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This article defines, illustrates, and explains the cause and significance of splits or "checking" in logs and beams including in log home structures. Checking or splits in solid logs used to construct both antique and modern log houses worry homeowners even though usually they do not present a structural problem.

But checks in structural wood beams as well as checks and splits in logs used to construct log homes can result in water or air leaks into the building. Also see ROT, TIMBER FRAME for a discussion of the cause and prevention of log checking during log or timber dryout, and for a case study of rot in timber frame construction.

Our page top photo shows the author's precision probing device exploring checking (also called splitting or cracking) of a structural wood beam in a pre-1900 home that had been moved to a new concrete block foundation. As solid wood beams and logs cure, shrinkage produces not only checking (large cracks that are normal and are not necessarily a problem) but also an actual reduction in log or beam diameter.

This series of articles provides information on the inspection and diagnosis of damage to new and older log homes and includes description of log house and log siding insulation values and alternatives, and also a description of the characteristics of slab-sided log homes as well as all other types of log home construction. We include illustrations of log structures from several very different areas and climates in both the United States and Norway. Our page top photo shows a modern kit log home constructed in New York State.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

An Owner-Builder's Guide to Shrinkage In Log Home Walls

Log homes will shrink considerably in wall height as the logs dry during the first one or two years after construction. This is so even in factory cut "dry" logs which may have absorbed moisture in transit or on site, and it is even more true if the logs used in construction were "air dried" or were used while still "green".

The more moisture that was present in logs at the time of construction of a log home, the greater the amount of shrinkage that will occur in overall wall height, and the larger and more extensive will be the checking cracks that occur in log walls.

Usually the crack in the wood beam or solid log radiates from the outer surface of the log towards the log center; it is not common for a log or beam split or crack (or checking) caused by the drying process to pass beyond the center of a log or beam. However more severe splits and cracks can occur in a wood structural member, even passing through its full diameter, due to structural loading or damage.

Log Checking or Splitting - Are Log or Beam Splits A Structural Concern on a Milled Log House?

Log checking, long horizontal splits in the log surfaces, will appear on both inside and outside surfaces of log walls and may vary considerably in width (hairline to 1/2") and length (a few inches to several feet). (Photo courtesy Arlene Puentes.)

Checks in logs (or other large timbers) are rarely a structural concern, but they may become a leak or rot problem.

Checks are only a cosmetic concern unless they are taking in water and therefore risking leaks into the building interior or causing rot or inviting insect damage, as we discuss below

What Problems Might Be Caused by Checking and Splits in Log Walls

Checks and splits in the upper radius of log walls on the wall exterior are of more concern than checks and splits in the lower half of these walls.

Checks even in the lower radius of log walls - that is just below the center or outward-most face of the curved log face may also be a problem if they occur in a position and shape to send water running down the log wall into the log interior. Rain or melting snow sending water into these checks can cause these problems:

• Air and water leaks into the log building interior, especially where the checks lead water to a poorly-sealed window or door frame. In particular, where a window or door has not been properly sealed by splines, gaskets, or other means in a log wall, and where checks in the log conduct water towards the window opening, water and even air infiltration leaks are likely on that log building. An indoor view of this leaky window on a new log home can be seen at Spline Gaps & Gasket Omissions.
• Rot damage or insect damage and even a severe mold contamination problem can follow cosmetic damage and drafty conditions if a leak into any building cavity remains unattended for long enough.

So as our photo (above left) shows, even a structurally harmless shrinkage crack or check in a log wall can lead to an interior leak if the window was not properly constructed. This particular log check reached to the center of the log and bypassed the caulk that the builder had placed around the window frame on the log wall exterior.

Checks in the lower radius of the curved outer face of a log wall and checks in weather-protected location are unlikely to cause damage and are only cosmetic.

Tips for Avoiding Leaks at Splits & Checks in Log House Walls

• If the building is to be constructed using milled logs or a log home kit be sure to follow the log manufacturer's instructions for receiving, storing, and protecting logs from weather at the site.
• Find out ahead of time if your log home logs are specified by their manufacturer as "green" or "kiln dried" or "sticker dried" - as the log moisture content will vary considerably depending on these conditions. Framing procedures of any building absolutely need to take into account the condition of the framing lumber, beams, or logs. Don't frame or build with green lumber or green logs assuming they won't move and change considerably in diameter.
• Measure the moisture of structural beams or logs for a log wall for a log home at the time the lumber is delivered as well as before use. Discuss any surprises or changes in the moisture level with your supplier before using the material.
• Protect the logs or wood beams from weather during construction as well. A framed-up log wall that is left exposed to the weather will absorb moisture even if it arrived "dry" at the building site.
• Be sure to install all of the splines, gaskets, caulk, T-jambs, or other sealing mechanisms required between logs in a log home wall as well as at all window and door openings.
• When checking appears on logs after construction this is a normal event. But if checks in the upper radius of logs on a log home can trap rain, leading it inside the log crack into the building at a window or door, you may need to seal these openings with a sealant approved by your log supplier.

Questions & Answers regarding this article

Questions & answers about splits or cracks in wood beams or in log home log walls.

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Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
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• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

LOG HOME ENERGY EFFICIENCY
LOG HOME GUIDE
  Antique & Old Log Cabins
  Cracks, Checking or Splitting Beams & Log Homes
  Condensation & Moisture in Log Homes
  Energy Efficiency of Log Homes
  Leak Diagnosis & Cure for Log Houses
  Log Wall Height Changes
  R-VALUES & THERMAL MASS in LOG HOMES
  Sealants, Caulks, & Coatings for Log Homes
  Shrinkage In Log Home Walls
  Slab Log Cabin Siding
  Spline & Gasket Designs for Log Buildings
  Spline Gaps & Gasket Omissions
  Types of Log Houses - Log Choices
  Vertical Log Walls on Cabins & Homes
  Wall Insulation Values in Log Homes
LOG HOME WALL INSULATION VALUES

• Thanks to Arlene Puentes for the photograph of a checked log in a log home exterior. Arlene Puentes, a licensed home inspector, educator, and building failures researcher in Kingston, NY. Photographs © Arlene Puentes 2006 All Rights Reserved. Text © Daniel Friedman Arlene Puentes 2008 All Rights Reserved.
• "The Logless Log Home," Jim Robbins, New York Times, 05/05/2010 Home section, p. D1 & D6.
• "Shop Talk," Martin Mintz, AIA, Builder Magazine, April 1986, detailed solutions for log shrinkage movement by using a "T" jamb at windows and doors. A January 1986 Builder Magazine article shows window installation details in 8" thick log walls.
• "Caulking, Chinking, Insulators, Sealants - which System works Best," Log Home and Alternative Housing Builder, Nov-Dec 1983.
• Lincoln Log Homes Marketing, Inc., 6000 Lumber Lane, Kannapolis NC 28081 704-932-6151
• Insulating Characteristics of log homes were neatly summarized by Roger Rawlings in "Log Homes in a New Light," Rodale's New Shelter, April 1983, p. 28
• Merrimac Log Homes, Henniker, NH, sells log home products, milled log home kits, log siding, and log home plans and log home construction accessories. 866-637-7462 or logs@mlhnh.com - merrimacloghomes.com
• PermaChink Systems, Knoxville TN 800-548-1231 provides a range of log chinking products, coatings, and sealants for log and other wood buildings.

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.

• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
• Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
• The Journal of Light Construction has generously given reprint permission to InspectAPedia.com for certain articles found at this website. All rights and contents to those materials are ©Journal of Light Construction and may not be reproduced in any form.
• Appliances and Home Electronics, - energy savings, U.S. Department of Energy
• Avongard foundation crack progress chart for structural crack monitoring
• Basement Moisture Control, U.S. Department of Energy
• Building Failures, Diagnosis & Avoidance, 2d Ed., W.H. Ransom, E.& F. Spon, New York, 1987 ISBN 0-419-14270-3
• Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 ISBN-13: 978-0471331728
• Building Pathology: Principles and Practice, David Watt, Wiley-Blackwell; 2 edition (March 7, 2008) ISBN-10: 1405161035 ISBN-13: 978-1405161039
• The Circular Staircase, Mary Roberts Rinehart
• Construction Drawings and Details, Rosemary Kilmer
• Crawl Space Moisture Control, U.S. Department of Energy
• 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.
• Domestic Building Surveys, Andrew R. Williams, Kindle book, Amazon.com
• 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.
• Guide to Domestic Building Surveys, Jack Bower, Butterworth Architecture, London, 1988, ISBN 0-408-50000 X
• "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
• Historic Preservation Technology: A Primer, Robert A. Young, Wiley (March 21, 2008) ISBN-10: 0471788368 ISBN-13: 978-0471788362
• Log Homes: Minimizing Air Leakage in Log Homes, U.S. Department of Energy
• Manual for the Inspection of Residential Wood Decks and Balconies, by Cheryl Anderson, Frank Woeste (Forest Products Society), & Joseph Loferski, October 2003, ISBN-13: 978-1892529343, $39.00 at Amazon.com or at the InspectAPediaBookstore
• 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
• Masonry Design for Engineers and Architects, M. Hatzinikolas, Y. Korany, Canadian Masonry (2005), ISBN-10: 0978006100, ISBN-13: 978-0978006105
• Masonry Structures: Behavior and Design, Robert G. Drysdale, Ahmid A. Hamid, Lawrie R. Baker, The Masonry Society; 2nd edition (1999), ISBN-10: 1929081014, ISBN-13: 978-1929081011
• Masonry, Engineered: Using the Canadian Code, J. I. Gainville, Cantext publications (1983), ASIN: B0007C37PG
• Masonry, Non-reinforced masonry design tables, Hans J. Schultz, National Concrete Producers Association and the Canadian Masonry Contractors Association (1976), ASIN: B0007C2LQM
• Moisture Control in Buildings, U.S. Department of Energy
• Moisture Control in Walls, U.S. Department of Energy
• Quality Standards for the Professional Remodeling Industry, National Association of Home Builders Remodelers Council, NAHB Research Foundation, 1987.
• Quality Standards for the Professional Remodeler, N.U. Ahmed, # Home Builder Pr (February 1991), ISBN-10: 0867183594, ISBN-13: 978-0867183597
• R-Value of Wood, U.S. Department of Energy
• Slab on Grade Foundation Moisture and Air Leakage, U.S. Department of Energy
• 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.
• "Vapor Barriers or Vapor Diffusion Retarders", U.S. DOE: how vapor barriers work, types of vapor diffusion barriers, installing vapor barrier
• Ventilation for energy efficient buildings, Purpose, Strategies, etc.,
• ...

Log Home Design, Inspection, Maintenance, Repair References & Product Sources

• Log Homes: Minimizing Air Leakage in Log Homes, U.S. Department of Energy
• Log Homes: Controlling Moisture in Log Homes, U.S. Department of Energy
• Log Homes: Log Home Design, U.S. Department of Energy
• Lincoln Log Homes Marketing, Inc., 6000 Lumber Lane, Kannapolis NC 28081 704-932-6151
• Merrimac Log Homes, Henniker, NH, sells log home products, milled log home kits, log siding, and log home plans and log home construction accessories. 866-637-7462 or logs@mlhnh.com - merrimacloghomes.com
• PermaChink Systems, Knoxville TN 800-548-1231 provides a range of log chinking products, coatings, and sealants for log and other wood buildings.