Replacing doors and windows in Montreal: permits by borough

The city-wide rule

A few rules from the City of Montréal apply in every borough (Portes et fenêtres on montreal.ca):

• Adding a door or window, or changing the size of an opening, always requires a permit.
• Bay windows that project from the wall and sliding patio doors always require a permit, new or replacement. The City gives the reasons: distance to the lot line, the share of the façade that is glazed, fire spreading through glass, and exits. If a patio door replacement is on your list, plan the permit from the start.
• Same-size replacement is where the boroughs part ways. In the City's own words, the regulation differs from one borough to the next.

We connect Montreal owners, landlords and syndicates with independent local window and door pros. The pro we match you with can help you put together the documents your borough asks for, but the rules below are the borough's, and the borough has the final word.

Same-size replacement: the 19-borough table

Most of the 19 boroughs require a permit even when the new window or door is identical in size to the old one. Here is how each treats a same-size replacement, with a link to its page on montreal.ca, which is in French. The City's main page on same-size replacement also has an English version. We checked these pages in September 2026; a borough page can change between our check and your project, so treat this table as a map, not a ruling.

Boroughs with particular rules

Le Sud-Ouest

The Sud-Ouest's rules reach into materials. PVC is not allowed as an exterior finish on windows anywhere in the borough, frames included, although hybrid windows, with PVC inside and aluminum outside, are accepted. Buildings identified as architectural witnesses (témoins architecturaux) need wood or aluminum. Where the doors and windows on a façade are original, the same form and model must be kept; otherwise the replacement is chosen from the borough's list of authorized models. Original stained glass and glass blocks are kept and put back, and sidelights, transoms and carriage openings must not be blocked. New units must also meet the borough's energy-rating requirement. The borough strongly recommends getting the permit before signing a contract. The Sud-Ouest area page describes the housing behind these rules.

Verdun

Verdun's rules focus on doors. The borough spells out the proportions of glass in a door, requires transoms (impostes) to be kept or restored when a door is replaced, and lets upper-floor balcony doors have shorter glazing and a guillotine sash. Much of Verdun was built up with plexes between the wars, so upper balcony doors come up often. More on the Verdun area page.

Côte-des-Neiges–Notre-Dame-de-Grâce

In its significant sectors (secteurs significatifs), CDN–NDG does not allow sliding windows. If you plan to replace hung or casement windows with sliders, first check whether your street falls in one of those sectors, and choose the style accordingly.

Rosemont–La Petite-Patrie

Rosemont publishes a list of accepted replacement models and has heritage sectors with their own requirements. It also allows a garage door to be replaced with a watertight one, which connects with the flood component of RénoPlex covered in our subsidy guide.

Le Plateau-Mont-Royal

The Plateau requires a permit even for a same-size replacement, and the new window must have the same characteristics as the original components. Repair is treated differently: repairing original windows needs no permit, except on classified heritage buildings, significant architectural witnesses, the Mont-Royal heritage site or protected areas. The Plateau also adds a surcharge to the analysis fee for work on the parts of a building visible from the street.

Villeray–Saint-Michel–Parc-Extension

Villeray–Saint-Michel–Parc-Extension tells owners plainly to wait until the permit is issued before buying materials. In a district where the duplex and triplex became the standard house after the Second World War, owners often do a whole façade at once, and an early order is the mistake to avoid.

Documents and analysis fees

For a same-size replacement in a City of Montréal borough, the permit file asks for:

• the contractor's quote (soumission), with taxes;
• colour photos of the façade, with each window or door to be replaced numbered;
• the certificate of location for the property;
• the manufacturer's technical sheet for the new windows or doors;
• for a condo, a letter of authorization from each co-owner or a resolution of the syndicate.

The borough charges an analysis fee calculated on the value of the work, with a minimum that is higher for commercial, industrial, institutional and mixed-use buildings than for residential ones. The fee is not refundable. Current rates are on the City's same-size replacement page.

This is where a detailed quote earns its keep. A quote that lists each opening with its dimensions, model and finish makes the permit file, and any subsidy application, far easier to assemble.

Condos: the syndicate's resolution

In a condo building, the windows of one unit are rarely one owner's decision alone. The permit file asks for each co-owner's written authorization or a resolution of the syndicate, so raise the project at the syndicate early and have the resolution ready when the file goes in. Our page for condo syndicates and co-owners covers the rest of the process.

Westmount and the reconstituted cities

Westmount is a separate city with its own Permits and Inspections Division, and it uses the terms permit and authorization certificate. Exterior projects fall under its architectural review by-law (by-law 1305) and need City Council approval, with two exceptions that matter for windows: restoring original components and replacing them identically. A file includes the manufacturer's shop drawings showing profiles, numbered photos and, where it applies, a letter from the co-owners' association; a widened opening also needs a lintel detail stamped by a structural engineer. Westmount has also adopted an inventory of older buildings with heritage value. See Westmount: windows and doors and our Westmount area page.

The Town of Mount Royal, Côte-Saint-Luc and the West Island cities each run their own permit offices as well. We have not reviewed their window rules, so ask the town hall before planning a replacement there. Most of the Town of Mount Royal is a designated National Historic Site, one more reason to ask first.

Laval, Longueuil, Brossard: check with the city

Off the island, each city sets its own rules. We have not checked the window permit requirements in Laval, Longueuil or Brossard, and we will not guess at them. Contact the city's permits department before you sign. RénoPlex, the City of Montréal subsidy, does not apply there either.

In what order: permit, subsidy, contract

1. Get a detailed quote, and check the contractor's licence. Window and door contractors in Québec need a licence from the Régie du bâtiment du Québec, with the number shown on their documents. The replacement windows page lists what a good quote should cover.
2. Read your borough's page to confirm whether a permit is needed and what the file must contain.
3. Apply for any subsidy that needs approval first. RénoPlex must approve your file before the work starts.
4. File for the permit with the quote, the numbered photos, the certificate of location and the product sheet.
5. Sign and order once the permit is issued. The Sud-Ouest strongly recommends it, and Villeray–Saint-Michel–Parc-Extension asks you to wait before buying materials. A window or door contract signed at home must be on paper and in French, and it carries a cancellation period; the Office de la protection du consommateur explains the rules.

When you send a request, tell us your borough. The pro we match you with can prepare a quote detailed enough for the permit file. Request a quote.