Log construction was the most common building technique in large regions of Sweden, Finland, Norway, the Baltic states and Russia, where straight and tall coniferous trees, such as pine and spruce, are readily available. It was also widely used for vernacular buildings in Eastern Central Europe, the Alps, the Balkans and parts of Asia, where similar climatic conditions prevail.
Log homes may be site-built or pre-cut in a factory for delivery to the site. Some log home manufacturers can also customize their designs. 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.
In a log home, the wood helps provide insulation. Wood’s thermal resistance (or resistance to heat flow) is measured by its R-value. The higher the R-value, the more thermal resistance. The R-value for wood ranges between 1.41 per inch (2.54 cm) for most softwoods, and 0.71 for most hardwoods. Ignoring the benefits of the thermal mass, a 6-inch (15.24 cm) thick log wall would have an R-value of just over 8.
Based only on this, log walls may seem not to satisfy modern energy standards. However, to what extent a log building interacts with its surroundings depends greatly on the climate. Because of the log’s heat-storage capability, its large mass may cause the walls to behave considerably better in some climates than in others.
Logs act like “thermal batteries” and can, under the right circumstances, store heat during the day and gradually release it at night. This generally increases the apparent R-value of a log by 0.1 per inch of thickness in mild, sunny climates that have a substantial temperature swing from day to night.
The use of wood is by itself a renewable resource. As trees are harvested, replacements can be planted. In addition, most major log home manufacturers are heavily involved in reforestation programs that replace more trees than are harvested. Not only are the trees renewable, all parts of the tree can be used beneficially with minimal waste. Bark is recycled for landscaping, bedding, and mulch. The trunks are kept primarily for the walls for homes and the smaller trunks and branches are valued for their furniture making abilities.