How to Identify & Evaluate Freezing, Water & Other Damage to New Concrete Slabs or Foundations
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How to Identify & Evaluate Freezing Water & Other Damage to New Concrete Slabs or Foundations
What are the trouble signs of freezing damage: flaking, cracking, heaving, in new concrete foundation walls, floors, slabs, footings?
When is concrete foundation damage severe enough to need repairs?
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This article describes How to Identify & Evaluate Freezing & Water Damage to New Concrete Slabs or Foundations.
This website describes how to recognize and diagnose various types of foundation failure or damage, such as
foundation cracks, masonry foundation crack patterns, and moving, leaning, bulging, or bowing building foundation walls.
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.
Freezing or Water Damage in Poured Concrete Slabs or Foundations
Foundation question about winter exposure: we have a new home being built and so far only the foundation has been poured and the bottom floor has been laid down. we are from Ontario Canada and it has been a bad winter with a lot of snow and ice.
Our floor has been exposed to an abundance of snow, ice and rain for at least 3 months.
The snow and ice has melted and then re froze. Our builder says that this is ok and it will cause no damage.
Is this true? Is it ok to have the floor exposed for the whole winter?
Foundation answer:
If the concrete was mixed and handled properly for a cold weather pour (some suppliers use special additives to prevent
freezing damage during concrete curing) and if the site was prepared and protected properly during the critical early
period of curing of the concrete (protect from rain, flooding, freezing), your new foundation is probably just fine.
However since things can and do go wrong in construction and in life, below we describe how to take a look at your
new foundation to see if there are any early signs of trouble. Certainly if there were serious damage to a new foundation, it would be
far less costly to repair it before, rather than after, framing and other subsequent steps in building construction.
While concrete continues to cure and harden for weeks or months after it has been poured, the new pour is most vulnerable to rain, frost, or water damage when the pour is very new - from the time right after the pour has been completed, for perhaps 24 to 48 hours. After that time, rain and water themselves are unlikely to damage the exposed concerete. Flaking and spalling are the two most common freezing or concrete mix (or finishing process) problems likely when a concrete poured wall or floor are brand new.
However both new or even older concrete in a poured building foundation slab or foundation walls might be damaged by water and frost from other mechanisms such as frost heaves caused by freezing wet soils which can push or even adhere-to and lift below-ground and on-ground structural components, and also settlement caused by soil subsidence due to compression (water causes compression of inadequately-compacted soil below a concrete footing or slab) or erosion (loss of soil washed out from below a concrete wall or floor).
Signs of trouble in a newly poured foundation wall, slab, or floor in cold, wet, or freezing weather
Concrete surface flaking - is a most common visible sign of inadequate cold-weather protection of concrete during a pour. If the surface of the new pour freezes, flakes of water/concrete may pop off; if the flaking is severe, repair or replacement may be needed. If flaking is trivial/superficial only, then this is probably only a cosmetic item.
Frost Heaves in Concrete Footings, Slabs, Floors, or Walls - cracks and/or movement in the foundation can occur due to failure to protect the new pour from freezing, combined with poor site drainage or incomplete site preparation. Either frost heave (frozen water expanding and pushing on the foundation) or settlement can occur in a new foundation, exacerbated if these conditions occur during particularly wet conditions followed by freezing weather.
Shrinkage Cracks in Concrete Walls, Floors, Slabs - some shrinkage cracks are typical in concrete regardless of the time of year of the concrete pour, especially if control joints were omitted, but large cracks (more than 1/8" wide) or cracks which include dislocation of the concrete (one side of the crack is more than 1/8" "out" or "above" the other in a wall or floor) may deserve further evaluation.
If there are many and severe shrinkage cracks in poured concrete we suspect that either the mix was improperly prepared or the pour was
improperly cured. Too-rapid "drying" of concrete can increase the risk of shrinkage cracks occurring as there may be insufficient water
to support the chemical curing process, hydration. So shrinkage cracks are not specifically a winter, cold weather, or rain-exposure
problem in concrete.
Concrete Surface Spalling - at any time of year, but perhaps worse when exposed to rain, if the concrete were poorly mixed in general, or lacked proper additives for cold weather use, you may see spalling (chipping off of surface areas, or soft crumbly surface areas) - spalling and bad mix can occur in any weather
Cold pour joints in concrete walls - these are not usually a problem but might, in extreme cases, result in foundation wall leaks
In sum, if a month or two after a new concrete slab or wall has been poured, you don't see flaking, shrinkage cracks or movement-related cracking, then the new pour has not been damaged by freezing or wet condition. But remember that other defects: cracks, settlement, spalling, can occur later in the life of the building.
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Additional technical contributors & reference sources for this article are listed below.
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"Best Practices for Concrete Sidewalk Construction," Balvant rajani, Canadian National Research Council
"Design Considerations for Perlite Roof Slabs," a chapter in "Perlite Concrete Grade for Lightweight Concrete Construction", United Perlite Corporation
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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