Drywall Finisher & Plasterer (453A) — Red Seal

Performs common occupational skills

What setup ratio is correct for a portable straight ladder reaching upper walls during taping?

1. Vertical orientation (1:1) so the climber does not have to lean
2. Base out one unit per four units of working height (4:1)
3. A 2:1 ratio for a steeper, faster climb to the top of the wall
4. Whatever feels stable once three-point contact is in place

The accepted geometry is a 4:1 ratio — the base of the ladder is set out one unit from the wall for every four units of working height (approximately 75°). The ladder must extend at least 1 m (about 3 ft, or three rungs) above the upper landing/support point. A vertical setup tips backward under any weight shift. A 2:1 ratio over-leans the ladder so the feet slide out as the worker climbs. Three-point contact protects climbing posture but does not replace the setup angle that prevents the base from sliding in the first place.

RSOS 2023 | A-2.01 Uses access and lifting equipment

Prepares, tapes and finishes drywall

During dry taping on a level seam, what width of mud is applied before paper tape goes down?

1. A six-inch spread of compound applied to the flat joint section
2. A two-inch ribbon of mud centred on the seam line only on the job
3. A spot of mud at each end of the joint with bare gypsum between
4. A continuous bead of caulk run along the seam before paper tape

Dry taping applies compound to both sides of angles, a six-inch spread on flat joints, then paper tape, overlapped and wiped down with a taping knife. The six-inch band gives the paper full bedding across the recessed factory edge so the centre line of the joint and the feather edges all sit on compound. A narrow ribbon leaves the tape edges unbonded. Spot mud leaves long bare runs where the tape blisters. Caulk has no embedment medium and the tape will not adhere across the joint at all.

RSOS 2023 | B-6.02 Embeds tape

Performs repairs and restorations

Which problems are considered visible drywall failures the finisher must diagnose?

1. Only paint colour drift caused by aging interior light fixtures on the job in the field
2. Mould, screw pops, water damage, cracks, bubbles, holes, fire and smoke damage
3. Furniture impact marks that occur after occupancy by the homeowner
4. Only manufacturer label residue left on the sheet during installation work

The recognized problem set includes mould, screw pops, water damage, cracks, bubbles, blisters, holes, fire damage, smoke damage. Each is a discrete failure mode with its own root cause and repair path. Paint colour drift is a paint defect handled by the painter. Furniture impact damage occurs after the finisher has handed off and is a touch-up scope item or warranty call. Manufacturer label residue is a hanging-stage concern, not a finishing-stage failure mode requiring root-cause assessment under the troubleshooting subtask.

RSOS 2023 | C-8.01 Determines cause of problem