New Mexico CID GS-30 Plastering, Stucco and Lathing Examination

Using the plaster volume formula cubic yards = area (sq ft) × thickness (in.) ÷ 324, how many cubic yards of plaster are required for 1,000 sq ft of three-coat stucco at a 7/8 in. nominal thickness, before waste?

• A1.54 cubic yards
• B3.09 cubic yards
• C2.70 cubic yards
• D8.75 cubic yards

A framed wall takeoff is 2,400 sq ft of three-coat portland cement plaster at 7/8 in. nominal thickness. Add 10 percent waste. How many cubic yards should be ordered?

• A6.48 cubic yards
• B8.15 cubic yards
• C5.19 cubic yards
• D7.13 cubic yards

Estimate two-coat cement plaster for 800 sq ft of CMU wall at the ASTM C926 two-coat masonry total of 1/2 in. Add 8 percent waste. How many cubic yards are required?

• A1.23 cubic yards
• B2.16 cubic yards
• C0.99 cubic yards
• D1.33 cubic yards

A standard expanded-metal lath sheet is 27 in. by 96 in. How many square feet does one sheet cover, and how many sheets are required for 540 sq ft before waste?

• A16 sq ft per sheet; 34 sheets
• B18 sq ft per sheet; 30 sheets
• C24 sq ft per sheet; 23 sheets
• D27 sq ft per sheet; 20 sheets

Order 27 in. by 96 in. expanded-metal lath for 1,620 sq ft of wall. Add 10 percent for laps and waste. How many sheets should be purchased?

• A90 sheets
• B81 sheets
• C99 sheets
• D108 sheets

A 48 ft by 10 ft framed wall receives 7/8 in. three-coat stucco. Deduct one 6 ft by 8 ft door and one 4 ft by 5 ft window, then add 10 percent waste. How many cubic yards of plaster should be ordered?

• A1.11 cubic yards
• B1.43 cubic yards
• C1.22 cubic yards
• D1.60 cubic yards

An exterior cement-plaster panel is 12 ft long by 10 ft high with no openings and continuous framing. Under ASTM C1063 wall limits, are intermediate control joints required in the field of this panel?

• AYes, because any wall over 100 sq ft needs a joint
• BYes, because the long dimension exceeds 8 ft
• CNo; 120 sq ft is under 144 sq ft, 12 ft is under 18 ft, and the length-to-width ratio is…
• DYes; every framed wall must be jointed at mid-height

A 20 ft long by 10 ft high exterior stucco wall has no openings. Which control-joint layout satisfies ASTM C1063 wall-panel limits?

• ANo field joint; 200 sq ft is still under the ceiling limit of 100 sq ft
• BOnly a horizontal joint at 5 ft, leaving a 20 ft edge
• CJoints at 4 ft on center both ways regardless of area
• DOne vertical control joint near mid-length, making two panels of about 10 ft by 10 ft

A 36 ft long by 12 ft high exterior stucco wall has no openings. Using ASTM C1063 limits of 144 sq ft and 18 ft, how many vertical field control joints are required and what is their combined length?

• AOne joint totaling 12 linear feet
• BNo field joints; 144 sq ft is only a recommendation
• CThree joints totaling 36 linear feet
• DTwo joints totaling 24 linear feet

A rectangular building is 40 ft by 28 ft in plan. All four exterior stud walls receive three-coat stucco and a continuous foundation weep screed. Ignoring door openings, how many linear feet of weep screed are required?

• A136 linear feet
• B112 linear feet
• C68 linear feet
• D1,120 linear feet

A morning temperature of 28°F has left frost on a masonry wall scheduled for a cement-plaster scratch coat. What should the contractor do?

• AApply plaster immediately so hydration heat melts the frost
• BDo not apply plaster to the frozen or frost-covered surface
• CAdd gypsum gauging plaster so the mix sets before it freezes
• DDouble the sand content and ignore the frost

Where must a foundation weep screed be placed on an exterior stud wall receiving portland cement plaster?

• AFlush with finished grade so the plaster can be buried for a clean look
• BNot less than 12 in. above earth and 8 in. above pavement
• CNot less than 4 in. above earth or 2 in. above paved areas
• DAt the midpoint of the first stud bay, regardless of grade

Before applying portland cement plaster directly to cast-in-place concrete, what surface condition must be corrected first?

• AThe wall must be painted with interior latex to seal suction
• BA polyethylene sheet must be glued over the concrete
• CForm-release oil, laitance, and other bond breakers must be removed
• DThe concrete must be left frozen so the plaster sets more slowly

What is the purpose of a dash-bond coat on masonry or concrete that will receive cement plaster?

• ATo color the finish coat before the brown coat is applied
• BTo replace the water-resistive barrier on wood-framed walls
• CTo create a rough, cement-rich mechanical key for the following plaster coat
• DTo serve as the finish coat on interior gypsum plaster

A CMU wall has high suction and dries a test dash of plaster in seconds. What is the correct preparation before the scratch coat?

• AApply plaster to the bone-dry wall so the masonry can steal water and speed the set
• BFlood the wall until water runs down and puddles at the base
• CSeal the block with oil-based primer to stop all suction
• DDampen the masonry uniformly so it is surface-moist but without standing water

A smooth, dense concrete wall has low suction and will receive two-coat cement plaster without metal lath. What preparation is most appropriate after cleaning?

• ASaturate the wall so water stands on the surface when plaster is applied
• BPrime the wall with oil-based enamel
• CApply an approved plaster bonding agent and follow the manufacturer's open time
• DSkip preparation because dense concrete already provides a mechanical key

On a wood-sheathed exterior wall in a dry (B) climate zone that will receive three-coat portland cement plaster, what water-resistive barrier arrangement does the 2021 IBC require?

• ANo barrier is required if self-furring lath is used
• BA single layer of 4-mil polyethylene stapled over the studs
• CTwo layers of 10-minute Grade D paper installed independently, or an approved equivalent…
• DOne layer of asphalt-saturated felt placed over the metal lath

How should the water-resistive barrier and metal lath meet a foundation weep screed?

• AThe barrier stops 6 in. above the screed so plaster can bond to bare sheathing
• BThe lath is held 2 in. above the screed to create a drip gap
• CThe barrier laps the attachment flange, and the lath covers and terminates on that flange
• DBoth the barrier and the lath are tucked behind the foundation plate

Unless the work is enclosed and heated, portland cement plaster should be applied only when the ambient temperature is:

• AAt least 20°F if calcium chloride is added to the mix
• BAny temperature as long as the mix water is hot
• CHigher than 40°F, with the plaster protected so it stays above 40°F during application an…
• DBelow 40°F so the plaster will not dry too quickly

In plastering, what is the function of grounds?

• AThey are the sand particles in the finish coat
• BThey are wood or metal strips that establish the finished plaster thickness and a true pl…
• CThey are the vertical control joints at building corners
• DThey are the weep holes in the foundation screed

An existing painted CMU wall will receive new cement plaster. What preparation is required?

• ALeave the paint; it evens suction
• BRemove coatings other than portland cement paint by mechanical means such as sandblasting…
• CCover the paint with 4-mil polyethylene and lath
• DWash the paint with soapy water and plaster while it is still slick

New concrete masonry that will receive cement plaster should be specified with which joint and surface condition?

• ADeeply raked joints and a glazed face so plaster cannot key
• BOpen-textured units laid with flush (untooled) joints to promote mechanical bond
• CStruck, ironed joints filled with form oil
• DUnits laid with the face shells buttered only on the back

A plasterer finds standing water on a predampened masonry wall. What should be done before the scratch coat?

• AApply the scratch coat immediately so the extra water improves hydration
• BWait until the surface is damp but free of standing water, then apply plaster
• CAdd extra cement to the mix and plaster through the puddles
• DBroom the water into the block cores and plaster at once

For interior gypsum plastering under the Gypsum Construction Handbook and ASTM C842 practice, what temperature range should be maintained before, during, and after application?

• AA uniform 55°F to about 80°F, held before plastering and during early dry-out
• BAny temperature above freezing if the mix water is heated
• CBelow 40°F so gypsum sets more slowly
• DAbove 100°F to force a rapid set

On a wood-framed stucco wall, when should flashings at windows, decks, and roof-to-wall intersections be in place relative to lath and plaster?

• AAfter the finish coat so the flashing color can be selected to match
• BBefore the water-resistive barrier, lath, and plaster, so water is directed out of the wa…
• COnly after the scratch coat has been moist-cured
• DFlashings are optional if self-furring lath is used

What is the ASTM C926 nominal thickness of three-coat portland cement plaster over metal lath on a vertical wall?

• A5/8 in. total
• B7/8 in. total (3/8 in. scratch, 3/8 in. brown, 1/8 in. finish)
• C1/2 in. total
• D1-1/4 in. total

What is the ASTM C926 nominal thickness of two-coat portland cement plaster applied directly to concrete masonry?

• A3/8 in. first coat plus 1/8 in. finish, for a 1/2 in. total
• B7/8 in. total, same as metal lath
• C1/4 in. total
• D1 in. scratch only, with no finish

What is the ASTM C926 nominal thickness of three-coat portland cement plaster applied directly to concrete masonry?

• A7/8 in. (3/8 + 3/8 + 1/8)
• B1/2 in. (3/8 + 1/8)
• C5/8 in. (1/4 in. first, 1/4 in. second, 1/8 in. finish)
• D1 in. (1/2 + 3/8 + 1/8)

For a portland cement–lime (CL) scratch coat, ASTM C926 / CMHA proportions by volume are approximately:

• A1 part portland cement, 3/4 to 1-1/2 parts lime, and 2-1/2 to 4 parts sand per sum of cem…
• B1 part portland cement and 8 parts gypsum plaster
• C1 part lime and 10 parts water with no sand
• DEqual parts portland cement, gypsum, and clay

Relative to the scratch coat, how much sand should a portland cement brown coat contain?

• ALess sand so the brown coat is richer and stickier
• BNo sand; brown coats are neat cement
• CSand equal to ten times the cement with no lime
• DThe same or a greater quantity of sand than the scratch coat (typically 3 to 5 parts for…

ASTM C1328 plastic (stucco) cement is produced in which types?

• ATypes N, O, and K only
• BTypes S and M
• CType I and Type III portland only
• DGypsum Types A and B

What is the nominal thickness of the portland cement plaster finish coat in ASTM C926 two- and three-coat work?

• A1/2 in.
• B3/8 in.
• C1/8 in.
• D3/4 in.

Why must portland cement plaster and gypsum plaster not be mixed together or applied as succeeding coats on each other unless a standard specifically allows the combination?

• AThe two binders are chemically incompatible; gypsum can cause deterioration of portland c…
• BGypsum makes portland cement plaster too dark
• CThe combination is stronger than either material alone, so codes forbid it as overkill
• DThey set at exactly the same time and cannot be troweled

What minimum expanded-metal lath weights does ASTM C1063 commonly require for portland cement plaster?

• A1.0 lb/yd² on walls and ceilings
• B2.5 lb/yd² on vertical surfaces and 3.4 lb/yd² on horizontal (soffit/ceiling) surfaces
• C6.0 lb/yd² on all surfaces
• DPaper-backed gypsum lath of any weight

What furring depth is built into self-furring metal lath used over solid sheathing or masonry?

• A1/16 in. dimples, which are only decorative
• B1/4 in. self-furring dimples or crimps so plaster can encapsulate the lath
• C1 in. hat channels factory-welded to every sheet
• DNo furring; self-furring lath is nailed flat to the substrate

Job-mixed portland cement plaster proportions in ASTM C926 are measured how?

• ABy weight of damp sand only
• BBy volume, with sand measured per the sum of the cementitious materials
• CBy shovel count with no need to check volume
• DBy the number of trowels of water in the mixer

A job-mixed portland cement–lime finish (Type F) is proportioned by volume approximately as:

• A1 part portland cement, 3/4 to 1-1/2 parts lime, and 1-1/2 to 3 parts sand
• B1 part portland cement and 8 parts sand with no lime
• C1 part gypsum and 1 part clay
• DNeat white cement with no aggregate

What is the preferred sequence for charging a plaster mixer?

• AWater first, then about half the sand, then cementitious materials, then the remaining sa…
• BAll dry materials dumped at once with no water until the last 10 seconds
• CCement first, then all the sand, then water last
• DLime putty only, with sand added on the wall

Sand used in job-mixed portland cement base-coat plaster should generally:

• APass a No. 4 sieve (nothing retained on No. 4) and meet the well-graded limits used with…
• BBe uniformly coarse gravel retained on a 3/8 in. sieve
• CContain clay loam for extra plasticity
• DBe beach sand with salt still in it

Interior full-thickness gypsum plaster is specified under which standard, and where may it be used?

• AASTM C926, on exterior stucco walls in any climate
• BASTM C842, for interior gypsum plaster on gypsum, metal, masonry, or concrete bases
• CASTM C1397, as the Class PB EIFS finish
• DASTM C1328, as plastic cement for exterior work

Portland cement used in job-mixed stucco should comply with which specification?

• AASTM C150 or an equivalent hydraulic cement listed by ASTM C926 (such as C595 blended cem…
• BASTM C36 for gypsum wallboard only
• CASTM D226 for asphalt-saturated felt
• DASTM C1396 for gypsum board

Masonry cement used in a C926 Type M plaster mix must comply with which specification and types?

• AASTM C91 masonry cement, Types N, S, or M as selected for the mix table
• BASTM C33 concrete aggregate only
• CASTM C216 facing brick
• DASTM C90 loadbearing CMU

Welded-wire or woven-wire plaster lath used with portland cement plaster must be:

• APainted black iron with no corrosion protection
• BCorrosion-resistant (typically galvanized) and installed to ASTM C1063 support, lap, and…
• CAluminum insect screen stapled to the sheathing
• DFiberglass window screen with 1/16 in. openings

What is the correct coat sequence for three-coat portland cement plaster over metal lath?

• AFinish, then brown, then scratch
• BScratch, then brown, then finish
• CBrown only, applied in one pass to 7/8 in.
• DFinish coat directly on the lath, then paint

How should a portland cement scratch coat be treated before the brown coat?

• ATrowel it glass-smooth so the brown coat slides
• BPaint it with oil-based enamel
• CCover it with polyethylene and leave it sealed until the finish coat
• DScore or scratch it horizontally to provide a mechanical key for the brown coat

What is the nominal scratch-coat thickness over metal lath in a three-coat portland cement plaster system?

• A1/16 in.
• B1/8 in.
• C3/8 in.
• D3/4 in.

After the brown coat is applied over metal lath, what combined base-coat thickness should exist before the finish?

• A3/8 in.
• B1/2 in.
• C3/4 in. (3/8 in. scratch plus 3/8 in. brown)
• D1-1/2 in.