screwdriver, it's rather unreliable and could be unsafe.
I'd also worry about the other effects of water or moisture on your building: mold, insect damage, rot.
On 2016-07-26 by Ken barrett
My basement is ash cinderblock from the 1950's. A 36" water main broke in the woods behind my house and eventually flooded me 7 times over a year..the block is severely discolored, black ,gray ..it is my back wall supporting my house..is there danger of collapse because it is "ash cinder?
My lawyer says he cannot find any information on ash cinderblock exposed to long term water damage..PLEASE HELP!! THANK YOU. MY EMAIL..kenbarrett67@gmail .com..
On 2016-05-24 9 by Charles
in the corner of the foundation on lower row of 12" cement blocks there is one broken cement block, with about 80% of the block gone.
I'm not sure how this happened but I'm trying to get the best method for fixing it. Is this a repair that I can do myself or do I need to contact a foundation contractor.
On 2016-04-12 by (mod) horizontal cracks in a foundation deserve careful examination
Horizontal cracking in a concrete block wall is more likely to be caused by earth pressure than a sinkhole.
I suggest that you ask for an evaluation by an experienced mason or by a structural or civil engineer who has familiarity with residential foundation repair.
On 2016-04-10 by JMCFLA
My house has a lower horizontal crack that turns into steps. It was small and has now (over 3 weeks) grown to go across the entire outside wall in 3 different sections at the same level, all of which have a long horizontal look then stairs with each of them.
I am afraid of sinkholes here in florida and wonder if that is what is causing these (a sinkhole under the bedroom) at that wall. Could it be something else? Thank you!!
On 2016-02-02 by David
If my cinder block foundation (crawl space) has an outline the shape of a rectangle on its outside face, does that mean moisture is building up behind it and wicking through?
On 2016-01-29 by Joe
Need reason for house length cinderblock separation, for insurance to repair
On 2015-08-19 by (mod) mold cleanup before foundation repair?
If building interior surfaces, ceilings, insulation, were wet it would make sense to remove wet materials that cannot be cleaned and dried - including insulation, and to be alert for visible mold or building IAQ complaints.
On 2015-08-19 by Anonymous
if a buildings ceiling falls in in the winter time and is not fixed for a long period of time should they look for black mold before putting on a new roof.
Also some of the installation was removed but not all of it. Can black mold come about because of them neglecting them to check the ceiling first?
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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
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
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: email@example.com [A primary resource for this article
 Center for Cave and Karst Studies or the Kentucky Climate Center, both at Western Kentucky University
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
http://www.dmme.virginia.gov/ 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
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