Replacing exterior siding: permits in Montréal and Laval

New siding looks like a simple choice of material. In Greater Montréal it is first a question of rules: depending on the borough or the city, the same job may need no permit, a regular permit, or a review under a site planning and architectural integration program (PIIA). This guide summarizes the City of Montréal page Réparer ou remplacer un revêtement extérieur (in French, updated September 1, 2026), the City of Laval page on exterior home renovation (in French) and the Régie du bâtiment du Québec (RBQ) list of licence subclasses, all read on November 3, 2026.

1. Repair or replace: the line that decides the permit

The City of Montréal explains that, depending on the extent of the work and the borough, a permit may be needed to repair or replace exterior siding, and that some areas or buildings follow special standards to protect their historic, architectural or landscape value. A few examples from the page:

• Rosemont–La Petite-Patrie: maintaining or repairing a wall covering (brick, stucco, wood clapboard), including repointing masonry and stripping or painting wood, needs no permit. Replacing the covering of an exterior wall does.
• Le Plateau-Mont-Royal: repointing needs no permit, except for a classified heritage building, a significant architectural landmark, a building in the declared Mount Royal heritage site or in a protection area. A permit is required for major repairs and to replace the cladding, a lintel or a sill.
• Mercier–Hochelaga-Maisonneuve: a permit is required when the replacement covers more than 50% of the cladding of one storey of a single wall, or when the material changes.

2. Banned materials and the 80% masonry rule

The list varies by borough. In Rosemont–La Petite-Patrie, the page bans among others plastic film, tar, mineral or vinyl paper, particle board or any material not designed for exterior use, glass or mirror reflecting more than 20% of daylight on more than 5% of a façade, and asphalt shingles except on a parapet cap. It adds that the front façade must generally be 80% masonry (a corner building has two front façades) and that a natural or artificial stone façade may not be painted. Mercier–Hochelaga-Maisonneuve also applies the 80% rule and bans vinyl (PVC) siding, except on an outbuilding under 15 m².

On the Plateau, an existing building must keep its original cladding materials. Banned there, unless original: concrete brick, hollow concrete block, vinyl, metal or wood-composite siding, and any masonry thinner than 40 mm except stucco or acrylic render. Before comparing quotes for a material, check that it is allowed at your address.

3. Laval: same material or new material

The City of Laval’s table separates two cases. Replacing the siding with the same material while adding insulation needs no permit, unless a PIIA applies to the property. Replacing it with a new material needs a permit. The City gives a 30-day processing time and a fee of $92 for the first $20,000 of work, plus $2.50 per $1,000 or part of $1,000. To find out whether a PIIA covers your lot, it points to its Info-règlements tool: a notice that special provisions apply to your zone means extra requirements. It asks owners to wait for the permit before starting and to post it, visible from the street, during the work.

4. What the borough will want to see

In Rosemont–La Petite-Patrie, the application includes the quote or a cost estimate grid with taxes, the certificate of location, the product sheet or a sample of the material, photos of the façades and the building form; an architect’s plans may be required. The review fee there is $9.80 per $1,000 of work, with a minimum of $167.40 for a residential-only building, and the average processing time is 2 to 4 weeks for like-for-like work, 8 to 10 weeks with changes. A detailed quote naming the exact material, its colour and the walls involved therefore does two jobs: comparing prices and supporting the permit application. The City also suggests filing all renovation requests (roof, doors and windows, balconies) at once.

5. Which RBQ licence?

According to Schedules II and III of the Regulation respecting the professional qualification of contractors and owner-builders (B-1.1, r. 9), subclass 7 covers insulation, waterproofing, roofing and “exterior wall cladding other than masonry”. Exterior masonry veneer walls fall under subclass 4.1, masonry structures. Ask for the licence number and look it up before signing.

6. What Montréal’s permits show

In the City of Montréal’s open building permit data (in French), 298 of the 20,621 permits issued from October 27, 2025 to October 26, 2026 mention “revêtement extérieur” (exterior cladding) in their description, mostly in Villeray–Saint-Michel–Parc-Extension (73), Rosemont–La Petite-Patrie (58) and Mercier–Hochelaga-Maisonneuve (41). To find licensed companies near you, see renovation in Rosemont–La Petite-Patrie, in Mercier–Hochelaga-Maisonneuve or in Laval, or describe your siding project so licensed companies can reply. The directory prepares no quotes and picks no company for you. See also replacing windows, often done at the same time.