Glossary of Timber Framing Terms


Beam a main horizontal member in a building’s frame
Braces smaller timbers placed diagonally between posts and girts or plates to make a structure more rigid
Collar Tie a timber placed horizontally and between rafters that control spreading or sagging of the rafters, usually placed parallel to the girts which connect rafter pairs at a given height
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
Hammer Beam a 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
Intermediate Wallplate major horizontal timber that connects posts
Joist smaller horizontal timbers parallel to each other to complete the floor frame
King Post a central, vertical post extending from the bent plate or girt to the junction of the rafters at roof peak
Knee Brace a short diagonal timber placed between the horizontal and vertical members of the frame to make them rigid
Plate the major horizontal timber which runs from one end of the frame to the other and supports the base of the rafters
Post upright or vertical timbers erected within the frame that provide structural support of the members above
Post with Teasle Tenon a post having an increased size at its top, providing extra strength for intersecting joinery
Principal Rafters a pair of inclined timbers that are framed into a bent and used with either purlins or secondary rafters or alone
Purlin a horizontal member of the roof frame which runs between rafters
Queen Posts a pair of vertical posts of a roof truss standing on the bent or girt and supporting the rafters or collar tie
Rafter sloping main timber of the roof frame
Ridge Pole horizontal timber which connects rafter pairs at the peak
Ridge Purlin the beams connecting rafter to rafter at the apex
Secondary Rafters smaller sized timber rafters placed between principal rafters
Sill Timber major horizontal timbers which lie on the foundation and form the lowest part of the frame
Strut a short timber placed in a structure either diagonally or vertically, designed to act in compression along the direction of its lengths
Summer Beam a major horizontal timber which spans the girts or plates


Dovetail a tenon that is shaped like a dove’s spread tail to fit into a corresponding mortice
Half-Dovetail this joint is one-half of a dovetail; used for joining collar ties to rafters, and braces to posts, and for other similar situations
Half-Lap a 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 the part of the whole timber beyond the shoulder which is let into another timber
Housing the shallow mortice or cavity for receiving the major part of a timber end, usually coupled with a smaller deep mortice to receive a tenon tying the joint together
Joinery the 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
Mortice & Tenon any joint consisting of a projection (tenon) on the end of one timber and a corresponding slot (mortice) on the other
Peg a hardwood dowel usually ranging from 5/8 of an inch to 2 inches in diameter
Scarf Joint a joint used to splice two timbers end to end
Shoulder the area of the void created when the waste around a tenon has been cut away
Tail the end portion of a birds-mouth joint which extends beyond the plate when there is a roof overhang
Tenon the projecting end of a timber that is inserted into a mortice
Trunnel also known as a tree-nail, a turned and tapered hardwood dowel used for securing timber joints. See “Peg”
Tusk Joint also called a tusk or through tenon, a mortice and tenon joint in which the tenon goes all the way through the corresponding mortice


Beetle a heavy wooden maul or mallet used in cases in which material would be damaged by a sledge hammer
Come Along a hand operated ratcheting wrench. Uses include tightening joinery during assembly, as a safety tie and for pulling frame components together during construction
Draw Knife a 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 a tool like a hammer with a wooden, rawhide or rubber head
Pike a long pole with a pointed steel head used in raising bents; also called a barn pole
Slick a wide bladed and long handled chisel pushed by hand to create flat surfaces


Chamfer a decorative edging or relief made at the timber’s corner
Pendant an ornamental termination to the low end of a hammer post, king post, queen post, etc.
Stop decorative end of a chamfer


Bay space between two timber bents
Bent a structural section of the frame which is composed of a line of vertical posts and the horizontal timbers that connect them
Bent Design the functional and artistic pattern of timbers creating the bent
Blue Board weather resistant, plaster-based drywall
Check a 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 a 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 the width of a building or overall length of a truss
Timber Frame a load-carrying structure of timbers ranging in size from 4×4 and up
Wall Decking lumber covering the walls usually 1″ tongue-and-groove