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:
•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.