Rebuilding a balcony: fibreglass deck, railings, permits

A worn balcony floor, a shaky railing, a gallery to rebuild: before choosing between wood and a fibreglass deck, find out what your borough or city requires. This guide summarizes the City of Montréal page Construire ou remplacer une terrasse, un balcon, une galerie ou un perron (in French, updated February 11, 2026) and the City of Laval page Balcon ou galerie (in French), both read on November 3, 2026.

1. Repair or replace, in Montréal

According to the City, in most cases maintaining or repairing a deck, balcony, gallery or porch needs no permit. A permit is required, however, before building, enlarging, altering or replacing one, with rare exceptions. Before applying, the City advises checking with the permit counter:

• the distance from the structure to the property lines, its dimensions and the height of the floor above the ground;
• the railing height and the spacing between balusters, and the type of privacy screen allowed;
• the materials, the number of balconies allowed per façade and the windows under the balcony (natural light bylaw).

2. Switching from wood to fibreglass: tell the borough before you buy

The Montréal page is clear: if you use materials different from the original ones for a repair, you must inform the permit counter before buying the materials and provide a professional-quality plan. Ahuntsic-Cartierville and LaSalle repeat this rule when dimensions or materials change. In Outremont, any change of dimensions or materials is subject to a PIIA review, with extra fees, delays and documents; in Verdun, such a change may be. Several boroughs ask for the manufacturer’s documentation or the product’s technical sheet.

3. Floor height changes everything

Several boroughs set their thresholds by floor height. In Rosemont–La Petite-Patrie, a balcony under 60 cm detached from the building can be built without a permit, but a floor more than 60 cm above the ground needs one; above 1 m, you must also consult a plans designer and a borough representative before buying materials. On the Plateau-Mont-Royal, above 60 cm the balcony must have a railing, and a rooftop deck always needs a permit. In Côte-des-Neiges–Notre-Dame-de-Grâce, repairing a balcony needs no permit, but replacing a railing does. In Pierrefonds-Roxboro, the page notes that materials and design must comply with the Québec Construction Code.

4. In Laval: the yard makes the difference

The City of Laval separates the back yard from the others. In a back yard, maintaining or repairing a balcony, gallery or porch needs no permit in most cases, unless the property is covered by a PIIA or the work involves the pool rules; the work must still comply with the urban planning code and the Québec Construction Code. In a front or side yard, or one facing a street, a permit is mandatory to repair, alter or build a balcony, porch or gallery. The residential fee is $92 for the first $20,000 of work, plus $2.50 per $1,000 or part of $1,000. For a building with 2 or more dwellings, a structural plan is required; for a prefabricated balcony, the plan can come from the supplier.

5. Balconies on large buildings

For façades of 5 storeys or more, the Régie du bâtiment du Québec (RBQ) lists signs of deterioration on balconies among the warning signs an owner can spot, and its façade maintenance guide asks that equipment attached to façades, balconies included, be checked during the mandatory inspection (see our guide on bulging brick walls).

6. The licence and the quote

According to Schedules II and III of the Regulation respecting the professional qualification of contractors and owner-builders (B-1.1, r. 9), subclass 6.1 covers wood framing and 6.2 non-structural wood or plastic work. Ask the company which subclass covers the structure, the deck and the railing, then check its licence. Ask for a quote that names the deck product and the railing, and states who applies for the permit.

In Montréal’s open permit data (in French), 1,914 permits issued from October 27, 2025 to October 26, 2026 mention a balcony, mostly in Rosemont–La Petite-Patrie (291), Mercier–Hochelaga-Maisonneuve (237) and the Plateau-Mont-Royal (227); 228 of them also mention fibreglass. See renovation companies in Rosemont, on the Plateau or in Laval, or describe the balcony you need rebuilt.