Advantages of Wood Construction
Light Yet Strong
Reinforced concrete is a manmade material which combines iron bars to resist tensile force and concrete to resist compressive force. However, weight by weight, coniferous wood is four times stronger. If one were to build two houses of the same strength out of reinforced concrete and wood, the wooden house would be much lighter. The energy of an earthquake is proportionate to the weight of a building. The heavier the building, the more it is affected by the earthquake. Therefore, a wooden house is more earthquake resistant.
A thick wall is formed by the large amount of air in cellulose, acting as a barrier to outside heat. Wood is twelve times more insulating than concrete. It transfers heat 1/500th as easily as iron and 1/1700th as easily as aluminum, and it is much less heat conductive than many other materials as well. Historically, iron safes were lined with wood. If there were a fire, the wood would stop the heat conducted by the iron, and save the bank notes inside from burning!
It is common sense that wood burns easily. However, this does not apply to thick logs. It has been proven in experiments that big trees in their natural state do not burn easily. A layer of charcoal forms on the outside part of the tree. It is difficult for the fire to reach the inside, as there is a lack of oxygen. Experiments have been conducted which compare wood, iron and aluminum. Results have shown that as temperature rises, iron softens, and in less than five minutes it loses more than half its strength. Aluminum goes limp in only three minutes. In comparison, it takes ten minutes for the strength of wood to decrease by 20%, and twenty minutes for it to lose half its strength. Heat can weaken wood, but it takes a very long time for heat to penetrate logs.
In order for a wall assembly to be considered a fire hazard, the fire resistance rating must be below 30 minutes. Wood frame exterior wall construction with drywall on one side is able to perform at this 30 minute rating. An 8” thick solid log wall performance is rated at 60 minutes, double the performance. Logs are an extremely poor conductor of heat and fire starts upon off-gassing of the material present.
Natural Air Conditioning
Wood reacts constantly to its surrounding environment. If the humidity is high, wood ab-sorbs moisture. If the humidity is low, it emits moisture. Wood acts as a “natural air conditioner,” keeping room temperature constant. Inside a log house, the air is neither too humid nor too dry. If one were to measure the humidity in a room with an air conditioner, one would find the area in front of the air conditioner to be cool, but the area near the door would be warm. Rooms made of wood don’t have the same unevenness, due to the wood’s humidity-adjusting properties.
It has been scientifically proven that a terpene substance emitted by wood is used for protection against insects. This substance is also effective in relaxing the mind and body. This is the “forest bath” effect. This effect does not change once the tree has been harvested. It continues to provide us with a deeply relaxing environment.
Contrary to popular belief, insects are not attracted to your log home. When the logs are set on your foundation, they dry to the relative moisture content of the area. Insects are not attracted to dry wood, they are attracted to the moisture in wood.
In order to maintain the “new” look with any house, there is maintenance. Log homes do require maintenance as does any other house, but they do not necessarily require more maintenance. For the log house, a clear UV coat every 5-10 years. For the con-ventional house, cleaning of siding, re-grouting brick veneer, etc. Logs as with many other building materials (even vinyl siding) have 2 main enemies: sun and water. The trick to eliminating maintenance is smart design. With a proper roof overhang & eleva-tion to protect the logs from the elements, maintenance is kept to a minimum!
The cost of building a log house has actually gone down compared to conventional construction. Dimensional lumber has more than doubled during the past 10 years due to increased manufacturing costs. The raw material (being the log) has been relatively the same price for the past ten years. Log homes used to be 30 – 35% more costly to build. Now, with smart design, the relative costs are much closer.
Passive solar can be employed to keep the summer sun out and let the winter sun in to reduce heating and cooling costs.