Solariums in Montreal: borough permits, heritage sectors and installers

A note on words: Canadian installers mostly say sunroom, and in Quebec solarium. A three-season room is glazed but usually unheated and lightly insulated, so it is used from spring to autumn; a four-season room is insulated and heated so it works in January; a solarium or conservatory has a glass roof as well as glass walls. Our Canadian sunroom and conservatory costs guide explains the difference in more detail.

Who decides: your borough

Montreal’s 19 boroughs issue their own building permits and apply their own zoning by-laws, so the rules and even the fees can differ between Rosemont and the Plateau. The city’s page on enlarging a building (agrandissement d’un immeuble) says a construction permit is needed for any enlargement, and that in some sectors buildings must also meet special standards to protect their historic, architectural or landscape value, in which case you must submit a site planning and architectural integration plan (PIIA).

Documents usually requested include the certificate of location, a cost estimate or quote including taxes, and professional-quality plans, signed and sealed by an architect where Quebec’s Architects Act requires it, with structural plans signed by an engineer.

Borough permit fees for an enlargement

What each borough page said in September 2026 for enlarging a building:

Source: Obtenir un permis pour l’agrandissement d’un immeuble, borough versions (montreal.ca, updated 6 February 2026). Worked examples are our arithmetic. Rosemont notes that the cost estimate must include the professional fees for the plans and taxes, and that extra fees can apply in heritage sectors. Fees are not refundable.

Heritage sectors: PIIA and declared heritage sites

Two layers of heritage control can apply to a Montreal solarium:

• PIIA (borough level). Many streets are covered by a plan d’implantation et d’intégration architecturale. The borough reviews how the addition fits the building and street, often with its planning advisory committee, before the permit is issued. Ask the borough whether your street is covered before you design.
• Declared heritage sites (Quebec level). Old Montreal and the historic and natural district of Mont-Royal are declared heritage sites under Quebec’s Cultural Heritage Act. For those areas, the Ministry of Culture and Communications must authorise work that changes the exterior appearance of a building or builds on the land, in addition to the borough permit, and the Mont-Royal site has its own conservation plan to guide those decisions.

Heated or unheated: why the building code cares

Quebec applies its own Construction Code, which is based on the National Building Code with Quebec modifications, and the RBQ administers it. Montreal’s heavy snow makes the structural side as important as the energy side. Under the energy efficiency rules for houses in Section 9.36, spaces that are not required to be heated are exempt from those energy requirements, and where the house wall is protected by an enclosed unheated space such as a sun porch or enclosed veranda, the insulation needed in that wall may be reduced slightly (by RSI 0.16). In practice that means a three-season room is usually treated as an unheated enclosure kept separate from the house by an exterior-grade wall and door, while a four-season room that is heated and opened up to the house must meet the insulation, glazing and air-tightness rules for the house itself. Remove the dividing door later, or add a heater, and you may need a new permit. See heating a conservatory and glazing, U-values and safety glass.

Snow. The roof of any sunroom has to be designed for the local ground snow load and rain load that the building code sets for Montreal. This matters more for a low glass or polycarbonate roof sitting under a taller house roof, where snow can slide or drift onto it. Ask who has checked the roof for snow load: the manufacturer’s engineering, a local engineer, or the city’s plan reviewer. Our guide to glass, polycarbonate or solid roofs covers the trade-offs.

Typical private prices

We have not found a reliable sunroom price survey for Montreal alone, so use the national ranges in our Canadian costs guide. HomeStars (updated August 2026) puts a three-season sunroom at $12,000–$45,000, a four-season sunroom at $25,000–$85,000, a solarium at $30,000–$80,000 and a conservatory at $50,000–$155,000. RenoQuotes (May 2026) quotes $150–$250 per square foot for three-season rooms and $400–$600 per square foot for four-season rooms. City permit fees above, drawings, electrical permits and any heritage application are usually extra unless the quote says they are included. Our guide to what to include in a realistic budget lists the other items that catch people out.

How to choose an installer in Montreal

• Check the RBQ licence. In Quebec, anyone who does renovation work for you must hold an RBQ licence. Check the number in the RBQ licence holders’ register before you sign. Licensed contractors must show their licence number on their identification and advertising.
• Know what the licence security covers. The RBQ says licence security is meant to compensate clients for losses tied to deposits paid, work not completed, poor workmanship and defects found within one year of the end of the work. Hiring an unlicensed firm can cut you off from that protection.
• Door-to-door sales. The Office de la protection du consommateur (OPC) says a contractor who solicits you at home, particularly for windows, doors, roofing, insulation or cladding, is an itinerant merchant. The contract must be in writing and can be cancelled within 10 days, and the merchant cannot ask for a deposit in those 10 days unless materials have been delivered.
• Put the details in the contract. The OPC suggests the contract shows the contractor’s licence number, start and end dates, liability insurance, a detailed description of the work and materials, the total price and payment terms.
• Ask who deals with the borough. Get in writing who prepares the plans, files the permit and any PIIA, and whether the price includes the fee. Our guide to contracts and payment stages helps.

Solarium and sunroom firms serving Montreal

These businesses appear in public business listings for the Montreal area. We have not checked their work, prices, licences or insurance, and they have not paid to appear. Many Quebec solarium makers are based in Laval, the North Shore or the South Shore and install across Greater Montreal; ask for the RBQ number of whoever actually does the installation.

You can also read our comparison of conservatory and sunroom options, our guide to comparing quotes, or request quotes.

FAQs

Sources

• Obtenir un permis pour l’agrandissement d’un immeuble, borough versions (montreal.ca)
• Site patrimonial déclaré du Mont-Royal (Banque d’information 311, ville.montreal.qc.ca)
• Site patrimonial du Mont-Royal (Répertoire du patrimoine culturel du Québec, patrimoine-culturel.gouv.qc.ca)
• The contractor and the licence, FAQ (rbq.gouv.qc.ca)
• Check a contractor’s licence (rbq.gouv.qc.ca)
• Before hiring a renovation contractor (opc.gouv.qc.ca)
• Section 9.36 Energy Efficiency, Part 9 (rdn.bc.ca copy of the code text)
• How Much Does a Sunroom Cost? (homestars.com)
• Sunroom Cost in Canada 2026 (renoquotes.com)

Last checked: September 2026. Fees and codes change, often each January, so confirm the current figure with the city before you rely on it.

Compare Conservatories is a comparison and referral service, not a sunroom or conservatory installer. We do not design, build or approve sunrooms, and a listing here is not a recommendation.