From the Log Homes Council – NH Codes Now Recognize Log Building Standards
For the first time ever, building a log home in New Hampshire is covered by an International Codes Council (ICC) Standard that is referenced in both the 2009 edition of the International Residential Code (IRC) and the International Building Code (IBC). This standard for log home energy efficiency is referred to as ICC400-2007.
Why does this matter? Why is it important to anyone building a log home outside of New Hampshire? It is relevant for two very important reasons. One: As energy codes continue to evolve throughout the country, it is vital that log construction techniques are evaluated accurately. Accurate building guidelines will insure that your log home will comply with new local energy codes. Two: New Hampshire is one of the most popular states for building log homes and therefore is the perfect location to evaluate building standards as they pertain to log homes.
Why Do Log Homes Need Special Attention?
According to Rob Pickett “the biggest threat to the construction of log homes today is the perception that log walls cannot comply with the new energy code.”
“The fact that existing log home owners are warm and comfortable with low energy bills is not enough to win the battle,” says Rob. One of the biggest hurdles for log homes is a code that relies on R-value alone to determine energy efficiency.
R-value is a measure of thermal resistance through a building element over a given area. As an example, there are insulation products on the market that provide R-values that reach R-17 and R-20. This implies that heat transfer through these products meets with a high level of resistance. By contrast, the average log wall generates an R-value of about 1.0 per inch of thickness. So a log wall of 8 inches only equals an R-8 level of resistance to heat transfer.
The problem with this mode of rating is that the U-factor was ignored. The U-factor (also called the overall heat transfer coefficient) describes how well a building element conducts heat. A quick example is the effect of heat on a metal pole versus a wooden pole of the same width. The heat is conducted through the metal, while the wood absorbs it.
When you consider that the unique mass of a log wall allows it to retain heat, control moisture, and prohibit airflow, the overall energy efficiency rating begins to reflect the actual energy performance that log homes have displayed over the years.
Since log home construction only makes up a small percentage of new homes each year, the fact that New Hampshire has created an energy code standard specifically for log home construction is a giant step in making the rest of the country, and world, aware of this need.
It is through the diligence of the Log Homes Council and technical experts like Rob Pickett, that future building codes will account for the true energy efficiency of log homes. To read the article in its entirety click here.