The following represent some of the typical joinery found in timber frame homes. Some of the notches offer striking exposed joinery, which adds to the distinct and unique atmosphere of your home.
Timber Identification Guide.
Timber Identification Guide
Principal Rafter
Roof Purlin
Tie Beam
Upper Connecting Girt
Lower Connecting Girt
Full Length Outer Post
Full Length Interior 'Queen' Post
Kneebrace (Curved)
Kneebrace (Straight)
The grouping of posts, tie beams, principal rafters and kneebraces form a timber section called a 'bent.'
The Notches of Timber Framing
Mortise-and-Tenon
This joint is really the definition of a timber frame. Most of the joints of a frame are variations on this joint. A mortise is the slot or cavity cut into the wood, while the tenon is the projection end of a timber that is inserted into the mortise.
Shouldered
Mortise-and-Tenon
Adding a shoulder to the mortise-and-tenon makes a considerable difference in strength. By having the lower surface of the beam project into the post, the full width of the beam supports the load rather than just the width of the tenon. This allows the joint to bear three to four times more weight than the simple mortise-and-tenon.
Scarf Joint, Scarfing
The early settlers were able to hew timbers of practically any length from the enormous trees of their virgin forests. Today such trees are rare, and we must rely on scarfing to produce the longer timbers. Scarfing is the method of joining or splicing two timbers end to end.
Dovetail
This popular notch (also used in furniture making) is commonly used in true timber framing to join smaller members such as joists and purlins. The wedging effect of the dovetail and the weight of the timber lock this joint into place.
Knee Brace
The knee brace is a small timber that is framed diagonally between a post and a beam, using a mortise-and-tenon joint. The rigidity of the frame is greatly dependent upon the effect of properly fitted knee braces.
Anchor-Beam Joint
(Dutch Tenon)
The Pennsylvania Dutch use this variation of the shouldered mortise-and-tenon where exceptional pull-out stresses are encountered. The protruding tenon can be rounded or carved to create visual interest without affecting strength.
Tusk Tenon
The tusk tenon can be used in place of the dovetail joint. When pegged, the tenon holds the joint together. The tusk is the lower housed area that allows a major cross section of the beam to bear the weight at the joint.
Tongue and Fork
The tongue and fork, an ancient joint, connects the rafters at their peak. This is a method for securely locking the rafters together without the use of a ridgepole.
