Glossary of Timber Framing Terms

Want to talk like a timber framer, learn a new language for an ancient art, or find an interpretation for something referenced in your timber frame construction schematics?

Included below are the most common terms used by timber framers, architects, designers, and building contractors when referencing plans, woodworking methods, and construction details.

Timber Pieces

  • Beam: Main horizontal member in a building’s frame. Structurally supports other horizontal members, such as floor joists. The three main types are girding, summer, and tie beams.
  • Braces: Smaller timbers placed diagonally between posts and girts or plates to make a structure more rigid and to support the frame. This helps prevent frame racking or twisting. Often referred to as angle, knee, or wind braces.
  • Collar Tie: Timber beam placed horizontally to connect rafters that control spreading or sagging of the rafters. It is usually placed perpendicular to the ridge and parallel to the girts, which connect rafter pairs at a given height. Also known as tie beams or tie collars.
  • Common Rafters: Closely and regularly spaced inclined timbers that support the roof covering, independent of the bent system.
  • Found Curve: Naturally occurring crooked timbers usually with two sides sawn and two sides with the bark removed, used as knee braces, posts, and beams.
  • Girt: Main horizontal beam that spans the width or length of the frame to connects posts. They are also known as girding beams or girders, and include bent, connecting, and sill girts.
  • Gunstock Post: Post having an increased size at its top, providing extra strength and support for intersecting joinery. Can also be referred to as a haunch or joweled post.
  • Hammer Beam: Horizontal timber projecting from the top of the wall or rafter that supports a roof truss. The design creates a large roof span with relatively short timbers.
  • Joist: Small, horizontal timbers or beams that run parallel to each other to complete the floor frame. Usually connect at each end to a girt or intermediary summer beam, or they are supported from below by a floor beam or girder.
  • King Post: Central, vertical post extending from the bent plate or girt to the junction of the rafters at roof peak. It is a key component in most common truss types.
  • Knee Brace: Short diagonal timber placed between the horizontal and vertical members of the frame to make them rigid.
  • Plate: Major horizontal assembly of timbers that run from one end of the frame to the other and support the base of the rafters. There are many different, location-based types which include the base/sill plate for the bottom, the top plate for the upper tier, and the raising plate for any additional levels.
  • Post: Upright or vertical timbers erected within the frame that provide structural support of the members above. Types of posts include corner, intermediary, queen, and king posts.
  • Principal Rafters: Pair of inclined timbers that are framed into a bent and used with purlins, secondary rafters, or are used alone.
  • Purlin: Horizontal connecting beam of the roof frame which runs perpendicular to the rafters. Create a horizontal framework with the principal rafters that make secondary rafters unnecessary. When installed at the midpoint below rafters, they provide support and allow for shorter rafter lengths.
  • Queen Posts: Pair of identical, symmetrical, and vertical posts of a roof truss. They stand on the bent or girt and extend, and support, from the rafters to the lower truss chord or collar tie.
  • Rafter: Main, supporting timber of the roof frame. Extends from the top wall plate to the ridge and generally positioned at a sloping angle, which then determines the roof pitch. Comes in different types depending on placement. These include the common, major, principal, and secondary rafters.
  • Ridge: Top horizontal beam that forms the house peak with the rafters. Also referred to as ridge beam, ridge plate, or ridge pole
  • Ridge Pole: Horizontal timber which connects rafter pairs at the peak.
  • Ridge Purlin: Beams connecting rafter to rafter at the apex.
  • Secondary Rafters: Smaller sized timber rafters placed between principle rafters.
  • Sill Timber: Major horizontal timbers which lie on the foundation and form the lowest part of the frame.
  • Strut: Short timber placed in a structure either diagonally or vertically, designed to act in compression along the direction of its lengths.
  • Summer Beam: Major horizontal timber which spans the girts or plates.

Joinery

  • Dovetail: Tenon that is shaped like a dove’s spread tail to fit into a corresponding mortise.
  • Half-Dovetail: This joint is one-half of a dovetail, and is used for joining collar ties to rafters, and braces to posts, and for other similar situations.
  • Half-Lap: Joint in which two timbers are let in to each other.
  • Joint: Part, or the arrangement of the part, where two or more timbers are joined together.
  • Haunch: Part of the whole timber beyond the shoulder which is let into another timber.
  • Housing: Shallow mortise or cavity for receiving the major part of a timber end, usually coupled with a smaller deep mortise to receive a tenon tying the joint together.
  • Joinery: Craft of connecting and securing the separate members of the timber frame to one another by means of specific cuts on the ends and/or sides of the timbers.
  • Mortise and Tenon: Any joint consisting of a projection (tenon) on the end of one timber and a corresponding slot (mortise) on the other.
  • Peg: Hardwood dowel usually ranging from 5/8 of an inch to 2 inches in diameter. Also see Trunnel for additional details.
  • Scarf Joint: Joint used to splice two timbers end to end.
  • Shoulder: Area of the void created when the waste around a tenon has been cut away.
  • Tail: End portion of a birds-mouth joint which extends beyond the plate when there is a roof overhang.
  • Tenon: Projecting end of a timber that is inserted into a mortise.
  • Trunnel: Derived from English pronunciation of “tree nail,” the proper name for the a turned and tapered hardwood dowel used for securing timber joints. See Peg for additional details.
  • Tusk Joint: Also called a tusk or through tenon, a mortise and tenon joint in which the tenon goes all the way through the corresponding mortise.

Timber Framer’s Tools

  • Beetle: Heavy wooden maul or mallet used in cases in which material would be damaged by a sledge hammer.
  • Come Along: Hand operated ratcheting wench. Uses include tightening joinery during assembly, as a safety tie and for pulling frame components together during erection.
  • Draw Knife: Sharp-edged tool having a blade with a handle at each end; by drawing it toward you, you can shave surfaces.
  • Framing Chisel: Large chisel with long, heavy blades: strong enough to be hit with a heavy mallet.
  • Mallet: Tool like a hammer with a wooden, rawhide or rubber head.
  • Pike: Long pole with a pointed steel head used in raising bents; also called a barn pole.
  • Slick: Wide bladed and long handled chisel pushed by hand to create flat surfaces.

Detailing

  • Chamfer: Decorative edging made with an angled cut on the corner of a post or beam. Helps relieve the sharp corner of the timber. Types include a bead, complex design or profile, and a stopped chamfer, extends to a specific point and then tapers off.
  • Pendant: Ornamental termination to the low end of a hammer post, king post, queen post, etc..
  • Stop: Decorative end of a chamfer.

Other Timber Framing​ Terms

  • Bay: Space between two timber bents.
  • Bent: Structural section of the frame which is composed of a line of vertical posts and the horizontal timbers that connect them.
  • Bent Design: Functional and artistic pattern of timbers creating the bent.
  • Blue Board: Weather resistant, plaster-based drywall.
  • Check: Separation of wood fibers caused by the natural process of wood drying.
  • Green Wood: Freshly cut wood that is not dried or seasoned.
  • Hand-Hewn: Timber squared off and shaped by hand.
  • Hardwood: Wood of certain deciduous trees (e.g., oak, walnut, ash, etc.).
  • Rough Sawn: Lumber and timber that has not been planed.
  • Scribing: Shaping one member to the surface which it touches, for example, to fit a board snugly to a surface which is not straight.
  • Span: Width of a building or overall length of a truss.
  • Timber Frame: Load-carrying structure of timbers ranging in size from 4×4 and up.
  • Wall Decking: Lumber covering the walls usually 1″ tongue-and-groove.

Contact us to hear this unique lingo utilized to reference the fine points of your new timber frame construction project.