As many of our readers know, 2010 was a year of change when it came to energy efficiency required in new home construction. For Katahdin, the upgrade required to meet new federal regulations was not a dramatic leap, as we had made energy efficiency a founding principle. The Energy Envelope System (EES) was introduced nearly a year before the new guidelines were developed, and our designers and engineers have been keeping close track on the process of defining appropriate measures for log homes with the International Energy Conservation Code (IECC) committee and governing body. For more information on the EES developed by Katahdin click here.
Other log home companies responded to the new requirements by offering various options to meet the IECC 2009 requirements, even though many continued to lobby for exceptions to the code for log homes on a state-by-state basis. Some of the options for higher R-value envelopes included logs that were drilled and filled with flexible foam insulation. Others took the approach that the only way to meet the requirements was to offer traditionally framed and insulated homes with log siding (often called hybrid log homes) to meet customers’ visual requirements while keeping the energy efficiency within guidelines.
Last month, we asked our readers what they thought about some of these hybrid log home systems, and we quickly came to the conclusion that the majority of those who responded felt strongly about the authenticity of their log home but also wanted energy efficiency in the new homes. Respondents also indicated that they didn’t know enough about manufactured hybrid insulated logs that some companies were marketing. Click here for more details of the survey. So we took a look at these newcomers to the log home industry to try to get a feel for the new approach.
According to our research, a few log home companies have developed new technology to create a log home design. Their hybrid insulated log unit is manufactured using high pressure techniques to form a log that consists of outside layers of log siding with an inner core of high-density foam insulation. Some companies even use what they call a “furniture-grade” siding with extremely low moisture content. The process is proprietary and relatively new. These pressure-treated, insulated hybrids are then assembled in the factory into wall panels with through-bolts and framing. Once assembled, the panels are tested for true alignment before leaving the warehouse. The panels are generally limited to eight feet in width, but are constructed to include gables at a height of up to 16 feet.
In some companies, the panels are also pre-wired at the factory with the electrical installed within the vertical joinery between the panels. One company even stains the panels a golden tint inside and out, using a low VOC stain at the factory. Other stain colors are available but would require a special order. Interior walls are constructed onsite and framed in with wallboard. Roof systems are constructed from engineered truss systems with no purlin treatments available.
Because the panels are so highly engineered, the cost for a hybrid insulated log home are higher than the typical manufactured log home. Panel assembly onsite usually requires a technician from the company and a general contractor with 2-3 helpers. The assembly on an existing foundation generally takes about 1.5 to 7 days to a dry-in stage.
We spoke with Katahdin’s technical support engineer Lany Sherman, who had concerns about the structural integrity of such a system. “I’d take a hard look at how the panels are connected and assembled,” he said. He expressed concerns over the strength of the panels and their ability to withstand variations in temperature and humidity. Sherman recalled seeing a hardwood basketball floor that had been damaged with water (see right). “You wouldn’t believe the waves that rose up from the floor when the wood swelled up,” he said. He explained that sometimes wood can be too dry and absorb water like a dry sponge, which can lead to warping and buckling.
As with any new technology, the true measure is the test of time. Ask questions and make sure you understand the benefits—as well as the downsides—to any new technology and you’ll feel confident in your decision.