NRCA ProCertified Slate Systems Installer

According to ASTM C406, which slate grade has the longest service-life expectancy?

• AGrade S1 (75-200 years)
• BGrade S2 (40-75 years)
• CGrade S3 (20-40 years)
• DGrade S4 (10-20 years)

Which standard establishes the physical property requirements (water absorption, modulus of rupture, depth of softening) for roofing slate?

• AASTM C406
• BASTM D1970
• CASTM D226
• DASTM C1167

Which U.S. region is historically the largest commercial source of Grade S1 roofing slate?

• AVermont and eastern New York (slate valley)
• BWestern Texas and New Mexico
• CFlorida Panhandle
• DNorthern Minnesota

What is the typical minimum headlap for slate roofing on slopes of 8:12 or greater in moderate climates?

• A3 inches
• B1 inch
• C6 inches
• D12 inches

If a slate is 20 inches long and the required headlap is 3 inches, what is the correct exposure?

• A8.5 inches
• B10 inches
• C7 inches
• D12 inches

Which fastener material is preferred for nailing natural slate roofing?

• ACopper or stainless steel slating nails
• BElectro-galvanized common nails
• CAluminum roofing nails
• DBright (uncoated) steel nails

How many nails are used per standard field slate?

• ATwo nails, one in each pre-punched hole near the head
• BOne nail through the center
• CFour nails, one at each corner
• DThree nails — two at the head and one at the tail

How tightly should a slating nail be driven?

• AJust snug — head flush with the slate, not compressing or biting into it
• BSet 1/8 inch below the slate surface using a nail set
• CHammered tight enough to dimple the slate face slightly
• DDriven until the head crushes into the slate to lock it

Which substrate is required beneath a natural slate roof?

• ASolid wood sheathing (typically minimum 3/4-inch boards or 5/8-inch plywood)
• BSpaced 1x4 wood lath only
• CSteel battens at 16 inches on center
• DOpen framing with no decking, slate nailed directly to rafters

What is the preferred valley construction for a natural slate roof?

• AOpen valley with metal flashing (typically copper or stainless steel)
• BClosed-cut valley with the slate woven through
• CCalifornia valley (woven) with shingle overlap
• DClosed valley using only roofing cement

What minimum weight of copper is typically specified for valley flashing under a slate roof?

• A16 oz/sq ft (cold-rolled copper)
• B8 oz/sq ft
• C4 oz/sq ft
• D32 oz/sq ft minimum, no lighter weights allowed

Why must step flashings be used at the intersection of a slate roof and a vertical wall (rather than a single continuous flashing)?

• AStep flashings provide individual lapped pieces for each course, allowing water to drain…
• BStep flashings are required only for aesthetic uniformity with adjacent walls
• CStep flashings prevent ice damming by adding mass to the wall
• DA continuous flashing is acceptable and step flashings are optional

What is the typical minimum vertical leg height for step flashings against a wall on a slate roof?

• AAt least 4 inches up the wall and 4 inches onto the roof
• B1 inch up the wall and 1 inch onto the roof
• C12 inches up the wall and 2 inches onto the roof
• DEqual to the slate thickness, no more

A chimney is 36 inches wide measured across the roof slope. What detail must be added to the up-slope side?

• AA cricket (saddle) to divert water around the chimney
• BAn additional layer of slate behind the chimney
• CA horizontal counter-flashing only, no cricket needed
• DRoofing cement filling the gap behind the chimney

What is the role of counter-flashing at a chimney or wall intersection?

• AIt is reglet-set into the masonry and laps over the step flashings to shed water away fro…
• BIt is the primary water barrier and replaces the step flashings
• CIt is purely decorative and serves no waterproofing function
• DIt is installed beneath the step flashings to anchor them

Which ridge construction style uses two rows of slates butted at the peak with a butt joint covered by sealant or a separate cap?

• ASaddle ridge
• BComb ridge
• CStrip ridge
• DInverted hip

Which OSHA standard governs fall protection on roofing work above 6 feet?

• A29 CFR 1926.501
• B29 CFR 1910.140
• C29 CFR 1926.1153
• D29 CFR 1926.100

Under OSHA 29 CFR 1926.502, what is the minimum tensile breaking strength of an anchor point for a personal fall arrest system?

• A5,000 lb per worker, or designed by a qualified person to a 2:1 safety factor
• B500 lb per worker
• C1,000 lb per worker
• D10,000 lb per worker, no exceptions

Which OSHA standard requires fall-protection training for each employee who might be exposed to fall hazards?

• A29 CFR 1926.503
• B29 CFR 1926.451
• C29 CFR 1926.1051
• D29 CFR 1926.95

Why are copper or stainless steel nails preferred over galvanized nails when fastening slate near copper flashings?

• AMixing zinc (galvanized) and copper creates galvanic corrosion that destroys the zinc and…
• BGalvanized nails are physically too short to penetrate the deck adequately
• CGalvanized nails are softer than copper and bend during driving
• DGalvanized nails cost more than copper, making them economically inferior

What is the purpose of a slate hook (also called a bib hook or single hook)?

• AIt is a metal hook driven into the deck that holds a replacement slate without re-nailing…
• BIt is a roof rake attachment for snow removal
• CIt is a synonym for a ridge anchor used for fall arrest
• DIt is a clip used at every slate during initial installation

When replacing a broken slate, what is the first step?

• AUse a slate ripper to cut the nails of the broken slate and slide it out
• BPry the slate up from the eave with a flat bar
• CCut the surrounding slates with a saw to gain access
• DDrill through the slate above and remove it first

What is the recommended minimum slope (rise:run) for a natural slate roof installed with standard headlap?

• A4:12 (33%)
• B1:12 (8%)
• C2:12 (17%)
• D12:12 (100%)

On a roof slope between 4:12 and 8:12, NRCA recommends what headlap?

• A4 inches
• B2 inches
• C1 inch
• D8 inches

Why must each slate have a side lap (offset) from the slate below?

• ATo prevent water from tracking straight down the side joints into the underlayment
• BTo make the roof look more uniform from the ground
• CTo allow easier replacement of damaged slates
• DTo reduce the total number of slates used per square

What is the minimum side lap recommended by NRCA between vertical joints of adjacent slate courses?

• A3 inches
• B0 inches (joints can align)
• C1/2 inch
• D12 inches

What is a 'starter course' on a slate roof?

• AThe first course of slate laid at the eave, installed face-down beneath the first visible…
• BA row of metal flashing at the eave that replaces the first slate course
• CThe ridge course laid first to establish a layout reference
• DA practice course used only during apprentice training

What is the typical projection of the first slate course beyond the fascia at the eave?

• A1.5 to 2 inches into the gutter
• B0 inches — flush with the fascia
• C6 inches beyond the fascia
• DEqual to the slate length

Which underlayment is most commonly specified beneath natural slate in cold climates?

• A30-lb asphalt felt (or heavier) with self-adhered ice-and-water shield (ASTM D1970) at ea…
• BSingle layer of 15-lb felt only
• CSynthetic underlayment alone with no eave protection
• DPolyethylene vapor barrier only

How far up the slope should ice-and-water shield extend at the eave in a snow-load region?

• AAt least 24 inches inside the warm wall line of the building
• BOnly to the edge of the fascia
• CTo the ridge — across the entire roof
• DExactly 12 inches up the slope from the eave

What is the approximate dead load of a typical 1/4-inch standard natural slate roof?

• A7-10 psf
• B2-3 psf
• C20-25 psf
• DLess than 1 psf

Before re-roofing an existing wood-framed home with natural slate, what is the most important pre-construction step?

• AHave a structural engineer verify the framing can support the added dead load
• BOrder slate matching the existing color from the same quarry only
• CConfirm gutter capacity is adequate
• DStrip the existing roof and immediately begin installation

Which is NOT a recognized commercial source of natural roofing slate in the United States?

• ANevada (Las Vegas region)
• BVermont
• CVirginia (Buckingham County)
• DPennsylvania (Peach Bottom area)

Imported slate from which country is most commonly used in U.S. residential slate roofing today?

• ASpain (especially Galicia)
• BBrazil — exclusively
• CRussia
• DJapan

What is the maximum water absorption permitted for a Grade S1 slate under ASTM C406?

• A0.25%
• B1.0%
• C5.0%
• DNo limit specified

How is the depth-of-softening test under ASTM C406 used?

• AIt measures degradation under acid exposure, reflecting durability in acid rain conditions
• BIt evaluates how quickly slate dries after rainfall
• CIt tests slate flexibility under load
• DIt measures the slate's resistance to UV light

Why is slate from a quarry with high pyrite content often rejected for long-term roofing applications?

• APyrite oxidizes to iron oxide and sulfuric acid, causing rust staining and slate deterior…
• BPyrite increases the slate's weight beyond OSHA worker-handling limits
• CPyrite changes the slate color to white, which clashes with most architecture
• DPyrite is radioactive and a regulated material

Where on a slate are the nail holes pre-punched (or drilled) for installation?

• ANear the head end, with the holes located so the next course's headlap covers them
• BAt the center of the slate
• CAt the bottom edge (tail) of the slate
• DSlate is installed without pre-punched holes — holes are drilled on the roof

Which tool is traditionally used to cut and shape natural slate by hand on the jobsite?

• ASlate cutter (shear-type tool) with stake and slater's hammer
• BWet diamond circular saw exclusively
• CStandard tin snips
• DHacksaw

What is a 'bevel' on a slate, and which side faces up?

• AThe chamfered edge created by snapping the slate from the underside; the bevel side faces…
• BThe bevel is on the head end and faces toward the ridge
• CThe bevel side faces DOWN to seat the slate flat
• DBevels are only used at the rake edge of the roof

On a dormer, how should the slate installed adjacent to the dormer's side wall be detailed?

• AStep flashings against the dormer wall, with counter-flashing or siding lapping over the…
• BContinuous L-flashing only with no step flashings
• CMortar bed at the slate-wall joint
• DCaulk-only seal at the joint

What is the function of a 'collar' or 'apron' flashing?

• AIt is the metal flashing on the down-slope side of a chimney or curb, lapping the slate b…
• BIt is a decorative slate band at the ridge
• CIt is a copper strap that ties two slates together
• DIt is the flashing at the top of a gable wall

Which is the BEST description of NRCA's recommended pipe penetration flashing for a slate roof?

• APre-formed copper or lead flashing with a flange that integrates into the slate courses
• BPlastic boot with rubber gasket — same as asphalt shingle roofs
• CRoofing cement molded around the pipe
• DAluminum step flashing wrapped around the pipe

What is the recommended slope at the bottom of an open valley to prevent water and ice from backing up under the slate?

• AValley should be at least as steep as the field roof slope, with a smooth metal surface
• BValley should be flatter than the field roof to slow water
• CValley should have a center crimp to direct water away from the centerline
• DBoth 'A' and 'C' are correct

What minimum width is typical for an open valley liner on a residential slate roof?

• A20-24 inches total width (8-12 inches each side of the centerline)
• B6 inches total width
• C48 inches total width minimum
• DWidth equal to the slate length

What is the recommended sequence for installing slate at an open valley?

• AInstall valley underlayment, then valley metal, then slate cut to a chalk line offset fro…
• BInstall slate first, then cut the valley after slate is in place
• CLay valley metal on top of the slate course
• DInstall valley last, after the ridge