DW Timber Frame Design



Timber Frame Glossary


Adze: An axelike tool with its blade at right angles to its handle, used to shape or dress timbers

Anchor Beam: Major tying beam. Joined to post with shouldered through-tenon, wedged from the opposite side

Anchor Bolt: A bolt protruding from the top of the foundation onto which the sill plate is fastened with a nut.


Backfilling: Replacing excavated soil around a foundation.

Bay: Space between two bents.

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

Beetle: A large wooden mallet typically weighing fifteen to twenty pounds.

Bent: Structural network of timbers or a truss that makes up one cross-sectional piece of the frame.

Bird's Mouth: A V-shaped notch that resembles a bird's open beak. It is cut into the base of a rafter and received by the plate.

Bressumer: English term for a beam supporting an upper wall of timber framing.


Cantilever Beam: A projecting timber that supports an overhang.

Carrying Sticks: Sticks placed under a timber to provide an easy hand hold for carrying. Typically, two carrying sticks and four people are needed to carry a timber in this way.

Chamfer: A simple bevel done for embellishment of a timber.

Check: Separation of wood fibers following the direction of the rays. Caused by the tension of uneven drying.

Collar Purlin: Horizontal longitudinal beam supporting collar ties.

Collar Tie: Horizontal connector between a pair of rafters used to reduce sagging or spreading of rafters.

Combination Square: A tool that can be used to lay out 45-degree and 90-degree angles. The stop is adjustable along the blade for use as a depth gauge.

Come-Along: A hand operated ratchet winch. Used for pulling joints together, as a safety tie when raising a bent, and for pulling the frame together during the raising.

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

Corner Chisel: A heavy duty L-shaped chisel struck with a mallet. Used for cleaning out corners of a mortise.

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

Cruck: 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.


Dead Load: Weight of building. (roof, floors, walls, etc.)

Depth: The vertical thickness of a beam.

Diagonal Grain: Grain that is other than parallel to the length of a timber. This will greatly reduce the strength of a timber.

Dovetail: A tenon that is shaped like a dove's spread tail to fit into a corresponding mortise.

Draw Knife: A knife blade with handles on both ends so that the knife can be pulled by both hands toward the user.

Drift Pin: Used to pin joints temporarily when test assembling a frame.

Drop: Ornamental pendant. The tear-shaped termination to the lower ends of the second-story post of a framed overhang. Also known as a Pendill.

Dutchman (also, inlay): A timber 'patch' to cover defect, previous joinery, or other blemish or error. Color and grain matching make them hard to find.


Framing Chisel: A heavy duty chisel typically with one-and-one-half to two-inch-wide blade. Designed to be used with a mallet.


Gable Roof: A double sloping roof that forms an A-shape.

Gambrel Roof: A double pitched roof with the lower slope steeper than the upper slope.

Girder: Major timber that spans between sills.

Girt: Major horizontal timber that connects posts.

Green Wood: Wood freshly cut that is not dried or seasoned.

Gunstock Post: A post wider at the top than the bottom. The wider portion provides more wood for intersecting joinery.


Half Dovetail: A dovetail tapered only on one side.

Half Lap: A joint in which the two timbers are lapped or let-in to each other.

Half-timbered Frame: An ancient building system in which the space between the timbers is filled with brick, plaster or wattle and daub, so that the timbers are revealed to the exterior and interior of the building.

Halving: The removal of half the depth of two timbers in order that they may cross each other. A half lap.

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

Hardwood: Wood of certain deciduous trees, e.g., oak, maple, ash, etc.

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 for tying the joint.


Joinery: The art or craft of connecting timbers using wood working joints.

Joint: The connection of two or more timbers.

Joists: Small, parallel timbers that complete the floor frame.


Kerfing: Either a series of cuts with a circular saw set at a desired depth to remove a section of wood or the hand-sawing along the shoulder of an assembled joint to improve the fit of the joint.

Keyway: A joint between the footing and foundation wall.

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

Knee Brace: A small timber that is framed diagonally between a post and a beam.


Lean-To: A shed section of a building that is framed into the main frame.


Mortise: A groove or slot into which or through which a tenon is inserted.

Mortise-and-Tenon Joint: Any joint in which a projection on one end of a timber is inserted into a groove or slot in another timber.


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

Overhang: Projection of second story beyond the first.


Peg: A wooden dowel one to one and one-half inches in diameter, usually of oak or locust.

Pike Pole: A long pole pointed with a sharpened spike used for raising frames. These tools were known as early as the fifteenth century, when they were called "butters".

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

Post: Vertical or upright timber.

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

Purlins: Horizontal timbers that connect rafter trusses.


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.


Rack: The action of straining or winching a frame to bring it into square or plumb.

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

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

Raising the Frame: Erecting the bents and roof trusses and joining and pegging the other timbers to the frame.

Rearing the Frame: English term equivalent to "Raisng The Frame."

Ridge Pole: A horizontal timber at the peak of the roof to which the rafters are attached.

Rip Saw: Saw designed to cut parallel to grain.

Roof Pitch: Inches of rise per foot of run. For example, a 45-degree roof has twelve inches of rise for each foot of run and is therefore called a "twelve pitch" roof.

Roof Truss: A structural network of timbers that form a rigid structure to support the roof.


Scarf: A joint for splicing two members, end to end.

Sheathing: The covering of boards or of waterproof material on the outside wall of a house or on a roof.

Shed Roof: A roof sloping in one direction.

Shim: Thin tapered pieces of material such as a shingle. Used for leveling timbers.

Shoulder of Timber: Point of intersection at the joint of two assembled timbers. Refers to timber with tenon.

Sill Timbers: Horizontal timbers that rest upon the foundation.

Slick: A chisel with a blade two and one-half or more inches in width. It is pushed by the hands instead of being struck with a mallet.

Soffit: The underside part of a building such as under a roof overhang.

Softwood: Wood primarily of a conifer or evergreen, e.g., pine, spruce, douglas fir, etc.

Span: The shoulder-to-shoulder distance.

Stress-skin Panels: A sandwich of materials, containing two skins, one inside and one outside, and a core of insulation.

Strut: A short timber placed in a structure either diagonally or vertically, designed to act in compression along the direction of its lengths.

Stub Tenon: Tenon that stops within the timber it joins.

Summer Beam: Major timber that spans between girts or plates.


Tenon: The projecting end of a timber that is inserted into a mortise.

Through Tenon: A tenon that passes through the timber it joins. It may extend past the mortise and be wedged from the opposite side.

Tongue and Fork: A type of joint in which one timber has the shape of a two prong fork and the other a central tongue that fits between the prongs.

Trunnel or Treenail: A peg. Sometimes refers to an extra-large peg.

Truss: Assemblage of timbers forming a rigid framework. Example: A bent.


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