Study guide · General Building (B) · Finish Trades
Finish Trades: The Rules the Exam Asks For
About 36 minutes · 7 sections
What this guide covers
Most Finish Trades questions are trade practice: how to prime new drywall, where the first strip of wallcovering goes, how to stretch carpet. Those are taught with the practice questions. This guide carries the fourteen code rules the section tests, in wet areas, drywall and ceilings, doors and glazing, and site work, and the arithmetic: paint, tile, carpet, baseboard, cabinets, and cut lists.
Key terms
- Type X gypsum board
- Gypsum board with a fire-resistance-rated core; 5/8-inch Type X is the garage-ceiling material under a habitable room.
- Hazardous location (glazing)
- A place the code lists where glass must be safety glazing: doors, next to doors, near tubs and showers, and others.
- Safety glazing
- Glazing that passes the impact test and carries a manufacturer's designation (or, for non-tempered glass with the official's approval, a certificate of compliance); tempered and laminated glass are the common kinds.
- Decorative glazing
- Glazing with a pattern, texture, or color that makes it obviously not transparent; the code excepts it from several safety-glazing locations.
The rules the exam tests
8 rules · 3 minTile, stone, and wet areas
Back tub and shower tile with glass-mat or fiber gypsum, fiber-cement, or cementitious backer.
Table R702.4.2 lists four materials: glass-mat gypsum backing panel (ASTM C1178), fiber-reinforced gypsum panels (ASTM C1278), nonasbestos fiber-cement (ASTM C1288 or ISO 8336 Category C), or nonasbestos fiber-mat-reinforced cementitious backer units (ASTM C1325). Wall panels in shower areas are one of these materials too. Install per the manufacturer's recommendations.
On the job
The exam tests that a tub or shower wall behind tile gets one of the four Table R702.4.2 backers — glass-mat gypsum, fiber-reinforced gypsum, fiber-cement, or cementitious backer units — installed per the manufacturer, and that the table names the standards.
Exact wording
Backers for wall tile in tub and shower areas, and wall panels in shower areas, are one of the materials in Table R702.4.2, installed per the manufacturer's recommendations: glass-mat gypsum backing panel (ASTM C1178), fiber-reinforced gypsum panels (ASTM C1278), nonasbestos fiber-cement backer board (ASTM C1288 or ISO 8336 Category C), or nonasbestos fiber-mat-reinforced cementitious backer units (ASTM C1325).
Residential Code § r702.4.2
Finish tub and shower floors and the walls 6 feet up with a nonabsorbent surface.
Nonabsorbent means the surface does not soak up water. Use it on bathtub and shower floors, on walls above a bathtub with a shower head, and in shower compartments. Those walls extend at least 6 feet above the floor.
On the job
6 feet above the floor, measured on the wall, is this code's number for the nonabsorbent finish in shower compartments and above tubs with shower heads.
Exact wording
Bathtub and shower floors, and the walls above bathtubs with shower heads and in shower compartments, are finished with a nonabsorbent surface. The wall surfaces extend at least 6 feet above the floor.
Residential Code § r327.2
Cove base is the concave trim where a tile floor meets a tile wall.
Cove base's curved face curves inward, while quarter round is the convex opposite. Bullnose has one rounded finished edge for an exposed field edge. A listello is a decorative band in the field.
On the job
The exam names the trim from its shape and location. Concave at the floor-to-wall joint is cove base.
Exact wording
Cove base is the tile trim with a concave curved face, set where a tile floor turns up to a tile wall. Bullnose has one rounded finished edge for an exposed field edge, quarter round is convex, and a listello is a decorative band in the field.
Standard trade practice
Use bullnose wherever a tile field ends in open wall space.
Bullnose is a field-size trim tile with one finished, eased glazed edge. The top course of a wainscot is one example. A V-cap wraps a countertop edge, cove base is concave at the floor line, and quarter round is a small convex strip.
On the job
The exam asks which trim closes the top of a wainscot. One finished edge on a field-size tile is bullnose.
Exact wording
Bullnose is a field-size trim tile with one finished, eased glazed edge, used wherever a tile field ends in open wall space, such as the top course of a wainscot. A V-cap wraps a countertop edge, cove base is concave at the floor line, and quarter round is a small convex strip.
Standard trade practice
A large tile floor that ridges up in the middle is missing movement joints.
Movement joints are the deliberate gaps at the perimeter and through the field that let tile, mortar, and slab expand. Without them the compression has nowhere to go and buckles the tile upward. Poor mortar coverage instead gives hollow tile and broken corners, early grouting discolors grout, and a contaminated slab debonds tile rather than ridging it.
On the job
The exam gives the symptom, tenting, and asks the cause. Missing movement joints is the answer; the other shortcomings produce different failures.
Exact wording
A large tile floor that lifts and ridges in the middle of the room most likely has no movement joints at the perimeter or through the field; tile, mortar, and slab all move, and with nowhere to go the compression buckles the tile upward. Poor mortar coverage gives hollow tile and broken corners, early grouting discolors grout, and a contaminated slab debonds tile rather than ridging it.
Standard trade practice
Scrape off thinset that has skinned over on the wall and spread fresh mortar.
Thinset that has stiffened and skinned over is past its open time, so it will not wet out the back of the tile. Recombing, misting with water, or spreading fresh mortar over the skin leaves a bond plane that fails.
On the job
The exam tests that skinned mortar is discarded, never revived. Adding water is the trap.
Exact wording
Thinset that has stiffened and skinned over on the wall is past its open time and will not wet out the back of the tile; it is scraped off and fresh mortar is spread. Recombing, misting with water, or spreading fresh mortar over the skin leaves a bond plane that fails.
Standard trade practice
Dark grout will stain honed marble unless you seal it first.
Seal porous natural stone such as honed marble with an impregnating sealer and let it dry before pigmented grout goes in. Otherwise pigment soaks in and shadows every joint. Acid etches marble, water carries pigment, and buffing won't close pores.
On the job
The exam asks what happens to the stone face before dark grout. An impregnating sealer is the answer.
Exact wording
Porous natural stone such as honed marble gets an impregnating sealer, allowed to dry, before a pigmented grout goes in, so the pigment cannot soak into the pores and shadow every joint. Acid etches marble, water carries pigment in, and buffing does not close the pores.
Standard trade practice
You cannot bury a slab crack under extra mortar. A membrane isolates it.
Fill hairline shrinkage cracks with no offset, then bond a crack isolation membrane over them so movement doesn't telegraph through. A thicker mortar bed, a patch alone, or a bonding agent still transfers it. Vertical displacement needs structural repair instead.
On the job
The exam tests that cracks are isolated, not bridged with more mortar or merely patched.
Exact wording
A slab with hairline shrinkage cracks that show no offset is prepared for tile by filling the cracks and bonding a crack isolation membrane over them; the membrane separates the tile from the slab's slight movement so the crack does not telegraph through. A thicker mortar bed, a patch alone, or a bonding agent still transfers the movement, and a crack with vertical displacement needs structural repair instead.
Standard trade practice
Take away
7 rules · 4 minDrywall, plaster, and ceilings
If a room sits over the garage, put 5/8-inch Type X on the garage ceiling.
Table R302.6: use at least 1/2-inch gypsum board or equivalent on the garage side of walls and attics facing the dwelling, on structure supporting a floor-ceiling assembly used for the separation, and on the interior side of exterior walls where a garage sits less than 3 feet from a dwelling on the same lot. Use at least 5/8-inch Type X or equivalent under portions of the dwelling above the garage or carport. Openings follow Section R302.5; attachment follows Table R702.3.5. Garage walls perpendicular to the dwelling wall are excluded, and a carport open on two or more sides with nothing enclosed above needs no separation.
On the job
A bedroom over the garage means 5/8-inch Type X on the garage ceiling; the garage-side walls take 1/2-inch. The perpendicular-wall exclusion and the open-carport exception are the qualifiers.
Exact wording
A dwelling's garage or carport is separated per Table R302.6: at least 1/2-inch gypsum board or equivalent on the garage side of walls to the dwelling unit and attics; at least 5/8-inch Type X gypsum board or equivalent under portions of the dwelling above the garage or carport; at least 1/2-inch gypsum board or equivalent on structure supporting a floor-ceiling assembly used for the separation; and, where a garage sits less than 3 feet from a dwelling on the same lot, at least 1/2-inch gypsum board or equivalent on the interior side of the exterior walls in that area. Openings in garage walls follow Section R302.5 and gypsum attachment follows Table R702.3.5. The wall rule does not apply to garage walls perpendicular to the dwelling wall, and a carport open on two or more sides with nothing enclosed above needs no separation.
Residential Code § r302.6
Separate a garage shared by several units from each unit with at least 1/2-inch gypsum.
Table R302.3.6 calls a garage or carport serving more than one dwelling unit a dwelling-shared accessory room or carport, and it sets the materials: at least 1/2-inch gypsum board or equivalent on the accessory-room side of walls to dwelling units and attics; at least 5/8-inch Type X gypsum board or equivalent where habitable rooms are above or below the shared accessory room; and at least 1/2-inch gypsum board or equivalent on structure supporting a floor-ceiling assembly used for the separation. Ducts crossing the separation are sheet steel of at least No. 26 gage or other approved material, with no openings into the accessory room. Protect other penetrations as fireblocking penetrations. Attach the gypsum board per Table R702.3.5.
On the job
This is the shared-accessory-room (including carport) version of the rule — commonly a garage serving more than one unit; the materials match the single-family table in R302.6. The exam's usual stem, a bedroom over a house's garage, is the R302.6 claim.
Exact wording
A shared accessory room — the table's term is a dwelling-shared accessory room or carport, one serving more than one dwelling unit — is separated from each dwelling unit per Table R302.3.6: at least 1/2-inch gypsum board or equivalent on the accessory-room side of walls to dwelling units and attics; at least 5/8-inch Type X gypsum board or equivalent where habitable rooms are above or below the shared accessory room; and at least 1/2-inch gypsum board or equivalent on structure supporting a floor-ceiling assembly used for the separation. Ducts through the separation are sheet steel of at least No. 26 gage or other approved material with no openings into the accessory room; other penetrations are protected as fireblocking penetrations. Gypsum board attachment follows Table R702.3.5.
Residential Code § r302.3.6
Install a where a pipe passes through a rated wall.
The firestop system must be approved and installed as tested under ASTM E814 or UL 1479, at a positive pressure differential of at least 0.01 inch of water. Its must be at least the wall's required fire-resistance rating.
On the job
A pipe through a rated wall needs an approved firestop system, tested per ASTM E814 or UL 1479, with an F rating at least equal to the wall's rating. Stuffing the hole is not a system.
Exact wording
A through-penetration of a fire-resistance-rated wall is protected by an approved penetration firestop system installed as tested per ASTM E814 or UL 1479, at a positive pressure differential of at least 0.01 inch of water, with an F rating not less than the wall's required fire-resistance rating.
Building Code § 714.4.1.2
Install suspended acoustical ceiling systems in accordance with ASTM C635 and ASTM C636.
The two standards are ASTM C635 and ASTM C636, and both apply to the same system. Meeting one alone does not satisfy the code, because the installation requirements come from the standards themselves, not from the code text.
On the job
The code hands suspended ceilings to two ASTM standards, and California's seismic detailing of splay wires and compression struts lives in those standards and the structural code, not in this sentence. The exam tests where the installation rules come from.
Exact wording
Suspended acoustical ceiling systems are installed in accordance with ASTM C635 and ASTM C636.
Building Code § 808.1.1.1
A casing bead gives plaster a straight edge where it stops against dissimilar material.
A casing bead, or plaster stop, has a flange over the lath and an exposed ground that sets plaster thickness. Its terminal edge is where plaster meets trim, a jamb, or another dissimilar material. Corner bead protects an outside corner, cornerite reinforces inside corners, and a control joint relieves movement within the field.
On the job
The exam names the accessory at a plaster edge. Casing bead is the stop; the others reinforce corners or relieve movement.
Exact wording
A casing bead, or plaster stop, is the lath accessory with a flange over the lath and an exposed ground that sets plaster thickness, giving plaster a straight terminal edge where it stops against trim, a jamb, or another dissimilar material. Corner bead protects an outside corner, cornerite reinforces inside corners, and a control joint relieves movement within the field.
Standard trade practice
Hang the ceiling gypsum board before you hang the wall panels.
Push the wall panels up tight against the ceiling panels, so the walls carry the ceiling edges and the corner joint closes. Hang walls from the top down, so any cut falls at the floor where the base covers it.
On the job
The exam asks the order: ceilings, then walls from the top down.
Exact wording
Gypsum board is hung on the ceiling first, then the wall panels are pushed up tight against the ceiling panels so the walls help carry the ceiling edges and the corner joint closes. Walls are hung from the top down so any cut falls at the floor where the base covers it.
Standard trade practice
Press paper joint tape into the wet bed coat. Dry compound will not bond.
Paper joint tape has no adhesive, so the wet compound is what holds it. Spread a bed coat on the joint, press the tape in, and wipe it tight. After the bed coat dries, coat the tape again. Tape on a bare joint, on dried compound, or on a dampened joint does not bond and blisters.
On the job
The exam tests that paper tape is embedded in wet compound. Tape first, or tape over dry compound, is the trap.
Exact wording
Paper joint tape has no adhesive; compound is spread on the joint and the tape is pressed into the wet bed coat, wiped tight, and coated again after the bed coat dries. Tape laid on a bare joint, on dried compound, or on a dampened joint does not bond and blisters.
Standard trade practice
Take away
10 rules · 8 minWindows, doors, and glazing
You lap flashing in so water runs out of the wall.
Approved corrosion-resistant flashing keeps water out of the wall cavity and off the framing, and it extends to the surface of the exterior wall finish. At window and door openings it may instead extend to a water-resistive barrier complying with R703.2 for subsequent drainage. Use self-adhered membranes complying with AAMA 711, fluid-applied membranes complying with AAMA 714, and mechanically attached flexible flashings complying with AAMA 712. Flash at exterior window and door openings, at chimney and masonry intersections, under and at the ends of copings and sills, continuously above projecting wood trim, where porches, decks, or stairs attach to a wall, at wall and roof intersections, and at built-in gutters. At window and door openings, follow the fenestration manufacturer's instructions, the flashing or barrier manufacturer's instructions, a registered design professional's design, or another approved method. Air seal around every window and door opening on the interior side of the rough-opening gap. Where no flashing instructions are provided, put pan flashing at the sill.
On the job
Shingle fashion means each piece laps over the one below, so water runs out, not in. Where the manufacturer gives no flashing instructions, the code's fallback is pan flashing at the sill, sealed or sloped to drain to the wall finish or water-resistive barrier, with flashing or protection at the head and sides.
Exact wording
Approved corrosion-resistant flashing is applied to keep water out of the wall cavity and off the framing, and extends to the surface of the exterior wall finish; at window and door openings it may instead extend to a water-resistive barrier complying with R703.2 for subsequent drainage. Overlapped flashing is applied in shingle fashion; self-adhered membranes used as flashing comply with AAMA 711, fluid-applied membranes with AAMA 714, and mechanically attached flexible flashings with AAMA 712. Flashing goes at exterior window and door openings, at chimney and masonry intersections, under and at the ends of copings and sills, continuously above projecting wood trim, where porches, decks, or stairs attach to a wall, at wall and roof intersections, and at built-in gutters. At window and door openings, flashing follows the fenestration manufacturer's instructions (or the flashing or barrier manufacturer's), a registered design professional's design, or another approved method; air sealing goes around every window and door opening on the interior side of the rough-opening gap, and where no flashing instructions are provided, pan flashing goes at the sill.
Residential Code § r703.4
Provide at least one side-hinged egress door in each dwelling unit.
A sliding door cannot be that egress door. Measure the clear width from the face of the door to the stop with the door open 90 degrees: at least 32 inches. The clear height is at least 78 inches, measured from the top of the threshold to the bottom of the stop. The egress door opens from inside without a key, special knowledge, or effort. Other doors need not meet these dimensions.
On the job
Side-hinged is the tested word: a sliding door cannot be the required egress door. 32 by 78 are the neighbors.
Exact wording
Each dwelling unit has at least one egress door. It is side-hinged, with a clear width of at least 32 inches between the face of the door and the stop with the door open 90 degrees, and a clear height of at least 78 inches measured from the top of the threshold to the bottom of the stop. It opens from inside without a key, special knowledge, or effort. Other doors need not meet these dimensions.
Residential Code § r318.2
When you replace an emergency escape window, you may keep the existing opening size.
In a building within the Residential Code's scope, your replacement window for an emergency escape and rescue opening is exempt from Section R319.2 (the opening's required dimensions) and Section R319.4.4 (bars, grilles, covers, and screens) if it is the manufacturer's largest standard size that fits the existing frame or rough opening, is the same operating style or gives equal or greater opening area, and is not part of a change of occupancy. When a window opening control device or fall protection device is used, put it at the height Section R319.1.1 sets, or as low as the device can be installed in the existing clear opening. Whether a device is required is decided by the window fall protection rule, not by this exemption.
On the job
The largest standard size that fits is the tested condition: a retrofit window need not meet the new-construction opening dimensions on those terms. The trap is the device: R319.5.1 sets where a control or fall-protection device goes when one applies, and does not make one required.
Exact wording
In a building within the Residential Code's scope, a replacement window for an emergency escape and rescue opening is exempt from Section R319.2 (the opening's required dimensions) and Section R319.4.4 (bars, grilles, covers, and screens) if it is the manufacturer's largest standard size that fits the existing frame or rough opening, of the same operating style or one giving equal or greater opening area, and the replacement is not part of a change of occupancy. This section also fixes where a window opening control device or fall protection device goes when one is used: at the height Section R319.1.1 sets, or as low as the device can be installed in the existing clear opening. Whether one is required is decided by the window-fall-protection rule, not by this section.
Residential Code § r319.5
Protect windows with sills under 24 inches inside and drops over 72 inches outside.
In a dwelling unit, this applies only when the operable window's clear opening bottom is less than 24 inches above the finished floor and more than 72 inches above the grade or other surface below outside. Then either the opening stops a 4-inch sphere at its largest opened position, or you install a window opening control device or fall prevention device complying with ASTM F2090. Where that window is an emergency escape and rescue opening, the device, once released so the window opens fully, must still leave the net clear opening area Sections R319.2.1 and R319.2.2 require.
On the job
This is the rule that decides whether a low bedroom window over a drop needs a control device: 24 inches inside and 72 inches outside are the triggers, the 4-inch sphere or an F2090 device is the fix, and on an egress window the device must still let the full opening area through. R319.5.1 only says where the device goes.
Exact wording
In dwelling units, an operable window whose clear opening bottom is less than 24 inches above the finished floor and more than 72 inches above the grade or other surface below outside must either keep a 4-inch sphere from passing through the opening at its largest opened position, or have a window opening control device or fall prevention device complying with ASTM F2090. Where that window is an emergency escape and rescue opening, the device, once released to let the window open fully, may not reduce the net clear opening below the area Sections R319.2.1 and R319.2.2 require.
Residential Code § r321.2
You need safety glazing in every swinging, sliding, or bifold door panel.
Use safety glazing in the fixed and operable panels of swinging, sliding, and bifold doors. Two exceptions: glazed openings too small for a 3-inch sphere to pass, and decorative glazing.
On the job
Glass in a door is hazardous by definition. The 3-inch-sphere and decorative exceptions are the qualifiers.
Exact wording
Glazing in the fixed and operable panels of swinging, sliding, and bifold doors is a hazardous location and needs safety glazing, except glazed openings too small for a 3-inch sphere to pass, and decorative glazing.
Residential Code § r324.4.1
Use safety glazing within 24 inches of a door when the sill is under 60 inches.
Glazing in a panel next to a door is a hazardous location where its bottom edge is less than 60 inches above the floor and it is either within 24 inches of either side of the door in the plane of the closed door, or on a wall less than 180 degrees from the door plane and within 24 inches of the hinge side of an in-swinging door. Four exceptions: decorative glazing; glazing separated from the door by an intervening wall or other permanent barrier; doors giving access to a closet or storage area 3 feet or less deep; and glazing adjacent to the fixed panel of a patio door.
On the job
24 inches and 60 inches: the sidelight rule. The arc on the hinge side of an in-swinging door is the qualifier the exam likes.
Exact wording
Glazing in a panel next to a door is a hazardous location where its bottom edge is less than 60 inches above the floor and it is within 24 inches of either side of the door in the plane of the closed door, or on a wall less than 180 degrees from the door plane and within 24 inches of the hinge side of an in-swinging door. Four exceptions: decorative glazing; glazing separated from the door by an intervening wall or other permanent barrier; doors giving access to a closet or storage area 3 feet or less deep; and glazing adjacent to the fixed panel of a patio door.
Residential Code § r324.4.2
You must use safety glazing in walls, enclosures, and fences around tubs, showers, and pools.
Glazing is in a hazardous location where its bottom edge sits less than 60 inches above any standing or walking surface, in a wall, enclosure, or fence containing or next to a hot tub, spa, whirlpool, sauna, steam room, bathtub, shower, or pool. That 60-inch measurement applies to single glazing and to each pane of multiple glazing. Glazing more than 60 inches horizontally from the water's edge of a tub, hot tub, spa, whirlpool, or pool, or from the edge of a shower, sauna, or steam room, is excepted.
On the job
Glazing in a wall, enclosure, or fence containing or next to a tub, shower, spa, hot tub, whirlpool, sauna, steam room, or pool is a hazardous location when its bottom exposed edge sits below 60 inches above a standing or walking surface. The escape is horizontal distance: more than 60 inches from the water's edge or the edge of the shower, sauna, or steam room.
Exact wording
Glazing in walls, enclosures, or fences containing or next to hot tubs, spas, whirlpools, saunas, steam rooms, bathtubs, showers, and pools is a hazardous location where its bottom edge is less than 60 inches above any standing or walking surface, for single glazing and each pane of multiple glazing. Glazing more than 60 inches horizontally from the water's edge of a tub, hot tub, spa, whirlpool, or pool, or from the edge of a shower, sauna, or steam room, is excepted.
Residential Code § r324.4.5
Tempered glass carries a permanent manufacturer's mark. Tempered is marked with removable paper.
Each pane carries the manufacturer's mark for the type and thickness of the glass. That mark may be omitted only where the building official approves and the glazing contractor furnishes an affidavit certifying each light is glazed per the approved construction documents. The manufacturer's permanent mark on tempered glass may be acid-etched, sandblasted, ceramic-fired, laser-etched, embossed, or otherwise permanent. The manufacturer provides the removable paper marking on tempered spandrel glass. Identify safety glazing per Section 2406.3.
On the job
Tempered glass is identified by a permanent mark, not a sticker, and that rule has no affidavit route. The type-and-thickness mark on ordinary glass can be waived by affidavit with the official's approval.
Exact wording
Each pane bears the manufacturer's mark for the type and thickness of the glass. That mark may be omitted only where the building official approves and the glazing contractor furnishes an affidavit certifying each light is glazed per the approved construction documents. Each pane of tempered glass, except tempered spandrel glass, is permanently identified by the manufacturer with a mark that is acid-etched, sandblasted, ceramic-fired, laser-etched, embossed, or otherwise permanent; tempered spandrel glass is provided with a removable paper marking by the manufacturer. Safety glazing is identified per Section 2406.3.
Building Code § 2403.1
Glazing in a hazardous location, mirrors included, must pass the impact test and be permanently marked.
Mirrors, single panes, laminated glass, and panes in multipane assemblies all count, and Section 2406.2 gives the impact test. Plastic glazing, glass block, and louvered windows may meet their own provisions instead. Mirrors and glass panels mounted on a surface that gives continuous backing support are excepted. The designation names who applied it and the standard it meets; a label meeting the same requirements works too. For glazing other than tempered glass, the designation may be waived where the building official accepts a certificate, affidavit, or other evidence of compliance. In a multipane assembly whose individual panes are 1 square foot or less, at least one pane carries the full designation and the others need only be marked CPSC 16 CFR Part 1201 or ANSI Z97.1.
On the job
For ordinary glass, safety glazing is glazing that passed the impact test and is marked as such; tempered glass, which breaks into small granular pieces, is the common product that passes. Section 2406 also gives separate compliant routes for plastic glazing, glass block, and louvered windows, and the marking rule has a certificate route for non-tempered glass and a light-touch rule for small divided lites.
Exact wording
Glazed areas in hazardous locations, including mirrors, single panes, laminated glass, and panes in multipane assemblies, must pass the impact test of Section 2406.2 or meet the plastic-glazing, glass-block, or louvered-window provisions. Mirrors and glass panels mounted on a surface that gives continuous backing support are excepted. Safety glazing in hazardous locations carries a permanent manufacturer's designation naming who applied it and the standard it meets, or a label meeting the same requirements. For glazing other than tempered glass, the designation may be waived where the building official accepts a certificate, affidavit, or other evidence of compliance. In a multipane assembly whose individual panes are 1 square foot or less, at least one pane carries the full designation and the others need only be marked CPSC 16 CFR Part 1201 or ANSI Z97.1.
Building Code § 2406
Take away
10 rules · 4 minMillwork, trim, and cabinets
The astragal laps the joint where a pair of doors meet.
An astragal is the vertical molding fastened to the edge of one leaf of a pair of doors, so it laps the joint where the two leaves meet. It closes the gap and carries weatherstripping or smoke seals. A mullion is a frame member between openings, a muntin divides glass within a sash, and casing trims the frame-to-wall joint.
On the job
The exam names the molding at the meeting edge of paired doors. Astragal, not mullion.
Exact wording
An astragal is the vertical molding fastened to the edge of one leaf of a pair of doors so it laps the joint where the two leaves meet; it closes the gap and carries weatherstripping or smoke seals. A mullion is a frame member between openings, a muntin divides glass within a sash, and casing trims the frame-to-wall joint.
Standard trade practice
A filler closes the gap between a cabinet and the wall or the next cabinet.
A filler is a strip of matching finished stock, ripped to width, that gives doors and drawer fronts room to open fully. A stile is a face-frame member, a cleat carries weight, and a mullion divides an opening.
On the job
The exam names the piece that gains door clearance at the end of a run: the filler.
Exact wording
A filler is a strip of matching finished stock, ripped to width, set between a cabinet and a wall or between two cabinets so doors and drawer fronts can open fully. A stile is a face-frame member, a cleat carries weight, and a mullion divides an opening.
Standard trade practice
A lipped cabinet door is rabbeted around its back edge.
The rabbet is a stepped cut along the back edge, so part of the door thickness drops into the face-frame opening while the rest laps onto the frame. An inset door sits entirely inside the opening and flush. Overlay doors, full or partial, are flat on the back and sit entirely on the frame face.
On the job
The exam names the door type from the rabbet. Lipped is the one that is partly in and partly over the frame.
Exact wording
A lipped cabinet door has a rabbet around its back edge, so part of the door thickness drops into the face-frame opening while the rest laps onto the frame. An inset door sits entirely inside the opening and flush; overlay doors, full or partial, are flat on the back and sit entirely on the frame face.
Standard trade practice
The stop is the strip the door closes against.
The stop limits the door's swing, and it is a narrow strip applied to the face of each jamb — the upright side member of the frame. Casing sits on the wall face, an astragal fastens to one leaf of a meeting pair, and the threshold runs under the door.
On the job
The exam names the strip the door closes against: the stop.
Exact wording
The stop is the narrow strip applied to the face of each jamb that the door shuts against and that limits its swing. Casing is on the wall face, an astragal is on a meeting door leaf, and the threshold is under the door.
Standard trade practice
A rabbet is an L-shaped step cut at the edge or end of a board.
The rabbet's step is open on two sides, leaving a ledge and a shoulder, and it is the standard seat for a cabinet back panel. A dado is a closed channel across the face, a miter is an angled corner cut, and a half-lap removes half the thickness of two overlapping pieces.
On the job
The exam distinguishes rabbet from dado by where the cut is: rabbet at the edge, dado in the face.
Exact wording
A rabbet is an L-shaped step cut along the edge or end of a board, open on two sides, leaving a ledge and a shoulder; it is the standard seat for a cabinet back panel. A dado is a closed channel across the face, a miter is an angled corner cut, and a half-lap removes half the thickness of two overlapping pieces.
Standard trade practice
A dado runs across the grain and a groove runs with it.
A dado is a flat-bottomed rectangular channel cut across the grain in a board's face to house a shelf or partition end. A stopped or blind dado stops before an edge. With the grain it's a groove; at the edge, a rabbet; a mortise takes a tenon.
On the job
The exam distinguishes dado from groove by grain direction, and from rabbet by location. A stopped dado is a subtype, not the definition.
Exact wording
A dado is a flat-bottomed rectangular channel cut across the grain in the face of a board to house the end of a shelf or partition; a stopped or blind dado is the version that ends before reaching an edge. A groove is the same cut running with the grain, a rabbet is at the edge, and a mortise receives a tenon.
Standard trade practice
The stool is the flat horizontal trim capping the rough sill inside a window opening.
The stool is the flat horizontal trim across the bottom of a window opening on the inside; it caps the rough sill, projects past the wall face, and carries the ends of the side casing. The apron is the trim applied flat to the wall under the stool. Casing runs around the opening, and an extension jamb brings the jamb out flush with the wall.
On the job
The exam names the horizontal member that projects into the room: the stool. The apron is the piece under it.
Exact wording
The stool is the flat horizontal trim across the bottom of a window opening on the inside; it caps the rough sill, projects past the wall face, and carries the ends of the side casing. The apron is the trim applied flat to the wall under the stool, casing runs around the opening, and an extension jamb brings the jamb out flush with the wall.
Standard trade practice
The mullion goes between units. The muntin divides the glass inside one sash.
A mullion is the vertical frame member between adjacent window or door units set side by side in one assembly, structural or not. A muntin divides glass within one sash. Stiles are vertical sash or door edges; rails are horizontal.
On the job
The exam tests mullion versus muntin: between units versus within a sash.
Exact wording
A mullion is the vertical member between adjacent window or door units set side by side in one assembly; it is part of the frame, and it may or may not be structural. A muntin divides the glass within one sash, stiles are the vertical edges of a sash or door, and rails are horizontal.
Standard trade practice
Strike your level line for base cabinets from the floor's high point.
A shim only raises a cabinet, so shim the rest up to the level line and the tops finish level for the countertop. Toe-kick exposure varies on an out-of-level floor; cover it with scribe or base. The countertop never slopes with the floor.
On the job
The exam asks what working from the high point accomplishes: every cabinet can be shimmed up to the line.
Exact wording
A run of base cabinets is laid out to a level line struck from the highest point of the floor, because shims can only raise a cabinet; every other cabinet is shimmed up to the line and the tops finish level for the countertop. Toe-kick exposure varies along an out-of-level floor and is covered by scribe or base; the countertop is never sloped with the floor.
Standard trade practice
On a prehung door, shim and fasten the hinge jamb before the latch jamb.
The hinge jamb carries the door and controls the swing, so shim it plumb and straight and fasten it at each hinge. Then shim the latch jamb to an even gap along the door edge. If you fasten the head or the latch side first, you fix the geometry before the hinge jamb is plumb.
On the job
The exam tests the sequence: hinge jamb first, then the latch jamb to the reveal.
Exact wording
A prehung door is set by shimming the hinge jamb plumb and straight and fastening it at each hinge first, because that jamb carries the door and controls the swing; the latch jamb is then shimmed to an even gap along the door edge. Fastening the head or the latch side first fixes the geometry before the hinge jamb is plumb.
Standard trade practice
Take away
7 rules · 3 minPainting and wallcovering
Orange peel is a sprayed coating that dried before it flowed out.
Orange peel comes from material too thick, the wrong tip or pressure, or air warm enough to dry the droplets before they level. The film ends up fine, bumpy, and dimpled. Sagging is runs from too much material, blistering is bubbles lifting the film, and alligatoring is a soft coat cracking over a hard one.
On the job
The exam names a defect from its look. Texture that never leveled is orange peel; lifting and cracking are the other names.
Exact wording
Orange peel is a sprayed coating that failed to flow out, leaving a fine bumpy, dimpled film; it comes from material too thick, the wrong tip or pressure, or air warm enough to dry the droplets before they level. Sagging is runs from too much material, blistering is bubbles lifting the film, and alligatoring is cracking of a soft coat over a hard one.
Standard trade practice
Prime new gypsum board with a primer-sealer over its entire surface before finish paint.
Face paper and dried joint compound absorb paint at different rates. Sealing the whole surface evens the suction, so the finish dries to one sheen and the joints do not flash. Spot-priming the joints or thinning the finish paint as a first coat leaves two absorption rates.
On the job
The exam asks both what to do first and why: whole-wall primer-sealer, because of suction. The distractors prime only the joints or skip the primer.
Exact wording
New gypsum board gets a primer-sealer over its entire surface before finish paint. Face paper and dried joint compound absorb paint at different rates; sealing the whole wall evens that suction so the finish dries to one sheen and the joints do not flash. Spot-priming the joints or thinning the finish paint as a first coat leaves two absorption rates on the wall.
Standard trade practice
Sand sound gloss enamel dull before you prime it.
To recoat sound, well-bonded gloss enamel on trim, sand the gloss dull, remove the dust, prime, then topcoat. Priming an unsanded gloss film, thinning the first finish coat, or sanding after the first coat all give the new paint nothing to grip.
On the job
The exam tests the order: de-gloss, dust, prime, paint. Primer without a sanded profile is the trap.
Exact wording
To recoat sound, well-bonded gloss enamel on trim, sand it dull, remove the dust, then prime and topcoat. Priming an unsanded gloss film, thinning the first finish coat, or sanding after the first coat gives the new paint nothing to grip.
Standard trade practice
Fresh cement plaster's alkali breaks down the paint binder. Cure, pH-check, or use an alkali-resistant primer.
Fresh portland cement plaster is strongly alkaline, and that alkali attacks the paint binder. Allow a cure period, check the pH, or use an alkali-resistant primer. The plaster is not acidic, and shrinkage or troweling residue is not the mechanism.
On the job
The exam asks why paint peels off green stucco. The answer is alkali attacking the binder, not acid and not shrinkage.
Exact wording
Fresh portland cement plaster is strongly alkaline, and a coating applied before it cures fails because the alkali breaks down the paint binder; the fix is a cure period, a pH check, or an alkali-resistant primer. The plaster is not acidic, and shrinkage or troweling residue is not the failure mechanism.
Standard trade practice
You wash mildew off and rinse it before any primer or paint goes on.
Use a mildew-killing cleaner on a sound exterior paint film, rinse, and let the surface dry before coating. Dry brushing, sealing over it, or relying on a mildewcide paint leaves living growth that bleeds through and lifts the new coating.
On the job
The exam tests that mildew is killed and rinsed off, not painted over. Any answer that coats the growth is wrong.
Exact wording
Mildew on a sound exterior paint film is washed off with a mildew-killing cleaner, rinsed, and allowed to dry before priming or painting. Dry brushing, sealing over it, or relying on a mildewcide paint leaves living growth that bleeds through and lifts the new coating.
Standard trade practice
Hang the first strip of wallcovering to a plumb line struck near the starting corner.
Do not use the corner or a window casing as the reference for the first strip, because corners and casings are seldom plumb. Any lean you start with grows with every strip that follows.
On the job
The exam tests the reference for the first strip: a struck plumb line, never the corner and never the trim.
Exact wording
The first strip of wallcovering is hung to a plumb line struck near the starting corner, not to the corner or a window casing, because corners and casings are seldom plumb and any lean grows with every strip that follows.
Standard trade practice
After you paste a wallcovering strip, book it. Hanging it wet blisters and opens seams.
After pasting an unpasted wallcovering, fold the strip paste side to paste side and let it stand the maker's specified time before hanging. That's booking. It lets the material expand fully so it hangs flat with tight seams.
On the job
The exam asks the next step after pasting: book it. Hanging wet, drying face up, or trimming edges are the distractors.
Exact wording
After paste goes on an unpasted wallcovering, the strip is folded paste side to paste side and left to stand for the maker's specified time before hanging; this is booking, and it lets the material expand to full size so it goes up flat with tight seams. Hanging right away lets the strip keep expanding on the wall, which blisters and opens seams.
Standard trade practice
Take away
8 rules · 3 minFloor covering
Use a reducer strip where two finished floors meet at unequal heights.
The reducer strip is transition molding: it sits on the thicker floor and tapers down to the thinner. A T-molding joins floors of equal height, a seam binder covers a flush joint, and an end cap ends a floor at a wall, track, or hearth.
On the job
The exam names the molding from the two floors it joins. Unequal heights means a reducer.
Exact wording
A reducer strip is the transition molding for two finished floors of unequal height; it sits on the thicker floor and tapers down to the thinner one. A T-molding joins floors of the same height, a seam binder covers a flush joint, and an end cap terminates a floor at a wall, track, or hearth.
Standard trade practice
You acclimate solid strip hardwood so its moisture balances with the room.
Acclimation means opening and stacking the solid strip hardwood in the room where it will be installed, with the heating and cooling running at normal living conditions. Boards that balance with the space show fewer shrinkage gaps and less cupping later. The wait is about moisture, not temperature, bowing, or finish cure.
On the job
The exam asks what acclimation accomplishes. Moisture equilibrium is the answer; the distractors offer temperature, flattening, and finish cure.
Exact wording
Solid strip hardwood is opened and stacked in the room where it will be installed, with the heating and cooling running at normal living conditions, so the boards' moisture content balances with the space and the floor shows fewer shrinkage gaps and less cupping later. The wait is about moisture, not temperature, bowing, or finish cure.
Standard trade practice
Test the slab for moisture before any adhesive goes down on a glue-down floor.
Compare the reading with the limit the flooring and adhesive maker sets. Slab age, damp-mopping, and leveling compound are not substitutes for that test. Leveling compound corrects flatness — it is not a moisture barrier.
On the job
The exam tests that the slab is tested, not assumed dry by age or appearance.
Exact wording
Before adhesive goes down for a glue-down floor on a slab, the slab is tested for moisture and the reading compared with the flooring and adhesive maker's limit. Slab age, damp-mopping, and leveling compound are not substitutes; leveling compound corrects flatness and is not a moisture barrier.
Standard trade practice
Run the in-situ relative humidity test with the building at service temperature and humidity.
Service conditions are the temperature and humidity the building will have in use; hold both before and during the test. Follow the probe manufacturer's F2170 procedure: each sealed test hole equilibrates 24 hours before you record the reading. Drill to 40 percent of the slab thickness for a slab drying from one side, not to a fixed inch.
On the job
The exam asks what makes the reading represent the finished floor's conditions: the building at service conditions. Reading within an hour or drilling to a fixed depth are the traps.
Exact wording
An in-situ relative humidity test of a slab is run with the building at its service temperature and humidity before and during the test, and each sealed test hole equilibrates for the required 24 hours before the reading is recorded, following the probe manufacturer's F2170 procedure. Probe depth follows slab thickness, 40 percent of the thickness for a slab drying from one side, not a fixed inch.
Standard trade practice
Patch and sand new plywood underlayment before any glue-down sheet vinyl goes down.
After you fasten new plywood underlayment, fill the panel joints and fastener heads with floor patching compound and sand smooth, because thin sheet flooring telegraphs: every joint and dimple shows through the surface. Adhesive and primer do not level anything.
On the job
The exam asks the next step after the underlayment is fastened: patch and sand the joints and fasteners.
Exact wording
Before glue-down sheet vinyl goes over new plywood underlayment, the panel joints and fastener heads are filled with floor patching compound and sanded smooth, because thin sheet flooring telegraphs every joint and dimple. Adhesive and primer do not level anything.
Standard trade practice
Blind-nail the strip flooring at an angle through the tongue. The groove takes no nail.
After the starter row, blind-nail every row. Drive the fastener at an angle through the top corner of the tongue so the next board's groove hides it. Nailing through the groove blocks the joint. Face-nail only where the blind nailer will not fit, such as the first and last rows, and set and fill those nails.
On the job
The exam tests where the nail goes: at an angle through the tongue, never the groove, and not through the face except at the first and last rows.
Exact wording
Rows of solid strip flooring after the starter row are blind-nailed, with the fastener driven at an angle through the top corner of the tongue so the next board's groove hides it. Nailing through the groove blocks the joint; face nailing is used only where the blind nailer will not fit, such as the first and last rows, and those nails are set and filled.
Standard trade practice
A knee kicker will not tension a whole room. Power stretch the carpet.
In a stretch-in job, hook one edge on the tackless strip, then power stretch the carpet across the room and hook the opposite strip. Side edges follow. Trim and tuck after the stretch. A knee kicker can't tension a full room; use it in closets and for edges.
On the job
The exam asks the next step after one edge is hooked: power stretch to the far wall. Trimming first or using a knee kicker across a room is wrong.
Exact wording
In a stretch-in installation, once one edge is hooked on the tackless strip, the carpet is pulled across the room with a power stretcher and hooked on the opposite strip; the side edges follow, and trimming and tucking come after the stretch. A knee kicker cannot develop the tension for a full room and is used in closets and to set edges.
Standard trade practice
Install tackless strip with its pins angled toward the wall.
Tackless strip is thin wood with rows of angled steel pins, fastened around the room perimeter, pins leaning toward the wall; stretched carpet backing hooks on and holds the stretch. A binder bar finishes an exposed edge, seaming tape joins two pieces, a reducer strip is a floor-height transition.
On the job
The exam names the perimeter strip from its pins. The distractors are other carpet accessories with different jobs.
Exact wording
Tackless strip is the thin wood strip with rows of angled steel pins, fastened around the room perimeter with the pins leaning toward the wall; the stretched carpet backing hooks onto the pins and holds the stretch. A binder bar finishes an exposed edge, seaming tape joins two pieces, and a reducer strip is a floor-height transition.
Standard trade practice
Take away
7 rules · 3 minLandscaping and site
Measure a retaining wall's 4-foot permit limit from the bottom of the footing.
No permit is required for a retaining wall 4 feet or less from the bottom of the footing to the top of the wall, unless it supports a or impounds Class I, II, or IIIA liquids. The same exempt list covers one-story detached sheds and playhouses up to 120 square feet, fences other than pool barriers not over 7 feet high, and painting, papering, tiling, carpeting, cabinets, countertops, and similar finish work. Being exempt never lets you build in violation of the code.
On the job
The 4 feet is measured from the bottom of the footing, not from grade; a 3-foot exposed wall on a 2-foot footing needs a permit. Surcharge and impounding Class I, II, or IIIA liquids are the other disqualifiers. Finish work itself — paint, tile, carpet, cabinets — needs no permit, which is the line a finish contractor is asked about.
Exact wording
Among the work exempt from a building permit is a retaining wall not over 4 feet in height, measured from the bottom of the footing to the top of the wall, unless it supports a surcharge or impounds Class I, II, or IIIA liquids. Exemption from a permit does not authorize work in violation of the code. The same list exempts one-story detached sheds and playhouses up to 120 square feet, fences other than pool barriers not over 7 feet high, and painting, papering, tiling, carpeting, cabinets, countertops, and similar finish work.
Building Code § 105.2
You shape a swale into the finish grade instead of laying pipe.
A swale is a wide, shallow depression with a continuous fall, so runoff flows along the surface to an outlet away from the building. A French drain collects subsurface water in a gravel trench, a dry well stores and infiltrates water, and an area drain is a grated inlet to buried pipe.
On the job
The exam names the surface channel formed by grading: the swale.
Exact wording
A swale is a wide, shallow depression graded into the finish grade with a continuous fall so runoff flows along the surface to an outlet away from the building; it is formed by grading rather than by piping. A French drain collects subsurface water in a gravel trench, a dry well stores and infiltrates water, and an area drain is a grated inlet to buried pipe.
Standard trade practice
The French drain is the gravel trench with a perforated pipe in it.
Filter fabric lines the trench of a French drain, washed rock fills it, and the perforated pipe collects water from the surrounding soil and carries it to a lower outlet. The other site drains are different: a dry well stores water to infiltrate, a catch basin is a boxed grated inlet with a sump, and an area drain is a flush surface inlet.
On the job
The exam names the gravel trench with perforated pipe: the French drain.
Exact wording
A French drain is a trench lined with filter fabric, filled with washed rock, and fitted with a perforated pipe that collects water from the surrounding soil and carries it to a lower outlet. A dry well stores water to infiltrate, a catch basin is a boxed grated inlet with a sump, and an area drain is a flush surface inlet.
Standard trade practice
Put rotor heads and fixed spray heads on separate valve zones.
A valve zone is the set of heads one valve runs for one run time. The two head types apply water at very different rates, so one run time overwaters the spray area while it underwaters the rotor area. Thread size, operating pressure, and backflow devices are not the reason.
On the job
The exam asks why the head types are zoned separately: precipitation rate.
Exact wording
Rotor heads and fixed spray heads go on separate valve zones because they apply water at very different rates; on one valve with one run time, the spray area is overwatered while the rotor area is underwatered. Thread sizes, operating pressure, and backflow devices are not the reason.
Standard trade practice
You flush new irrigation laterals with the risers open after the solvent cement cures.
Run water through until the shavings, dirt, and cement squeeze-out blow out of the open risers. Install the heads only after the lines run clean. Flushing and testing both come before you backfill the trenches.
On the job
The exam asks the next step after the glue cures: flush with the risers open, then install heads.
Exact wording
After the solvent cement cures on new irrigation laterals and risers, the lines are flushed with the risers open so shavings, dirt, and cement squeeze-out blow out, and the heads go on only after the lines run clean; flushing and testing come before backfill.
Standard trade practice
Set a container-grown tree so its root flare sits at or slightly above finish grade.
The root flare is the topmost structural roots. Find it and remove any excess nursery soil above it. The top of the root ball sits at finish grade only when the flare is at the top of the ball. Backfill around the ball, not over the trunk. A sunken ball holds water against the trunk and buries roots; a ball well above grade dries out.
On the job
The exam's usual answer is root ball top level with finish grade; the stipulation that makes it right is that the flare is at the top of the ball. Buried flare is the failure the rule prevents.
Exact wording
A container-grown tree is set with its root flare, the topmost structural roots, at or slightly above the surrounding finish grade; find the flare first and remove any excess nursery soil above it, so the top of the root ball is at grade only when the flare is at the top of the ball. Backfill goes around the ball, not over the trunk. A sunken ball holds water against the trunk and buries roots; a ball well above grade dries out.
Standard trade practice
Place drain rock against a segmental block retaining wall before any native soil.
The rock zone is the free-draining rock the wall design and the manufacturer call for. Add a perforated drain line at the base where the design requires one. Trapped water tips most low walls over. Filter fabric alone gives water no path out, a waterproofing coat holds water in, and grouted cores block drainage.
On the job
The exam asks what goes behind the wall first: drain rock and a drain line, before any soil.
Exact wording
Before native soil is backfilled behind a segmental block retaining wall, the free-draining rock zone the wall design and manufacturer call for is placed against the blocks, with the perforated drain line at the base where the design requires one; trapped water is what tips most low walls over. Filter fabric alone gives water no path out, a waterproofing coat holds water in, and grouted cores block drainage.
Standard trade practice
Take away
7 rules · 3 minFinish arithmetic
To order paint, multiply net area by coats and divide by coverage per gallon. Round up.
Net area is the wall area minus the openings. Any fraction of a gallon means one more gallon. Example: 2,300 net square feet, two coats at 350 square feet per gallon, is 13.1 — order 14 gallons.
On the job
Deduct the openings, multiply by coats, divide by the spread rate, round up.
Exact wording
Gallons equal net area times coats divided by the coverage per gallon, rounded up, where net area is the wall area minus openings. Example: 2,300 net square feet, two coats at 350 square feet per gallon, is 13.1, order 14 gallons.
Standard trade practice
Count both the walls and the ceiling for drywall. The openings usually stay in.
Add the wall area and the ceiling area, divide by the drywall sheet area, multiply by (1 + waste percent), then round up. Usually you leave openings in that area, because the cutouts around them are waste. Example: a 12-by-14 room 8 feet high is 416 + 168 = 584 square feet; ÷ 32 = 18.25; with 10 percent waste, 20.1, so order 21 sheets.
On the job
Walls and ceiling both count, and the openings stay in. The exam pairs this with paint, where openings come out.
Exact wording
Drywall sheets equal wall area plus ceiling area, divided by the sheet area, times (1 + waste percent), rounded up; openings are usually not deducted because the cutouts are waste. Example: a 12-by-14 room 8 feet high is 416 + 168 = 584 square feet; ÷ 32 = 18.25; with 10 percent waste, 20.1, order 21.
Standard trade practice
Add waste to the net tile area before you divide by a box's coverage.
Waste is the extra tile for cuts and breakage, added as a percent: net area times (1 + waste percent). Divide that by the coverage per box, then round up to whole boxes. Example: 180 square feet at 10 percent waste is 198; at 12 square feet a box, 16.5, order 17.
On the job
Waste first, then divide by the box, then round up.
Exact wording
Tile boxes equal net area times (1 + waste percent), divided by the coverage per box, rounded up to whole boxes. Example: 180 square feet at 10 percent waste is 198; at 12 square feet a box, 16.5, order 17.
Standard trade practice
You buy carpet by the and one square yard covers nine square feet.
You order carpet by the square yard, so divide the room's square feet by 9 and the answer is your yardage: a 12-by-15-foot room is 180 square feet, 20 square yards.
On the job
Nine square feet to the square yard.
Exact wording
Carpet is figured in square yards: square feet divided by 9. Example: a 12-by-15-foot room is 180 square feet, 20 square yards.
Standard trade practice
When you measure baseboard, subtract the door widths from the room perimeter.
Baseboard linear feet equal the room perimeter minus the width of door openings and other breaks, times (1 + waste percent). Example: a 14-by-16 room with two 3-foot doors and 10 percent waste is (60 − 6) × 1.10 = 59.4, so order 60 feet.
On the job
Perimeter, minus the doors, plus waste.
Exact wording
Baseboard linear feet equal the room perimeter minus the width of door openings and other breaks, times (1 + waste percent). Example: a 14-by-16 room with two 3-foot doors and 10 percent waste is (60 − 6) × 1.10 = 59.4, order 60 feet.
Standard trade practice
For cabinet cost, add the material and labor rates per linear foot, then multiply.
Linear feet are the length of the cabinet run along the wall, and you multiply the combined rate by that length. Example: 22 feet at $310 material and $95 labor is 22 × ($310 + $95) = $8,910.
On the job
Add the two per-foot rates, then multiply by the run.
Exact wording
Cabinet cost equals linear feet times the sum of the material and labor rates per linear foot. Example: 22 feet at $310 material and $95 labor is 22 × ($310 + $95) = $8,910.
Standard trade practice
Round pieces per board down. Round the board count up.
Pieces per board equal the stock length divided by the piece length, dropping any fraction. Boards equal the piece count divided by pieces per board; any leftover pieces mean one more board. A real cut list first reduces the usable stock length by saw kerf and end trim. Ignore them only when the problem says to or the stock leaves enough slack. Example: 14 shelves 34 inches long from 96-inch stock is two per board, seven boards.
On the job
Round down for pieces per board, round up for boards. A real cut list subtracts saw kerf and end trim from the stock length first; ignore kerf only when the stem says to or leaves enough slack.
Exact wording
Pieces per board equal the stock length divided by the piece length, rounded down, with saw kerf and end trim ignored only where the problem says to ignore them or the stock leaves enough slack (a real cut list reduces the usable stock length by kerf and trim first); boards needed equal the piece count divided by pieces per board, rounded up. Example: 14 shelves 34 inches long from 96-inch stock: two per board, seven boards.
Standard trade practice
Take away
Important numbers to know
Where people go wrong
Sounds right: "Moisture-resistant (green board) drywall is fine behind tub or shower tile."
Where’s the catch?
Sounds right: "Any door will do as the egress door."
Where’s the catch?
Sounds right: "The 4-foot retaining wall exemption is measured from grade."
Where’s the catch?
Sounds right: "Glass beside a door only needs safety glazing if it touches the door."
Where’s the catch?
Sounds right: "Tempered glass is labeled with a sticker."
Where’s the catch?
Sounds right: "Deduct the openings for drywall the way you do for paint."
Where’s the catch?
Where to look it up
- Tile backers and wet-area finishes
- CRC R702.4.2 and Table R702.4.2; R327.2
- Garage separation
- CRC R302.6 and Table R302.6 for a dwelling's own garage or carport; R302.3.6 and Table R302.3.6 for a garage shared between units
- Firestopping penetrations in rated walls
- CBC 714.4.1.2
- Suspended ceilings
- CBC 808.1.1.1 (ASTM C635 and C636)
- Flashing
- CRC R703.4 (openings: R703.4.1)
- Egress door and replacement egress windows
- CRC R318.2; R319.5
- Safety glazing locations and identification
- CRC R324.4; CBC 2403.1 and 2406
- Permit exemptions (retaining walls, fences, sheds)
- CBC 105.2
Glossary
Every term this guide defines, in one place. Each is also defined where it first appears.
- Backer board
- A cement, fiber-cement, or glass-mat gypsum panel behind tile in wet areas; the code's table names the acceptable types.
- F rating
- The hours a firestop system resists flame passage in its test; it must be at least the rating of the wall it penetrates.
- Shingle fashion
- Each flashing piece laps over the one below it so water runs out, never behind.
- Spandrel glass
- Opaque glass used to hide floor edges and structure in a glazed wall; tempered spandrel glass gets a removable paper mark instead of a permanent one.
- Square yard
- Nine square feet; carpet is bought by it.
- Surcharge
- A load behind a retaining wall beyond the soil itself, such as a slope, a footing, or a driveway; it removes the permit exemption.
- Through-penetration firestop system
- A tested assembly (ASTM E814 or UL 1479) that restores a rated wall where a pipe or duct passes through.
Keep going
- Practice questions for General Building (B) — Finish Trades is 20% of the exam.
- Job scenario: The Hall Bath Gut
- Also in Finish Trades: Finish Trades: Where the Job Gets Judged
- Every number on one page — this guide’s figures alongside every other General Building (B) guide’s.
Test yourself: 17 questions for this guide
A paid account adds more ways to practice and prepare: study questions after every chapter, practice questions for every topic, timed practice exams, and job scenarios drawn from real jobs. A free account gets you one timed practice exam and saves your progress across devices. Here is one of this guide's questions:
What goes behind the tile on a tub or shower wall?
AnswerA backer from Table R702.4.2: glass-mat gypsum, fiber-reinforced gypsum, fiber-cement, or cementitious backer units, installed per the manufacturer.
Residential Code § r702.4.2
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