All new roofs would be white under a Montreal borough's proposed bylaw aimed at taking advantage of a white roof's cooling effects.
Mayor François Croteau of Rosemont-La Petite-Patrie wants to make white roofs mandatory on new buildings. Roofs requiring repairs would have to be painted white as well.
Croteau's idea is supported by a Concordia University engineering professor, who says all the world's roofs should be changed to cooling colours.
"Ten metres squared of white roof is equivalent, in cooling the globe, the equivalent to one tonne of [carbon dioxide]," Prof. Hashem Akbari says.
Akbari is trying to persuade 100 of the world's largest cities to switch to light-coloured roofs. Changing all the roofs in the world would be equal to getting rid of all the world's cars for 20 years, he says.
If Croteau gets his way, many of his borough's roofs will be white within about 15 years.
The bylaw would not apply to buildings with peaked roofs, which many residential houses have.
Croteau said making the switch to white roofs would be more expensive in the short term. But, he said, the cost would be offset eventually because white roofs are more durable.
Councillors in Rosemont-La Petite-Patrie will vote on the proposal in October.In looking for this story I found some of the research that backs up the reasoning, I had no idea of the impact that changing the colour of the roof could have. If there were a wholesale transition to white roofs, there would be a 33% reduction in the urban heat island effect.
Sarah Thomson, candidate for mayor of Toronto is backing this idea as well, though she is running a distant third of fourth.
You can even calculate the savings from moving to a light coloured roof from a dark one.
I like the idea of showing people that is saves money and not any sort of forced mandate.