Ontario's Drywall, Acoustic and Lathing Applicator apprenticeship, trade code 451A, the Red Seal Lather trade: Grade 10 entry, two levels, 4,800 hours on the job plus 600 hours of in-school training, voluntary status, and the certifying exam.
Applies in: Ontario
In Ontario, a lather apprentice registers under the trade name Drywall, Acoustic and Lathing Applicator, code 451A. Find a drywall, lathing, or interior systems contractor willing to sponsor you, register the apprenticeship with Skilled Trades Ontario, and work through two levels that combine 4,800 hours on the job with 600 hours of in-school training, 5,400 hours in total. At the end, the trade has a certifying exam, and passing it earns a Certificate of Qualification with the Red Seal endorsement under the name Lather (Interior Systems Mechanic), recognized across Canada.
The name causes the first confusion. Job postings say lather, drywall installer, or interior systems mechanic. The Ontario system says Drywall, Acoustic and Lathing Applicator 451A. They are the same apprenticeship. Skilled Trades Ontario lists Drywall, Acoustic and Lathing Applicator 451A as a Red Seal trade, and its trade report ties the trade to the Red Seal name Lather (Interior Systems Mechanic). Use code 451A whenever a form asks for the trade, and expect Lather (Interior Systems Mechanic) on the national exam material.
The second point matters just as much. Drywall, Acoustic and Lathing Applicator is a non-compulsory trade in Ontario. Nobody needs a licence or certificate to do lathing and interior systems work in this province, and you can work in the trade without ever registering. The apprenticeship is not permission to work. It is structured training, a logbook of signed-off skills, a Certificate of Apprenticeship, and the path to the certifying exam and the Red Seal endorsement. Do not assume the Ontario rule travels with you. Job Bank records lather certification as compulsory in Quebec and voluntary in all other provinces and the Yukon. If Quebec is in your plans, the certification requirement there is a different conversation.
What the trade covers, in Skilled Trades Ontario's own description, is erecting exterior structural steel studs and sheathing, shaft wall systems, installing and finishing lath and drywall, partition walls and furring, ceiling systems, and access flooring types, as well as applying thermal and sound insulation. A lather reads, interprets, and applies blueprints and specifications for job layout, erects light gauge steel studs and demountable partitions, applies insulation and fire stopping, and installs lath, drywall, moulded and cast forms, and ceiling systems. This is framing and lining work: the steel and board skeleton that other trades then finish. It is not the same trade as Drywall Finisher and Plasterer 453A, which finishes and plasters surfaces. The two trades share a National Occupational Classification group, 73102, but they register under different codes and follow different training standards.
The sponsor comes first. Skilled Trades Ontario is clear that an apprenticeship begins when you sign a Training Agreement with a sponsor and register it, and that finding a sponsor is the key first step. A sponsor can be an individual employer, such as a drywall and lathing contractor, an interior systems firm, or a commercial framing contractor, or a group of employers, such as a union or consortium.
The application steps, from Skilled Trades Ontario's start-an-apprenticeship page, are:
The program totals 5,400 hours: 4,800 hours of on-the-job training and 600 hours of in-school training across two levels. The apprenticeship programs chart marks the trade as hours-based, which means you must complete the on-the-job training for the entire duration of the prescribed hours, and hours-based trades carry a ratio of one journeyperson to one apprentice. About 80 per cent of an Ontario apprenticeship is paid work on the job and about 20 per cent is classroom learning, according to Skilled Trades Ontario.
The rhythm is work, then a block of in-school training, then work again. The in-school training runs on the layout and blueprint reading the trade depends on, alongside the installation methods for stud, lath, drywall, and ceiling systems. Attend when invited through the training system, keep your logbook current, and make sure your recorded hours match what your sponsor reports. Lathing work punishes careless measuring in a way that shows up later: a wall framed out of square or a ceiling set off level is visible in every finished surface, which is why the logbook skills around layout, levelling, and cutting exist.
Drywall, Acoustic and Lathing Applicator 451A has a certifying exam. Skilled Trades Ontario issues a Certificate of Apprenticeship when you complete the apprenticeship program, and a Certificate of Qualification when you pass the certifying exam. Because the trade is part of the Interprovincial Red Seal Program under the title Lather (Interior Systems Mechanic), passing the exam also carries the Red Seal endorsement, which is the credential recognized in every province and territory.
Experienced lathers who never registered have a parallel door. The Trade Equivalency Assessment lets experienced tradespeople document equivalent qualifications or experience and seek the Certificate of Qualification without completing the apprenticeship. The application guide requires verifiable evidence of competency against the Training Standard and experience at least equal to the required training time, 5,400 hours for this trade, supported by work experience verifications from references who know the work first-hand.
Do not start work assuming the Ontario voluntary status applies everywhere in Canada. Quebec treats lather certification as compulsory, so check the destination province before you move for work. Do not confuse this trade with Drywall Finisher and Plasterer 453A, which is the finishing and plastering trade, or with General Carpenter, which frames in wood rather than steel stud and drywall systems. Do not let months of site work go unrecorded. In an hours-based trade, unrecorded hours are hours you may have to work again, so keep the logbook signed and the hours submitted. And do not pay for a course that promises the certificate on its own. The certificate comes through Skilled Trades Ontario on completion of the program and the certifying exam, not through a private training provider alone.
Drywall, Acoustic and Lathing Applicator, trade code 451A. That is the Ontario trade name in the Skilled Trades Ontario apprenticeship programs chart, and the Red Seal title is Lather (Interior Systems Mechanic). The national occupation group is Plasterers, drywall installers and finishers and lathers, National Occupational Classification 73102, a group the lather trade shares with Drywall Finisher and Plasterer 453A, a different Ontario trade. When a form asks for the trade, put down 451A. The code, not the shared NOC group, is what separates this apprenticeship from the plastering and finishing trade.
The program is 5,400 hours: 4,800 hours of on-the-job work experience and 600 hours of in-school training, delivered across two levels. Skilled Trades Ontario describes the on-the-job portion as approximately three years, and the trade report describes the technical training as five months across two levels. The apprenticeship programs chart marks the trade as hours-based, which means you complete the full prescribed on-the-job hours rather than progressing on competency sign-off alone. Job Bank describes the occupation route as a three- or four-year apprenticeship program in plastering, drywalling, or lathing, or a combination of over three years of work experience and some high school, college, or industry courses in plastering, drywalling, or lathing. The hours are the fixed part; the calendar time follows how steadily the work comes.
No. Drywall, Acoustic and Lathing Applicator 451A is non-compulsory in Ontario. You do not need to be a registered apprentice or a certificate holder to do lathing and interior systems work in this province, though registration is still how you get the structured training, the Certificate of Apprenticeship, and the certifying exam. Job Bank records the national position for lathers (interior systems mechanics) the same way: trade certification is compulsory in Quebec and available, but voluntary, in all other provinces and the Yukon. Do not assume the Ontario rule travels with you to Quebec.
Grade 10 is the academic entry grade listed in the Skilled Trades Ontario apprenticeship programs chart for Drywall, Acoustic and Lathing Applicator 451A. Skilled Trades Ontario also requires apprentices to be at least 16 years old, to have legal permission to work in Canada, and to have a sponsor in Ontario. Job Bank describes completion of secondary school as usually required for the occupation nationally, so treat Grade 10 as the floor, not the competitive standard: a diploma, and comfort with measuring, layout, and reading drawings, will matter to a sponsor deciding whether to take you on. The in-school training runs on blueprint reading and layout, so math and technical reading are worth arriving with.
First find a sponsor, an employer or group sponsor responsible for your training. Then apply: if you are 18 or older, apply online through the Skilled Trades Ontario Portal; if you are 16 or 17, or you cannot apply online, complete the paper Application for Apprenticeship Training, signed by you, a parent or guardian if you are under 18, and your sponsor, and submit it to Skilled Trades Ontario. Once approved, you and your sponsor sign a Training Agreement, which registers you as an apprentice, and you receive a Registered Apprentice Wallet Card.
Yes, through the Trade Equivalency Assessment. It exists for tradespeople who never completed an Ontario apprenticeship but hold equivalent qualifications or experience and want an Ontario Certificate of Qualification. The bar is documented proof: competency against the Training Standard and experience at least equal to the required training time, which the Trade Qualifier guide records as 5,400 hours for this trade, supported by work experience verifications from references who saw the work. Check the current Trade Qualifier application guide before relying on that route, because the evidence bar is documentary.
Where a figure could not be verified on a Skilled Trades Ontario or Job Bank page at the time of writing — any examination fee, any wage figure, and the calendar dates of the in-school training blocks — this guide says so and points to the Skilled Trades Ontario trade page instead of carrying a secondary source's figure. Check that page before you pay anything or plan around a date.