NCCER Carpenter flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Fall protection trigger height

OSHA construction standards require employers to protect workers 6 feet or more above a lower level with guardrails, safety nets, or a personal fall arrest system.

Ladder 4-to-1 rule

The base of a straight or extension ladder is placed 1 foot away from the wall for every 4 feet of working height, and the ladder extends 3 feet above the landing.

Board foot formula

Board feet equals nominal thickness in inches times nominal width in inches times length in feet, divided by 12. A nominal 2x6 that is 10 feet long equals 10 board feet.

Actual size of a 2x10

A nominal 2x10 is dressed to 1-1/2 inches thick and 9-1/4 inches wide. Framing layout uses actual dimensions, while lumber is bought and sold by nominal size.

GFCI protection on site

Ground-fault circuit interrupter protection is required for temporary 120-volt receptacles on construction sites; the device trips within milliseconds when current leaks toward ground.

Scaffold top rail height

Guardrails on supported scaffolds use a top rail 42 inches above the platform, a midrail at roughly 21 inches, and toe boards where falling materials could strike workers below.

Lumber grade stamp

A stamp on framing lumber gives species group, grade, moisture content, grading agency, and mill; those values drive the allowable spans in joist and rafter tables.

3-4-5 squaring method

Measure 3 feet along one line and 4 feet along the perpendicular, then shift the corner until the diagonal equals 5 feet. Multiples such as 6-8-10 work for large layouts.

Batter boards

Horizontal boards set about 2 to 3 feet outside the building corners, carrying string lines that mark the building lines so corners can be reestablished after excavation.

Control joint spacing

Saw-cut contraction joints are spaced about 2 to 3 times the slab thickness in feet, so a 4-inch slab receives joints roughly 8 to 12 feet apart.

Rebar cover against earth

Concrete cast directly against the ground needs at least 3 inches of cover over reinforcement, while concrete exposed to weather needs about 2 inches of cover.

Wall form stripping time

Vertical wall forms are normally stripped 24 to 48 hours after concrete placement, while slab forms and shores stay until the concrete reaches the strength assumed in design.

Plot plan

A site drawing at small scale showing property lines, the building footprint, setbacks, utilities, and benchmark elevations used to lay out and check the structure.

Footing depth and frost line

Footings must bear on undisturbed soil below the frost depth set by the local code, and be wide enough for the soil bearing capacity and the imposed wall load.

King stud

The full-height stud nailed at each side of a rough opening that runs from sole plate to top plate and carries the header and the loads above the opening.

Jack stud (trimmer)

A shorter stud fastened against the king stud that supports one end of a header over a door or window, running from the sole plate up to the header.

Cripple stud

Short studs placed above a header or below a window sill, aligned with the common stud spacing, that carry wall covering and transfer loads to the header or plate.

Rim joist

The perimeter member that caps the ends of the floor joists, squares the floor system, and provides nailing for the subfloor edge and exterior wall plates.

Joist bridging

Solid blocking or cross bridging placed between floor joists at midspan and bearing points to prevent twisting, spread loads, and reduce floor bounce under foot traffic.

92-5/8-inch precut stud

A stud 92-5/8 inches long, combined with one bottom plate and a double top plate, frames a wall to about 97-1/8 inches for standard 8-foot ceiling construction.

6/12 roof pitch

The roof rises 6 inches for every 12 inches of horizontal run, which is an angle of about 26.6 degrees; framing square rafter tables give lengths directly for that pitch.

Rafter run and length

On a gable roof the run of a common rafter is half the building width, and rafter length equals the square root of the run squared plus the total rise squared.

Birdsmouth seat cut

The notch letting a rafter sit flat on the wall plate, formed by a horizontal seat cut and a vertical plumb cut; seat depth should not exceed one-third the rafter depth.

Ridge board

The horizontal board at the roof peak against which opposing rafters are nailed; it is normally one size thicker than the rafters and its top edge sets ridge height.

Drip edge

Metal flashing at the roof perimeter that sheds water clear of the fascia; it is installed under the underlayment at the eaves and over it along the rakes.

Ice dam membrane

A self-adhering waterproof underlayment applied along the eaves and in valleys to stop water backed up by ice from penetrating the roof deck and leaking inside.

Door rough opening size

Frame the rough opening about 2 inches wider and 2-1/2 inches taller than the door slab so the prehung frame can be shimmed, plumbed, and leveled in place.

Type X drywall

Gypsum board with core additives that provide a fire-resistance rating, usually 5/8 inch thick, used on garage ceilings, furnace rooms, and other rated assemblies.

Drywall screw spacing

Fasten panels with screws 12 inches on center in the field and 8 inches on center along panel edges, keeping screws about 3/8 inch from the edges.

Shimming a prehung door

Plumb and shim the hinge side first, placing shims behind each hinge, then level the head jamb and adjust the latch side to an even gap of about 1/8 inch.

Coped inside corner

An inside trim joint in which the end of one molding is cut to match the profile of the mating piece, keeping the joint tight as the material shrinks and moves.

Window flashing sequence

Install sill pan flashing first, set and level the window, then apply side flashing and finally head flashing, lapping each layer so water always sheds outward.