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NRCA EPDM study materials
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NRCA EPDM practice questions

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Question 1EPDM roof system installation knowledge and performance

In a fully adhered EPDM roof assembly, what is the primary function of the bonding adhesive applied to the membrane underside?

  1. It provides a slip sheet between membrane and deck
  2. It acts as a vapor retarder beneath the insulation
  3. It transfers wind uplift loads from the membrane to the substrate Correct answer.
  4. It seals membrane seams against ponding water

Explanation

Fully adhered systems rely on continuous adhesive contact so that wind uplift forces are distributed into the deck rather than concentrated at fasteners or perimeter terminations. The adhesive is a load-transfer layer, not a moisture or seam component.

Question 2EPDM roof system installation knowledge and performance

Which attachment method is most appropriate for a ballasted EPDM system on a roof with adequate structural capacity?

  1. Membrane bonded with contact adhesive to the deck
  2. Membrane mechanically fastened in the field of each sheet
  3. Loose-laid membrane restrained by rounded river rock or pavers Correct answer.
  4. Membrane adhered with low-rise foam adhesive

Explanation

Ballasted assemblies leave the membrane loose and hold it down with a uniformly distributed load of stone or pavers, which requires verified structural capacity. Adhesive or fastener methods belong to adhered or mechanically attached systems.

Question 3EPDM roof system installation knowledge and performance

What is the purpose of a batten strip in a mechanically attached EPDM roof?

  1. To bond two membrane sheets together chemically
  2. To weight down the perimeter edge against uplift
  3. To clamp the membrane along a seam line while fasteners pass through it Correct answer.
  4. To provide a drainage channel at the roof slope break

Explanation

Battens are placed over the membrane at seam locations and fastened through the sheet, clamping it to the deck while the seam is then covered. They are a mechanical restraint device rather than an adhesive or drainage element.

Question 4EPDM roof system installation knowledge and performance

Why must EPDM membrane be allowed to relax before seaming and termination work?

  1. Because relaxed membrane absorbs splice adhesive faster
  2. Because the membrane stretches during unrolling and can pull seams apart if restrained while stressed Correct answer.
  3. Because relaxation is required to activate the talc release agent
  4. Because relaxation increases the membrane's resistance to ozone

Explanation

EPDM is elastic and arrives with built-in stress from rolling and handling. If it is fastened or seamed while still stretched, subsequent contraction can stress seams and terminations, so sheets are broomed or allowed to relax first.

Question 5EPDM roof system installation knowledge and performance

Which component is installed at the base of a wall to mechanically clamp the EPDM membrane and seal the top edge of the flashing?

  1. Cricket
  2. Drip edge
  3. Termination bar with sealant Correct answer.
  4. Counterflashing reglet

Explanation

A termination bar fastens the membrane to the wall and is typically sealed along its top edge to shed water. Drip edges, reglets, and crickets serve different functions at edges, walls, and drainage transitions.

Question 6EPDM roof system installation knowledge and performance

A roofing crew is installing EPDM over a concrete deck. Which substrate preparation step is essential before applying bonding adhesive?

  1. Prime the deck to promote adhesion and control dust Correct answer.
  2. Install a drainage mat over the deck
  3. Install a slip sheet to allow membrane movement
  4. Apply a flood coat of asphalt

Explanation

Concrete is porous and dusty, so priming improves adhesive bond and consolidates the surface. Slip sheets, asphalt flood coats, and drainage mats are not part of standard adhered EPDM preparation over concrete.

Question 7EPDM roof system installation knowledge and performance

What does the term 'splice' refer to in an EPDM roof system?

  1. The transition between membrane and metal edge
  2. A factory edge of the membrane roll
  3. The field joint where two membrane sheets are joined with adhesive or tape Correct answer.
  4. The fastener pattern at the perimeter

Explanation

A splice is the field seam joining adjacent EPDM sheets, formed with splice adhesive or pressure-sensitive tape. Factory edges, edge transitions, and fastener patterns are distinct elements.

Question 8EPDM roof system installation knowledge and performance

Which condition most directly causes membrane billowing and seam stress in a loose-laid ballasted EPDM assembly?

  1. Oversized scuppers
  2. Too many field splices
  3. Inadequate ballast weight or coverage Correct answer.
  4. Excess splice adhesive at seams

Explanation

Loose-laid membrane depends on ballast to resist wind uplift; insufficient weight or coverage allows the membrane to lift and billow, stressing seams. Adhesive quantity, scupper size, and splice count do not drive billowing in this way.

Question 9EPDM roof system installation knowledge and performance

Why is a primer applied to EPDM membrane surfaces immediately before splice adhesive or tape is used?

  1. To remove surface contamination and prepare the rubber for a consistent bond Correct answer.
  2. To increase seam thickness for wind uplift resistance
  3. To color-code the seam for inspection
  4. To soften the membrane so the seam can be stretched

Explanation

Splice areas are cleaned and primed so the adhesive wets and bonds consistently to the EPDM surface. Priming is a surface preparation step, not a means of stretching, coding, or thickening the seam.

Question 10EPDM roof system installation knowledge and performance

A crew is installing EPDM flashing at an outside corner of a wall. Which approach produces a watertight corner?

  1. Stretch a single sheet of flashing tightly around the corner
  2. Fold the flashing and fasten only at the top
  3. Cut the flashing and leave the gap open for sealant
  4. Form a separate corner piece and splice it to the field flashing with adhesive Correct answer.

Explanation

Outside corners are typically made with a dedicated corner piece spliced to the run flashing so the seam is properly bonded and supported. Stretching, leaving gaps, or fastening only at the top compromises the flashing.

Question 11EPDM roof system installation knowledge and performance

In a mechanically attached EPDM system, why are fasteners and battens placed at seam lines rather than randomly in the field?

  1. Because fasteners at seams eliminate the need for termination bars
  2. Because seam-line fastening reduces membrane elasticity
  3. Because the seam covering conceals the fasteners and the seam line is a structurally convenient row Correct answer.
  4. Because fasteners bond better to the seam adhesive

Explanation

Placing fasteners along seams lets the seam cover strip hide them and creates orderly, predictable load rows. It does not improve adhesive bonding, replace termination bars, or intentionally alter elasticity.

Question 12EPDM roof system installation knowledge and performance

What is the function of a pipe boot in an EPDM roof system?

  1. To drain condensate from the roof assembly
  2. To provide a preformed, watertight seal around a penetrating pipe Correct answer.
  3. To anchor the membrane to the deck at the penetration
  4. To support the pipe above the roof surface

Explanation

A pipe boot is a preformed flashing accessory that seals the membrane around a pipe penetration, often with a clamping ring and sealant. It is not a structural support, drain, or primary anchorage.

Question 13EPDM roof system installation knowledge and performance

A designer specifies a fully adhered EPDM system on a roof with high wind uplift demand. Which detail most improves the assembly's uplift resistance at the perimeter?

  1. Reduced splice adhesive along field seams
  2. Enhanced perimeter attachment with increased fastener density and edge securement Correct answer.
  3. A single layer of ballast at the perimeter
  4. Larger field splices spaced farther apart

Explanation

Perimeter and corner zones experience the highest uplift, so enhanced attachment such as closer fasteners and robust edge securement is the appropriate response. Reducing seam quality or adding minimal ballast does not address uplift.

Question 14EPDM roof system installation knowledge and performance

Why must EPDM membrane not be installed in contact with asphalt or coal tar products?

  1. Because EPDM chemically bonds permanently to asphalt
  2. Because asphalt increases the membrane's flexibility
  3. Because oils and solvents in those products can degrade the EPDM compound Correct answer.
  4. Because asphalt prevents seam adhesive from curing

Explanation

Asphalt and coal tar contain oils and aromatic compounds that can migrate into and degrade EPDM. Separation layers or compatible substrates are required to prevent contact.

Question 15EPDM roof system installation knowledge and performance

A crew is installing EPDM over an existing roof as a re-cover. Which consideration is most critical before proceeding?

  1. Removing all existing flashing regardless of condition
  2. Verifying that the existing roof and deck can support the added load and are suitable as a substrate Correct answer.
  3. Applying new ballast to the entire existing roof
  4. Increasing the membrane thickness to compensate for the old roof

Explanation

A re-cover requires confirmation that the structure can carry the additional weight and that the existing assembly is sound and compatible. Wholesale flashing removal, added ballast, or thickness changes are not substitutes for that evaluation.

Question 16EPDM roof system installation knowledge and performance

What role does a compression termination play at the edge of a ballasted EPDM roof?

  1. It allows the membrane to float freely at the edge
  2. It replaces the need for any perimeter fastening
  3. It provides the primary waterproofing for the field of the roof
  4. It mechanically secures the membrane at the roof edge to resist wind uplift and prevent ballast loss Correct answer.

Explanation

Perimeter edges of ballasted roofs need a secure termination, often a compression bar or edge metal, to hold the membrane and ballast in place under wind. It is a perimeter restraint, not field waterproofing or a replacement for fastening.

Question 17EPDM roof system installation knowledge and performance

Which factor most affects the required cure or dwell time before an EPDM splice is tested?

  1. The slope of the roof
  2. The color of the membrane
  3. The number of fasteners in the field
  4. The adhesive system used and ambient temperature and humidity Correct answer.

Explanation

Splice adhesive or tape systems have specified dwell and cure requirements that vary with product and with temperature and humidity conditions. Membrane color, fastener count, and slope do not govern seam cure.

Question 18EPDM roof system installation knowledge and performance

During a seam probe inspection of an EPDM splice, what does a probe that lifts the seam edge indicate?

  1. A seam that has been over-primed
  2. A properly cured seam with normal edge lift
  3. A seam that is ready for ballast
  4. An incomplete bond that requires repair before the seam is accepted Correct answer.

Explanation

Probing checks bond integrity; if the probe can lift the seam edge, the bond is incomplete and the seam must be repaired. A sound seam resists probing along its edge.

Question 19EPDM roof system installation knowledge and performance

Why is it important to install EPDM membrane with proper overlap at seams, typically following manufacturer requirements?

  1. To reduce the number of fasteners needed at the perimeter
  2. To increase the membrane's resistance to ultraviolet light
  3. To allow the membrane to be stretched during installation
  4. To provide sufficient width for a bonded splice that will not be stressed at the seam edge Correct answer.

Explanation

Manufacturer-specified overlap provides enough width for cleaning, priming, and bonding so the splice carries load without edge stress. Overlap does not add UV resistance, permit stretching, or change perimeter fastener needs.

Question 20EPDM roof system installation knowledge and performance

A roof has a large penetration with a curb. Which flashing approach is appropriate for the EPDM membrane at the curb?

  1. Ballast the membrane against the curb without fastening
  2. Run membrane up the curb and terminate it with a bar and counterflashing Correct answer.
  3. Terminate the membrane at the curb base with sealant only
  4. Cut the membrane around the curb and rely on the penetration boot

Explanation

Curbs are flashed by carrying membrane up the vertical face and terminating it mechanically with a bar, then protecting the top edge with counterflashing. Sealant alone, a pipe boot, or loose ballast does not provide a durable curb flashing.

Question 21EPDM roof system installation knowledge and performance

How does membrane thickness selection influence the performance of an EPDM roof system?

  1. Thicker membrane eliminates the need for a vapor retarder
  2. Thicker membrane removes the need for perimeter fastening
  3. Thicker membrane generally provides greater resistance to punctures and foot traffic but does not change seam chemistry Correct answer.
  4. Thicker membrane allows installation without seam adhesive

Explanation

Increased thickness improves physical toughness such as puncture and traffic resistance, while seams still rely on the same adhesive or tape systems. Thickness does not substitute for vapor control, attachment, or seaming.

Question 22EPDM roof system installation knowledge and performance

In a fully adhered EPDM assembly over a steel deck, what is the role of the insulation attachment pattern relative to the membrane adhesive?

  1. Insulation fasteners should be omitted where adhesive is used
  2. Insulation must be securely fastened so the adhered membrane's uplift loads transfer through it to the deck Correct answer.
  3. Insulation must be ballasted instead of fastened
  4. Insulation should be left loose to allow the membrane to move

Explanation

In an adhered assembly the membrane adhesive bonds to the insulation, so the insulation itself must be firmly attached to the deck to complete the load path. Loose insulation or omitted fasteners breaks that path.

Question 23EPDM roof system installation knowledge and performance

A ballasted EPDM roof shows seam separation near the perimeter after a wind event. Which combination best explains the failure?

  1. Over-primed seams causing them to become brittle
  2. Excessive ballast weight causing the membrane to compress
  3. Insufficient perimeter securement combined with wind-driven membrane movement stressing seams Correct answer.
  4. Too few field splices concentrating stress

Explanation

When perimeter restraint is inadequate, wind can lift and move the loose-laid membrane, and that movement concentrates stress at seams until they separate. Excess ballast, primer, or splice count do not produce this pattern.

Question 24EPDM roof system installation knowledge and performance

Why is it critical that splice adhesive be applied only to clean, dry, primed EPDM surfaces?

  1. Clean surfaces allow the membrane to stretch during seaming
  2. Primer requires moisture to activate
  3. Dry surfaces prevent the adhesive from curing too quickly
  4. Moisture or contamination interferes with adhesive wetting and can produce an unbonded seam Correct answer.

Explanation

Adhesive bonding depends on intimate contact with a prepared surface; moisture, dust, or talc prevents wetting and results in a weak or open seam. Primer does not require moisture, and clean surfaces are not about stretching.

Question 25EPDM roof system installation knowledge and performance

A designer is comparing mechanically attached and fully adhered EPDM for a roof over a lightweight deck with strict height and load limits. Which reasoning is most sound?

  1. Mechanically attached systems may reduce adhesive weight and allow fastener-based load transfer, but fastener pull-out capacity on the deck must be verified Correct answer.
  2. Ballasted systems are preferred because ballast reduces structural load
  3. Membrane thickness alone determines which attachment method is acceptable
  4. Fully adhered systems always weigh less because adhesive is lighter than fasteners

Explanation

Mechanically attached assemblies avoid the weight and substrate demands of full adhesion but depend on the deck's ability to hold fasteners. Adhesive and fasteners are both light; ballast adds substantial load; thickness does not govern attachment choice.

Question 26EPDM roof system installation knowledge and performance

In an EPDM roof system, what is the primary purpose of a batten strip used in a mechanically attached assembly?

  1. To distribute fastener clamping force along the membrane seam Correct answer.
  2. To increase the membrane's resistance to ultraviolet degradation
  3. To provide a decorative finish at the roof edge
  4. To bond the membrane to the insulation board

Explanation

In mechanically attached EPDM systems, fasteners alone can create point loads that tear the membrane. A batten strip spreads the clamping force across the seam area so the membrane is held uniformly and seam integrity is maintained under wind uplift.

Question 27EPDM roof system installation knowledge and performance

When installing EPDM membrane over a steel deck, which substrate condition must be verified before insulation or membrane placement?

  1. The deck has been primed with splice adhesive
  2. The deck has been coated with a reflective white finish
  3. The deck has been pre-drilled with fastener holes at seam locations
  4. The deck is free of sharp protrusions, debris, and standing water Correct answer.

Explanation

EPDM membrane and insulation can be damaged by sharp edges, fasteners, or debris trapped beneath them. Standing water can also compromise adhesion and insulation performance. The deck must be clean, dry, and smooth before any component is installed.

Question 28EPDM roof system installation knowledge and performance

What is the function of an EPDM pipe boot in a roof system?

  1. To provide a bonding surface for seam tape
  2. To support the pipe above the roof surface
  3. To drain water from the roof deck
  4. To seal the membrane around a pipe penetration and allow movement Correct answer.

Explanation

A pipe boot is a preformed flashing accessory that fits around a pipe and seals the membrane-to-pipe transition. It accommodates minor pipe movement and thermal expansion while maintaining a watertight seal.

Question 29EPDM roof system installation knowledge and performance

Why must EPDM membrane be kept separate from asphalt or coal tar products?

  1. These products contain oils that can migrate and degrade EPDM Correct answer.
  2. They cure EPDM prematurely
  3. They are too heavy for roof structures
  4. They attract birds that damage the membrane

Explanation

Asphalt and coal tar contain aromatic oils and solvents that can plasticize or soften EPDM, leading to swelling and loss of strength. A separation layer or compatible substrate is required to prevent direct contact.

Question 30EPDM roof system installation knowledge and performance

What does a probe that lifts the seam edge during inspection of an EPDM splice most likely indicate?

  1. The primer was applied too heavily
  2. The splice is fully cured and acceptable
  3. The membrane is too thick for the seam
  4. The splice has incomplete adhesion or a void Correct answer.

Explanation

A seam probe should meet resistance and not lift the seam edge. If the edge lifts easily, it signals an unbonded area, often from insufficient adhesive, contamination, or inadequate pressure, and the seam must be repaired.

Question 31EPDM roof system installation knowledge and performance

Which edge termination method is typically used at the perimeter of a ballasted EPDM roof?

  1. A compression termination bar fastened through the membrane Correct answer.
  2. A pipe boot fitted over the edge
  3. A splice tape applied to the wall
  4. A loose membrane edge covered by stone

Explanation

At the perimeter of a ballasted roof, the membrane must be mechanically terminated to prevent ballast from pushing the edge and to resist wind. A compression bar clamps the membrane to the wall or edge, creating a secure termination.

Question 32EPDM roof system installation knowledge and performance

In a fully adhered EPDM system, what is the role of the insulation attachment pattern?

  1. It controls the cure time of the splice adhesive
  2. It must be sufficient to resist wind uplift and support the adhered membrane Correct answer.
  3. It determines the color of the membrane
  4. It replaces the need for a vapor retarder

Explanation

In a fully adhered assembly, wind uplift is transferred through the membrane to the insulation and then to the deck. The insulation attachment pattern must be designed to carry those loads without delamination or fastener withdrawal.

Question 33EPDM roof system installation knowledge and performance

What is the purpose of a primer when preparing EPDM membrane for a splice?

  1. To increase the membrane's thickness at the seam
  2. To clean and prepare the surface so adhesive bonds reliably Correct answer.
  3. To lubricate the membrane for easier handling
  4. To provide UV protection to the splice

Explanation

EPDM surfaces can have dust, talc, or release agents that interfere with adhesion. Primer cleans and activates the surface, promoting a strong, durable bond between the membrane and splice adhesive or tape.

Question 34EPDM roof system installation knowledge and performance

A crew is installing EPDM flashing at an outside corner. Which practice helps ensure a watertight corner?

  1. Leaving the corner open to drain
  2. Forming a gusset or pleat to relieve stress and allow proper overlap Correct answer.
  3. Stretching the membrane tightly around the corner without folds
  4. Cutting the membrane flush with the corner and sealing with caulk

Explanation

Outside corners concentrate stress and are difficult to seal if the membrane is forced. A gusset or pleat provides material to accommodate the corner geometry, allowing proper overlapping and sealing without tension.

Question 35EPDM roof system installation knowledge and performance

During a re-cover of an existing roof with EPDM, which condition is most critical to evaluate before installation?

  1. The color of the existing membrane
  2. The structural capacity of the existing roof to support the added weight Correct answer.
  3. The number of roof drains
  4. The age of the building's HVAC system

Explanation

A re-cover adds weight from new insulation, membrane, and ballast or fasteners. The structure must be evaluated to confirm it can carry the additional load safely, and the existing roof must be suitable as a substrate.

Question 36EPDM roof system installation knowledge and performance

Why are fasteners and battens placed at seam lines in a mechanically attached EPDM system?

  1. To locate attachment where the membrane is reinforced and can transfer load Correct answer.
  2. To allow the membrane to be installed without seams
  3. To make the roof easier to walk on
  4. To reduce the number of insulation boards

Explanation

Seam lines provide an area where the membrane is doubled or reinforced and can accept fasteners and battens without creating isolated stress points. This improves wind uplift resistance and protects the membrane from tearing.

Question 37EPDM roof system installation knowledge and performance

What does proper overlap at EPDM seams typically ensure?

  1. Increased membrane flexibility
  2. Sufficient width for adhesive or tape to develop a watertight bond Correct answer.
  3. Reduced membrane weight
  4. A decorative appearance along the seam

Explanation

Manufacturer requirements specify a minimum overlap so the splice has enough bonded area to resist peel and shear forces. Inadequate overlap reduces seam strength and increases the risk of water infiltration.

Question 38EPDM roof system installation knowledge and performance

A crew is flashing a large curb penetration with EPDM. Which approach is appropriate?

  1. Seal the curb with splice tape only
  2. Run the membrane flat across the curb opening
  3. Leave the curb unflashed and rely on the drain
  4. Wrap the membrane up the curb and terminate with a batten or counterflashing Correct answer.

Explanation

Curb flashing must extend up the vertical face and be terminated mechanically or with counterflashing to shed water. This creates a continuous waterproof path from the field membrane to the curb.

Question 39EPDM roof system installation knowledge and performance

Which factor most directly affects the required dwell time before an EPDM splice is tested?

  1. Ambient temperature and adhesive type Correct answer.
  2. The number of workers on the roof
  3. The color of the membrane
  4. The slope of the roof

Explanation

Splice adhesive and tape cure at rates influenced by temperature and product chemistry. Colder temperatures slow cure and require longer dwell time before probing or testing the seam.

Question 40EPDM roof system installation knowledge and performance

Why is it important that splice adhesive be applied only to clean, dry, primed EPDM surfaces?

  1. Dry surfaces cause the adhesive to cure too quickly
  2. Primer is required to make the membrane flexible
  3. Adhesive will discolor the membrane if surfaces are dirty
  4. Contaminants and moisture prevent proper adhesion and can cause seam failure Correct answer.

Explanation

Dirt, moisture, and unprimed surfaces interfere with the adhesive's ability to bond to the EPDM. Proper cleaning, drying, and priming ensure the adhesive develops full strength and the seam remains watertight.

Question 41EPDM roof system installation knowledge and performance

In a loose-laid ballasted EPDM assembly, what condition most directly causes membrane billowing and seam stress?

  1. Wind pressure entering under the membrane through openings or edges Correct answer.
  2. Excessive ballast weight uniformly distributed
  3. High ambient humidity during installation
  4. Membrane installed with too few seams

Explanation

Loose-laid membrane can lift when wind enters beneath it, creating billowing that stresses seams and terminations. Proper perimeter securement and ballast design reduce this risk.

Question 42EPDM roof system installation knowledge and performance

A designer specifies a fully adhered EPDM system on a roof with high wind uplift demand. Which detail most improves uplift resistance?

  1. Reducing the number of insulation layers
  2. Using a lighter-colored membrane
  3. Continuous adhesive coverage and proper fastener pattern at perimeters Correct answer.
  4. Installing the membrane with larger overlaps

Explanation

Uplift resistance in a fully adhered system depends on continuous bonding of membrane to substrate and secure perimeter attachment. Incomplete adhesive coverage or weak edge fastening creates weak points where wind can peel the membrane.

Question 43EPDM roof system installation knowledge and performance

What is the primary function of a compression termination at the edge of a ballasted EPDM roof?

  1. To clamp the membrane and prevent ballast from pushing it off the edge Correct answer.
  2. To allow water to drain over the edge
  3. To bond the membrane to the ballast
  4. To provide a decorative cap

Explanation

A compression termination mechanically holds the membrane edge so ballast and wind cannot displace it. It is a structural and waterproofing detail, not a decorative one.

Question 44EPDM roof system installation knowledge and performance

Why is membrane thickness selection important for an EPDM roof system?

  1. Thinner membrane improves seam adhesion
  2. Thickness determines the membrane's color
  3. Thicker membrane offers greater resistance to punctures and foot traffic Correct answer.
  4. Thicker membrane eliminates the need for insulation

Explanation

EPDM membrane thickness is specified based on expected traffic, puncture risk, and warranty requirements. Thicker membrane provides more material to resist damage, but it does not replace other components.

Question 45EPDM roof system installation knowledge and performance

In a mechanically attached EPDM system, why must the fastener and batten spacing follow the manufacturer's uplift design?

  1. Spacing affects the adhesive cure time
  2. Spacing controls the roof's drainage rate
  3. Spacing controls the load per fastener and the membrane's ability to resist wind uplift Correct answer.
  4. Spacing determines the membrane's UV resistance

Explanation

Fastener spacing determines how wind uplift loads are distributed to the deck. Wider spacing increases load per fastener and can lead to membrane tearing or fastener withdrawal, so the design must be followed.

Question 46EPDM roof system installation knowledge and performance

A designer is comparing mechanically attached and fully adhered EPDM for a roof over a lightweight deck with strict height limits. Which consideration is most relevant?

  1. The mechanically attached system requires no seams
  2. The adhered system eliminates the need for insulation
  3. The mechanically attached system always weighs less
  4. The adhered system may require more adhesive and substrate preparation but can reduce fastener count Correct answer.

Explanation

Fully adhered systems distribute wind loads over the entire membrane area and may reduce the number of fasteners penetrating the deck, which can be beneficial for lightweight or height-limited structures. However, they require proper substrate preparation and adhesive application.

Question 47EPDM roof system installation knowledge and performance

What is the primary reason EPDM membrane must not be installed in direct contact with asphalt or coal tar?

  1. Coal tar is flammable at roof temperatures
  2. Asphalt is too slippery for roof traffic
  3. Asphalt prevents the membrane from curing
  4. Aromatic oils can migrate into the EPDM and cause swelling or loss of properties Correct answer.

Explanation

Asphalt and coal tar contain aromatic hydrocarbons that can be absorbed by EPDM, leading to swelling, softening, and reduced performance. A separation layer or compatible substrate is required.

Question 48EPDM roof system installation knowledge and performance

During a seam probe inspection, what does a probe that meets resistance and does not lift the seam edge indicate?

  1. The splice is too brittle and will fail
  2. The splice has developed adequate adhesion Correct answer.
  3. The membrane is too thin at the seam
  4. The primer was not applied

Explanation

A probe that cannot easily lift the seam edge indicates the adhesive has bonded properly across the splice. This is the expected result of a successful seam.

Question 49EPDM roof system installation knowledge and performance

Why is proper overlap at EPDM seams critical for long-term performance?

  1. It reduces the need for perimeter attachment
  2. It provides the bonded area needed to resist peel and shear forces over time Correct answer.
  3. It allows the membrane to stretch more
  4. It improves the membrane's UV stability

Explanation

Seam strength depends on the bonded area created by the overlap. Insufficient overlap reduces the splice's ability to carry peel and shear loads, increasing the risk of separation and leakage.

Question 50EPDM roof system installation knowledge and performance

A crew is installing EPDM over a concrete deck. Which substrate preparation step is essential before applying bonding adhesive?

  1. Cleaning and priming the concrete to remove dust and improve adhesion Correct answer.
  2. Painting the concrete with asphalt
  3. Wetting the surface to improve grip
  4. Applying a layer of ballast

Explanation

Concrete can be dusty, porous, and alkaline, which can interfere with adhesive bonding. Cleaning and priming create a suitable surface for the adhesive to bond the membrane.