"Log Home Inspection" course

This thread is dedicated exclusively for those students currently enrolled in the InterNACHI course titled, “Log Home Inspection.

Upon successful completion of this course, the student will be able to:

perform a visual inspection of a log home;
identify and describe its framing and finishes; and
report observed wood decay defects.
And, in keeping with InterNACHI’s commitment to Continuing Education, this course is open and free to all members, and can be taken again and again, without limit.

Students are free to pose questions and comments here and join in the conversation with other students. The thread will be monitored by the course instructor.

Contact: Director of Education, Ben Gromicko ben@internachi.org

Inspector training courses: www.nachi.org/education.

Thank you.

I am looking forward to this class as I have a log home to inspect soon and need to brush up. I was disappointed to find that there is not a template for log home inspection in my Home Inspector Pro library, so i will need to create one.

From the Course:


Starting in the mid-1970s, the development of new building techniques, increased buyer expectations, advances in materials technology, and efforts to develop standardization have resulted in an increase in the general sophistication and quality of newer log homes. Of course, poorly built homes are still going up, and some of them are very big and expensive, with big and expensive lawsuits to match.

Many modern log-home manufacturing operations are designed to provide a high level of quality control. Local trees or logs are stored in an area of the manufacturer’s log yard to be peeled and dried under controlled conditions. Logs may be graded by one of three certified grading programs in the U.S.

Modern log homes are sometimes designed using computer-aided design (CAD) programs and use proprietary engineering. Logs are cut and assembled in the yard by an experienced crew using a job-site crane. When the log shell is complete, it’s disassembled, loaded onto a truck, and delivered to the home site, where it’s often assembled by a local contractor under the supervision of a manufacturer’s representative.

Homes may be delivered from the yard to destinations anywhere in North America, or loaded into shipping containers and shipped abroad. Inspectors may see homes assembled abroad using these methods and shipped to the U.S. A number of Scandinavian countries export log homes to the U.S. This means that inspectors may often see homes built from tree species that aren’t indigenous to the area in which the home is located. Learning about logs in general as a building material increases the chances that an inspector will spot problems before they become serious.

From the Articles:

The walls are made of logs, placed either vertically or horizontally, depending on the style and size of the cabin. The logs are notched at the corners to allow them to fit together. Corner-notching is a notable characteristic of log cabin construction because it provides stability by locking the log ends in place, enabling the logs to fit together in a secure manner. Many different methods of corner-notching exist, ranging from simple “saddle”-notching, to the common “V”-notching or “steeple”- notching, which get their name from the shape of the notch cut into the wood. These notching methods are marked by a cut into the wood that allows another cut piece of wood to fit together like a puzzle piece. Another commonly used technique, “square”-notching, differs in that the logs are secured with the addition of pegs or spikes.

The number of logs used per wall varies with the size of the cabin. The spaces between the logs are usually filled with a combination of materials in a process known as “chinking” and “daubing.” This process seals the exterior walls, protecting them from weather and animal damage.

Inspecting a Log Home

Log Wall Exterior

The inspector shall inspect exterior surfaces of log walls, when such surfaces are visible, looking for:

•the presence of mold, mildew or fungus;
•cracks located at tops of logs and facing up;
•discoloration, graying, bleaching or staining of logs;
•loose or missing caulking;
•separation of joints;
•the condition of chinking, to include cracking, tears, holes or separation of log courses; and
•the condition of log ends.

Other Exterior Concerns

In addition to the items specified in InterNACHI Standards of Practice 2.1 and 2.2, the inspector shall inspect:

•downspout extensions;
•grading and water flow away from log walls; and
•vertical support posts under and on all porches.

Log Wall Interior

The inspector shall inspect interior surfaces of log walls, when such surfaces are visible, looking for:

•separation between logs, including light or air penetration from outdoors;
•separation between exterior log wall and interior partition walls; and
•separation between log walls and interior ceilings.

Other Interior Concerns

In addition to the items specified in InterNACHI Standards of Practice 2.4 and 2.6, the inspector shall inspect:
•dlip joints, adjustable sleeves, looped water supply lines, flexible hose sections, and flexible ductwork that are visible as part of the standard heating and plumbing inspections.


The inspector is not required to:

•inspect or predict the condition of the interiors of logs.
•predict the life expectancy of logs.
•climb onto log walls. However, the inspector may inspect log walls by use of a ladder, if this procedure may be done safely and without damaging the walls.
•inspect components of the porch support system, or of the plumbing or heating systems, that are not readily visible and accessible.

In going through this Log Home Certification, there are many things that one learns in dealing with log homes. This particular issue isn’t quite having to do with rot or structural issues, but merely a failure issue that can affect the rest of the home.

This Vent pipe has sheared off due to snow load and will cause water to enter the attic area where there is a vaulted ceiling and cause related issues to the finish materials inside the home. Recommend having the homeowner repair the issues to reduce further potential water related issues in this area and for continued functionality of the vent pipe for its’ intended use.

worley 2.jpg

Mold can be very harmful if left unchecked and not treated and can be easily unseen and in areas that are hard to reach. One of the best ways to treat for mold is to have an Abatement company come in and search the affected area, remove and treat with an abrasive solution to reach those spaces and to clean the affected areas with HEPA vacuums to reduce further related issues.

This photo shows the west side of home during construction phase monitoring. Vertical adjustable log supports are installed on concrete piers clad with stone veneer. Recommend consulting with builder to monitor and adjust vertical logs to accommodate log structure shrinkage. The drying and moisture balance of the logs may be a slow process and should be monitored by a qualified log home specialist.

I found the log home inspection course very informative. There were some construction methods that are typically hidden that I was not aware of. The log homes that I’ve inspected that are over 15-20 years old always seem to have deteriorated logs from mold & fungi to wood destroying insects. The course will help me to identify the cause of defects (still will recommend a specialist).

Great course. I found this to be extremely informative especially in the decay process of the logs. It will be a great help.

For this module I chose to talk about a home i recently inspected that had severe moisture intrusion in the crawlspace and undermining of 30% of the foundation. What was interesting is that I didn’t notice the discoloration in the soil until just now as I was preparing to write this piece for the log home course. I already knew about the moisture and documented it as such, just didn’t notice the discoloration. DSCN0597.JPG

If you look at the foreground versus the rest of the soil around the edges and furnace you can clearly see the discoloration (increased moisture content).

For the reading and writing portion of this module, I chose the following two articles:
Brownfields and Redevelopment
I was unfamiliar with this term until reading this article. I can see that there is a possibility of running into this type of situation, especially in Colorado, where I live. In particular, we live very near the Rocky Flats Nuclear superfund site. In fact, I believe they are building homes either on the old site or at the very least near it. Extra precautions and some simple due diligence should keep me or any inspector out of harm’s way when it comes to brownfield developments. Appreciate the article for pointing out the risks.

Bug Zappers
A very interesting article pointing out that bug zappers are ineffectual against the most annoying and biting insects, female mosquitos. Something I did not know. Coming from the Midwest, everyone had a bug zapper on their back porch. After reading the article, not only did I learn that they’re ineffective, but that they actually spread bug parts, bacteria and viruses up to 7 feet from the device. I believe the articles more “green” suggestions as to how to control mosquitos is much more effective; install bat houses. Love this idea. Bats are a great resource to have on your property. As long as they’re not getting in to the house or attic.

Attached is a photo from a recent log home inspection. It shows a sill log on top of a CMU foundation. The entire structure was extremely well put together as was delightful to inspect. Both the buyer and seller were present, and this dual agency transaction went smoothly

While the energy code is not friendly to log home performance, thermal mass is now a factor in examining the R value, based on the thickness of the log and it’s species. Default values are now assigned so that computations can be made with some certainty. A blower door test with infared thermal imaging would be the best method to examine the performance of a log home.

Items of critical importance to a log home inspection include the foundation and drainage on site. Wall performance and integrity is important, and the roof structure is the king pin to successful moisture penetration from wind, rain and snow. Doors and windows may move due to settling and humidity, and a free standing chimney provides many opportunities for moisture intrusion.

Electrical outlet on the west side of the kitchen was tested. The outlet was found not to be GFI protected. It is recommended to have a professional electrical contractor be contacted for further evaluation.

Heating oil is used extensively in some parts of the country along with rural properties. Heating oil is safe as long as it is used and stored properly. As an inspector there are multiple things we can watch for to indicate the possibility of a leak. Current leaks or drips along with signs that the tank has been patched indicating past leaks. Legs should be stable and in good condition in order to support the load of a full tank. All lines from the tank should be in good condition with no warn rusty or loose connections.


Kitchens should be properly exhausted to the exterior and not to an attic crawl space or areas between floors with sufficient air flow to push the exhausted air to the exterior. The venting should be of proper size and type. The duct should be smooth and straight as possable. The ducts should be made from metal with as few seams as possible. Any necessary seams should be properly sealed with an approved sealing method.

The corners on this log house were in satisfactory condition. There was, however, no flashing for water run off. A large soffit on the house protected the logs from sun and moisture. This house was approximately 25 years old.

Log Home Basics is a consumer-oriented article. It explains the R-value of logs, along with basics of air leakage and moisture concerns. The consumer will benefit from the information on log-house construction. The article ends with helpful reminders for inspectors to keep in mind during their inspections.

Fireplace Fuel brings helpful details to the table for both inspector and client. There are certain hazards to be avoided by utilizing the proper fuel. This article provides useful information of what one should and should not use in their fireplace. Log homes often have showcased fireplaces. Help the client use them wisely.

The picture attached shows moisture, water stain and apparent mold growth underside of the roof deck, and the dirty insulation indicate air movement in this attic. Recommend a qualified roof contractor to assess and repair as needed to avoid any further damage.


Article: Inspecting Log Homes
Wood decay could be developed by directly runoff on the exterior log walls, especially log extensions at outside corners. It first happens at log extension is because the exposed end-grains absorb moisture much faster than the rest surface of logs. The decay wood always appears as dark discoloration.

Article: Log Home Basics
By reading this article I noticed that the Standards of Practice for inspecting log home are now being written and reviewed by a committee appointed by International Association of Certified Home Inspectors. Although no Standards of Practice for inspecting log home has been published in 8/22/06, they are not in effect or binding upon any inspectors.

The loose stones used for a foundation were displaced at the south west corner of the cabin and the bottom course of logs were in contact with soil. This is a conducive condition for wood destroying organisms. A qualified person should make repairs to properly support the structure and provide clearance from surrounding soil.