1. Plumb
   Butt joint
2. Header
   Air-dried

A line, a piece of timber or a wall which is completely vertical (not slanted in any way) is said to be plumb. Common tools used to check for plumb include the spirit level and the plumb bob. The verb “plumb” can be used to mean to make an object perfectly vertical or to find the vertical height or depth of something.

1. Undercut
   Truss
2. Square
   Biscuit joiner

A right angle (90 degrees) is also called a square corner and hence, square is the word for the tool which carpenters use to check right angles. It is a common hand tool which comes in the form of a simple “try square” or can be designed with other features, in which case it is known as a “combination square.”

1. Level
   Ridge
2. Live load
   Crossbeam

Crossbeams are used on a wide variety of structures including cathedral ceilings. They strengthen the structure, making it capable of bearing a greater load and withstand rocking forces such as earthquakes. Crossbeams may be styled to add a decorative element to the structure they are supporting.

1. Finger joint
   Proud
2. Apron
   Landing

Generally speaking, the term apron is used in construction to refer to a component which is adjoining or adjacent to a primary feature. That includes the trim which is placed at the base of a window (inside and out). It can be used to cover unsightly joints and adds a finished look to the structure.

1. Beading
   Plumb bob
2. Crown
   Awl

While any heavy weight or tool on a string can act as a plumb bob, the weight which is typically used is pointed, as this helps to ensure greater accuracy. The plumb bob is a traditional device which still comes in handy, especially when a carpenter needs to plumb a very tall wall.

1. Cross bracing
   Load-bearing walls
2. Cat’s paw
   Cripple

Cripple studs and cripple rafters are used as framing elements. Cripple studs, for example, are placed vertically below or above an opening, such as a door or window. Because they make room for the opening in the wall, they are shorter-than-regular studs which go from floor to ceiling.

1. Molding
   Miter
2. On center
   Apron

Miter cuts are typically made at an angle of 45 degrees at the end of a piece of timber. Therefore, when two pieces of timber with miter cuts are placed end-to-end, they form a miter joint which measures 90 degrees.

1. Header
   Dovetail joint
2. Plumb
   Rake wall

Headers are weight-bearing, horizontal pieces of timber which are placed at the top of an opening whenever that opening is wider than the distance between two studs. The header supports the weight above the opening, and further support can be given by placing cripples (short studs) from the header up to the top plate

1. On center
   Dead load
2. Joist
   Fire block

Most often the largest dead load a structure has to bear is the weight of the structure itself. Its roof, walls, staircases and elevated floors are all dead weight. The terms permanent load and static load can be used in place of the more macabre “dead” load.

1. Cat’s paw
   Ridge
2. Live load
   Awl

There are several different types of awls, but the one most often used by carpenters is the brad awl. It is used to create pilot or starting holes for nails and screws. Another type of awl is the scratch awl, which can be used to etch a line in a piece of wood for the teeth of a saw to follow.

1. Load-bearing walls
   Undercut
2. Truss
   Valley rafter

Undercutting a door can help to make room for it to pass freely over newly installed flooring. The undercut can also refer to making an angle cut at the back or side of a piece of wood so that it fits snuggly against another piece of wood.

1. Finger joint
   Fire block
2. Rake wall
   Soffit

Two pieces of timber can be securely joined by cutting finger-like projections in the end of each. The “fingers” interlock when the pieces of wood are placed together, creating a finger joint (also called box joint or comb joint). Finger joints can be used to join pieces of wood together lengthwise or to form a corner.

1. On center
   Air-dried
2. Level
   Cat’s paw

The word level means completely horizontal, just as plumb means completely vertical. Carpenters can use the same tool, a spirit level, to verify both level and plumb conditions as they build. Many spirit levels also have the ability to check whether a surface slopes at 45 degrees.

1. Crossbeam
   Molding
2. Valley rafter
   Biscuit joiner

Molding (also called wall trim) is often made of softwood with a decorative profile to add a finished look once the molding is installed. An engineered hardwood material known as MDF (medium-density fibreboard) is sometimes used but there are some health and safety concerns with this.

1. Cross bracing
   Cripple
2. Beading
   Fascia board

Beading by itself can form an attractive yet simple trim. It is often combined with other designs, however, to create more intricate molding styles with such names as bead and leaf; bead and spindle; bead and dart; and bead and reel.

1. Apron
   Landing
2. Proud
   Butt joint

On its own, a butt joint held together by only glue is weak and liable to fail under minimal stress. To improve the strength of this simple joint, carpenters often use some type of fastener, such as nails, screws, biscuits and dowels.

1. Miter
   Crossbeam
2. Cat’s paw
   Square

The cat’s paw is a kind of pry bar which sometimes goes by the name claw bar. It is used to dig in around embedded nails and pull them out, sometime with the assistance of a claw hammer.

1. Joist
   Header
2. Soffit
   Plumb bob

Joists can be found in floor and ceiling framing. They run parallel to each other and are set to sit atop a beam which is placed across the studs. In some cases, there are other beams running under (or carrying) the joists which help to provide added support.

1. Dead load
   Dovetail joint
2. Plumb
   Biscuit joiner

The biscuit joiner is a power tool with a small circular blade. It used to cut slots in pieces of timber which are to be joined. A small oval disc called a biscuit is loaded with glue and placed in the slots, joining the two pieces of timber together.

1. Rake wall
   Butt joint
2. Awl
   Soffit

Soffits are used in conjunction with vertical fascia boards when constructing the eaves of a roof. Apart from finishing an eave, soffits can be used inside a building to fill in the empty space between the ceiling and the top of a cupboard or cabinet.

1. Crown
   Truss
2. Cripple
   Proud

The term “flush” means two surfaces are completely level with each other. In cases where they are not, then the lower surface is said to be “shy” while the upper one is “proud.”

1. Finger joint
   On center
2. Fascia board
   Valley rafter

On center measurements are typically taken between the centers of neighboring studs. As long as all the studs are identical, then the on center measurement is the same as the distance between the edges of the studs

1. Level
   Soffit
2. Molding
   Cross bracing

Cross bracing acts as a form of reinforcement and can be found on various parts of a building, including between rafters and floor joists. The technique is also used to strengthen furniture such as tables and chairs. Other forms of bracing include K-bracing and V-bracing.

1. Molding
   Ridge
2. Live load
   Cripple

There is a board (aptly called the ridge board) which runs horizontally along the ridge of the roof. The roof’s sloping rafters meet the ridge board on either side, and it helps to provide support for all other elements of the roof.

1. Dovetail joint
   Awl
2. Load-bearing walls
   Plumb bob

The dovetail joint is quite similar to the finger joint, but with sloping sides on the pins instead of having them straight. The dovetail joint is said to be much stronger than the finger joint and it can be made even stronger with the application of glue.

1. Undercut
   Dead load
2. Fire block
   Header

Fire blocking material can slow down or stop fire which occurs within the walls of a building. It works by sealing off sections of the space inside the wall and by preventing drafts of air from fueling and moving the fire. Common fire blocking materials include drywall, mineral wool, cement board and spray foam.

1. Square
   Beading
2. Load-bearing walls
   Beading

Some load-bearing walls also act as partitioning walls, but there are many partitioning walls which do not contribute to bearing the structure’s weight – they simply divide up the space inside. Care must be taken when remodeling a structure, since knocking out a load-bearing wall can compromise its integrity.

1. Proud
   Landing
2. Apron
   Joist

The full term for the platform between two flights of stairs is the “intermediate landing.” Although it is typically used when stairs need to change direction, it is not always necessary. A spiral staircase allows the climber to ascend the stairs while constantly changing direction.

1. Crown
   Butt joint
2. Air-dried
   Cross bracing

It is expected that timber used in framing a house will not lie completely flat. To make the timber appear flat when it is used as flooring, carpenters lay it with the crown (curve) up. The weight of the furniture and occupants of the house will then cause it to flatten out.

1. Landing
   Landing
2. Fascia board
   Finger joint

The fascia board runs right along the edge of the roof and is connected to the ends of the rafters. The underside of the roof is then fitted with the soffit boards, and the finished look of the eaves is created.

1. Crown
   Rake wall
2. Dovetail joint
   Miter

A rake (or raked) wall may be sloped in one or both directions. Also, the slopes do not have to be the same length, neither do they have to cover the entire length of the wall. It all depends on the design of the structure.

1. Square
   Level
2. Ridge
   Truss

Traditionally, trusses are constructed from scratch, but it is now commonplace for carpenters to use pre-fabricated trusses. The pre-fabricated trusses can save time, labor and material but care must be taken that they may not completely match the requirements of a specific structure.

1. Plumb
   Joist
2. Valley rafter
   Beading

Valley rafters are typically found on hip roofs where the building is made up of different sections and has what are called internal corners. The valley rafter offers support to shorter rafters known as cripples.

1. Biscuit joiner
   Plumb bob
2. Dead load
   Air-dried

Wood which is to be air-dried is stacked in a cool, dry location with some amount of protection from heavy rain. To allow for circulation of air around the pieces of lumber, they are stacked with spacers (sometimes called stickers) between them. It can take several years to air-dry timber to its optimal moisture content.

1. Undercut
   Live load
2. Fire block
   Fascia board

A live load is any weight which is not fixed to or forms a part of the structure. This includes the weight of people moving through the structure. Movable furniture is also considered to be live load whether or not it actually moves after being placed in a particular spot.