Timber Frame Glossary Part 1

Timber Frame Glossary Part 1

What are bents? What are beams? What exactly is a batten? Don't be ashamed if you don't know. We have put this timber frame glossary together to give you the basics on timber frame homes.

Intro to Timber Frame Homes

Timber frame homes are often composed of signature arrangements of posts, beams, trusses, pockets, and many other framing options. You don't need to be an expert to be able to appreciate the unique beauty and the components that make timber frame home building so awesome!

Timber frame homes may contain up to 200 key structural components that will be invisible to its occupants once the building is complete. In a conventional built home, there are thousands of individual wood parts within those components that all end up hidden upon completion.

Below is our timber frame glossary with of the most common terms you will hear related to timber frame homes.

Timber Terms A-G

Anchor Beam: A major tying beam joined to post with a shouldered through-tenon wedged from the opposite side.

Glossary term anchor beam
Anchor Beam

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

Baseboard: Interior trim used on the wall of a room, located along the floor.

Batten: A thin, narrow piece of lumber used for covering panel or siding edges.

Bay: Space between two bents. There will typically be a bent on each end and additional frame members that connect the bents to form the structure.

Beam: Any horizontal timber that is supported at the ends and can serve as supporting joists, non-load bearing or load-bearing.

Beam Pocket: A notch in a wall or receiving member prepared to receive the ends of a beam.

Bent: The basic building block of a post-and-beam home, made up of structural beams that form a cross section through the building. Typically, bents are spaced between 12' and 16' apart. Bents are connected with joists and purlins, giving the structure its shape.

Bevel siding: Boards of varying width tapering to a thin edge and used as building-side covering.

Bird's mouth

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.

Blind Mortise: A mortise that does not extend completely through the piece.

Board Foot: The quantity of lumber derived from a piece of rough, green lumber that is 1" thick, 12" wide, and 1" long or its equivalent in thicker, wider, narrower, or longer lumber.

Brace: Typically, a diagonal short piece that runs between posts and girts, providing rigidity to a frame and helping to prevent the frame from cracking (leaning) in high winds. Braces can also be attached in the horizontal plane, running from one girt to another.

Braced Frame: Also known as a timber frame.

Bridging: Short pieces of wood placed between beams or joists to prevent lateral movement.

Buck: A wooden frame set into a log wall used to frame windows and doors.

Buckling: Bending of a timber as a result of a compressive force along its axis.

Door casing

Cant: A triangular strip of lumber made by ripping a square timber diagonally.

Cantilever Beam: A projecting timber that supports an overhang.

Casing: Lumber used as interior trim around window and door frames.

Carrying Sticks: Sticks placed under a timber to provide support and an easy grip for carrying. Typically, two carrying sticks and four people are needed to carry a timber.

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

Checks: The separation of wood fibers, caused by the tension of uneven drying, following the direction of the sun's rays.

Clear: Describes lumber nearly free from blemishes, defects or knots.

Coarse: Describes lumber which has unusually wide growth rings for its species.

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.

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

Crown post

Cope: A circular-arc notch cut on the tension face of a bending member, placed adjacent to the members load-bearing surface to reduce stress parallel to the grain notch.

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. The pair used is typically cut from the same tree for consistency. Each half of the cruck is called a "blade".

D-Log: A profile you can choose for milling log home timbers. Named for its shape, each log is milled round on the outside and cut flat on the inside, which provides a traditional log home look outside with a straight log wall on the inside.

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

Diagonal Grain: Grain that is other than parallel to the length of a timber, which typically greatly reduces the strength of a timber.

Dimensional Lumber: Planed lumber sold according to its nominal size.

Dormer: A structural element of a building that protrudes from the plane of a sloping roof surface, used to create usable space in the upper level of a building.

Dovetail joint

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

Dowell: A cylindrical wooden pin used for holding two pieces of wood together.

Draw Boring: Intentional offsetting of holes in a mortise-and-tenon joint, used so the joint is drawn tight during peg installation.

Dress: To plane one or more sides of a piece of sawn lumber.

Drift Hook: Drift pin.

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

Drop: An ornamental pendant that makes a tear-shaped termination to the lower ends of the second-story post of a framed overhang. Also known as a Pendill.

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

Eased-Edged: A piece of wood slightly rounded or bull-nosed on each edge.

Eave: That part of a roof, which projects beyond the face of a wall.

Edge Distance: The distance from the center of a peg hole to the edge of the member, measured perpendicular to the grain direction.

Edge Grain: Describes lumber that is sawn along a radius of the annual rings or at an angle less than 45 degrees to the radius is edge-grained; this term is synonymous with quarter sawn.

Egress: An opening (door, window, bulkhead or skylight) from which people may exit the building, which must follow local code requirements.

End Distance: The distance from the center of a peg hole to the end of the member, measured parallel to the grain direction.

End Match: To tongue-and-groove the ends of lumber.

Equilibrium moisture content: The moisture content at which wood neither gains nor loses moisture when surrounded by air at a given relative humidity and temperature.

Excessive Bending and Deflection: Describes anything greater than allowable bending of timbers within a frame that have been established by building codes.

Face Side: The side of a piece of wood or timber that shows the best quality.

Feather Tenon: A round, shouldered machined fillet or feather that is glued into a machine-made (router) slot or mortise on each side of the joint.

Fiber Failure: Failure from tension in the lower fibers of a timber.

Flashing: Weatherproofing strips formed from metal, which channel water in a specific way.

  • Step flashing is a series of short flashings that are layered between courses of roofing.
  • Counter flashing is a piece of flashing that covers step flashings if no siding exists, such as at a log wall.
  • Head flashing covers a window or door unit.

Flat Grain: Describes lumber that is plain sawn or sawn tangential to the annual rings, as opposed to edge-grain or quarter sawn.

Flutes: Hollows or grooves cut longitudinally for ornamental purposes.

Furring strips

Full-Width Notch: A notch on the tension or compression face of a bending member that extends across the full width of the face.

Furring: Any flat piece of lumber used to bring an irregular framing to a flat surface. Specifically, a narrow strip of lumber nailed to rafters, studding, and joists as backing.

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.

Glulam: An engineered support beam made up of laminations of dimension lumber that have been glued together.

Grain: Describes the arrangement or direction of internal wood elements (spiral grain, cross grain, etc.) and the relative width of the growth rings (coarse grain, fine grain, etc.) It can also be used to designate the angle of the growth rings in relation to the axis of the board (edge grain, flat grain).

Green Lumber: Unseasoned or wet lumber; lumber in which free water still remains within cells. Specifically, lumber which has a moisture content above the fiber saturation point (approximately 25% to 30%).

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.

That's all for now. Be sure to check out Part 2 of our timber frame glossary for the rest of the list.

Thanks to the following resources:


DIY Doctor





New Energy Works

The Forestry Forum

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