Glossary of Building Terms

Glossary of Building Terms

A “Check” is a long crack that appears as the sap wood of a timber shrinks around the heartwood over time. Checking is not a structural problem, and usually occurs only on one or two sides of a beam.

A projecting structure, such as a beam, floor or rafter system, which is supported at only one end.

Cutting a board or piece of plywood the long way and following the grain. Often times a table saw is used for this purpose, a skill saw will do an adequate job.

A board is said to “run wild” when it is nailed into place running past its stopping point and then cut in place.

The supports on the bottom of the building. The heavy beams the building sits on.

Put a nail or other fastener in on an angle rather than end nailing it.

The main framing supports in a floor or ceiling system. Run perpendicular to the rim joists. Typically 16″ or 24″ on center along the Rim Joist.

The joists that frame the outside of the structure’s deck. The rim joist is the board that the joists are nailed perpendicular to. Will have the layout for joist on the side, typically 16″ or 24″ on center.

The way the wood arcs. On the narrower side of the lumber the wood grows with a natural arc or bend in it. The crown can be found by holding the lumber so the narrow side of the board is upright and sighting down the top of the board. Some boards are easier to determine than others and one should just guess if it is not apparent. Always place the crown up when framing for better weight support.

Plumb is the opposite of level. Holding a level perpendicular to the ground is plumb. Walls are said to be plumb and floor systems are referred to as level.

Most commonly referred to a cut on a rafter that is perpendicular to the ground. On a traditional gable roof where the water drains off two sides the plumb cut would be the one at the peak of the roof. A plumb cut can also refer to the cut at the end of the rafter where the water drips.

Is a type of rip cut in the sawing of logs into lumber. By cutting the boards in a radial pattern from the center it results in boards that have the growth ring mostly perpendicular to the longest edge of the board. It is typically more stable lumber but results in a lower yield from the log.

As a noun it refers to a carpentry tool. As a verb is refers to putting a structure to true 90-degree angles.

A ninety-degree angle. A framing square is most often used to square the ends of boards. A square cut when referred to rafters pertains to the tail at the end of the rafter is cut on a ninety-degree angle rather than a plumb cut.

The opposite of an angle using 90 degrees as a standard. Example the reverse angle for 34 degrees is 56. 90-34=56 Level: As a noun it is the tool with bubbles inside windows that indicate whether something is level or plumb. As an adjective or verb level can mean something is at a true 90-degree angle to the earth.

A structural part of the rafter system that is nailed to opposing rafters. The purpose is to prevent the rafters from pushing the walls apart. Collar ties are important in snow country. They help in supporting the weight of a snow load. Collar ties can be 1” or 2” lumber and sometimes a cable is used in place of collar ties.

The framing lumber in a wall that contains the layout. The wall plates are the two boards that hold the studs in place.

The common support lumber inside a wall usually placed on a 16 or 24” layout. Jack or trimmer studs: The wall framing lumber that the header sits on. Found on each side of a door or window.

Any short stud used in framing a wall. Usually found under window sills and or above headers.

The wall framing lumber that holds the jack stud and the header together. The king studs are the same length as common studs.

Is the older non-living center of the tree. Usually harder and darker in color when seen in a cross section, it no longer conducts water and its main function is support of the tree.

The heavy piece of lumber found over doors or windows to properly transfer the weight of the building away from the opening. The header prevents premature sagging.

The map which is scratched out on lumber. It is used to know where to nail key pieces of lumber. It eliminates the need to measure each item separately.

An 8/12 pitch describes how steep a slope is. An 8/12-roof pitch goes up 8″ for every foot or 12” it goes over. If you went out level four feet you would be able to plumb up 32″”. 4×8=32” The reverse is the same for coming down a slope. Common pitches begin at a 3/12 for a flat roof and 12/12 for a steep roof. Steeper roofs such as steeples and or A frame buildings can be as high as 20/12.

A board foot is a volume of measurement for wood. It is calculated as 12″ x 12″ x 1″ thick. A 1x6x8 is 4 board feet. A 2x6x8 is 8 board feet. Abbreviated Bd. Ft.

A square foot is the two sides of a building or a room times each other. The square footage of the 8×12 shed is 96 Square feet. A 1″x6″x8′ is 4 square feet. A 2″x6″x8′ is 4 square feet. Abbreviated Sq. Ft.

A lineal foot refers to the total length of the material. A 1x6x8 and a 2x6x8 both are 8 lineal feet.

Both mental and physical strength used to achieve a job usually associated with hand tasks.

The length is the span of the rafter on a level line and the run is the length measured down the rafter.

The extension of the roof on the gable end side. There are many names and many ways to build the framing.

The extension of a roof, past the walls, on any side.

The end of the rafter that extends out past the wall. It is the part of the rafter that creates the overhang on the drip edge side of a roof.

Lumber that has been run through a mill and squared into some sort of format. Before this stage it is rough lumber, a plus sized board that is recognizable by its rough texture. The opposite of dimensional lumber is using trees in the natural round state as framing material.

The part of the roof under the overhangs. The finishing off of the rafter tails and or overlooks. Often times the soffit has a screen in it to ventilate an insulated roof.

The main trim board that is wrapped around all sides of the rafters.

The narrower of the two fascia trim boards. Mainly for decorative purposes its only functional purpose is for a bit more overhang to protect the building from the elements.

The side of a roof where water does not drip off. A gable roof traditionally has two gable ends and a hip roof does not have any.

Roof Styles

A four-pitched roof traditional on Dutch style barns.

A very steep gabled roof traditionally on chalet type buildings. It typically extends close to or all the way to the ground.

A two-pitched roof traditionally seen in snow country. It sheds the majority of the snow off the back of the building.

Rain falls off the building on all four sides.

The most common two-pitched roof.

Four gable ends connected to create four valleys.

A one-pitched roof. Rain falls off on one side only.

An outcropping of the roof. Typically a window is placed in the dormer. Many types exist and can be incorporated with any type of roof.

When a roof is built on top of or joined to another roof a valley is created. Water drains into the valley from both roofs and travels together down and off.

As a noun: The boards that are part of the buildings finish. The opposite is the framing boards. Trim boards are traditionally between 3/4” and 5/4”. As a verb: The process of installing the final finish boards on the building.

A piece of wood or stone placed beneath a door, a door sill.

A nail or screw sticking out of the lumber or material. A miss.

The small vertical board nailed over a joint where larger siding boards meet. The batten covers up the seam where two square end boards touch.