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Timber Frame Glossary

TIMBER PIECES

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
Girt:	major horizontal timber that connects posts
Gunstock Post:	a post having an increased size at its top, providing extra strength for intersecting joinery
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
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
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 principle 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

JOINERY

Dovetail:	a 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; 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 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:	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
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:	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 mortise
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 mortise and tenon joint in which the tenon goes all the way through the corresponding mortise

TOOLS

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 wench. Uses include tightening joinery during assembly, as a safety tie and for pulling frame components together during erection
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

DETAILING

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

OTHER TERMS

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 4x4 and up
Wall Decking:	lumber covering the walls usually 1" tongue-and-groove