Flat roof in Vimont

For the Code, flat means 2:12 or less

The Code de l'urbanisme defines a flat roof as a roof with a slope of 16.7% or less, which is also written 2:12. Above this threshold, it speaks of a sloped roof.

A gentle slope, clearly visible from the street, can fall on the flat roof side. Do not measure the slope yourself. In a roofing in Vimont project, have us establish the slope first.

What the Code expects of a flat roof

For a flat roof, article 380 requires a green or white covering, or one with a solar reflectance index of at least 78. The area page gives the full list. The Code does not specify what applies to an existing roof redone identically.

The shed and the small garage

The article covers main buildings and accessory buildings. The exception that matters to a homeowner is the one for residential accessory buildings with a footprint of less than 40 m². Article 380 does not apply to these small buildings.

The text of the exception refers to accessory buildings. For an extension or a garage attached to the house, ask the Service de l'urbanisme (the City's urban planning department) how it classifies the structure before choosing the covering.

Saint-Elzéar/Des Laurentides: the flat roof exemption

The City places the Saint-Elzéar core in the Vimont station area, and notes that its heritage has largely disappeared. The Code de l'urbanisme nevertheless keeps a territory of heritage interest named Saint-Elzéar/Des Laurentides.

In a territory of this kind, changing the roofing materials of a main building may require PIIA approval. The Code provides three exemptions:

• replacing a material with the same material of a similar colour
• replacing it with a material that preserves or restores the original or traditional features
• renovation work on a flat roof

The third exemption, the flat roof one, applies to all of Laval's heritage territories, not only to Saint-Elzéar/Des Laurentides. The Code adds that no objective or evaluation criterion is specific to this area.

The exemption covers the PIIA only. The permit rule and article 380 remain those of the whole city. An address in the territory may still require approval for other work, and the City makes the call. The exact boundaries of the territory appear on the Code's maps. The Info-règlements tool shows whether special provisions apply to your zone.

What you can observe without going up

Even a flat roof is not a place to walk. Stay inside or on the ground.

• Under the flat part, look for stains on the ceiling and note where they are.
• From an upstairs window overlooking the roof, check whether water lingers there two days after rain.

Frequently asked questions