What Emergencies Can a Roof Inspection Reveal?
May 4, 2026Are you planning to redo your building’s roof in Montreal? Before choosing your membrane, know that a rule now applies in almost all boroughs: the white roof is no longer an option, it’s an obligation. Whether you own a duplex, a triplex, or a commercial building, this regulation directly affects you. Here’s what you need to know to make the right choices, avoid permit refusals, and get the most out of your work.
Key Takeaways
- During the renovation or construction of a flat roof in Montreal, the authorized materials are: a white material, painted white or covered with a reflective coating, or a material with a solar reflectance index (SRI) of at least 78.
- This regulation applies in many boroughs during the renovation or construction of a flat roof.
- Dark roofs absorb solar heat and contribute to urban heat islands, which harms air quality and residents’ health.
- Any owner renovating or replacing their flat roof covering is affected, whether it’s a residential, commercial, or industrial building.
- The City of Montreal’s RénoPlex program can offer financial assistance of $50 per square meter for renovating a roof with a white membrane.
What exactly is a white roof?
A white roof is not necessarily painted white. It refers to any flat roof covering whose surface reflects the sun’s rays rather than absorbing them. Unlike dark colors, white reflects heat outwards and prevents the temperature from rising inside the building.
In practice, it can take several forms: a white TPO (thermoplastic polyolefin) membrane, a reflective coating applied to an existing roof, or white gravel. What matters is the material’s ability to reflect heat. The technical criterion for obtaining your permit is the Solar Reflectance Index (SRI): the higher it is, the cooler the roof remains under the sun, which reduces heat islands and air conditioning demand.
Why is Montréal making white roofs mandatory?
Dark roofs attract UV rays and store heat. Across thousands of buildings in the same neighbourhood, the effect builds up and creates urban heat islands: temperatures rise locally, smog intensifies, air quality deteriorates, and heat waves become more dangerous for residents.
The regulation was introduced as part of a sustainable development approach to counter this phenomenon and improve air quality in Montréal. By reflecting rays rather than absorbing them, a white roof helps keep temperatures cooler, both inside buildings and in the surrounding streets.
What the regulation actually says
In Montréal, the rules vary depending on the type of roof and the borough. The standards apply to flat roofs, meaning any roof with a slope of less than 16.7%. Here is a reference table based on the City of Montréal’s official roofing page:
| Situation | Permitted materials | What you need to do |
| Flat roof refurbishment | White material, reflective coating, white gravel, or SRI ≥ 78 | Choose a compliant covering |
| New construction or extension | White material or SRI ≥ 56 (existing buildings) | Confirm the SRI with the manufacturer or a professional |
| Roof occupied by mechanical equipment or a terrace | Partial exemption possible | Check with your borough |
These requirements do not apply to areas of the roof occupied by mechanical equipment such as an air conditioner or heat pump, or to a terrace.
Do you need a permit?
Not always. A standard membrane replacement generally does not require a permit. However, as soon as you modify the insulation or the roof structure, a permit becomes mandatory.
A job site that does not comply with the execution conditions may receive a notice of offence and be required to make corrections, or even be shut down. If you have any doubt, consult a professional roofer before you start. 
What you gain daily
The white roof is not just a regulatory constraint. In urban areas, a reflective roof reduces air conditioning costs in summer and helps lower the temperature in densely populated neighborhoods. This is a direct benefit to your energy bill.
This type of membrane also tends to deteriorate more slowly than a dark membrane subjected to extreme heat cycles. A well-installed white roof can therefore last longer — a long-term saving that is often underestimated.
Financial assistance available
If you are planning a compliant renovation, check your eligibility for the City of Montreal’s RénoPlex program. For buildings with 1 to 5 dwellings, it can offer $50 per square meter for a white membrane, and up to $88 per square meter for a green roof. This can represent significant assistance depending on the size of your roof.
Next steps if you need to redo your roof
- Check your roof type: flat or sloped, and its inclination (a flat roof is any roof with an inclination of less than 16.7%).
- Consult a professional roofer: they will confirm if your building is subject to regulations according to your borough.
- Request a quote with compliant materials: ensure that the proposed membrane mentions the SRI or is explicitly qualified as compliant.
- Learn about RénoPlex: if your building has 1 to 5 dwellings, you could receive renovation assistance.
A necessary choice that benefits you
The white roof regulation in Montreal addresses a very real climatic reality. By choosing the best reflective coating for your roof, you comply with municipal rules while reducing your energy costs and extending your roof’s lifespan. With a good roofer by your side, the transition is simpler than it seems.
Our team can assess your roof, confirm your regulatory compliance, and propose suitable options for your building.
Contact us for a free quote.
Frequently Asked Questions
Does the white roof regulation apply to single-family homes in Montreal?
It mainly targets flat roofs. Single-family homes often have a sloped roof,
generally not covered by this obligation. Check with your borough based on
your roof’s inclination.
Can I apply a reflective coating to my existing roof instead of replacing it?
Yes, in some cases. A reflective coating can be applied to a roof in good condition.
A roofer will assess if this option is viable and if it meets the required SRI for your borough.
What is SRI and how do I know if my membrane is compliant?
SRI measures a material’s ability to reflect solar heat. It is listed in the
manufacturer’s specifications. A professional or your borough’s permit counter
can confirm your project’s compliance.
Do white roof works always require a permit in Montreal?
Not always. A standard replacement may not require a permit. But any modification
to the structure or insulation requires one. If in doubt, consult your borough
before starting work.
Are there exceptions to the white roof rule?
Yes. Areas occupied by mechanical equipment or a terrace are generally exempt.
Some heritage buildings may also be subject to specific rules depending on the borough.
