The old expression “Raise high the roof-beam” regains its meaning when the structure in question is a timber frame. As the crane lifts the oversized timbers and swings them into place, the crew taps the hand-cut mortise and tenon joints together with huge mallets called beetles or “persuaders” and then pounds in wooden pegs that are the only nails. When all the timbers have been fitted into place, the frame looks and acts like the skeleton of the house, defining its outline while holding all the structural weight.
Timber framing is the most sophisticated form of what is called post and beam construction. “Post and beam” is the oldest method of building, dating back at least to the early Greeks. It includes any structure built of vertical posts that hold up beams laid horizontally across them. The posts and beams may be of wood or stone, or even concrete, in modern times.
It is easy to understand the great popularity of post and beam homes when standing in a finished timber frame and looking up at the heavy-beamed cathedral ceiling filled with light from the huge expanses of glass. There is great satisfaction, as well, in knowing that your home is a secure haven that connects you to the traditions of the past and will stand strong well into the future.
The Timber Framing Process
A traditional timber frame uses a bent system–in part, specifically to facilitate raising the frame. The bent assembly represents a cross section of the structure, including posts, tie beam, and rafters. The bents are trial assembled in the shop, to ensure an exact fit. Then they are taken apart, coded, and stacked to await shipment.
At the time of the raising, the timbers are first assembled on the ground. The bent that will go up last is assembled first, followed by the next in order of placement, with the first bent to be raised on the top of the pile. The crane lifts the first bent up and places it on the floor deck. It is braced to hold it steady while the connecting girts are fitted into the bent. They too are braced. The next bent is flown in by the crane and connected up with the girts. Once the two bents are tied together by the connecting girts, we have a more stable structure to work on.