A log cabin is commonly built two ways. A scribed home or a chinked home. If you are interviewing home inspectors that would be the first question to ask if they know the difference. A certified log cabin home inspector will be able to tell you the difference. A log cabin home inspection is totally different then a general home inspection for framed conventional home. A log cabin home inspection concentrates areas of the home that are foundation related and settling to just name a few. Additionally, not every home inspector is certified for home inspections. They must pass a completely different course and 120 class room hours. Also, the home inspector should have this entity specifically on his business insurance. Below you will find a list of elements that is inspected on a Log Cabin Home Inspection.
Settling is the loss of wall height over time. It's one of the major concerns for a log home. Let's look at some of the causes and consequences of settling.
Log homes may be built from green logs, which are recently cut with a high moisture content. Or, they were built with logs that have been kiln-dried so that their moisture content is no higher then 19%. Some log homes may have been built using logs with moisture content somewhere between the two extremes.
Moisture content is important because as long as logs continue to lose bound water [which is the water contained in the woods cell material as opposed to the water in the cell cavities] the logs will continue to shrink in diameter. When logs shrink the log walls settle which will result in height loss. When a home has stopped settling then the home has reached its (EMC) equilibrium moisture content with its environment.
If the home has a gable roof and the fables are built using green logs, the gable will settle as the logs dry. Normally, in framing a gable roof, the ends of the ridge are supported by the gabled wall at each end of the roof. If that wall is losing height because the logs are settling, what is happening to each end of the ridge? If the ridge is securely fastened to the logs, roof connections are going to be stressed until some roof or wall framing components break or become disconnected. Either way both are bad events.
Doors and Windows
When constructing a log cabin home, normally the contractor will have a settling space above the doors and windows so that the weight of the wall will not bear on the doors and windows. The settling space is typically covered with trim which is installed in such a way that it can slide as settling takes place. A newer home built with green logs that has no settling space installed above the doors and windows is a major deficiency. An inspector who fails to notice this condition would be making a major mistake.
As walls lose height, anything connected to them also loses height. If a staircase rests on a floor at the bottom and, at the same time, is attached to a landing or floor joists that are losing height as the walls settle, after a while, the treads will no longer be level. There are a number of ways to correct this. but you have to know what to look for.
Partition walls in log homes are typically framed conventionally. This means that although the log walls will settle, the partition walls will not. If the partition walls are framed from floor to ceiling, as they would be in a conventional home, something bad will happen as the settling log walls transfer weight tot he partition walls that were not designed to bear a load. The stress will build until the weakest component fails. The intersections of conventional walls and log walls have to be framed using methods that will allow the log walls to settle while the conventional walls stay put. Failure to use a connection method that will accommodate different settling rates can cause major problems.
Plumbing Pipes and Rigid Conduit
In homes of two stories or more, plumbing pies and rigid conduit that are installed vertically will accumulate stress as log walls settle. There are ways to accommodate settling. Using slip joints and coils are two methods for overcoming this problem. Flexible copper tubing is sometimes used instead of rigid copper pipe. It is also possible to see the methods and materials used, and sometimes it may not be.
In order to accommodate settling, log homes sometimes use screw jacks, which must be adjusted occasionally. Screw jacks are often hidden behind trim, so you have to know where to look for them. Posts that support porch roofs and lofts are common places to find screw jacks. They maybe installed at the top or bottom of a post.
Most home inspectors are familiar with wood decay. Designing features that direct runoff onto log walls, especially extensions at outside corners, will encourage the development of decay. This is decay you can see because it usually appears as dark discoloration. It happens first at log extensions because the exposed end-grain absorbs moisture faster than the rest of the log's surface. Lower logs are also at risk due to being soaked by rain or splash back and are less protected by roof overhang.
Hidden decay is a big problem with log cabin homes. Hidden decay can not be seen and at times can destroy the home. A common scenario is that the home is located in a region with high humidity. If an impermeable finish coating is applied to log exteriors while the interior log moisture content is high enough to allow decay to take place, that moisture will be trapped inside the log and decay will continue as long as there is adequate moisture in the wood. There are tests that can be performed to determine this.
Logs become deteriorated by weather. finish coatings are designed to protect log surfaces from UV damage and excessive checking caused by log drying. Some coatings also prevent attack by some wood-destroying insects. In the report it will be noted if there is enough coating on the logs . This is done by a spray test.
Wood Destroying Insects (WDO)
In the State of Florida it is recommended to have an exterminator perform this test, due to regulation. While performing our inspection we will look for obvious signs of WDI. However, an exterminator will also treat the contaminated area while performing the inspection.
To learn more about Log Cabin Home Inspections, click here.