Log home are constructed of logs, these logs are composed of various layers of wood cells. These cells differ with tree species in terms of function, size, concentration, proportion and chemical composition. They determine how trees grow, how they react after they've been cut for logs, and what properties they have that make them good (or not) for home construction.
Checks, spiral grain, knots, insect holes and logs with sweep and taper are commonly found in log homes. These imperfections are not defects and are to be expected in most homes. It's only when they cause problems that they are considered defects.
Sweep refers to bowing in a log. No naturally shaped logs are perfectly straight. Logs too radically bowed shouldn't be used in log homes. However, occasionally, inspectors will see logs whose bowing looks excessive. The difference in size between the ends of logs is referred to as its taper. Knots indicate where branches grew in the live tree, and may be tight or loose. Knots affect the angle of grain as wood fibers bend to grow around the limb, so they may have an effect on log strength, but determining the extent to which this condition is a problem would require the services of a certified log grader.
Any plant species that grows taller than 20 feet when mature and has a dominant single stem (i.e., the tree trunk) can be referred to as a "tree." Plants that mature at less than 20 feet are called shrubs and aren't used for building.
Sapwood helps to support the tree, but its main function is to transport water and mineral nutrients from the soil to the leaves. Its cells also store carbohydrates and provide protection. Sapwood is typically light in color.
The trunk and branches grow in diameter and circumference through new cells created in the cambium. Most new cells live only a short time. As the tree expands in diameter, sapwood cells slowly become closer to the center of the tree and their function changes from transporting fluids through the tree to storage of various toxic chemicals and compounds (extractives) created by the tree, often in response to injury. Cells that serve as storage are part of the heartwood, and it's the extractives they contain which give them their typically darker color. Some extractives are toxic to insects and decay fungi, which is why heartwood is more resistant to attack than sapwood.
Photosynthesis takes place in the leaves. During this process, leaves absorb carbon dioxide (CO2) and sunlight to produce sugars and carbohydrates. This is used as food and transported throughout the tree through the phloem. This food provides energy for growth and protection processes.
In climates where relative humidity is subject to significant swings, logs with only left-hand grain may distort more than those that also have right-hand grain. This distortion can open gaps that may allow moisture intrusion or insect infiltration, or increase air leakage through the building envelope.
Virtually all trees start growing with left-hand grain. Some, prompted by genetic code after 10 to 40 years, will start to change grain direction and eventually develop a right-hand spiral. This process happens slowly. Because the butt of the log is older than the tip, severity of the slope of the grain will vary from one end to the other. Some trees never change direction and remain left-hand spiral trees.
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 a clear-wall (a wall without windows or doors) R-value of just over 8.
You may be able to find certified or licensed home inspectors who specialize in log homes but you will probably have to do some searching. You may also want to contact a local log home restoration company and ask if they can inspect the home.
Checks, spiral grain, knots, insect holes and logs with sweep and taper are commonly found in log homes. These imperfections are not defects and are to be expected in most homes. It's only when they cause problems that they are considered defects.
Sweep refers to bowing in a log. No naturally shaped logs are perfectly straight. Logs too radically bowed shouldn't be used in log homes. However, occasionally, inspectors will see logs whose bowing looks excessive. The difference in size between the ends of logs is referred to as its taper. Knots indicate where branches grew in the live tree, and may be tight or loose. Knots affect the angle of grain as wood fibers bend to grow around the limb, so they may have an effect on log strength, but determining the extent to which this condition is a problem would require the services of a certified log grader.
Any plant species that grows taller than 20 feet when mature and has a dominant single stem (i.e., the tree trunk) can be referred to as a "tree." Plants that mature at less than 20 feet are called shrubs and aren't used for building.
Sapwood helps to support the tree, but its main function is to transport water and mineral nutrients from the soil to the leaves. Its cells also store carbohydrates and provide protection. Sapwood is typically light in color.
The trunk and branches grow in diameter and circumference through new cells created in the cambium. Most new cells live only a short time. As the tree expands in diameter, sapwood cells slowly become closer to the center of the tree and their function changes from transporting fluids through the tree to storage of various toxic chemicals and compounds (extractives) created by the tree, often in response to injury. Cells that serve as storage are part of the heartwood, and it's the extractives they contain which give them their typically darker color. Some extractives are toxic to insects and decay fungi, which is why heartwood is more resistant to attack than sapwood.
Photosynthesis takes place in the leaves. During this process, leaves absorb carbon dioxide (CO2) and sunlight to produce sugars and carbohydrates. This is used as food and transported throughout the tree through the phloem. This food provides energy for growth and protection processes.
In climates where relative humidity is subject to significant swings, logs with only left-hand grain may distort more than those that also have right-hand grain. This distortion can open gaps that may allow moisture intrusion or insect infiltration, or increase air leakage through the building envelope.
Virtually all trees start growing with left-hand grain. Some, prompted by genetic code after 10 to 40 years, will start to change grain direction and eventually develop a right-hand spiral. This process happens slowly. Because the butt of the log is older than the tip, severity of the slope of the grain will vary from one end to the other. Some trees never change direction and remain left-hand spiral trees.
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 a clear-wall (a wall without windows or doors) R-value of just over 8.
You may be able to find certified or licensed home inspectors who specialize in log homes but you will probably have to do some searching. You may also want to contact a local log home restoration company and ask if they can inspect the home.
About the Author:
Napoleon Home Inspections has over 4,000 inspections and is considered the Premier Home Inspector in the Barrie and Simcoe County area. Learn about the Barrie Home Inspector Services before buying your home.
0 comments:
Post a Comment