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CA C-39 Roofing Contractor study materials
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CA C-39 Roofing Contractor practice questions

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Question 1Roofing Systems, Materials, and Installation Methods

One roofing square, the standard unit for measuring roof area, is equal to what area?

  1. 1,000 square feet
  2. 120 square feet
  3. 100 square feet Correct answer.
  4. 10 square feet

Explanation

Roofing materials are ordered by the square, which is defined as 100 square feet of finished roof surface. A 20-square roof therefore covers 2,000 square feet. Bidding and material takeoffs are always converted to squares before ordering.

Question 2Roofing Systems, Materials, and Installation Methods

At the eaves of an asphalt shingle roof, how is the metal drip edge related to the underlayment?

  1. The drip edge is placed under the underlayment.
  2. No drip edge is used when an ice barrier membrane is present.
  3. The drip edge is placed over the underlayment. Correct answer.
  4. The underlayment is turned back 12 inches from the eave.

Explanation

At eaves the drip edge is applied over the underlayment so water draining off the underlayment passes onto the metal and away from the fascia. At rake edges the sequence reverses, with the underlayment lapping over the drip edge. The ice barrier does not eliminate the drip edge.

Question 3Roofing Systems, Materials, and Installation Methods

Which roof component is installed along the eaves specifically to keep water backed up by ice from getting under the shingles?

  1. Rake trim
  2. Ridge vent
  3. Valley flashing
  4. Ice dam protection membrane Correct answer.

Explanation

A self-adhering ice dam protection membrane bonds to the deck and seals around fasteners so that water backed up behind an ice dam cannot reach the deck or the interior. It is applied along the eave edge before the underlayment and shingles. Ridge vents and valley flashing perform unrelated functions.

Question 4Roofing Systems, Materials, and Installation Methods

What is the primary purpose of a ridge cap on a shingled roof?

  1. To support the ridge board
  2. To anchor the top course of shingles
  3. To exhaust attic air
  4. To cover the junction where two roof planes meet Correct answer.

Explanation

The ridge is the intersection of two sloping planes and cannot be covered by field shingles alone, so a cap product is bent and lapped over the joint to shed water. Ridge caps are not structural and do not provide ventilation unless a vented cap is selected for that purpose.

Question 5Roofing Systems, Materials, and Installation Methods

How are fasteners for asphalt strip shingles to be driven?

  1. Flush with the shingle surface without cutting into it Correct answer.
  2. Until the head is about 1/8 inch below the surface
  3. Left protruding about 1/4 inch to allow movement
  4. Angled up through the exposed butt edge

Explanation

The nail head should bear on the shingle surface without being driven through it. Overdriving cuts the shingle and leaves a path for water; underdriving leaves the head proud where it can be damaged or lift the course above. Fasteners are driven perpendicular to the deck.

Question 6Roofing Systems, Materials, and Installation Methods

In a normal wind zone, how many fasteners are typically required per standard three-tab shingle?

  1. Four Correct answer.
  2. Eight
  3. Six
  4. Two

Explanation

Manufacturers require four fasteners per three-tab shingle in ordinary wind areas, placed on the nailing line. In high-wind areas the count is increased to six, with the extra nails set closer to the ends. Two nails cannot hold the corners down.

Question 7Roofing Systems, Materials, and Installation Methods

Roof slope is stated as which of the following?

  1. Inches of rise per foot of rafter length
  2. Degrees of arc per foot of run
  3. Inches of rise per 12 inches of horizontal run Correct answer.
  4. The ratio of ridge height to building width

Explanation

Roof slope is the ratio of vertical rise to horizontal run, expressed over a constant 12-inch run, so a 6:12 roof rises 6 inches for every 12 inches of horizontal travel. Rafter length includes the hypotenuse and is not the run. Slope determines the material systems permitted.

Question 8Roofing Systems, Materials, and Installation Methods

What is the main function of underlayment beneath asphalt shingles?

  1. To bond the shingles to the deck
  2. To act as a secondary barrier against water intrusion Correct answer.
  3. To provide the finished weather surface
  4. To stiffen the roof deck

Explanation

Underlayment is a secondary weather barrier that protects the deck and interior while shingles are being installed and if wind-driven or backed-up water gets past the shingles. It does not add structural stiffness and shingles are not bonded to it. Shingles remain the primary roof covering.

Question 9Roofing Systems, Materials, and Installation Methods

For asphalt shingles on roof slopes between 2:12 and 4:12, what underlayment application is required?

  1. Double underlayment lapped 19 inches at the head Correct answer.
  2. A single layer of No. 15 felt lapped 2 inches
  3. No underlayment where the ice barrier spans the full roof
  4. One layer applied only along the ridge

Explanation

On slopes from 2:12 up to 4:12 the code requires two layers of underlayment applied shingle-fashion with head laps of about 19 inches. The reduced slope slows drainage and raises the risk of water working laterally under the shingles. Above 4:12 a single layer with standard laps is acceptable.

Question 10Roofing Systems, Materials, and Installation Methods

A self-adhering ice barrier membrane at the eaves must extend from the eave edge to a point at least how far?

  1. 6 inches past the exterior wall line
  2. 12 inches past the ridge line
  3. The full length of the rake edge
  4. 24 inches inside the interior warm wall line Correct answer.

Explanation

The membrane must reach at least 24 inches inside the warm interior wall line so that any ice-dam back-up is stopped before it reaches a plane above the heated space. A shorter strip can allow water to pass behind the membrane and enter the building.

Question 11Roofing Systems, Materials, and Installation Methods

How is step flashing installed where a shingle roof meets a vertical sidewall?

  1. In individual pieces, each lapped by the shingle course above Correct answer.
  2. As a single continuous L-shaped piece along the wall
  3. Over the finished shingles and sealed with mastic only
  4. Under the underlayment only, with no shingle contact

Explanation

Step flashing is installed in individual pieces, one per shingle course, with each piece lapped by the shingle above and by the next piece upslope. This shingle-like integration lets water shed down the wall line without a continuous seam to open. Surface-applied mastic is not a substitute.

Question 12Roofing Systems, Materials, and Installation Methods

Standing-seam metal roof panels are commonly attached with clips or fasteners that allow what?

  1. The panels to be walked on during installation
  2. Movement from thermal expansion and contraction Correct answer.
  3. Water to drain beneath the panel
  4. The seams to be soldered after forming

Explanation

Metal expands and contracts significantly with temperature, so concealed clips and slotted fasteners hold the panels down while permitting lengthwise movement. Restraining the panels rigidly causes oil-canning, fastener elongation, and seam failure. The concealed-fastener design is what allows standing-seam panels to be used on low slopes.

Question 13Roofing Systems, Materials, and Installation Methods

Balanced attic ventilation is generally sized at a net free vent area of 1 square foot for each how much attic floor area?

  1. 1,000 square feet
  2. 50 square feet
  3. 150 square feet Correct answer.
  4. 500 square feet

Explanation

The general rule is a 1:150 ratio of net free vent area to attic floor area, with roughly half the venting low at the intake and half high at the exhaust. Some codes permit 1:300 where a vapor retarder and balanced placement are provided. Balanced intake and exhaust prevents the attic from drawing conditioned air.

Question 14Roofing Systems, Materials, and Installation Methods

Fasteners used to attach roof sheathing made of preservative-treated lumber should be which of the following?

  1. Aluminum roofing nails
  2. Standard drywall screws
  3. Hot-dip galvanized or stainless steel Correct answer.
  4. Electroplated common nails

Explanation

Modern preservative treatments are corrosive to steel, so the code requires fasteners with adequate corrosion resistance, such as hot-dip galvanized or stainless steel. Electroplated coatings are far too thin for this exposure. Aluminum is also attacked in many treated-wood environments.

Question 15Roofing Systems, Materials, and Installation Methods

SBS modified bitumen cap sheets can be installed by which of the following means?

  1. Torching, hot mopping, or cold adhesive Correct answer.
  2. Loose laying with ballast only
  3. Stapling directly to the deck
  4. Nailing through the cap sheet alone

Explanation

SBS modified bitumen products are made in torch-grade, moppable, and cold-adhesive versions, and the method is selected to match the specified product and substrate. The membrane must be fully adhered or properly ballasted as a system. Staples and exposed nails cannot develop the required continuous seal.

Question 16Roofing Systems, Materials, and Installation Methods

Seams of EPDM single-ply membrane are most commonly joined by which method?

  1. Hot-air welding with a hand gun
  2. Splice adhesive applied over a primer Correct answer.
  3. Mechanical crimping
  4. Solvent welding with PVC cement

Explanation

EPDM is a thermoset rubber that cannot be heat-fused, so seams are made with a splice adhesive or splice tape over cleaned, primed laps. Thermoplastic membranes such as TPO and PVC are the products joined by hot-air welding. Proper lap preparation is what determines seam strength.

Question 17Roofing Systems, Materials, and Installation Methods

When installing wood structural panel roof sheathing, the panel edges should be spaced how?

  1. Overlapped by 1 inch
  2. About 1/8 inch apart Correct answer.
  3. About 1 inch apart
  4. Butted tightly together

Explanation

Panel edges are spaced about 1/8 inch to allow for moisture-related expansion; tight butting causes panels to buckle and ridge at the joints. The gap is left at panel ends and edges and is covered by the underlayment. Overlapping panels would create an uneven deck.

Question 18Roofing Systems, Materials, and Installation Methods

In an open valley on an asphalt shingle roof, the valley metal is left how?

  1. Restricted to slopes steeper than 8:12
  2. Buried beneath the underlayment only
  3. Exposed, with shingles trimmed back from the center line Correct answer.
  4. Fully covered by woven shingle courses

Explanation

An open valley leaves the metal pan visible along the valley center line, with each shingle course trimmed back and the metal edges turned up. This speeds drainage in the highest-flow part of the roof. A closed or woven valley instead carries the shingles across the intersection.

Question 19Roofing Systems, Materials, and Installation Methods

Where should fasteners be placed when installing asphalt strip shingles?

  1. Anywhere within 1 inch of the shingle edge
  2. Through the exposed butt edge of each shingle
  3. Just below the shadow line at the top of the exposure
  4. Within the manufacturer's nailing zone above the exposure line Correct answer.

Explanation

Nails belong in the nailing strip specified by the manufacturer, positioned above the exposure line so the next course covers them. Nailing in the exposed area leaves the fastener unsealed and vulnerable. Nails set too close to the edge tear out or split the shingle.

Question 20Roofing Systems, Materials, and Installation Methods

A conventional built-up roof membrane resists water mainly because of what?

  1. A single layer of modified bitumen
  2. Multiple plies of felt laminated in hot bitumen Correct answer.
  3. Mechanically attached panels only
  4. The gravel surfacing by itself

Explanation

Built-up roofing is a multi-ply membrane in which layers of felt or ply sheet are bonded with mopped bitumen, building a continuous waterproof laminate. The plies, not the surfacing, provide the redundancy that makes the system durable. Surfacing protects the bitumen from sunlight and traffic.

Question 21Roofing Systems, Materials, and Installation Methods

What minimum roof slope is generally required for standing-seam metal roof panels with continuous seams?

  1. 3:12
  2. 6:12
  3. 4:12
  4. 1/4:12 Correct answer.

Explanation

Because standing seams are raised and fasteners are concealed, these panels can be used down to about 1/4:12, subject to the manufacturer's listing. Through-fastened exposed-fastener panels typically need 3:12 or steeper. The slope must always meet the product approval for the specific profile.

Question 22Roofing Systems, Materials, and Installation Methods

In a cold climate, where should a vapor retarder be located within a roof assembly?

  1. Between the underlayment and the shingles
  2. On the warm side, below the insulation Correct answer.
  3. On the cold side, above the insulation
  4. On top of the deck beneath the shingles

Explanation

A vapor retarder belongs on the warm side of the insulation so it stops moisture-laden interior air before that air reaches the cold plane where it would condense. If vapor reaches a cold surface it condenses, wetting insulation and decking. Placement below the insulation keeps the dew point inside the conditioned zone.

Question 23Roofing Systems, Materials, and Installation Methods

Which practice improves the wind-uplift resistance of an asphalt shingle roof in a high-wind region?

  1. Installing over a single layer of No. 15 felt only
  2. Six fasteners per shingle plus tab cement Correct answer.
  3. Increasing the exposure of each course
  4. Reducing the number of fasteners to avoid splitting

Explanation

High-wind installations increase fastening to six nails per shingle and rely on a sealed or cemented tab to resist uplift. Starter courses at the eave and rake are also critical because uplift pressures are highest at the perimeter. Reducing fasteners or increasing exposure weakens the system.

Question 24Roofing Systems, Materials, and Installation Methods

Compared with wood shingles, wood shakes are characterized as being which of the following?

  1. Sawn smooth on both faces
  2. Split, with a thicker butt Correct answer.
  3. Uniform in thickness
  4. Applied without fasteners

Explanation

Shakes are split along the grain on at least one face and are thicker and heavier at the butt, while shingles are sawn and more uniform. The rougher, heavier shake requires a different exposure and a heavier deck and underlayment. Both are fastened with corrosion-resistant nails.

Question 25Roofing Systems, Materials, and Installation Methods

A cricket is required on the upslope side of a chimney when the chimney is wider than what dimension?

  1. 12 inches
  2. 72 inches
  3. 30 inches Correct answer.
  4. 48 inches

Explanation

A chimney wider than 30 inches measured parallel to the ridge needs a cricket to divert water around it rather than letting water pond against the back face. Below that width, flashing and backer detailing are permitted without a cricket. A missing cricket leads to chronic leakage at the uphill side.

Question 26Roofing Systems, Materials, and Installation Methods

In roofing measurement, one square of material covers which area?

  1. 1,000 square feet
  2. 100 square feet Correct answer.
  3. 50 square feet
  4. 10 square feet

Explanation

Roofing material is sold by the square, a unit of area equal to 100 square feet of finished roof surface. Manufacturers print the number of squares covered on shingle bundles and roll labels so quantity can be ordered directly from the roof area.

Question 27Roofing Systems, Materials, and Installation Methods

What is the primary function of a metal drip edge installed along a roof eave?

  1. It directs water away from the fascia and deck edge into the gutter Correct answer.
  2. It replaces the need for underlayment along the eave edge
  3. It seals the joint between the fascia board and the exterior wall sheathing
  4. It supports the lower ends of the roof rafters where they overhang

Explanation

Drip edge is a metal flashing at the eave and rake that sheds water clear of the fascia and deck edge, directing it into the gutter rather than letting it wick back under the roofing. It also guides water over the edge of the underlayment.

Question 28Roofing Systems, Materials, and Installation Methods

On an asphalt shingle roof, what does the term exposure refer to?

  1. The amount of direct sunlight a roof surface receives
  2. The total length of a shingle before it is trimmed at a rake
  3. The portion of a shingle left uncovered by the course above Correct answer.
  4. The number of shingle courses that overlap at a hip or ridge

Explanation

Exposure is the part of a shingle course that remains exposed to weather after the next course is installed over it; the overlapped portion is the headlap. Exposure plus headlap equals the shingle length, and the manufacturer's nailing line sets the exposure for correct weathering.

Question 29Roofing Systems, Materials, and Installation Methods

Galvanized steel roofing is protected from corrosion primarily by a coating of which metal?

  1. Aluminum
  2. Zinc Correct answer.
  3. Copper
  4. Chromium

Explanation

Galvanizing is a zinc coating applied to steel; zinc corrodes preferentially and continues to protect the steel even where the coating is scratched. Heavier zinc coatings are specified for harsher environments.

Question 30Roofing Systems, Materials, and Installation Methods

How are seams of thermoplastic membranes such as TPO and PVC typically closed?

  1. Pressure-sensitive splice tape applied along the seam
  2. Solvent cement brushed onto both edges
  3. Heat welding with a hot-air welder Correct answer.
  4. Mechanical batten strips fastened over the joint

Explanation

TPO and PVC are thermoplastics, meaning they soften when heated, so seams are closed by hot-air welding that fuses the two sheets into a continuous bond. Weld quality is checked by probing or air testing the seam.

Question 31Roofing Systems, Materials, and Installation Methods

In a closed-cut valley, how are the shingles from the two roof planes finished?

  1. Both planes are woven alternately over and under each other across the valley centerline
  2. One plane runs through the valley; the other is cut parallel to the centerline Correct answer.
  3. Shingles on each plane are cut square at the valley line and butted tightly together
  4. Both planes are cut back several inches so that the metal valley pan stays fully exposed to view

Explanation

In a closed-cut valley, shingles from one plane are carried across the valley centerline and nailed, then shingles from the adjoining plane are laid over them and cut along a line parallel to the centerline. This keeps the valley closed while producing a straight, clean cut line.

Question 32Roofing Systems, Materials, and Installation Methods

A kick-out flashing is installed at the base of a roof-to-wall intersection mainly to do what?

  1. Seal the joint between two abutting roof planes at a hip
  2. Flash the top of a chimney where it passes through the ridge line
  3. Cover the exposed ends of a ridge vent at the gable
  4. Direct water away from the wall and into the gutter Correct answer.

Explanation

A kick-out flashing, or diverter, turns the last of the step flashing outward so water draining down the wall/roof corner is thrown into the gutter instead of running behind the siding and fascia. Missing kick-outs are a common source of hidden wall rot.

Question 33Roofing Systems, Materials, and Installation Methods

When fastening asphalt shingles, the nail should penetrate through the roof sheathing by at least how much?

  1. 1/8 inch
  2. 1/2 inch
  3. 1/4 inch
  4. 3/4 inch Correct answer.

Explanation

Shingle nails must extend at least 3/4 inch through or into the sheathing so the shingle is pulled tight against the deck. Undriven or short nails allow the shingle to lift and are a common cause of wind damage.

Question 34Roofing Systems, Materials, and Installation Methods

What is the purpose of the flood coat and gravel surfacing on a built-up roof?

  1. To provide the primary waterproofing layer of the roof
  2. To fill low spots and establish positive drainage slope
  3. To protect the bitumen from degradation by sunlight Correct answer.
  4. To add weight so the membrane resists wind uplift

Explanation

In a built-up roof the plies and bitumen do the waterproofing, while the flood coat and gravel or mineral cap protect the bitumen from ultraviolet light and weathering. Without that surfacing the bitumen oxidizes and cracks prematurely.

Question 35Roofing Systems, Materials, and Installation Methods

Where a masonry wall rises above a roof, how is counterflashing usually secured to the wall?

  1. It is screwed to the top edge of the base flashing
  2. It is set into a reglet cut into the masonry and sealed Correct answer.
  3. It is nailed to the roof deck and covered by the membrane
  4. It is bonded to the wall face with construction adhesive only

Explanation

Counterflashing overlaps the base flashing and its upper edge is anchored in a reglet, a groove cut into the masonry, then sealed so water cannot get behind it. This lets the flashing shed water over the base flashing while allowing minor movement.

Question 36Roofing Systems, Materials, and Installation Methods

A roof has a continuous ridge vent, but the soffit vents have been covered by insulation. What is the most likely result?

  1. The attic will stay dry because the ridge vent still exhausts warm air
  2. The ridge vent will pull air from the conditioned space below
  3. Exhaust ventilation will be ineffective because intake airflow is restricted Correct answer.
  4. Positive pressure will build in the attic and force air out through the ridge vent

Explanation

Attic ventilation depends on balanced intake and exhaust areas; the ridge vent can only exhaust as much air as enters at the soffits. Blocking the intake starves the system, so attic heat and moisture are not removed.

Question 37Roofing Systems, Materials, and Installation Methods

What is the purpose of H-clips installed between wood structural panel roof sheathing?

  1. They fasten the panels down where nails cannot reach the framing
  2. They support panel edges between framing and keep them aligned Correct answer.
  3. They permit the panels to expand and contract without buckling at the edges
  4. They transfer wind uplift loads from the panels to the roof framing

Explanation

An H-clip bridges the gap between two panels where an edge falls between framing members, holding the edges in line and providing support so they do not deflect under load. Panels are still fastened to framing with the specified nails or staples.

Question 38Roofing Systems, Materials, and Installation Methods

In a cold climate, ice dams at the eaves are most often caused by which condition?

  1. Snowmelt refreezing only on shaded north-facing slopes
  2. Insufficient attic exhaust ventilation in the summer months
  3. Rainwater freezing in the gutter after a winter storm
  4. Warm air from the house heating the upper roof deck and melting snow Correct answer.

Explanation

Ice dams form when heat escaping through the ceiling warms the upper roof, melts the snow there, and the meltwater refreezes when it reaches the colder eave. The cure is air sealing, insulation, and ventilation rather than more eave flashing alone.

Question 39Roofing Systems, Materials, and Installation Methods

Visible waviness known as oil canning in the flat pans of standing-seam metal panels is most often caused by which of the following?

  1. Too many fasteners installed along the panel seams
  2. Stresses from forming and installing thin, wide pans over framing that is not flat Correct answer.
  3. Water trapped beneath the panels after the roof is completed
  4. Thermal expansion of the panels being fully restrained at the clips

Explanation

Oil canning is elastic buckling of a thin, flat pan; it comes from residual stresses in forming and handling combined with slight deviations in the substrate. Choosing a heavier gauge or a narrower pan and using straight, true framing reduces its appearance.

Question 40Roofing Systems, Materials, and Installation Methods

What is the minimum roof slope usually required for a built-up roof with asphalt and gravel surfacing?

  1. 1/2 inch per foot
  2. 1/8 inch per foot
  3. 1 inch per foot
  4. 1/4 inch per foot Correct answer.

Explanation

Built-up roofing is a low-slope system that requires a minimum slope of about 1/4 inch per foot to provide positive drainage. Flatter decks need special design such as additional plies, a drainage layer, or tapered insulation.

Question 41Roof Framing, Sheathing, and Structural Considerations

What is the primary function of a ridge board in conventional roof framing?

  1. They tie opposing rafters together to resist outward thrust.
  2. They give rafters a nailing surface at the peak and help align them. Correct answer.
  3. They set the width of the eave overhang.
  4. They carry the full roof load down to the foundation.

Explanation

In conventional framing the ridge board is mainly a alignment and nailing member at the peak. The rafters bear on the wall plates and transfer roof loads through the walls, while rafter ties or ceiling joists resist outward thrust.

Question 42Roof Framing, Sheathing, and Structural Considerations

Where is a rafter tie normally installed in a roof frame?

  1. Along the ridge between rafter pairs
  2. In the upper third of the attic space
  3. Midway up each individual rafter
  4. Across the lower ends of opposing rafters Correct answer.

Explanation

A rafter tie is placed across the lower ends of opposing rafters, typically at or near the wall plate line, to resist the outward thrust of the roof. Collar ties are the members placed higher, in the upper third of the roof.

Question 43Roof Framing, Sheathing, and Structural Considerations

Roof slope is commonly expressed in which format?

  1. Inches of rise per foot of run Correct answer.
  2. Pounds per square foot of deck
  3. Degrees per foot of run
  4. Feet of span per inch of depth

Explanation

Roof slope is usually stated as rise in inches per 12 inches of horizontal run, such as 6:12 or 4:12. This ratio describes the steepness of the roof plane and is used with framing tables and roofing material requirements.

Question 44Roof Framing, Sheathing, and Structural Considerations

What does a roof sheathing span rating such as 24/16 indicate?

  1. Panel thickness measured in thirty-seconds of an inch
  2. Allowable roof and floor span in inches Correct answer.
  3. Maximum allowable building height for the panel
  4. Number of nails required at each framing support

Explanation

The first number in a span rating is the maximum allowable roof support spacing in inches, and the second number is the maximum floor support spacing. A 24/16 panel may span 24 inches on a roof and 16 inches on a floor under the rating conditions.

Question 45Roof Framing, Sheathing, and Structural Considerations

What is the purpose of H-clips between roof sheathing panels?

  1. They support edges and maintain uniform spacing Correct answer.
  2. They replace the nails that are required at panel edges
  3. They create a vapor barrier between adjacent panels
  4. They transfer wind uplift loads from the panels to the rafters

Explanation

H-clips are placed between panel edges where the edges are otherwise unsupported, helping keep the panels aligned and maintaining consistent gapping. They are not a substitute for required edge nailing or structural blocking.

Question 46Roof Framing, Sheathing, and Structural Considerations

A birdsmouth cut on a rafter is used to do what?

  1. Seat the rafter on the wall plate Correct answer.
  2. Join two rafters at the ridge
  3. Form the fascia attachment at the eave
  4. Fasten a collar tie to the rafter

Explanation

A birdsmouth consists of a plumb cut and a level cut that let the rafter bear flat on the wall plate. The depth of the notch is limited so the rafter retains adequate strength.

Question 47Roof Framing, Sheathing, and Structural Considerations

For a given roof load, what happens to the required roof sheathing thickness as rafter spacing increases?

  1. It usually increases for wider spacing Correct answer.
  2. It is unrelated to the rafter spacing used
  3. It decreases because fewer rafters carry the load
  4. It stays the same if the panel grade is the same

Explanation

Sheathing spans between rafters, so wider spacing creates a longer unsupported span and generally requires a thicker panel or a higher span rating. The sheathing manufacturer’s span rating must match or exceed the rafter spacing.

Question 48Roof Framing, Sheathing, and Structural Considerations

Which roof type has two sloping planes that meet at a ridge and vertical triangular end walls?

  1. Gable roof Correct answer.
  2. Shed roof
  3. Gambrel roof
  4. Hip roof

Explanation

A gable roof has two sloping roof planes that meet at a ridge, and the triangular end walls are the gable ends. A hip roof slopes on all sides, a shed roof slopes one direction, and a gambrel has two slopes per side.

Question 49Roof Framing, Sheathing, and Structural Considerations

When using a rafter span table, which set of factors must be known?

  1. Roof covering color, underlayment type, and eave overhang width
  2. Rafter size, species, spacing, load, and slope Correct answer.
  3. Chimney location and the size of any skylight openings
  4. Number of shingles per bundle and the length of roofing nails

Explanation

Span tables are organized by member size, species and grade, spacing, load conditions, and sometimes slope or deflection limits. All of these affect the allowable span and must be matched to the design.

Question 50Roof Framing, Sheathing, and Structural Considerations

A collar tie is most effective when installed where?

  1. Below the ceiling joists in the attic
  2. At mid-height of the rafter span
  3. In the upper third of the roof near the ridge Correct answer.
  4. At the eave line, level with the wall top plates

Explanation

Collar ties are installed in the upper third of the roof, connecting opposing rafters near the ridge to help resist ridge separation. They do not replace rafter ties, which are located at the lower ends of the rafters.