The Art of Constructing Energy Efficient Log Homes
Increasing energy efficiency is a big topic today for those planning to build a new home. Log homes are attractive when built and appeal to people who like a rustic home or a home that seems to blend in with its surrounding environment.
A log home built in the middle of a standard subdivision may look out of place but an energy efficient log home set in a naturally wooded lot in the country looks like it belongs there.
There are considerations if you are building or buying a log home. The wood of the logs provides some insulation and the level of insulation depends on what type of wood is used - soft or hard.
The thickness of the logs provides benefits of thermal mass and an R-value between 0.71 per inch for hardwoods and 1.41 for softwoods.
When compared to an insulated conventional stud wall a log wall is not energy efficient. However, the mass of the wood's thickness changes calculations for energy efficiency.
Built in the right area, a log home's walls store energy generated from the sun during the day and releases the heat gradually throughout the night.
This adds to the R-value of a log home. For this reason, log homes are particularly energy efficient when built in areas where day and night temperatures have a wide fluctuation.
Logs used must be seasoned for six months or more before being used to construct an energy efficient log home. Wood shrinks as it dries and even when the homes are built the logs retain about 15% water.
Over the years, the logs gradually and the shrinkage that results can lead to gaps between logs which create leaks and draft and greatly increase the cost of heating and cooling the home.
The best woods to use for increasing energy efficiency are Fir, Pine, Cedar, and Spruce. Experienced home builders know the problems that can arise due to shrinkage of logs after home construction.
Many builders kiln dry logs as part of the process of creating building supplies. Builders may also use plastics and caulking to seal gaps between logs.
When seals or caulk sealing is used it adds to the maintenance of the home as sealants must in inspected and resealed as needed.
The wood in logs will also absorb moisture even after they have dried. Log homes can absorb water quickly and easily and this can cause wood rot and lead to insect infestations in the wood.
This is why constructing energy efficient log homes involves deep roof overhangs that keeps most rain from the walls of the log home. Use of gutters and downspouts are recommended as are good drainage conditions around the home.
One common way to prevent moisture damage is to use logs that have been waterproofed and treated with insecticides. Those treatments can be reapplied every few years just as you would paint a frame home to maintain the exterior.
The problem of measuring energy efficiency of a log home has made the construction difficult under some area building regulations.
Building codes often have an R-value requirement and the thermal mass of log homes is only now being considered as a way to meet code standards.
Some states have added special conditions for log home construction to meet to fulfill local building codes but these special conditions may not result in increasing energy efficiency.
Before planning construction of a log home check the building codes in your state, county and city. Some regions will allow a home to be approved in inspections as long as it meets the lowest code standard of state/county/city regulations.
Other states require the builder to meet the highest set standard. This may not be as complicated as it sounds as most city and county building codes are based on the requirements set by that particular state.
Energy efficiency of your log home depends in large part on building the structure in climates where the thermal mass of the thick logs will provide some benefits.
That means building log homes in areas of moderate climates. In extremely heat or extreme cold, the R-value provided by thermal mass does not yield an energy benefit.
Log homes are often prized by environmentalists. Years after a log home has been used the parts used to build it can be reused and made into other lumber products when a log home is demolished.
In fact, logs homes are most often deconstructed rather than being demolished. For many, energy efficiency is a real focus as these are seen a environmentally friendly and environmentally responsible dwellings.