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This article explains the inspection and diagnosis of rot and leak damage on older log homes and other log structures that used vertical logs to form the building walls.
This series of log cabin articles provides information on the inspection and diagnosis of damage to new and older log homes and includes description of log home insulation values and alternatives, and also a description of the characteristics of slab-sided log homes. Our page top photo shows an older vertical-log walled log home along the Susquehanna river in Pennsylvania.
At left is a vertical-log cabin in northern Minnesota. Photographed in 2006, this log cabin was built in the late 1920's or early 1930's as a fishing camp.
Thanks to the wisdom of the owners who at least kept a decent roof on the cabin, the log building endured for many decades. But it was in rough condition by the turn of the century, needing floor structure, roof, wall, and window repairs.
The vertical placement of most of the logs on this building permitted the original builders to use local cedar logs cut on this rocky point of land extending into a great lake even though the logs varied widely in diameter.
There was no problem of mating logs of different sizes at the building corners when this approach was used, yet the building corners and structure remained intact, even absent the structural tie of overlapping log ends.
The original log structure was not chinked nor well-sealed but inside the builders nailed furring strips between vertical logs, in some instances using oakum or newspaper as a chinking material behind the furring.
Checking, Cracks, Leaks & Rot Concerns at a Vertical Log Walled Home
Checks in vertical logs do not pose the same risks as in horizontal logs in a building wall, because the checks or cracks naturally drain. This condition puts the logs at less risk for rot or frost damage. But the damage risks are not zero.
For example in the vertical log wall cabin shown here, the builder, or someon else later, poured concrete around the ends of the vertical logs (photo, below left). Unfortunately this detail, illustrated below, trapped water around the base of every log in the wall. Eventually, even though these were rot-resistant cedar logs, they decayed, as you can see at below right.
In comments and photographs below we illustrate the types of damage and log home failures that occurred in this structure.
The principal causes of rot and carpenter ant damage we found at this Minnesota log cabin were
Rot at the bottom end of logs placed on sill beams that stretched between piers (Photo above right)
Rot at the bottoms of logs behind horizontal trim boards - the boards may have been added later to cover existing damage, but the absence of any caulking let wind-driven rain enter and become trapped behind the trim boards causing extensive rot in these areas (Photo above left).
Carpenter ant damage to interior partitions due to wood close to soil where floor beams rested on or close to dirt in more shallow areas of the crawl space at the right side of the building.
Rot damage to several interior areas due to roof leaks, including fungal growth at the top of vertical logs inside where leaks at roof eaves soaked into the exposed end grain of the vertical logs. (Photo below left)
If you see fungus like this growing on a wood structure you can safely assume that significant rot damage is present and that the conditions that caused this damage are old and protracted.
The green cabin underwent an extensive renovation and reconstruction after 2000 and it remains in frequent use as a dry (no plumbing) guest cottage.
Our photo (left) shows the original 1930's home-made sink that included plumbing that drew water from and emptied back into the lake - a system that was removed completely when the cabin was repaired and renovated.
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Questions & answers or comments about the design, construction, & repair of vertical log wall cabins & homes.
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"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
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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.
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 firstname.lastname@example.org - 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.