ACT Shower Receptors

TCNA Handbook Method B415 illustrates a residential shower receptor that drains water at two levels. What is this drain principle called?

• ASingle-stage gravity drainage
• BTwo-stage water-in, water-out drainage
• CPressure-balanced backflow drainage
• DLinear trench drainage

According to TCNA B415, what minimum slope must the pre-slope under the pan liner have toward the drain?

• A1/8 inch per foot
• B1/4 inch per foot
• C1/2 inch per foot
• D1 inch per foot

What is the function of the pre-slope in a TCNA B415 shower assembly?

• ATo compensate for an out-of-flat finished floor surface
• BTo tilt the pan liner toward the drain so trapped water exits through weep holes
• CTo support the weight of the tile and bond it to the substrate
• DTo replace the need for a waterproofing membrane

Which two materials are the most commonly specified sheet pan liners in TCNA B415 installations?

• APolyethylene (PE) and rubberized asphalt
• BChlorinated polyethylene (CPE) and polyvinyl chloride (PVC)
• CBituthene and EPDM only
• DHot-mopped lead sheet and copper

What is the minimum height the B415 pan liner must extend up the walls above the finished curb?

• A1 inch
• B2 inches
• C3 inches
• D6 inches

According to IRC P2709, what is the allowed range for the finished curb height measured from the top of the curb to the top of the drain?

• ANot less than 1 inch and not more than 4 inches
• BNot less than 2 inches and not more than 9 inches
• CExactly 4 inches
• DNot less than 6 inches and not more than 12 inches

IRC P2709 requires the finished curb (threshold) to sit at what minimum distance below the finished sides and back of the shower receptor?

• A1/4 inch
• B1/2 inch
• C1 inch
• D2 inches

IRC P2709 requires the finished shower floor to slope uniformly toward the drain within what range?

• ANot less than 1/8 inch per foot and not more than 1/4 inch per foot
• BNot less than 1/4 inch per foot and not more than 1/2 inch per foot
• CNot less than 1/2 inch per foot and not more than 1 inch per foot
• DNo minimum or maximum is specified

What is the role of the weep holes in a B415 two-stage shower drain?

• AThey release positive air pressure from the trap below the drain
• BThey allow water that has penetrated the tile and mortar to exit at the pan liner level
• CThey vent sewer gases from beneath the slab
• DThey equalize hot and cold water pressure

Which of the following is an approved method for protecting drain weep holes during placement of the top mortar bed?

• ASealing the weep holes with silicone caulk
• BPlugging the weep holes with mortar to be drilled out later
• CSurrounding the drain barrel with pea gravel or a manufactured weep hole protector
• DLeaving the weep holes uncovered with no protection at all

What approximate minimum thickness for the top mortar bed (over the pan liner) is specified for a B415 shower receptor per ANSI A108.1A-2.3.6?

• A1/2 inch
• B1-1/4 inch
• C3 inches
• DThere is no minimum

In a B415 assembly, how should the pan liner be handled at an inside corner where two walls meet?

• ACut the liner along the corner and seal with caulk
• BFolded against the wall — never cut
• CTrimmed to a strip and stapled into the corner
• DLeft out of the corner and replaced with sheet metal flashing

At an outside corner of a curb (such as where the curb meets a door jamb), what detail does TCNA B415 specify for waterproofing the cut liner edges?

• AA field-fabricated lap joint sealed with silicone
• BA preformed dam corner adhered with liner-compatible sealant
• CA bead of grout pressed into the corner
• DAluminum L-flashing nailed over the cut

Why are fasteners not permitted through the pan liner below the height of the finished curb?

• AFasteners would create code violations in inspection
• BAny penetration below the curb height becomes a potential leak under water head pressure
• CFasteners interfere with the drain clamping ring
• DThey make the curb visually unattractive

IRC P2709 requires the drain flange to be installed in what relationship to the subbase?

• ARecessed at least 1/2 inch below the subbase
• BFlush with the subbase
• CProud of the subbase by at least 1 inch
• DSet on a layer of compressible foam

The dry-pack (deck mud) used for the B415 pre-slope is best described as which of the following?

• AA high-flow self-leveling underlayment
• BA stiff sand-and-portland-cement mixture with limited water, low slump
• CA thinset mortar with latex additives
• DPure portland cement paste

In a B415 shower with a wood-framed curb, how is the pan liner detailed over the curb?

• AThe liner is cut at the curb and butted against a separate strip
• BThe liner is folded over and wrapped down all three sides (interior face, top, exterior f…
• CThe liner stops at the inside face of the curb
• DThe liner is replaced by sheet metal at the curb

Why is metal lath applied over the wrapped pan liner on the curb in a traditional B415 installation?

• ATo provide a mechanical bond for the mortar bed that will form the finished curb shape
• BTo shield the liner from UV damage
• CTo meet electrical bonding requirements
• DTo reinforce the framing structurally

If the pre-slope under the pan liner is omitted (the substrate is flat), what is the most likely failure mode?

• AThe tile will crack at movement joints
• BWater that penetrates the tile will pond on the flat liner with no path to the weep holes
• CThe grout will be permanently discolored
• DThe drain will overflow during normal use

What is the typical thickness of Chloraloy CPE shower pan liner used in B415 assemblies?

• A10 mils
• B20 mils
• C40 mils
• D100 mils

For seaming a CPE pan liner (such as Chloraloy), which adhesive is normally specified?

• APVC solvent cement
• BSilicone caulk
• CA CPE-compatible chemical weld adhesive (e.g., Oateyweld or manufacturer-approved equival…
• DConstruction adhesive (Liquid Nails)

Which best describes the order of installation in a TCNA B415 shower receptor (bottom to top)?

• ATile, top mortar bed, pan liner, pre-slope, subfloor
• BSubfloor, pre-slope, pan liner, top mortar bed, thin-set, tile
• CSubfloor, pan liner, pre-slope, top mortar bed, tile
• DSubfloor, top mortar bed, pre-slope, pan liner, tile

Why is the pan liner loose-laid (not adhered) over the pre-slope in a B415 assembly?

• AAdhesive would discolor the tile above
• BThe liner must be free to accommodate movement and not be punctured or stressed by uneven…
• CLoose laying speeds the installation and saves labor cost
• DAdhered liners cost more

If a local plumbing code is more restrictive than IRC P2709 (for example, requiring a 1-1/2 inch curb height differential below sides/back), which governs?

• AThe IRC P2709 minimum
• BTCNA B415
• CThe local plumbing code (more restrictive provision)
• DManufacturer instructions

What is the purpose of the clamping ring on a two-stage shower drain?

• ATo support the strainer weight
• BTo mechanically clamp and seal the pan liner between the drain flange and the ring, formi…
• CTo trap debris before it reaches the trap
• DTo attach the drain to the framing

How should holes be cut into the pan liner for the drain barrel and clamping ring bolts?

• ACut a large square opening for clearance and trim later
• BCut precisely around the drain barrel and bolt holes so the clamping ring sits firmly on…
• CBurn the holes through with a torch for a tight seal
• DSlit the liner radially from the center

After the top mortar bed cures, how is the pan liner assembly typically tested for leaks before tile is set?

• AVisual inspection only
• BA flood test — plug the drain weep holes and strainer, fill the receptor with water to wi…
• CSpraying with a garden hose for 5 minutes
• DSmoke testing through the drain

What is the slope tolerance the top mortar bed must avoid in a B415 shower receptor?

• AHumps or valleys that impede water flow toward the drain
• BSlight texture from the wood float
• CColor variation within the mortar
• DMinor surface dusting after cure

Why is a wood subfloor reinforced or sheathed differently for a B415 shower receptor than for a dry-area floor?

• AShower mortar beds are much heavier and require additional dead-load capacity
• BShower areas always require steel framing
• CShower floors must vibrate dampen
• DThere is no special framing requirement

What is the typical sequence for installing a preformed dam corner at the outside corner of a curb?

• ASet the corner first, lap the pan liner under it, no sealant required
• BLap the pan liner over the corner, no fasteners or adhesive
• CApply liner-compatible sealant/adhesive to the dam corner contact area, press the dam cor…
• DUse roofing nails to hold the dam corner in place

Within the ACT Consortium, who is jointly responsible for administering the ACT Shower Receptors certification?

• ACTEF and IMI in partnership with NTCA, TCAA, and IUBAC
• BOSHA and the EPA
• CASTM and ANSI
• DICC and the local plumbing inspector

A shower drain barrel projects 1/4 inch above the surrounding subbase after the rough plumbing is installed. What is the proper installer response before placing the pre-slope?

• ABuild the pre-slope around the high drain and continue
• BCoordinate with the plumber so the drain flange is set flush with the subbase; if not cor…
• CCover the drain with sheet metal and re-pour
• DDrill the drain barrel down with a hole saw

If the top mortar bed is poured before the weep hole protector is installed, what is the practical result?

• ASlightly slower curing
• BMortar packs into the weep holes and the secondary drain path is permanently sealed, trap…
• CThe drain strainer fits more tightly
• DImproved bonding between liner and mortar

Which of the following is NOT permitted in a TCNA B415 assembly?

• ASheet pan liner of CPE or PVC
• BTwo-stage clamping drain with weep holes
• CPan liner penetrated by drywall screws at the bottom of each wall
• DFolded inside corners with continuous liner

What is the role of the pre-slope thickness at the drain in a B415 receptor?

• AIt can taper to zero at the drain so the liner sits flush with the drain flange
• BIt must be at least 1 inch thick at the drain
• CIt must be at least 3 inches thick at the drain
• DIt must be the same thickness as the top mortar bed

Why must the pre-slope cure (set up) before the pan liner is laid over it?

• AWet mortar would stain the underside of the liner
• BAn uncured pre-slope can compress, deform, or be damaged by foot traffic, destroying the…
• CLiner adhesives require dry substrate
• DCure time prevents efflorescence

Which TCNA Handbook detail is the primary residential 'water-in/water-out' shower receptor method using a sheet pan liner?

• AB414
• BB415
• CF125
• DEJ171

Why is the curb finished AFTER the liner is wrapped and lath is applied — not before?

• ASo tile can be installed first
• BBecause the wrapped liner and lath provide the mechanical key and waterproof base for the…
• CBecause the plumber sets the curb
• DBecause IRC requires the curb finish be done first

Which statement about the pan liner and the curb in B415 is correct?

• AThe pan liner ends at the inside face of the curb
• BThe pan liner is brought over the curb so the entire curb is waterproof on three sides (i…
• CThe curb itself is fully waterproof by tile and grout — no liner is needed
• DOnly the inside face of the curb requires liner

What is the most common 'never-dries' failure mode for a B415 shower receptor?

• AStrainer clogged with hair
• BWeep holes blocked by mortar with no weep hole protector installed
• CTile installed with the wrong color grout
• DInsufficient mortar coverage under the tile

Which best describes the proper relationship between the pre-slope slope and the top mortar bed slope?

• AThe pre-slope is steeper than the top bed
• BThe top bed is steeper than the pre-slope
• CBoth slope toward the drain at the same rate (typically 1/4 inch per foot)
• DNeither needs to slope if a linear drain is used

When tile is set over the cured top mortar bed of a B415 shower, what bond material is appropriate?

• AMastic (organic adhesive)
• BANSI A118.1 or A118.4 thin-set mortar appropriate for wet area service
• CPVA glue
• DConstruction adhesive

Which corner detail of the pan liner is MOST likely to be flagged during a third-party ACT field assessment?

• AA clean folded inside corner with no cuts
• BAn outside curb-jamb corner with a preformed dam corner sealed with manufacturer-approved…
• CA cut inside corner sealed with silicone caulk
• DA pan liner extended 3 inches above the curb on all sides

The pan liner is which of the following in the assembly hierarchy?

• ADecorative finish layer
• BVapor retarder only
• CPrimary waterproofing layer that intercepts and drains water through the weep holes
• DStructural support layer

Which of these is the correct slope expressed as a percent for 1/4 inch per foot?

• AApproximately 1 percent
• BApproximately 2 percent
• CApproximately 5 percent
• DApproximately 10 percent

Which prerequisite must a candidate meet to sit for the ACT Shower Receptors written/online exam?

• AA college degree in construction management
• BHold the CTI credential OR be an IUBAC journeyman tile setter
• CA state plumbing license
• DTwo years of HVAC experience

What is the passing score on the ACT Shower Receptors WRITTEN exam?

• A70%
• B75%
• C80%
• D84%