Unlike conventional homes, the exterior walls of log homes consist of a single material- wood. How log walls behave after original construction depends of their moisture level at the time of original construction, the methods used to construct the walls, the wood species, and the quality of maintenance.
In addition to the systems commonly inspected in a conventional home, inspection of log homes typically includes examination of the following:
- General type: manufactured or handcrafted;
- Wall logs: condition and general construction method;
- General structural integrity;
- Corner notches: type and fit;
- Log extensions: configuration and condition
- Chinking: type and condition;
- Finish coating: condition; and
- Settling accommodation.
Inspection is limited to those components that are readily visible at the time of the inspection.
Check the finish coating by spraying logs with water. Water should form beads and run off instead of soaking into the wood.
Lower wall logs are less protected by roof overhangs and more likely to suffer deterioration of the exterior finish, damage from impact, abrasion, insects and wood decay than logs located higher in walls.
The following are areas of special concern in lower wall logs:
- Moisture damage- Logs lower in the wall are those least protected from rain by roof overhangs. Rain driven by wind against log wall exteriors drains to the lower logs, increasing their risk of moisture-related damage.
- Splash back- Water from rain or snowmelt pooling on the ground near foundations absorbs fungal spores from the soil. As droplets of water from rain and roof drainage strike the ground, spore-containing water is splashed onto logs, inoculating them with fungal spores and providing spores with the moisture they need to germinate. Smoother logs will shed spores more readily and allow easier removal of fungal colonies. Logs with an intact finish will help prevent fungi from penetrating the finish coat and damaging or discoloring wood.
- UV damage from direct sunlight. UV breaks down wood cells. These damaged wood cells deteriorate the bond between wood and the finish coat, increasing the chances for moisture penetration of the finish coat. Damaged cells also provide food for various kinds of fungi and moisture intrusion of the finish coat will allow these fungi to become active.
- Wood-destroying insects- logs closer to the ground are more likely to suffer damage from wood-destroying insects. The types of insects likely to be a problem will vary with region and climate. Inspectors should familiarize themselves with insect species likely to be found locally and learn to recognize evidence of infestation.
- Contact with vegetation- vegetation will hold moisture against logs and provide access for insects. Vegetation should be cut back from exterior walls.
- Transition areas- transition areas are areas in which dissimilar materials meet, such as where sill logs rest upon a floor assembly or foundation. Transition areas are always more vulnerable to moisture intrusion than other parts of the home because they require proper flashing installation, building methods and/or sealant application. In an effort to reduce costs, these seemingly simple procedures are sometimes performed by non-professionals, sometimes with unsatisfactory results.
This article provides only a small portion of the information necessary to inspect log homes capably.
Most home inspectors are unaware of the important differences between inspecting conventional homes and log homes. This ignorance creates liability for both the inspector and his client. To become qualified to inspect log homes, take the Log Home Inspection course offered by the International Association of Certified Home Inspectors (InterNACHI), available at: