Today I’d like to talk about log homes and the importance of adequate roof overhangs. In my 30-plus years of working on log homes, there are a number of themes that run through many of the problems we see. One of the most prominent causes of rot is the lack of adequate overhangs.
An overhang refers to the part of the roof that extends beyond the wall. The purpose of the overhang, or eve of the roof, is to move water off the roof into a gutter system or directly onto the ground. I can’t really say why so many log homes are designed without adequate overhangs, but it happens a lot.
There is no question that log homes need more of an overhang than a conventional house. This is because logs are more vulnerable to deterioration from the elements than conventional home building materials, and therefore need more protection. The fact that conventional roof systems are so widely used on log homes, along with the additional cost of extending overhangs, results in many log homes being built without enough protection.
What effect does this have? Well, all kinds of issues can stem from a lack of overhangs, but mainly log rot occurs from inadequate overhangs. Water and logs do not mix well. This is why almost without fail, when I look at a house with rot I ask myself this question: “If that section of roof had not been dumping water on this area for X number of years, would this rot be here?” Almost always the answer is “no”.
What to do? If you are thinking of building a log home, the answer is simple: build bigger overhangs. This means a minimum of 24″ all around on a one story home. Any wall 12 feet or higher needs at least 36″. This is a case where more is better so remember – these are minimum recommendations.
On an existing home, it gets a bit more complicated. We have done eve extensions and worked with carpenters to do overhang extensions on existing homes. Many times, it’s recommended to concentrate efforts on the sections that are causing the most problems. Finding a creative professional who can work out the issues of roof lines and connections is also important.