Because of their connection to nature and how they convey a feeling of rustic sanctuary, log and timber homes remain a popular dream for many home buyers.
However, that rustic dream is in danger of being legislated out of existence, reports NAHBNow, the official news blog for the National Association of Home Builders.
Over the last few years, building codes – and energy codes in particular – have changed dramatically as code officials have ratcheted up requirements in the interest of durability, safety and energy conservation.
However, some of these changes are potentially harmful and threatening to the log and timber home building industry.
Of particular concern are the standards for insulation included in the International Energy Conservation Code (IECC). Only in the 2007 ICC Standard on the Design and Construction of Log Structures (ICC 400-2007) are the unique attributes of log construction accurately addressed. ICC 400 is the only ANSI-approved consensus standard on the construction and design of log structures. (Learn more about ICC 400 by clicking here.)
The R-values of low-mass insulations—such as fiberglass—as compared to the R-value of wood is one of the greatest causes of confusion between standard building practices and log home construction. Since the two are not comparable on an apples to apples basis, the difference is often misunderstood.
“The way it’s currently written, the R-value prescriptive is through the roof. A log wall will never have an R-value that can comply with that,” said Donna Peak, executive director of the NAHB Building Systems Councils. “But full log walls do have rigorous insulation properties that the codes don’t take into consideration.”
Traditional stick-built home builders use fiberglass, cellulose, mineral wool and other insulation products in framing cavities with R-values from 11 up to 21. Doing so is impractical and cost-ineffective for log home construction. The ICC 400 calls for a 5” log, which has been found to be more energy efficient than the average stick-built home.
“For quite awhile now we’ve been using 6” thick logs and exceeding energy performance, house against house, energy bill against energy bill,” said Mark Elliott, chairman of the Log & Timber Homes Council and vice president of Coventry Log Homes in New Hampshire. “But because everyone is used to using more insulation, log homes are expected to increase too, even when it’s not necessary.”
Even though logs have natural characteristics that allow them to absorb heat or cool air and radiate it back into the home, many people still don’t accept that log walls can perform as well as they do, he added.
In recent years, code requirements in jurisdictions across the country, especially those in Northern states, have called for log home builders to use thicker logs – in some cases up to 10”.
Elliott said that this is concerning for two reasons: 1) it adds to the cost of the home, and 2) using a larger log means using more of the tree than is necessary – which is wasteful. The extra 2-4” is wood that could have been used to finish interior non-log walls, among other purposes.
The rising costs resulting from this inefficient practice, and other code changes, affect consumers and the log home industry at-large.
“NAHB did a study a few years ago that showed that for every $1,000 increase on a home, a little over 200,000 people were taken out of the market for that home,” Elliott said. “That is a staggering number. The increase in cost takes the opportunity to own a log home completely out of their grasp.”
The Building Systems Councils hopes to lessen the impact of the code changes by garnering support for the ICC 400, which according to Peak, is the “bible of log home construction.”
The standard first appeared on the scene in 2007, just before builders began to adopt the 2009 building codes. Elliott said it really helped people understand that constructing a log home is different than building the average stick-built home.
The 2012 – and most current version – of the ICC 400 addresses even more issues and brought log home standards in line with the 2012 energy codes.
“Unfortunately, the codes cycle is pretty difficult to keep up with. And not just for manufacturers but even from a building official side,” Elliott. “Many don’t even know there is a standard just for log home construction since it is such a small portion of the market.”
That’s where Rob Pickett, a well-known building code consultant within the systems-built industry, comes in.
Since states and local jurisdictions have begun to review and adopt the 2015 building codes, he’s been conducting research and making phone calls to track their activity.
The ultimate goal, Pickett said, is to make sure that the ICC 400 is adopted so that log homes remain affordable and do not become illegal to build.
He’s also working on getting a statement added to the IECC building thermal envelope section that advises folks to check the ICC 400 for thermal provisions for the log wall.