Traditional Mortise and Tenon Joinery

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The top of a post or end of a beam is sawed by hand into a tenon. A corresponding mortise is cut with drill and chisel in the side of another timber. Peg holes, slightly offset, are drilled in each timber. The tenon is inserted into the mortise and a hardwood peg is driven through the holes, drawing the timbers tightly together. This is the joiner's craft, the essence of timber framing. Repeated hundreds of times in a hundred or more timbers, the result is a structural frame whose joints can hold tight for centuries. A timber frame is literally defined by these pegged connections. (Post and beam, on the other hand, relies on metal fasteners to make the connections between timbers.)

The use of mortise and tenon joinery in building is so ancient that its origins are obscure. We know it was used for temples and houses in classical Greece and Rome, and probably reached its highest expression and refinement in the halls, manors and churches of medieval Europe. Similar traditions and levels of refinement evolved in Japan, China, and southeast Asia. Wherever forests, iron and civilization met, it seems, timber framing became a standard for building.

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Over the centuries, individual joints were perfected through a long process of trial, error and improvement, each joint designed and executed to resist the forces particular to individual places in a frame. So we have the English tying joint designed to efficiently lock together post, plate, and tie beam; the wedged half-dovetail to resist the outward thrust of the roof load where a tie beam meets a post below the plate; the diminished haunch soffit tenon to join joist to summer beam or other carrying timber while preserving as much carrying capacity as possible. And so on.

In most historic American timber frame houses, a majority of the timbers and their elegant wooden connections were unceremoniously buried behind plaster in the walls and ceiling. More often than not, the frame simply wasn't seen as an aesthetic element of the building, but simply as the structure to which the finishes were applied.

That situation has changed, and today most people who commission timber frame buildings do so out of an appreciation for the beauty and integrity of the timbers and joinery. These are left exposed and become the aesthetic focus of the building. In cutting our frames, we remain keenly aware not only of the long tradition of craftsmanship that traces timber framing's history, but also the expectation that the finished frame will be both the sound structure of a house and an enduring thing of beauty.

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