How does drywall perform compared to plaster walls for Toronto homes in terms of durability and insulation?

Plaster is more durable, harder, and more soundproof than drywall — but drywall is faster to install, easier to repair, far less expensive, and has been the universal standard in Toronto home construction since the 1960s. For GTA homeowners renovating older homes, the plaster-versus-drywall decision comes up constantly, and the right choice depends on the home's character, your budget, and your long-term plans.

Durability is where plaster has a clear advantage. Traditional three-coat plaster over wood lath creates a wall surface that is significantly harder than standard drywall. Plaster resists dents, dings, and surface damage that would easily puncture 1/2-inch drywall. In established Toronto neighbourhoods like Cabbagetown, the Annex, Rosedale, Riverdale, High Park, and Leslieville, original plaster walls in well-maintained homes have lasted 80-120 years. Drywall, by comparison, is a softer gypsum-core panel covered by paper facing — a wayward doorknob or moving-day mishap can punch through it. However, plaster's rigidity is also its weakness. While drywall flexes slightly with the building's seasonal movement (critical in Toronto's freeze-thaw climate), plaster cracks. Hairline cracks in plaster walls and ceilings are nearly universal in older Toronto homes and are caused by decades of foundation settling and framing movement.

Sound insulation is another area where plaster outperforms. A traditional plaster-and-lath wall assembly weighs roughly 3-4 times more than a standard drywall wall, and sound transmission is directly related to mass. Homeowners who strip plaster and replace with standard 1/2-inch drywall often notice a dramatic increase in sound transmission between rooms. If you are replacing plaster with drywall and want to maintain similar sound performance, consider using 5/8-inch drywall or a sound-dampening product like QuietRock ($55-$90 per 4x8 sheet in the GTA) or adding a layer of mass-loaded vinyl behind the drywall.

Thermal insulation is a more nuanced comparison. Plaster itself has slightly better thermal mass than drywall — it absorbs and slowly releases heat, which can moderate temperature swings. However, old plaster-and-lath walls in Toronto homes typically have no insulation in the wall cavities, whereas a modern drywall wall assembly includes insulation (minimum R-20 for basement walls, R-24 for above-grade exterior walls per Ontario Building Code) and a 6-mil polyethylene vapour barrier. A properly insulated and vapour-barriered drywall wall dramatically outperforms an uninsulated plaster wall in terms of actual energy efficiency — which matters enormously in Toronto's climate, where heating costs from October through April are significant.

When to Keep Plaster vs. Replace with Drywall

Keep the plaster if it is in reasonably good condition (no large-scale cracking, delamination from the lath, or water damage), if maintaining the home's heritage character matters to you, and if you are not doing a full gut renovation. Plaster repair — patching cracks, re-adhering loose plaster to lath using plaster washers, and skim coating damaged areas — is a specialized skill, and GTA plasterers typically charge $4-$8 per square foot for repair work. This is more expensive than drywall per square foot, but avoids the mess and cost of full demolition.

Replace with drywall if the plaster is extensively damaged (widespread delamination, water damage, large sections falling away from lath), if you need to access the wall cavities for electrical, plumbing, or insulation upgrades, or if you are doing a full renovation. Removing plaster and lath is one of the messiest demolition jobs in residential renovation — it generates enormous volumes of heavy, dusty debris. Budget $3-$6 per square foot for plaster demolition and disposal, plus $2.50-$4.00 per square foot for new drywall installation and Level 4 finishing. A full room conversion typically runs $3,000-$7,000 depending on size and complexity.

One important note for pre-1990 Toronto homes: original plaster, joint compounds, and textured coatings may contain asbestos. Ontario Regulation 278/05 requires testing before disturbance and certified abatement if asbestos is confirmed. Never demolish plaster in a pre-1990 home without testing first — the cost of a test ($50-$150 per sample) is negligible compared to the health and legal consequences of disturbing asbestos.

For most GTA homeowners, drywall is the practical choice for new work and renovations. Its lower cost, easier repairability, and compatibility with modern insulation and vapour barrier assemblies make it the standard for good reason. Browse drywall professionals in the Toronto Construction Network directory at torontoconstructionnetwork.com/directory?trade=insulation to find contractors experienced with both plaster removal and drywall installation.