timber frame

BTimber Frame Bents

Bay: Space between two bents (shown to the right).

Beam: A main horizontal member in a building's frame.

Bent: A group of timbers perpendicular to the ridge, usually the cross frame of a building, sometimes including rafters, assembled on the ground and then reared up into position (shown to the right).

Brace: Any oblique timber (permanent or temporary) that resists distortion of a frame.  Also see Knee Brace. Visit our page on bracing.

C

Cantilever Beam: A projecting timber that supports an overhang.

Chamfer: Bevel cut at the long arris of a timber right through or decoratively stopped before the ends.  A bevel at the leading arrises of a tenon, to ease assembly. A simple bevel done for embellishment of a timber.

 

Timber Frame Collar TieCollar Beam/Collar Tie: Horizontal member fitted between a pair of opposed rafters, used depending upon position, to prevent sagging or spreading of the rafters.

Collar Purlin: Horizontal longitudinal beam running under the collar beams and usually supported by crown posts.

Common Purlin/Principal Purlin: In a roof frame, lengthwise member regularly spaced in sets, connecting principal rafters and carrying the roof sheathing.

Common Rafters/Principal Rafter: Closely and regularly spaced inclined timbers that support the roof covering. Independent of the bent system.

Compound Roof: Hip roof (outside corner) or valley roof (inside corner) formed where two adjacent roofs join at an angle.

Timber Frame CorbelCorbel: 1.Block protruding from a wall to support the springing point of a masonry arch or a roof or floor member. 2.Heavy timber placed under the bottom cord of a wooden bridge at the piers and abutments to distribute concentrated stress from live and dead loads.

Crown Post: Central vertical post of a roof truss that connects the bent plate or girt to the collar tie or collar purlin.

Cruck Frame: Primitive truss formed by two main timbers, usually curved, set up as an arch or inverted V. Each half of the cruck is called a blade, and a pair is often cut from the same tree.

D

Dragon Beam: Horizontal timber bisecting the angle formed by two wall plates or adjacent jetty beams, used to carry the foot of a hip rafter or the inner ends of joists from the adjacent walls or both; sometimes framed at its inner end into a short diagonal timber joining the plates.

Dropped Tie Beam: Sloping beam from wall post to wall post lying below the level of the plate. 

G

Girt: Major horizontal timber that connects posts.

H

Hammer Beam: A roof bracket projecting from the top of the wall that supports a roof truss. The design createsTimber Frame Hammer Beam a large roof span with relatively short timbers.

Hoisting Beam: Projecting beam from a gable peak for lifting materials to upper floors of a building.

J

Jack Rafter: Roof framing member that lies in the common pitch and terminates at the hip or valley rafter. In a valley system, the jack runs from the ridge down to the valley; in a hip system, it runs from the eaves up to the hip.  In general, any rafter shortened from its full run between ridge and plate is called a jack.

Timber Frame King Post with wind strutsK

King Post: A central, vertical post extending from the bent plate or girt to the junction of the rafters.

Knee: Alternative term for short brace, but often implying a naturally curved piece, usually taken from the base swell of certain trees, that presents long grain, if of unequal length, to both timbers being braced.  Knees are termed hanging (if beneath the beam), standing (if above the beam) and lodging or lying (if bracing beam to beam).Timber Frame Knee Brace

Knee Brace: A small timber that is framed diagonally between a post and a beam (Shown to the right).

N

Nailer Beam: Small horizontal wall timber for fastening vertical boarding, a typical element in barns and outbuildings.

O

Overall Length: Total length of timber including length of tenons on either end.

Overhang: Projection of second story beyond the first or projection of roof over wall.

P

Plates: Major horizontal timbers that support the base of the rafters.

Timber Frame PostsPost: Vertical or upright supporting timber (shown to the left).

Post and Beam/Timber Frame: 1.Structural system made up primarily of vertical and horizontal members. 2.Such a system in which floor and roof loads are carried by principal timbers simply butted together and fastened with structural hardware. 3.Structural system of heavy timbers connected by woodworking joints.

Principal Purlin: In a roof frame, lengthwise timber connection principal rafters and carrying common rafters.

Principal Rafters: A pair of inclined timbers that are framed into a bent.

Purlins: Horizontal timbers that connect rafter trusses.

Purlin Plate: Timbers used to support common rafters near the centre of their span and itself supported by posts or struts.

Timber Frame Queen Post TrussQ

Queen Post: A pair of vertical posts of a roof truss standing on the bent plate or girt and supporting the rafters or collar tie.

Queen Struts: Pair of struts extending from tie beam to collar beam in a truss like assembly, which are sometimes confused with queenposts, the tension members in a queenpost truss.

R

Rafter: In a roof frame, any inclined member spanning any part of the distance from eaves to peak.

Rafter Feet: The lower ends of the rafters that are framed into the plate or tie beam.

Rafter Heel: Inboard end of a rafter foot (birdsmouth).

Rafter Peak: The point where the tops of the rafters meet.

Rafter Run: Horizontal distance covered by pitched rafter.

Raised Bottom Chord: Uncommon species of truss in which bottom chord, normally base-tied, is raised to join rafters higher up, providing space for domed ceilings beneath while employing special tension bracing between rafter feet and chord.

Relish: 1.In a mortise cut near the end of a timber, material the width and depth of the mortise remaining between the mortise-end and the end of the timbers. 2.In a tenon, material between the peghole and the end of the tenon, equal in cross-section to the path of the peg through the tenon.

Ridge Beam/Ridge Tree: In a roof frame, the continuous longitudinal timber at the peak of the roof to which the rafters and sometimes wind braces are attached; ridges are often five-sided or otherwise non orthogonal in section to allow square connections.

Ridge Purlin: In a roof frame, a ridge member, continuous or interrupted by rafter apexes, lying in notches or trenches on one side of the roof; if continuous, sometimes itself trenches where it crosses a principal rafter.

STimber Frame Scissor Truss

Scissor(s) Truss: Rigid assembly of timbers framing a gable roof, comprising upper chords (rafters) sloped at theroof pitch and lower chords (scissors) pitched to cross one another under the roof peak and then run on to join opposing rafters in mid-span. Rafter peak and scissor crossing are typically joined by a short post.

Sill: Horizontal timber that rests upon the foundation and links the posts in a frame; usually fastened to the foundation.

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: Major timber that spans between girts or plates.

Swing Beam: Large, transverse barn beam under which animals walking around a central post used to thresh grain.

T

Telescoping Framing: Steeple framing, concealed from the outside that lodges the bottom timbers of any given stage several feet within the frame of the stage below, contributing stability.

Tie Beam: Important horizontal transverse frame member that resists the tendency of the roof to spread the walls. The tie beam may be found at the top of the walls, where it is able to receive the thrust of the rafters directly, or it may be found as much as several feet lower down the walls where it joins principal posts in tension connections.

Timber Frame/Post and Beam: Frame of large timbers connected by structural woodwork joints and supporting small timbers to which roof, walls and floor are fastened.

Timber Frame Topping out CeremonyTopping Out: In accordance with ancient Scandinavian and timber framing traditions, if the Purchaser wishes, a tree will be placed on the ridge of the timber frame upon completion of the raising (shown to the left), and/or a coin (provided by Purchaser) will be placed under a Timber Frame Ceremony placing a coin under a postchosen post (shown to the right).  This tradition pays homage to the trees used in the frame and as a token of thanks for a successful raising. Family and loved ones also can sign the wooden pegs (which sometimes families have had blessed first) with their own names or in memory of someone. Often wishes of well-being and good fortune or blessings are written on the pegs and various people are given the honors of driving them in to secure the blessings on their home. These traditions can be used as a dedication to a loved one!

Trimber: non-structural timbers (for looks).

Truss: Assemblage of timbers forming a rigid framework. To support the roof.

 

W

Walking Beams: Two parallel beams laid on the ground used to assist moving timbers with a pivoting action.

Wind Brace: A brace lying in the plane of the roof, usually running from a principal rafter to a ridge or purlin.

Y

Yoke: Short horizontal beams between two timbers, especially between tops of cruck blades.

Timber Frame Glossary

 

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TimberhArt Woodworks (formerly Acorn Timber Frames)
L. Daniel and Kimberley Reagan
195 Fuller Rd., Hantsport NS B0P 1P0
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