Styles/Trusses

In the world of timber framing there are many different styles. For the sake of this discussion we are concerned with two basic styles of timber frame construction that have more to do with the way the roof is framed than any other aspect of the structure. These two styles of timber frame construction are Bent systems and Common Rafter systems. We'll discuss each, and then explain the system that Mill Creek uses and why.

Bent framing is what many people think of when they hear the words "timber frame". In a Bent system, a complete "bent," consisting of two posts connected to two rafters tied with some type of collar tie and other connecting timbers, is built flat on the floor deck of the building, braced and secured, then raised up into a standing position. Perhaps you have seen old pictures of a "barn raising," where many people with long pike poles are pushing a large bent up into position. This would be continued down the length of the building, perhaps every 10-12 feet. These "bents" would then be connected together by beams running between each bent. At the roof, horizontal members called "purlins" would connect the bents, and support the roof load. For simple floor plans laid out in a grid structure, this type of framing works well.   

The other method of timber framing, and the one that Mill Creek employees prefer, is that of the Common Rafter system. Instead of large "bents," the supporting structure for the roof system is built, at its simplest, from horizontal beams supported by vertical posts. This system of posts and plates is constructed, then the roof system of "Common Rafters" is built on top. In its simplest form, the rafters run up from the horizontal plate, joined at the peak, and connected with a collar tie. These rafter pairs are then spaced no more than four feet apart for the length of the building. This is very similar to the way that conventionally framed homes are built, except that we are using very large timbers in place of 2x4 lumber.  This system also allows a crew of three people along with a mechanical lift to assemble a complete timber frame home. 

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