Lath and Plaster Specialists for Pre-1940 Homes
Toronto Drywall Pro has worked on drywall and plaster systems across the Greater Toronto Area since 2002, and older Toronto homes are a large share of that work. The Annex Victorians, Cabbagetown row houses, Rosedale estates, and Leaside brick semis were all built with lime plaster on wood lath - a durable system when it’s maintained, but one that develops specific failure patterns as it ages.
Not every drywall crew takes on plaster, because it behaves differently than modern gypsum board and the repair approach has to match the material. Our licensed, bonded, and WSIB-compliant crew handles plaster restoration and modern drywall repair in the same visit, so a mixed wall gets one consistent finish.
Plaster Repair Cost in Toronto (2026 Pricing)
- Single crack repair with re-tape and skim coat (3-day cycle minimum): $1,500 to $1,700
- Medium section repair (1 to 4 sq ft): $1,700 to $2,000
- Large section or water-damaged area: $2,000 to $3,000
- Full ceiling conversion (plaster removal + new drywall): Quoted on-site by sq ft
Single-crack repairs are the most common call in pre-1940 homes. Price depends mainly on how much plaster has lost its key, whether the lath behind it is sound, and how much texture matching the surrounding wall needs. Every job starts with a free on-site assessment, usually booked the same week.
What Does Lath and Plaster Repair Involve?
Plaster repair - also called lath and plaster repair, heritage plaster restoration, or lime plaster crack repair - is the process of stabilising, patching, or replacing sections of original plaster ceilings and walls in older buildings. It is specialised work in Toronto because pre-1940 plaster is mechanically keyed to wood lath strips (not glued or screwed), dries out over decades, and cracks in patterns that differ from modern drywall failure.
What Does Plaster Repair Include?
- Probe and tap assessment to identify key failure zones before any cutting begins
- Mechanical re-keying using construction adhesive and washer screws for stable sections
- Removal of fully failed sections down to the lath substrate
- New drywall patch installation over existing lath
- Fibre-reinforced USG Durabond setting compound applied in two coats, with lightweight drywall compound for the final skim
- Skim coat and texture matching to surrounding original plaster surface
- Stain-blocking primer on water-damaged areas so the finish paint coat doesn’t flash or bleed
Who Needs Plaster Repair?
Homeowners in older Toronto neighbourhoods - the Annex, Cabbagetown, Rosedale, Leaside, Riverdale, Forest Hill, and High Park - with pre-1940 plaster ceilings that are cracking, sagging, or showing key failure. Condo boards and unit owners in converted Victorian buildings and older low-rise condos, where original plaster walls sit behind modern finishes. Landlords managing pre-war rental stock and duplexes. Buyers who’ve just taken possession of an older Toronto home and are assessing what needs immediate attention.
Key Failure, Cracks, and Water-Damaged Plaster We Fix
Key failure (plaster separation from lath). The most serious plaster failure. The lime base coat has lost its mechanical grip on the wood lath keys and the ceiling or wall is sagging or hollow-sounding when tapped. Small areas are re-keyed using construction adhesive and plaster washers. Large areas require removal down to the lath and replacement with new drywall.
Crack along lath seams. Plaster cracks that follow straight lines at 16-inch centres are following the lath edges. These are structural movement cracks rather than cosmetic surface cracks. We open them with a grinder, embed fibreglass mesh tape, and skim with setting compound.
Random map cracking (alligatoring). A network of cracks across the face coat indicates the finish coat has dried out and shrunk over decades. The base coat is still sound. We apply a bonding primer, skim with a flexible setting compound, and re-finish.
Water-damaged plaster sections. Plaster that has been wet loses its mineral bond and becomes soft or crumbly. We remove the affected section completely, dry the lath, and install new drywall over the existing lath substrate with the correct transition to the surrounding plaster. If the leak also soaked modern drywall in the same room, our water damage drywall repair service covers it in the same visit.
Plaster bulge without key failure. Sections of plaster that bulge but haven’t separated can be stabilised with plaster washers and adhesive when the face is sound. We probe and tap the area to confirm how much is at risk before recommending stabilisation versus removal.
Why Pre-War Toronto Plaster Fails
In the Annex, Cabbagetown, Rosedale, Leaside, and Forest Hill, the original lime plaster is often still the wall and ceiling substrate after 80 to 100 years. That plaster was installed by tradespeople using techniques and materials that modern drywall crews don’t learn, and it fails differently than gypsum board.
The typical failure sequence in a Toronto pre-war home starts with the finish coat cracking as the plaster dries out over decades, followed by water infiltration through roof or window issues accelerating the base coat separation, and eventually ceiling sections that are hollow-sounding and at risk of falling. The Toronto Drywall Pro crew has worked in hundreds of these homes across the Annex, Riverdale, and Rosedale and understands both the repair options and the point at which conversion to drywall is the better investment.
Repair or Replace? Knowing When to Stop Patching
There’s a point in every plaster ceiling where repair is no longer the right investment. If the key failure covers more than half the ceiling area, re-keying what remains and patching the failed sections leaves the rest of the ceiling at risk - the adjacent sections are usually at the same stage of failure and will need repair within a few years. A full removal and drywall replacement at that point costs less over a 5-year horizon than multiple rounds of partial repair.
We’ll tell you during the estimate which side of that line your ceiling is on. If stabilisation is viable, we scope it accurately with a realistic assessment of how much of the adjacent ceiling is also at risk. If replacement is the better option, we explain why - the material and labour cost difference, the performance difference, and the timeline for the next repair cycle if stabilisation is chosen instead. Ceilings that also carry an old textured finish can be handled alongside popcorn ceiling removal, with dustless containment for asbestos-era pre-1980 homes.
How We Compare
| Feature | Typical Provider | Toronto Drywall Pro |
|---|---|---|
| Assessment | Patch what is visible | Probe and tap test maps every hollow or loose section before cutting |
| Fill material | Premixed joint compound over the crack | Setting-type compound, bonding agent on cut edges, and fibreglass mesh tape |
| Loose plaster | Tear out the whole ceiling | Re-key sound sections with plaster washers, remove only failed areas |
| Dust control | Drop sheets only | Plastic containment, floor protection, and HEPA extraction |
| Crew | Drywall and plaster split across subcontractors | One in-house crew from tear-out to primer |
| Coverage | Varies | Licensed, bonded, WSIB-compliant, $2M insured, operating since 2002 |
Plaster Restoration Across Toronto and the GTA
Toronto plaster repair is our most common plaster call, followed by North York and Etobicoke homes from the same era. We also restore original plaster in older farmhouses and village cores in Richmond Hill and Vaughan, and in early post-war homes in Mississauga and Brampton. Call 647-933-7780 to book a free on-site assessment anywhere in the GTA.
