Crew training: the glossary, and a page for each trade.

The words we use on a job, in plain language. Pick a trade to open its training page, or read the glossary below.

Training pages by trade

Walk the job site · 3D

Each trade has a 3D shop or job site. Walk it station by station, watch the real work, find the mistakes, pass the checks. Progress is kept in this browser.

Glossary

Site and excavation

Grade: The level of the ground surface. Finish grade is the final surface; rough grade is before final shaping.
Over-excavation: Digging deeper than the plans call for to remove weak soil, then replacing it with compacted fill.
Compaction: Mechanically packing soil or gravel so it will not settle under a slab or footing.
Shoring: Temporary bracing that holds a trench or excavation wall from caving in.

Site and excavation training page →

Foundations and concrete

Footing: The widened concrete base under a foundation wall or post that spreads the load into the soil.
Stem wall: The short concrete wall that rises from the footing and carries the framed wall above.
Rebar: Steel reinforcing bar set inside concrete to carry tension.
Anchor bolt: A bolt cast into the concrete that ties the sill plate to the foundation.
Slump: A measure of how wet or stiff a concrete mix is, taken before it is placed.

Foundations and concrete training page →

Framing

Plate: The horizontal member at the top or bottom of a stud wall. Sill plate sits on the foundation; top plate caps the wall.
Header: A beam over a door or window opening that carries load around it.
Shear wall: A wall braced to resist sideways forces from wind and earthquakes.
Blocking: Short pieces of lumber fitted between framing members for stiffness or as a nailing surface.
On center (OC): Spacing measured from the center of one member to the center of the next.

Framing training page →

Roofing

Underlayment: The water-resistant layer under the finished roofing material.
Flashing: Thin metal or membrane that directs water away at valleys, walls, chimneys and penetrations.
Pitch: The slope of a roof, stated as rise over a 12 inch run.
Eave: The lower edge of the roof that overhangs the wall.
Ridge: The horizontal line where two roof slopes meet at the top.

Roofing training page →

Windows, doors and weatherproofing

Rough opening: The framed hole a window or door is installed into, sized larger than the unit.
Sill pan: A waterproof tray under a window or door that catches and drains any water that gets in.
Head flashing: Flashing above an opening that sheds water over the top of the frame.
Weather-resistive barrier (WRB): The water-shedding layer behind the exterior finish, often called house wrap.
Shim: A thin wedge used to set a unit plumb, level and square in its opening.

Windows, doors and weatherproofing training page →

Plumbing

Rough-in: Installing supply and drain lines inside walls and floors before they are closed up.
DWV: Drain, waste and vent: the system that carries wastewater out and lets air in behind it.
Trap: The curved section of drain that holds water to block sewer gas.
Stub-out: The end of a pipe left sticking out of the wall, where a fixture will connect.
Shutoff valve: A valve that stops water to a fixture or to the whole house.

Plumbing training page →

Electrical

Rough-in: Running cable and setting boxes before the walls are closed.
Circuit: A path from the panel, through the devices on it, and back.
Panel: The box that distributes power to circuits, each protected by a breaker.
GFCI: Ground-fault circuit interrupter: a device that cuts power fast when it senses current leaking, used near water.
Home run: The cable that runs from a circuit's first box back to the panel.

Electrical training page →

Heating, cooling and ventilation

Load calculation: The math that sizes heating and cooling equipment to the actual house.
Supply and return: Supply ducts deliver conditioned air to rooms; return ducts bring it back to the equipment.
Register: The grille where air enters or leaves a room.
Mini-split: A ductless heat pump with an outdoor unit connected to one or more indoor heads.
CFM: Cubic feet per minute: how much air moves past a point.

Heating, cooling and ventilation training page →

Insulation and air sealing

R-value: A measure of resistance to heat flow. Higher is better.
Air sealing: Closing gaps and cracks so air does not leak through the building envelope.
Thermal bridge: A path, often framing, where heat bypasses the insulation.
Vapor retarder: A layer that slows moisture moving through a wall or ceiling.
Blower door test: A fan test that measures how leaky a house is.

Insulation and air sealing training page →

Drywall and plaster

Taping: Embedding paper or mesh tape in joint compound over the seams between sheets.
Skim coat: A thin layer of compound or plaster over a whole surface to even it out.
Levels of finish: The industry's 0 to 5 scale of how much compound and sanding a drywall surface receives. Level 5 is the smoothest.
Corner bead: A metal or vinyl strip that protects and straightens an outside corner.
Float: To flatten and smooth wet plaster or compound with a trowel or knife.

Drywall and plaster training page →

Tile and waterproofing

Substrate: The surface the tile is set on, such as backer board or a mortar bed.
Membrane: A waterproofing layer under or behind tile, in a shower especially.
Thinset: The cement-based adhesive that bonds tile to the substrate.
Flood test: Filling a shower pan with water for a set time to prove it holds before tile goes on.
Lippage: The height difference between the edges of two neighboring tiles.

Tile and waterproofing training page →

Cabinetry and millwork

Face frame: The solid frame on the front of a cabinet box that the doors attach to.
Inset: Doors and drawers set inside the face frame, flush with it.
Reveal: The small, even gap showing between a door or drawer and its frame.
Scribe: To cut a piece to follow an uneven wall or floor so it fits tight.
Toe kick: The recessed base under a cabinet so you can stand close.

Cabinetry and millwork training page →

Floors and paint

Acclimation: Letting flooring sit in the house so it adjusts to the room's moisture before install.
Floating floor: Flooring that is joined to itself but not fastened to the subfloor.
Primer: The first coat that seals the surface and helps the paint stick.
Cutting in: Brushing a clean line at edges and corners before rolling the field.
Sheen: How glossy a finish is, from flat to high gloss.

Floors and paint training page →

Construction project management

RFI: Request for information: a written question to the designer or owner when the plans are unclear or conflict.
Submittal: Product data, shop drawings or samples sent for approval before anything is ordered or built.
Change order: A written change to the scope, price or schedule of the contract, signed before the work is done.
Critical path: The longest chain of dependent tasks. A delay on it delays the finish date.
Retainage: A percentage of each payment held back until the work is complete.
Lien waiver: A signed release of lien rights, given in exchange for payment. Conditional waivers take effect only when payment clears.

Construction project management training page →

Finish carpentry

Casing: The trim framing a door or window opening.
Reveal: The small, even offset between a jamb and its casing.
Coped joint: A joint where one molding is cut to the profile of the other so it stays tight if the wall moves.
Mitered joint: A joint where two pieces are each cut at an angle, usually 45 degrees, to meet at a corner.
Stool and apron: The window sill shelf, and the trim piece under it.
Scribe: To cut a piece to follow an uneven wall or floor so it fits tight.
Backband: A molding applied around the outer edge of casing to add depth.

Finish carpentry training page →

General guidance, not a specification. The drawings, the engineer and the building inspector govern every job.