In today's economy energy efficiency is a subject that most people are aware of including log home owners and those people contemplating the purchase of a log home. With this in mind we occasionally get asked about the R-value of our chinking and/or backing materials since many people assume that they provide some insulation value to the exterior walls. In point of fact, neither the Perma-Chink nor the backing material contributes any significant insulation value to a wall. What they do is eliminate outside air infiltration into the home. This has a much greater impact on the overall energy efficiency of a home than adding a minor amount of insulation to a wall.