Plasterboard Meaning: What Ontario Homeowners Should Know

If you've come across the term plasterboard while researching a renovation or new build in Ontario, you're not alone. The word shows up in British product listings, older Canadian building specs, and conversations with contractors who trained in the UK or Australia — and it can leave homeowners wondering whether it's the same as drywall, a different product entirely, or something to specifically request. Understanding the plasterboard meaning puts you in a better position to communicate clearly with your contractor, read building material specs, and make informed decisions about your project.

Plasterboard Meaning: The Definition

Plasterboard is a rigid wall and ceiling panel made from a gypsum core sandwiched between two sheets of paper. The gypsum — a soft calcium sulphate mineral — is mined, processed into a slurry, and poured between a backing sheet and a face sheet of paper. Once the panel cures and dries, it's cut to size and shipped to job sites. When installed on wall or ceiling framing, plasterboard creates a flat, paintable surface that can be finished smooth or textured.

In Canada and the United States, this same product is called drywall — or sometimes gypsum board, gypsum wallboard, or Gyproc (a common trade name). The term plasterboard is the standard name used in the United Kingdom, Ireland, Australia, and New Zealand. You may also see it labelled as plasterboard in product data sheets from European manufacturers or in older Canadian building literature that drew on British standards. Regardless of the name, the product is functionally the same.

Plasterboard = drywall = gypsum board = Gyproc. These are all the same product. In Ontario, your supplier and contractor will almost universally use the term drywall or gypsum board.

Why the name 'plasterboard' makes sense

The name is actually quite descriptive. Before plasterboard was invented in the early 1900s, interior walls were built using wet plaster applied in two or three coats over a wood lath frame — a slow, highly skilled, and expensive process. Plasterboard (or drywall) replaced that system by delivering a dry, pre-made board that mimics a plaster finish. The 'plaster' in the name refers to the gypsum core, which behaves similarly to plaster, and the 'board' refers to its rigid sheet form. The North American name 'drywall' simply emphasises that it installs dry — no wet plaster coats required.

Plasterboard Types Used in Ontario Construction

Whether you call it plasterboard or drywall, not all sheets are the same. Ontario contractors select different panel types based on location, fire requirements, moisture exposure, and acoustic needs. Here are the most common types you'll encounter on a GTA project:

• Regular gypsum board (white board): The standard interior panel, available in 3/8", 1/2", and 5/8" thicknesses. Used on most walls and ceilings in dry, conditioned areas.
• Type X fire-rated board: Contains glass fibres in the core that slow combustion. A single layer of 5/8" Type X provides a 45-minute fire rating, while double-layered assemblies can achieve 1 to 2 hours.
• Moisture-resistant board (green board): Has a moisture-resistant paper face and is used in bathrooms, laundry rooms, and other high-humidity areas — though it is not waterproof and should not be used as a direct tile backer.
• Cement board / tile backer: Not technically gypsum board, but often grouped with plasterboard products. Used as a tile substrate in showers and wet areas.
• Soundproof drywall (QuietRock or IsoMax assemblies): Engineered panels with laminated viscoelastic polymer layers that significantly improve STC (Sound Transmission Class) ratings.
• Abuse-resistant board: Has a fibreglass-reinforced core and harder face paper, designed for high-traffic commercial corridors and stairwells.
• Flexible board: Thinner (1/4") panels designed to curve around arched openings and radiused walls.

The most common plasterboard thickness in Ontario residential construction is 1/2" for walls and 5/8" Type X for garage-to-living-space separations and fire-rated assemblies. Ceilings in most homes use 1/2" or 5/8" board, with 5/8" preferred on longer joist spans to reduce sag over time.

Plasterboard vs lath and plaster: older Toronto homes

If you own a Toronto home built before approximately 1950, there's a reasonable chance the original interior walls are still lath and plaster rather than plasterboard. Lath-and-plaster walls consist of narrow horizontal wood strips (lath) nailed across the studs, with three coats of lime or gypsum plaster applied over top. These walls are hard, dense, and highly resistant to sound transmission — but they crack with settling, are nearly impossible to patch invisibly, and add significant weight. During renovations, most contractors replace damaged lath-and-plaster sections with standard 1/2" drywall. A full replacement of lath and plaster with plasterboard is a significant but worthwhile upgrade on a whole-home renovation.

Ontario Building Code Requirements for Plasterboard

The Ontario Building Code (OBC) — O. Reg. 332/12 governs how gypsum board must be installed in new construction and major renovations across the province. Understanding these requirements helps you confirm your contractor's work meets minimum standards.

• Garage-to-dwelling separation: The OBC requires a minimum 5/8" Type X gypsum board on the garage side of any wall or ceiling separating a garage from the living space. This is one of the most commonly cited fire code requirements on residential projects.
• Basement suite fire separations: Fire separations between a secondary suite and the rest of the house must achieve a minimum 30-minute fire-resistance rating, typically accomplished with a single layer of 5/8" Type X.
• Vapour barrier placement: In above-grade walls, a polyethylene vapour barrier is installed between the insulation and the plasterboard. The board goes on after the barrier — never in contact with the exterior sheathing without a thermal break.
• Fastener spacing: The OBC references CSA A82.27, which specifies screw or nail spacing for gypsum board installation. Typically, screws are spaced maximum 300 mm (12") on centre for ceilings and 400 mm (16") for walls.
• Ceiling sag prevention: Boards installed on ceilings must span no more than 610 mm (24") between supports for 1/2" board, or up to 610 mm for 5/8" board when the long edge runs perpendicular to the framing.
• Firestop requirements: All penetrations through fire-rated plasterboard assemblies (pipes, electrical boxes, ducts) must be sealed with listed firestop products to maintain the rating.

If your renovation touches a fire separation — basement suite, garage wall, or party wall between units — always confirm your drywall type and assembly with your permit drawings. Using standard 1/2" board where 5/8" Type X is required is a common and costly inspection failure.

Plasterboard and vapour control in Ontario's climate

Ontario falls primarily within ASHRAE Climate Zone 6, where heating dominates for six or more months of the year. This means moisture management behind the plasterboard is critical. The warm, humid interior air in winter tries to migrate outward through the wall assembly; if it reaches the cold sheathing without a vapour barrier, condensation occurs inside the wall cavity. The standard Ontario wall assembly — from interior to exterior — is: plasterboard, vapour barrier, batt insulation between studs, exterior sheathing, house wrap, cladding. The plasterboard itself is not a vapour barrier, but it does act as the finished interior surface that the poly barrier is stapled against.

How Plasterboard Is Installed on a GTA Project

Whether you're finishing a basement, adding a room, or drywalling a full new build, the installation process follows a consistent sequence. Understanding these steps helps you manage your project timeline and communicate expectations with your drywall contractor.

1. Frame inspection and prep: Before any board goes up, the framing must be straight, plumb, and at the correct spacing — typically 16" or 24" on centre. Any blocking required for fixtures (cabinets, grab bars, TV mounts) must be added at this stage.
2. Rough-ins complete: Electrical, plumbing, and HVAC rough-in must be inspected and approved before the walls are closed in. In Ontario, this typically means a rough-in inspection from the municipal building department.
3. Vapour barrier installation: 6-mil polyethylene sheeting is stapled to the warm side of the wall framing, lapped at seams, and acoustically sealed at penetrations and perimeters with acoustic sealant.
4. Board hanging: Plasterboard sheets are cut to size and fastened to the framing using drywall screws (preferred over nails for residential work). Ceilings are done first, then walls. Boards are typically hung horizontally on walls to minimise the number of butt joints.
5. Taping and mudding: Joint compound (mud) is applied over the taped seams in multiple coats — typically a tape coat, a fill coat, and a finish coat — with light sanding between coats.
6. Priming and finishing: Once all seams are sanded smooth and the surface is dust-free, a drywall primer is applied before painting or texturing. Skipping primer is one of the most common mistakes on DIY projects.

The taping and finishing stages are where the quality of the work becomes visible. A poorly taped wall will show seams, cracks, and screw pops within the first year — especially on ceilings in homes with seasonal humidity swings. Professional taping and multiple skim coats produce a Level 4 or Level 5 finish, which is the standard for painted walls and ceilings in Ontario residential construction. Level 5 — a full skim coat over the entire surface — is recommended under critical lighting conditions or with gloss paints.

Common plasterboard installation mistakes in Ontario homes

• Hanging boards with the paper face against the vapour barrier rather than the room — this traps moisture
• Using 1/2" board on ceilings with 24" joist spacing, leading to visible sag within a year
• Skipping acoustic sealant at the base of walls, which undermines soundproofing in party walls and suites
• Failing to back-block butt joints, causing ridging and cracking at end-to-end seams
• Over-driving screws and tearing the paper face, which weakens the holding power of the fastener
• Using moisture-resistant (green) board instead of cement board in shower tile assemblies

Plasterboard Costs in Toronto and the GTA

Material and labour costs for plasterboard installation in the GTA vary based on board type, finish level, and project complexity. Here are realistic price ranges as of 2025:

• Standard 1/2" gypsum board (material only): $12–$18 per sheet (4'×8') from GTA suppliers
• 5/8" Type X fire-rated board (material only): $16–$22 per sheet
• Soundproof drywall (e.g., QuietRock): $80–$120 per sheet, depending on thickness and rating
• Labour — hang only: $1.50–$2.50 per square foot for residential work
• Labour — hang, tape, and finish to Level 4: $3.50–$5.50 per square foot
• Full basement drywall (hang, tape, finish): $4,500–$9,000 for a typical 1,000 sq ft basement
• Garage-to-house fire separation (Type X install): $800–$1,800 depending on square footage

These are supply-and-install estimates. Costs increase when there are high ceilings, complex ceiling details like coffers or soffits, or when extensive soundproofing assemblies are specified. Labour costs in the City of Toronto tend to run 10–15% higher than in outer 905 municipalities due to travel time, parking, and higher overhead for trade contractors operating in the city core.

It's worth noting that spending more on quality taping and finishing is almost always a better investment than upgrading finishes before the substrate is properly done. A premium paint on a poorly taped wall will highlight every imperfection. Budget accordingly: the finishing stage should represent roughly 40–50% of total drywall labour costs on a well-run project.

Is plasterboard the right choice compared to other interior finishes?

For most Ontario residential and light commercial projects, plasterboard (drywall) is the clear choice on cost, speed, and availability. Alternatives like wood panelling, fibre cement board, or reinstating traditional wet plaster are either far more expensive, harder to source, or require a skill set that's becoming increasingly rare. The one area where a different substrate genuinely outperforms standard plasterboard is in tile wet areas: always use a tile-specific cement board or waterproof backer in showers and around bathtubs, regardless of what a budget contractor may suggest.

Work with a Drywall Contractor Who Knows the Difference

Now that you understand the plasterboard meaning and how it applies to Ontario construction, the next step is working with a contractor who handles installation with the right materials, correct OBC compliance, and a clean finish. Konstruction Group provides drywall installation and drywall taping and finishing services across the GTA, from single-room renovations to full new builds and multiplex projects. We work to the finish level your project demands — and we pull the permits when required.