CEM 121 Exam 2

Site Plan (Plot Plan)

A view from above that shows property outlines, building locations, bearings, setbacks, and easements on a lot.

Bearing

The direction of a line expressed in degrees, minutes, and seconds (e.g., N 40° 28' 36" W).

Plan North vs. True North

Plan North is an orientation aligned to the building walls when they do not run true North/South, differing slightly from True North.

Contour Line

A line on a site plan connecting points of equal ground elevation; closely spaced lines indicate a steep slope, while widely spaced lines indicate a gradual slope.

Benchmark (BM)

A permanent reference marker of known elevation

Setback

The minimum required distance between a building and the property boundaries.

Floor Plan

A horizontal section cut typically 42" to 48" above the finished floor, showing room layouts

Reflected Ceiling Plan (RCP)

A plan displaying items on or in the ceiling layout, such as light fixtures, diffusers, structural framing, and ceiling grids.

Demolition Plan

A floor plan indicating existing components to be removed or modified during remodeling

Architectural Elevation

A vertical projection of an interior or exterior building face

Building Section vs. Wall Section

Building sections cut through the entire structure; wall sections detail a specific wall assembly

Schedule (Architectural)

A systematic table specifying item marks, sizes, quantities, materials, and hardware (e.g., Door, Window, Room Finish, Equipment schedules).

Footing

The concrete base that distributes structural building loads directly onto firm, undisturbed soil below the frost line.

Keyway

A groove molded into the top of a concrete footing to provide a shear key and secure lock for the foundation wall.

Slab-on-Grade (Monolithic / Floating)

A ground-level concrete slab; a monolithic/floating slab incorporates thickened, turned-down footings poured as a continuous unit.

Grade Beam

A reinforced concrete beam spanning from footing to footing or pile cap to pile cap across weak or disturbed soil pockets.

Auger Cast Pile

A deep foundation pile installed by drilling a 12"-14" continuous hole with an auger and pumping concrete under pressure as the auger withdraws.

Caisson

A large-diameter (typically 18" to 72") drilled deep-foundation shaft inspected at base grade, reinforced with a rebar cage, and filled with concrete.

Expansion Joint (Foundation)

A compressible joint (typically 1/2") placed between a slab and wall or around columns to allow thermal movement and prevent cracking.

Waterstop

A flexible PVC or elastomeric strip embedded across cold/construction joints in concrete foundation walls to block underground water infiltration.

Cast-in-Place Concrete

Concrete poured and cured inside custom formwork built directly at the construction jobsite.

Precast Concrete

Concrete cast and cured in a controlled plant/factory, then transported to the job site (often pretensioned or posttensioned).

Pretensioning vs. Posttensioning

Pretensioning stretches tendons before concrete is placed; posttensioning tensions cables through cast-in tubes after concrete hardens.

One-Way Slab System

A cast concrete floor slab system where main reinforcing bars span in one direction supported by parallel beams or joists.

Two-Way Slab (Flat Plate / Flat Slab)

A concrete slab system reinforced to span loads in two directions; flat slab includes drop panels and column capitals to resist punching shear.

Waffle Slab

A two-way joist concrete floor system created by square domes/pans arranged in a grid with solid concrete column heads.

Rebar Size Designation

Rebar sizes are numbered in eighths of an inch (e.g., #4 = 4/8" or 1/2" diameter, #5 = 5/8" diameter).

Stirrup

A vertical loop or U-shaped bar reinforcing concrete beams against shear forces

Bolsters and Chairs

Wire or plastic supports that hold rebar at the correct height in formwork

W-Shape (Structural Steel)

Wide-flange steel beam designation where the first number is nominal depth in inches and the second is weight in lb/ft (e.g., W21x147).

Open-Web Steel Joist

A lightweight shop-fabricated truss joist with top and bottom chords and zig-zag web angles, standardized by the Steel Joist Institute (SJI).

Metal Decking

Corrugated steel sheet panels installed across structural steel beams to act as permanent forms and support for concrete floor slabs.

Sill Plate (Mud Sill)

A horizontal wood plate anchored with anchor bolts directly to the top of the concrete foundation wall.

Rim Joist (Header Joist)

The perimeter framing member nailed to the sill plate on edge, into which the ends of floor joists are fastened.

Trimmer Stud vs. King Stud

A king stud runs continuous from sole plate to top plate on the side of an opening; a trimmer stud sits inside the king stud directly underneath the header to support it.

Cripple Stud

Short wood framing studs positioned between the top plate and header or between the rough sill and sole plate.

Rough Sill

The horizontal framing member framing the bottom of a rough window opening.

Platform Framing (Western Framing)

Framing method where each floor is built as a complete subfloor platform upon which the next story of stud walls is erected.

Balloon Framing

Framing technique where exterior wall studs run continuous from the foundation sill to the roof top plate, using notched ribbons to support joists.

Rafter vs. Ridge Board

A rafter is an angled structural member supporting roof sheathing; the ridge board is the horizontal apex board connecting rafter tops.

Bird's Mouth

A notched cutout (consisting of a plumb cut and seat cut) enabling a rafter to seat flat on the stud wall top plate.

Roof Pitch / Slope

The ratio of vertical rise to horizontal run, traditionally designated per 12 inches of run (e.g., 4" rise / 12" run).

Stringer

The inclined structural beam member supporting the treads and risers of a stairway.

Stair Tread vs. Riser

A tread is the horizontal walking surface of a stair; a riser is the vertical board between steps (number of risers = treads + 1).

Rough-in Plumbing (Stage 2)

The installation of water supply, drain, waste, and vent piping before pouring slabs or closing wall framing.

DWV System

Drain-Waste-Vent piping network that directs waste away while venting gases and maintaining equalized atmospheric pressure.

Cleanout (CO)

A capped, accessible fitting on a drainage pipe allowing cleanout tools to enter and clear blockages.

PEX Tubing

Cross-linked polyethylene flexible plastic tubing commonly used for residential hot and cold potable water distribution.

PVC vs. CPVC

PVC is rigid plastic used for cold water and DWV systems; CPVC is chemically chlorinated plastic approved for hot and cold pressure piping.

Hydronic Heating System

A closed-loop system where water heated in a central boiler is circulated via pumps through pipes to terminal convectors or radiant coils.

Duct Size Callout (e.g., 20x14)

20" Width by 14" Depth

Ceiling Diffuser vs. Floor Register

A ceiling diffuser distributes supply air laterally in multiple directions; a floor register covers a supply or return opening with directional louvers.

Unit Cooling vs. Remote Cooling

A unit cooler is a self-contained window/wall unit cooling one room; a remote system locates the compressor/condenser outdoors away from indoor coils.

Evaporative Cooler (Swamp Cooler)

Cooling system that pulls dry outside air through water-saturated fiber pads, cooling air via moisture evaporation (raises indoor humidity).

Welding Reference Line

The continuous horizontal line of a welding symbol upon which all weld symbols, dimensions, and contour notations are anchored.

Arrow Side vs. Other Side (Weld)

Symbols placed below the reference line apply to the arrow side; symbols placed above the reference line apply to the opposite/other side of the joint.

Fillet Weld Symbol

A right-triangle symbol where the vertical leg is always drawn on the left side of the symbol.

Weld All-Around Symbol

A circle placed at the intersection/elbow of the arrow and reference line indicating the weld encircles the perimeter of the joint.

Field Weld Symbol

A small flag placed at the junction of the arrow and reference line specifying the weld must be completed on site rather than in a fabrication shop.

Weld Size & Length Notation (e.g., 1/4 [Fillet] 2-12)

1/4" weld leg size, 2" weld segment length, spaced 12" on-center (intermittent pitch).

Weld Finishing Contours (C, G, M)

Chipping, Grinding, Machining.