Windows and Glass in Toronto: A Guide for Old Toronto and East York
In old Toronto and East York, window problems split between century-old houses with single-pane wood sashes and condo towers with sealed-unit window walls. 36.5% of homes here were built in 1960 or earlier, while 53.4% of households live in buildings of five or more storeys. Either way, most problems end in a glass or hardware repair in the existing frame, and that split decides whether you need a heritage permit, a building permit or your condo corporation's approval first.
Toronto and East York is the city's oldest and most vertical area: 36.5% of dwellings predate 1961 and 53.4% are in apartment buildings of 5+ storeys (2021 Census).
Original wood sashes with single glass are usually best re-glazed, not replaced; the City's heritage grant requires sound or repairable original windows to be kept.
In a heritage conservation district, replacing windows visible from the sidewalk needs a heritage permit; routine maintenance does not.
New glass in an existing sash is generally treated as repair. If a failed frame means a whole window has to go in, Toronto's no-permit rule covers only single-dwelling detached, semi and row houses; in duplexes, apartments and condos that needs a building permit.
Downtown condo glazing is mostly window wall, and a record wave of units completed in 2024–2025 is heading toward its first seal failures.
In a condo, report fogged or broken windows to management first; windows are often common elements under the declaration.
On this page
Old Toronto and East York have the city's oldest houses and most of its newest towers, and that split decides what kind of glass problem you're likely to have. In the Toronto and East York council area, 36.5% of homes were built in 1960 or earlier, yet 53.4% of households live in apartment buildings of five or more storeys. In a Victorian or Edwardian house, the usual jobs are cracked single panes, loose glazing and draughty wood sashes, often on a street where visible window changes need heritage approval. In a condo, it's more often a fogged sealed unit in a window wall or balcony door, and the condo corporation may be the one responsible.
The rules split the same way. New glass in an existing sash is generally treated as a repair, and even a whole same-size window in a single-family house needs no building permit. Replacing a whole window in a duplex, apartment building or condo does, and a heritage conservation district adds its own permit for replacing visible windows. This guide covers the housing, climate and rules that matter here, and why most problems end in a glass or hardware repair rather than a new window.
What the housing looks like here
Compared with the city as a whole, Toronto and East York is denser, older and more likely to be rented.
| 2021 Census | Toronto and East York | City of Toronto |
|---|---|---|
| Apartments, 5+ storeys | 53.4% | 46.7% |
| Apartments, under 5 storeys | 20.5% | 14.0% |
| Single-detached houses | 11.2% | 23.3% |
| Semi-detached houses | 7.7% | 6.2% |
| Condo dwellings (owned + rented) | 36.6% | 30% |
| Rented households | 56.2% | 48% |
| Built 1960 or earlier | 36.5% | 29% |
| Built 2016–2021 | 11.2% | 7% |
Victorian and Edwardian houses: Cabbagetown, the Annex, Riverdale
Cabbagetown is the largest continuous area of preserved Victorian housing in North America, with most of its brick houses dating from before the First World War. The Annex's large Victorian and Edwardian houses were mostly built between 1880 and the early 1900s.
Where original windows survive in these houses, they are typically wood sashes with single panes of glass. That's the type the City's heritage grant asks owners to keep and restore. Their problems are glass and glazing problems, not seal failures: a cracked pane, dried-out putty that lets the glass rattle, a sash that sticks or has been painted shut.
Single glazing also explains the winter condensation many owners fight. A single-glazed window loses about 10 to 20 times as much heat as the same area of insulated wall, and a storm window or sealed double unit cuts that loss almost in half. At −18 °C outside, single glazing starts to condense at roughly 12–27% indoor humidity, against 41–49% for double glazing. Keeping winter humidity near the low end of Health Canada's 30–50% range also helps. For a sound original sash, the answer is usually re-glazing, fresh putty and freeing the sash, not a new window.
East York: veterans' housing, second storeys and towers
East York grew differently. After the Second World War it took in returning veterans, and many inexpensive homes were built by the government, including around Topham Park, predominantly single-detached homes with front yards and back gardens. Many of those bungalows have since added second floors, while apartments became plentiful in Thorncliffe Park and Crescent Town.
The result is houses with two or three generations of windows: an original opening, a 1990s replacement and a sealed unit installed with the second-storey addition. Sealed units wear out gradually. In a 25-year field study of more than 2,400 units, 4.9% had failed at 10 years, 7.9% at 15 and 9.2% at 25. If the frame is sound, one fogged unit can be replaced on its own.
Downtown condo towers
Most recent growth is vertical. Mount Pleasant West (+32.8%), Church-Yonge Corridor (+29.8%) and Waterfront Communities-The Island (+29.4%) were Toronto's fastest-growing neighbourhoods from 2016 to 2021. Their glazing is mostly window wall, a system that evolved in the 1960s, beginning in the Greater Toronto Area. In early systems, sealed units often fogged after only a few years of service, and failures in the late 1990s and early 2000s led to tighter testing and inspection rules.
GTHA condo completions set a record in 2024, then reached 29,291 units in 2025, nearly matching it. That glass is now heading into the years when first seal failures and warranty expiries appear. Orientation matters: south-facing sealed units often last under 12 years, and edge sealants are six to eight times more permeable at 60 °C than at 20 °C, so sun, not cold, drives much of the ageing. When a window-wall unit fogs, the fix is a new sealed unit in the existing frame, once management confirms who's responsible.
Climate: the mildest winters in the GTA, still hard on glass
Downtown is the warmest part of the region in winter. Toronto City Hall has 3,520 heating degree-days, against 3,890 at Pearson and 4,260 in Newmarket. January averages −4.2 °C in the Annex and −6.3 °C at Pearson.
Milder doesn't mean easy on glass:
- Summers are getting hotter. Days above 30 °C rose from 9.7 a year (1961–1990) to 14 a year (1991–2020). Heat ages sealant fastest.
- Winter sun still cracks glass. Thermal stress builds when the centre of a pane warms while its edge stays cold in the frame. Static shadows, insulating blinds and heat vents aimed at the glass all raise the risk. On narrow downtown lots, a neighbour's wall often shades half a window.
Rules: heritage districts, permits, condos and rentals
Heritage conservation districts
Most of Toronto's heritage conservation districts are in the old city, including five Cabbagetown districts, Rosedale North and South, the East Annex, Madison Avenue (West Annex Phase 1), Harbord Village, Riverdale, Yorkville-Hazelton, Kensington Market, the St. Lawrence Neighbourhood and Kingswood Road South near Balmy Beach.
In a district you're not required to replace existing windows, but if you choose to replace existing windows and doors that are visible from the sidewalk, you will need a heritage permit. Routine maintenance and changes not visible from the street don't need one. The City's guidance doesn't specifically address re-glazing a broken pane. Matching glass in the existing sash is closer to maintenance, but if the job would change what the street sees, such as a new sash or different muntins, check with Heritage Planning first.
For Part IV or Part V designated houses, the Toronto Heritage Grant Program can help pay for the repair of existing, original windows and doors, one grant per property every five years. The next deadline is November 7, 2026. Its guidance is blunt: original windows that are sound or repairable must be retained and restored, and you need three estimates.
Building permits
New glass in an existing frame doesn't change the opening and is generally treated as a repair. For whole windows, Toronto doesn't require a permit to replace a window or door in an existing opening of a detached, semi-detached or row house with one dwelling unit, as long as the size, location and structural support don't change. Replacing windows or doors in any other type of building needs a permit, and so does adding or enlarging an opening. With one in five homes here in a low-rise apartment building, that distinction matters: a glass-only repair that keeps the frame is a different job from window replacement, and if you're unsure how yours is classed, ask Toronto Building. Our permit guide has more detail.
Condos and rentals
Under the Condominium Act's default, the corporation repairs common elements and owners maintain their units, but the declaration can change that split. Report a fogged or broken window to management before booking anyone. See who's responsible for condo glass; your declaration governs, and this isn't legal advice.
With 56.2% of households renting, Toronto's property standards by-law matters too. Exterior windows and doors must be weather-tight and in good repair, openable windows need screens, and windows and exterior doors must lock from inside.
Break-ins and broken glass
Several downtown neighbourhoods lead the city for break-ins. In 2025 the highest rates were in University, Yonge-Bay Corridor, Rosedale-Moore Park and Kensington-Chinatown, and the Annex had the highest count at 149. If glass is broken, put on gloves and closed shoes before cleaning up, keep children and pets out of the room, and don't tape and leave a cracked glass door in use. Then get the opening boarded or re-glazed through our emergency glass repair service.
Neighbourhoods we serve
We work across the old city and East York, including Cabbagetown, the Annex, Harbord Village, Riverdale, Rosedale, Yorkville, Kensington Market, St. Lawrence, the Church-Yonge Corridor, Mount Pleasant West, the waterfront condo neighbourhoods, Topham Park, Thorncliffe Park and Crescent Town. Other areas are listed on our service areas page.
What we'd do
- Original wood sash with a cracked pane: re-glaze in matching single glass and re-putty rather than replace the sash. That keeps the house's character and keeps the job on the maintenance side in a heritage district.
- Fogged sealed unit in a house or addition: replace just the sealed unit if the frame opens, closes and locks properly. Our foggy window repair page explains the process.
- Condo window wall or balcony door: confirm responsibility with management first, then get an itemized quote the corporation or your insurer can use. Sliding-door glass must be safety glass under the Ontario Building Code, and tempered glass can't be cut after it's made, so the replacement is ordered to size.
- Rotted, cracked or warped frame: that's a window-replacement job, not a glass repair, and in a heritage district or multi-unit building it brings the permits above into play. We'll tell you if that's where you are.
Next step
Send us a photo of the window and the frame around it, and tell us whether you're in a house, a heritage district or a condo. We'll tell you whether a glass-only repair will work and what approvals to line up first. Start on our Toronto window repair page or contact us for a free quote.