How to Repair Foundation Cracks Using Polyurethane Foam Injection InspectAPedia® -
Foundation Crack Repair with Polyurethane Foam
How to Stop Basement or Crawl Space Water Leakage Through Cracks
Guide to sealing foundation cracks
Foundation crack repair materials & sources
Questions & answers about foundation crack sealing procedures using injectable polyurethane foam
This article explains how to use polyurethane foam to repair a concrete basement (or crawl area) wall or slab crack in order to stop basement or crawl space water entry.
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Also see
How to Seal Cracks in Concrete for a description of various products and methods used to seal or repair cracks in poured concrete walls, foundations, floors, & slabs.
and see
FOUNDATION REPAIR METHODS for a more extensive discussion of types of foundation damage and how it is repaired.
[Photograph of this foundation crack repair process using foam injection, courtesy of Applied Technologies]
A variety of site conditions can lead to cracks in a concrete or other masonry foundation wall. Speaking
generally, foundations may be damaged and cracks may appear from innocent causes unlikely to affect the
structure such as shrinkage cracks, initial settlement, or from potentially more serious causes such as
ongoing settlement, unusual pressures or loading, or from improper construction.
Before repairing a foundation crack by sealing it against water entry,
it is important to diagnose the cause of the crack and its effects on the building structure.
If there is an underlying ongoing problem causing foundation movement or damage, that problem should be corrected.
Cracks in concrete walls that are larger than 1/4", cracks which are increasing in size, or cracks which
are indicative of foundation movement should be evaluated by a professional.
The diagnosis and evaluation of foundation cracks and structural
foundation damage and repair methods are discussed at
FOUNDATION REPAIR METHODS
Shrinkage cracks and in some cases other foundation cracks such as those caused
by minor initial settlement might not be a structural concern but may still form
an opening leading to water leaks into the building.
Concrete shrinks as a natural process of it curing. This shrinkage
causes the concrete to develop stresses and to relieve it, the basement
wall cracks.
Concrete shrinkage cracks are a common condition in a concrete foundation
[or also in concrete slabs unless control joints were used in the wall or floor design] and occur when concrete shrinks
as it dries and cures.
Shrinkage cracks are easy to recognize and to distinguish from cracks that occur
later in the life of a foundation because [usually] the cracks are not continuous and tend to
extend in a very irregular line through the concrete (as shown in the photo)
range in length from a few inches to the entire height of the concrete wall, extending from
wall top to bottom.
Concrete shrinkage cracks virtually always extend through the full thickness of
the foundation wall, which means they can provide a ready path for water entry into the building.
Common areas for a shrinkage concrete crack to develop
are under a basement window, above a doorway in the middle of a long
wall or where the foundation "steps down." Shrinkage cracks also often occur near the middle of a large poured
concrete wall [or floor] if no control joints were used. [Concrete control joints are very often omitted in residential
construction. Shrinkage cracks and how to recognize and diagnose them are discussed further at
SHRINKAGE vs EXPANSION vs SETTLEMENT.
Once concrete cracks in a basement or crawl space wall or floor slab, it is possible for water to leak into a
building through the crack. There are several ways to repair a basement
crack leak. An easy, quick, and effective measure to stop basement
or crawl space water entry through a foundation crack is to perform an injection of
polyurethane foam into the basement crack. [Also be sure to find and fix the sources of
water outside.]
Both commercial and home-owner "do it yourself" kits and equipment are available to
seal foundation cracks using this foam method. [Photograph of this foundation
crack repair kit, courtesy of Applied Technologies].
Polyurethane foams are injected into the basement crack in a
liquid form. This allows a gentle and slow filling process of the
basement crack that will completely fill the crack. After a few minutes
the polyurethane will begin to react with the water in the crack to
begin foaming. Water is actually the catalyst that converts the liquid
polyurethane into foam. This foaming action increases the volume of the
polyurethane up to 30 times its liquid form.
As the polyurethane foam expands it fills the basement crack
from bottom to top and front to back. The finished foam will be a
closed cell structure that will not allow water to leak into the
basement crack. In fact, if there are any voids in the soil outside of
the basement- such as under a rock or if the foundation is backfilled
with gravel-the polyurethane foam will expand and extend out into the
void.
The polyurethane foam forms a strong bond to the concrete. This bond will be able to withstand the hydrostatic pressure that may develop
from high subsurface water levels. High underground or "subsurface" water levels are typically
caused by heavy rains and most-often by failure to direct roof runoff or nearby surface runoff away from the building.
This concrete crack repair process using polyurethane injection is likely to be more successful and more
durable than other crack patching methods. Surface patching of the crack is just that. Only the
inside of the basement wall is covered by a repair. Chiseling out the crack and filling it with hydraulic cement only fills a portion of the crack.
Water can still enter the basement crack and will eventually force out the patch or hydraulic cement. [Forces that tend to cause
separation of poorly-bonded concrete surface patches include the molecular action of crystallizing mineral salts left behind as
moisture passes through the masonry wall.]
Basement crack injection is a quick repair process that stops water leaks. The technician does not have to drill into the concrete to
do it. For this reason the basement crack repair is a clean process. The technician will attach ports to the surface of the basement crack
that allow the liquid polyurethane to enter the basement wall and stop the leak.
Once the basement wall crack is completed, water will not be able to leak into the basement. Now the homeowner's possessions will be
safe. As will any insulation on the basement walls, the drywall or the framing used to finish the basement.
Questions & Answers regarding this article
Questions & answers about foundation crack sealing procedures using injectable polyurethane foam.
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Thanks to Aaron Kuertz author and contributor of this article on foundation crack repair using polyurethane foam, and foundation crack repair materials (updated 06/02/2009)
Aaron Kuertz aaronk@appliedtechnologies.com, is with Applied Technologies in Fairfield, Ohio.
The foam sealant discussed here as well as other foundation crack repair products are available from Applied Technologies and include a polyurethane foam used to seal leaky basement cracks (this is not a structural repair it's a waterproofing measure). The company sells other foundation repair products (dowel rod epoxy) as well as foundation and basement waterproofing, drainage, and damp proofing products as well. 1-877-277-5948, 513-939-3767 or Fax: (513) 939-3787
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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