Glossary of Terms

BASEBOARD

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

 

BATTEN

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

 

BAY

Bays are the areas between bents. A four-bent frame has three bays; a three-bent frame has two bays. The size of a bay is limited by the floor or roof load that the frame must bear, and by the size and strength of the timbers in the frame.

 

BEAM

A structural timber supported at two or more points, but not throughout its full length, and carrying a transverse load.

 

BENT

Timber framers often think, talk, design and build in bents. A bent consists of the posts, beams and braces that are within the same plane in a frame. A profile bent forms a cross-sectional plane of the structure, and generally defines it shape. Most houses have three or four profile bents. Wall bents or ridge bents run longitudinally; they are perpendicular to profile bents.

 

BEVEL SIDING

Boards of varying width, tapering to a thin edge, and used as covering for sides of buildings.

 

BLEEDING

An exudation of resin, gum creosote, or other substance from lumber.

 

BLUE STAIN

A bluish discolouration, caused by certain fungi, which seldom penetrates beyond the sapwood, mostly in pine.

 

BOARD FOOT

The quantity of lumber contained in (or derived from) a piece of rough, green lumber, 1 inch thick, 12 inches wide, and 1 foot long, or its equivalent in thicker, wider, narrower, or longer lumber.

 

BRACE

Braces add rigidity to a frame. They typically run diagonally between posts and girts, and help prevent the frame from racking (leaning) in high winds. Braces are occasionally used in the horizontal plane, running from one girt to another.

BRESSUMER

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

 

BRIDGING

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

BUCK

Frame of dimensional lumber set into a log wall and used to frame windows and doors.
 

BUILDER'S RISK INSURANCE

Insurance policy carried during construction that covers damage to home or property caused by fire, wind, theft or vandalism
 

BUILDING CODE

Standards of construction designed to protect the health and safety of a home's occupants.
 

BUILDING PERMIT

Permit issued by a municipality that allows construction work on a specific site to go forward according to approved plans. Ensures that all proposed construction work meets building code and is added to the tax rolls.
 

CANT

A triangular strip of lumber, which is made by ripping a square timber diagonally.
 

CASING

Lumber used as interior trim around window and door frames.
 

CHAMFER

A simple bevel done for embellishment of a timber
 

CHECK

A longitudinal crack in timber, generally caused by faulty seasoning.
 

CLEAR

Lumber almost completely free from blemishes, defects or knots.

 

COARSE

As applied to the grain of lumber, that which has unusually wide growth rings for the species.
 

COLLAR TIE

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

 

COST-PLUS

Type of contract made between a general contractor and a home owner that stipulates the owner will pay for the cost of building materials as the project progresses, plus an added percentage for the general contractor's fee. This type of contract is opposite of a fixed-price contract

 

CRUCK

A framing member cut from a bent tree so as to form one-half of a rigid frame.

 

DEMURRAGE

Additional fees charged by the transportation company after time spent unleading the trailer exceeds the pre-set limit.

 

DORMER

A design feature in gabled roofs where small perpendicular gabled roofs are added to the roof system to form valleys with the main roof.

 

DOVETAIL

Tenon shaped like a dove's spread tail, fitting into corresponding mortise to form a joint.

 

DOWELL

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

 

DRESS

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

 

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.

 

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 GRAIN

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

A unit (door window skylight) from which people may exit the building. Local egress code requirements vary.
 

END MATCH

to tongue-and-groove (T&G) 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.

 

FACE SIDE

that side of a piece, which shows the best quality.

 

FINE GRAIN

Having narrow annual rings.

 

FLASHING

Weatherproofing strips formed from metal, which channel water in a spacific 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

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

Any flat piece of lumber used to bring an irregular framing to a flat surface; in particular, a narrow strip of lumber, which is 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.

 

GAS FILLED WINDOW

Insulating glass units with a gas other than air in the air space; to decrease the unit's thermal conductivity “U value” (see U value)

 

GENERAL CONTRACTOR

A professional who oversees a construction project, including the scheduling, supervision and payment of subcontractors

 

GIRDER

A principal horizontal beam, or a compound structure acting as a beam, carrying a vertical load and bearing vertically upon its supports.

 

GIRT

Major horizontal timber that connects posts. Beams – also called girts – are framing members that run horizontally. If they are part of a bent, they are called bent girts; if they connect two different bents, they are called connecting girts.

 

GLAZE

To fit a window frame with glass.

 

GLULAM

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

GRADE

A term to denote the quality or classification of lumber in relation to its adaptability for different uses; also the procedure of separating lumber into different established classes or grades.

 

GRAIN

A term used with reference to the arrangement or direction of the wood elements (spiral grain, cross grain, etc.) and to the relative width of the growth rings (coarse grain, fine grain, etc.) It is also 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 the cells; lumber which has a moisture content above the fibre saturation point (approximately 25 to 30%).

 

GRILLES

A decorative grid installed on or between glass panes, that does not actually divide the glass.

 

GUNSTOCK POST

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

 

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.

 

HAND-PEELED

The process of removing the bark and outer layer (cambium) of a log. Hand-peeling is usually done using a drawknife, although some companies use machines to achieve a hand-peeled look

 

HARDWOOD

Conventional term used to denote the timber of broad-leaved trees belonging to the botanical class of Angiosperms.

 

HEADER

Built-up horizontal member of a home's frame that tops a window or doorway.

 

HEARTWOOD

The inner layers of wood which in the growing tree have ceased to contain living cells, as opposed to the sapwood, which contains growing cells. Heartwood is generally darker in colour than sapwood, though in some species the difference is scarcely perceptible.

 

HEWN

Cut with an axe or an adze. (also called Hand Hewn)

 

HIP

A hip is the angled ridge formed by two adjoining planes.

 

HOLD-DOWN ROD

A metal rod that provides extra anchorage of the roof system to the logs. These are desirable in high wind areas.

 

HOUSING

A groove or trench in a piece of wood made for the insertion of a second piece.
 

JAMB

The side of a window, door, or other such opening.

 

JOINERY

The fitting and joining together of pieces of wood into a finished article or structure. It refers to “fine carpentry”, “bench carpentry”, and similar forms of fine woodworking, but not to cabinetwork or pattern making.

JOIST

A piece of dimensional or structural timber used to support the floorboards or the ceilings of a building. Joists span from one girt to another to carry a floor or flat ceiling. Sometimes, the joists are supported mid-way across a room by a larger summer beam, which runs perpendicular to them.

 

KERF

The groove formed in wood while being sawn or the thickness of the wood removed as sawdust.
 

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

 

KILN

A heated chamber for drying lumber.

 

KILN-DRIED LUMBER

Lumber, which has been seasoned in a dry kiln, usually, though not necessarily, to a lower moisture content than that of air seasoned lumber.

 

KINGPOST

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.
 

KNOT

That portion of a branch or limb embedded in the tree and cut through in the process of lumber manufacture. Knots are classified according to size, form quality and occurrence. As regards size, a pin knot is one not over one-half inch in diameter, a small knot is one over one-half inch in diameter but not more than three-quarters of an inch in diameter, a medium knot is one over three-quarters of an inch but not over 1 ½ inches in diameter, a large knot is one over 1 ½ inches in diameter. As to form, a round knot is one circular or nearly circular in form; a spike knot is one which has been formed by sawing the embedded branch in a lengthwise or nearly lengthwise direction. With reference to quality, a sound knot is solid across its face, is as hard as the surrounding wood and shows no indication of decay; an unsound knot is solid across its face but contains incipient decay; a decayed knot is softer than the surrounding wood and contains advanced decay; a tight knot is one so fixed by growth or position that it will firmly retain its place in the piece; an intergrown knot is one whose rings of annual growth are partially or completely intergrown with those of the surrounding wood; an encased knot is one whose rings of annual growth are not intergrown and homogeneous with those of the surrounding wood (the encasement may be partial or complete and may be composed of either pitch or bark); a loose knot is one which is not held firmly in place by growth or position and which cannot be relied upon to retain its place in the board; a hollow knot is an apparently sound knot with a relatively large hole in it. With regard to occurrence, a single knot is one occurring by itself with the fibres of the wood deflected around it; a knot cluster is a grouping of two or more knots together as a unit with the fibres of the wood deflected around the entire unit; branch knots are two or more knots branching from a common centre.

 

LADDER (FRAME)

Overhang or projection framing.

 

LAG-SCREWBOLT

Fastener used in log home construction

 

LAMINATED

A type of construction in which layers of wood, the grain in all cases running lengthwise of the assembly, are joined by gluing or other means to form a single member.

 

LAP SIDING

Boards are used to cover the sides of buildings, the lower edge of one board being lapped over the upper edge of the board below.

 

LATERAL LOAD

Those loads imposed perpendicularly to a wall surface by winds and earthquakes
 

LOG PROFILE

The cross-sectional shape of a log.
 

LOG SIDING

Log siding is often milled from dimensional lumber stock and may be used to cover dormers or garages. Also used to give a log appearance inside or outside conventionally framed homes.

 

MILLWORK

Building materials made of finished wood and including such items as inside and outside doors, windows or door frames, panel work, mouldings and interior trim. It does not include flooring, ceiling or siding.
 

MOISTURE CONTENT

The amount of water in wood, generally expressed as a percentage of the oven-dry weight of the wood.
 

MORTISE

The cut made in a board to take a tenon.
 

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.
 

MOULD

A superficial fungus growth, which usually appears in the form of a woolly or furry coating.
 

MOULDING

Lumber which has been worked on its side or edge to a uniform cross section, other than rectangular, so as to give it an ornamental effect.
 

MULLION

A horizontal or vertical member that holds together two adjacent plates of glass or sash.
 

NOMINAL MEASURE

In worked lumber, the dimensions of the rough board before dressing, i.e., 2” x 4”.
 

NOSING

Edge of a board worked into the form of a semi-circle.
 

OSB

Oriented strand board; an engineered wood product created by laminating shreds of wood into sheets
 

PARTITION

A term used to describe an interior wall, load bearing in nature or not.
 

PASSIVE SOLAR GAIN

Solar heat that passes through material and is captured naturally, not by mechanical means.
 

PEG

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

PITH

The small, soft core occurring at the centre of a tree or log.
 

PLATE

Plates are girts that connect the wall posts and support the lower end of rafters. Plates are major horizontal timbers that support the base of the rafters.
 

PLYWOOD

A piece of wood made of two or more layers of veneer joined with glue and laid with the grain of adjoining piles at right angles.
 

POST

Vertical or upright timber.
 

PRESERVATIVE

Any substance that will, for a period of time, prevent the action of wood-destroying fungi, borers of various kinds, and similar destructive agents.
 

PURLIN

See “beam”. Usually refers to an exposed roof beam utilized as an architectural or design feature.
 

QUARTER-SAWN, QUARTER-CUT

Lumber cut in a radial direction, that is, at right angles to the direction of the annul rings. In softwoods it is usually called “edge grain”. “Rift sawn” is another term for quarter sawn.
 

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.
 

R VALUE

A measure of the overall heat transmission due only to the difference in air temperature on either side of the material.
 

RABBET

A longitudinal channel, groove, or recess cut out of the edge face of any wooden member, especially one intended to receive another member. (Little furry thing with big ears, brings chocolate eggs?)
 

RAFTERS

Rafters support the roof. They run perpendicular to the roof's ridge, and typically span from a plate to a ridge beam, or from the top of one post to the top of an adjacent higher post. In a long roof plane, they might span from a wall plate to a plate midway up the roof, to the ridge beam at the peak.
 

RAFTERS – COMMON

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

 

RAFTERS – JACK

Jack rafters are common rafters cut off at varying length to meet a hip or valley rafter. The jacks meet the hip or valley at a compound angle that is easily laid out with a framing square.

 

RAILS

The horizontal pieces of wood in panelled woodwork such as doors, as opposed to stiles, which are the vertical pieces.

 

RESAW

A circular saw or band saw used to saw boards, cants, planks, etc., into thinner lumber; the act of sawing a piece of lumber into two or more thinner pieces.

 

RIDGE BEAM

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

RINGS

The growth layer put on in a single growth year and comprising spring wood and summer wood.

 

RIP

To saw a board lengthwise.

 

ROUGH LUMBER

Lumber that has not been planed or dressed.
 

SAPWOOD

The outer layers of the tree, containing living cells. The sapwood is generally lighter in colour than the heartwood.
 

SASH

The framed casement part of a window in which the glass is fixed.
 

SASH FRAME

The outer frame with sill in which the sliding sashes or casements are suspended.
 

SCARF JOINT

A joint for splicing two members, end to end.
 

SEASON CHECKS

Cracks occurring in lumber while seasoning.

 

SEASONING

The act of drying timber, either naturally in the open or artificially in a dry-kiln; the removal of moisture from wood to improve its serviceability.
 

SHAKE

A shingle split (not sawn) from a bolt of wood and used for roofing and siding, or a shingle manufactured in imitation of above.
 

SHEATHING

Lumber used to cover the framework of buildings.
 

SHIM

Thin tapered pieces of material such as a shingle. Used for levelling timbers.
 

SHIPLAG

A pattern of lumber in which one-half the thickness of the board is cut from the upper side of the edge, and a similar section from the lower side of the opposite edge.
 

SHOULDER OF TIMBER

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

SIDING

Lumber used as the finish covering of exterior walls.

SILL

A piece of wood (or other material) used to support a door or window, or placed on a masonry or other foundation as a base for the framework of a building, or which is used for other similar purposes of support.
 

SIPS

SIPs are high-performance building panels for floors, walls and roofs in residential and commercial buildings. Each panel is typically made using expanded polystyrene (EPS), or polyisocyanurate rigid foam insulation sandwiched between two structural skins of oriented strand board (OSB), but other surfaces are also available to meet your needs. The result is a building system that is very strong, predictable, energy efficient, and cost effective.
 

SNOW LOAD

The anticipated weight of snowfall, as determined by building authorities.
 

SOFTWOOD

The timber of trees belonging to the botanical group of Gymnosperms, i.e., conifers, or evergreens, e.g., pine, spruce, Douglas fir etc.
 

SPAN

The shoulder-to-shoulder distance.
 

SPIRAL GRAIN

An arrangement of the fibres in a tree in which they follow a consistently curved course or spiral direction around the bole of a tree.
 

SPLINE

A rectangular strip of wood, which is substituted for the tongue on heavy flooring (industrial uses including railroad car flooring material) and for similar purposes.
 

SQUARE RULE

A gain or a housing at every joint including tops of the posts.
 

STARTER LOG

A half-height log, which is used to start an odd numbered wall.
 

STILE

A vertical piece of a sash, door, or piece of framing to which the rails are attached.

STRAIGHT GRAIN

Implies that the direction of the principal fibres is parallel to the axis of the tree or log. A board is straight-grained when these fibres are parallel to its length.
 

STRINGER

The sloped support member for a run of stairs.
 

STRUCTURAL TIMBER

Timber to be used in construction to bear loads, and therefore graded on the basis of the suitability of the entire piece for that purpose.
 

SUB-FLOOR

The solid surface over the joists (usually plywood), on which the flooring will be laid.
 

SURFACED LUMBER

Lumber that has been dressed or planed by running it through a planing machine.
 

TEMPERED GLASS

Special heat-treated high strength, safety glass.
 

TENON

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

THERMAL PERFORMANCE

The ability of a material to act as a barrier to the transfer of heat.
 

THROUGH TENON

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

TIMBER

Standing trees of commercial size; felled trees or logs suitable for sawing; as applied to manufactured wood, sawn or hewn wood 4 inches or over in thickness and 4 inches or over in width.
 

TONGUE

A projection on the edge of a board machined to fit into a groove in the adjacent piece.
 

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.
 

TRUSS

Loosely speaking, a truss is an assembly of timbers that goes from one side of the room to the other without touching the floor. An assemblage of timbers forming a rigid framework.
 

T-STRIP

a wooden ‘T' shaped strip that stabilizes log ends at exterior window and door openings.
 

U VALUE

A measurement of thermal conductance. The reciprocal of R Value (see R Value).
 

ULTRAVIOLET

Type of radiation in wavelengths shorter than those of visible light, and longer than those of X Rays.
 

VAPOUR BARRIER

Thick poly that protects batt insulation from moisture.
 

VENEER

A thin piece or layer of wood of uniform thickness cut on a veneer machine, and either sawn, sliced or rotary cut.
 

VERTICAL-GRAINED

Synonymous with Quarter-Sawn.
 

WAINSCOT

Wooden panelling or boarding on a room wall.
 

WALKING BEAMS

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

WANE

As opposed to square-edged material, wane denotes the absence of wood on the edge of sawn or hewn timber and the presence of bark or a sapwood surface from which bark has fallen.
 

WARP

Any variation from a true surface, such as bow, cup, twist, etc., often caused by defective seasoning.
 

ZERO-CLEARANCE

Self-contained fireplace unit that can be placed in close proximity to other combustible building materials