Based on the Red Seal Lather (Interior Systems Mechanic) exam blueprint: steel framing, drywall, ceilings, fire and sound barriers and exterior systems
Practice on the go and jump straight back to where you left off.
About the certification
In Ontario, Drywall, Acoustic and Lathing Applicator is trade code 451A, a non-compulsory trade administered by Skilled Trades Ontario. Across Canada it is the Red Seal trade Lather (Interior Systems Mechanic), so passing the Certificate of Qualification exam also earns the interprovincial Red Seal endorsement.
The Red Seal exam has 125 multiple-choice questions in 4 blocks: common occupational skills (27 questions), framing activities (37), interior systems (45) and exterior systems (16). Between 20 and 40% of the questions test knowledge and recall, 55 to 60% procedural and application, and under 10% critical thinking. The Red Seal self-assessment guide gives the pass mark as 70%.
ExamHub's free 451A practice quiz has 181 original questions weighted to the real exam blocks and tasks, with an explanation and a source for every answer. Questions draw on Ontario's Construction Projects regulation (O. Reg. 213/91), the Ontario Building Code and free public gypsum, steel framing and ceiling guides; rules that come from one manufacturer or one project specification are labelled as such.
What's covered
Categories follow the 4 Red Seal exam blocks; the bank puts the same emphasis on each area as the real exam.
Try a few
Five sample questions from the question bank, with the answer and explanation.
Why: O. Reg. 213/91 s. 26.3(4) sets the top of a guardrail system at 0.9 m minimum and 1.1 m maximum above the surface it is installed on. The system also needs an intermediate rail midway between the top rail and the toe board, and a toe board at least 89 mm high. The 1.0 to 1.2 m range sounds reasonable but allows heights the regulation does not.
Why: Steel stud framing is installed 13 mm short of the underside of the roof or floor structure and left free to move, so the slotted track can absorb structural deflection. Screwing through the slots or running studs tight defeats the deflection allowance.
Why: GA-216 s. 4.2.2.1: loose-fill (attic) insulation is installed right after the ceiling panels are applied and before panel joints are taped or any other wet finishing begins. Wet finishing under unprotected cold surfaces adds moisture that can lead to sag. Source: GA-216-2010 s. 4.2.2.1.
Why: CGC states that in multi-layer applications only the joints of the face layer need be finished. Finishing the base layer joints is not required for the fire rating. Corner joints are not an exception to this rule.
Why: Sentence 9.25.3.3.(9) requires penetrations of the air barrier system, such as electrical wiring, boxes, piping or ductwork, to be sealed with compatible material such as tape or caulking so the air barrier stays continuous over the entire surface. Loose insulation does not provide an air seal. Source: OBC O. Reg. 332/12 Art. 9.25.3.3.
FAQ
The Red Seal Lather (Interior Systems Mechanic) exam has 125 multiple-choice questions. ExamHub's bank has 181 questions, and Test Mode draws a 125-question timed simulation.
The Red Seal self-assessment guide for this trade gives the pass mark as 70%. The Red Seal exam page does not state a time limit, and ExamHub's Test Mode allows up to 4 hours.
4 blocks: common occupational skills (27 questions), framing activities (37), interior systems (45) and exterior systems (16).
No. Drywall, Acoustic and Lathing Applicator (451A) is a non-compulsory trade in Ontario. Skilled Trades Ontario issues the Certificate of Qualification when the exam is passed, and the trade is part of the Red Seal program as Lather (Interior Systems Mechanic).
No. These are original practice questions written from the Red Seal standard and free public sources. They are not copies of exam questions.