Unionville · Markham
Unionville windows, inside the heritage district and beyond it
Main Street Unionville stood in for Stars Hollow in the first season of Gilmore Girls. For owners, the more useful fact is that the old village is a heritage conservation district, and window work inside it follows its own plan. Around it, Unionville's later houses need the ordinary things: a fogged sealed unit, a crank that spins, a patio door that drags. We connect you with an independent local professional suited to whichever house you have.
At a glance
- Housing
- 19th-century village houses around Main Street; later subdivisions beyond
- Rules
- Heritage permit for exterior window changes inside the district
- Common jobs
- Wood sash repair, arched glass, fogged sealed units, shop windows
- Local word
- The district plan calls sealed units “thermopane” units
Inside the heritage district: permits and repair-first rules
Every property in the Unionville Heritage Conservation District needs a heritage permit from the City before exterior changes, and windows count. Heritage staff can approve work that follows the district plan, which is clear about the order of things: repair original frames and sash, limit the repair to the damaged parts, and replace only a window that is beyond saving, in the same material, style and proportion.
The plan also asks owners not to resize original openings to fit stock windows, and it treats traditional exterior storms as the way to make an old window warmer. The heritage district window guide walks through the permit.
The district also takes in houses from the 1950s to the late 1970s that aren't heritage buildings. For those, the plan allows a historically complementary approach, such as a more traditional window style when windows are replaced. The permit still applies.
Windows typical of the old village: tall double-hungs and arched accents
The plan describes the village's windows precisely. Double-hung sash that are longer than they are wide are characteristic. Brick houses often have segmental arches, a shallow curve across the head of the opening, and gables carry the occasional round, Gothic or ogee-arched accent.
Each shape changes the job. A double-hung that rattles or sticks usually needs new cords, weatherstrip or glazing putty, the work described under wood window repair. A cracked pane in a Gothic gable window needs glass cut to a template of the opening; arched and transom window glass explains how that's done.
Newer homes around the village: fogged units, cranks and patio doors
Beyond the district boundary, Unionville's houses are much later. No heritage permit applies there, and the City's building permit page lists same-size window and door replacement among work that doesn't need a building permit.
- Foggy sealed units: a unit that has lost its seal is swapped for a new one made to size, with the grilles matched and the frame left alone.
- Casement cranks and latches: when a casement won't close snugly, the operator or a hinge arm is usually the culprit, not the window.
- Sliding patio doors: a door that drags usually needs rollers or an adjustment first.
Main Street shops and plate glass
Shop windows on Main Street Unionville are inside the district too, so changing a storefront's glass, frame or divisions is an exterior alteration that needs a heritage permit. Even a like-for-like pane is worth a call to heritage staff before ordering. The City's heritage grant can also help restore authentic historic storefronts. For the glass itself, including temporary boarding while a custom pane is made, see storefront glass repair.
Getting a quote that works for the heritage grant
Markham's Heritage Property Grant, launched in 2026, can pay part of the cost of repairing original windows and doors in the districts. It asks for two professional quotes for the identical scope of work.
When you send a request, say that you're applying and which windows are original. We pass that on, and you can ask the pro whether their quote can itemize each window so it lines up with a second quote. Routine maintenance such as painting isn't eligible, so ask for repair and painting as separate lines. Check current eligibility before work starts.
Unionville questions
Does replacing a window in the Unionville district need a heritage permit?
Yes, if the house is inside the heritage district. Exterior window changes there need a heritage permit from the City, and heritage staff can approve work that follows the district plan. Outside the boundary, no heritage permit applies. The heritage district guide explains the steps.
How do I find out whether my Unionville house is in the district?
The district is centred on the old village, but its boundary is fixed by the plan, not by how old a house looks, and it includes some houses from the 1950s to the 1970s. Start with the City's heritage districts page, and ask heritage staff to confirm your address before anyone measures for new windows.
Can fogged glass be replaced on a non-heritage house in the district?
Usually, yes. A house from the 1950s to the 1970s inside the district often has sealed units that can be swapped in the existing frames, leaving the window's appearance unchanged. Because the house is still in the district, check with heritage staff before any change that shows from outside, such as new frames or a different grille pattern. See foggy window repair.
Is a thermopane the same thing as a sealed unit?
Yes. Thermopane is an older word for two or more panes sealed together around a spacer, and it's the term the Unionville plan uses. Most glass pros now say sealed unit or insulated glass unit. When the plan says original windows in good condition shouldn't be replaced with thermopane units, it means an old single-glazed sash shouldn't be swapped for a modern double-glazed one.
Can I use snap-in grilles on a Unionville heritage window?
No. Markham's heritage plans rule out snap-in muntins and tape that imitates divided panes. Where a replacement window is approved, the pane division has to read from outside: true divided lites, or muntin bars fixed to the exterior of the glass.