4 ms·

It has been a requirement in Montreal for all new roofing for a few years now. Either green (vegetated) or light (with a solar reflection material). So most peo

It has been a requirement in Montreal for all new roofing for a few years now. Either green (vegetated) or light (with a solar reflection material). So most people have white elastomer roofs installed. Someone correct me if I’m wrong but I believe it’s the only Canadian city with that requirement.

xattt 5y ago
Where do solar panels fit into this if you have complete coverage of your roof?
krylon 5y ago
Has this had a measurable impact? (honest question, I like the idea very much.)
- arboghast 5y ago
  So when I moved to Montreal in 2016 I bought a 2 floors condo built before the new law was passed (2005 I believe). Above the second floor it had gravel roof I think, I’m not sure what it was but it was very hot in the summer (not so much on the first floor). After replacing it with elastomer, temperature definitely went down a little bit on the thermostat but I personally don’t feel much of a difference. This could be because, in the morning, the sun is facing the large windows which warms the inside even more. Anecdotal, of course. Regardless, roof had to be changed. But the AC is definitely ON when it’s 25C and above regardless of the roof type.
ipaddr 5y ago
Wouldn't this be a net negative with more heating days than cooling days to worry about?
- mgbmtl 5y ago
  Montreal has more days where heat is a problem (ex: for elderly people), than when cold is a problem. There are a lot of efforts put into reducing heat zones, from too much asphalt, not enough trees, etc. (I once ran for borough council :-) Since 2010, most Quebec building standards have also been updated pretty massively. I don't have references, but where I live, we had 1" insulation in the walls, and now the minimum requirement for new buildings is 1.5". Doors and windows tech have improved a lot too in the past 10-15 years. Overall, as I went through upgrades, our heating bills went down pretty significantly, but AC usage keeps going up.
- 1over137 5y ago
  Many of the "heating days" would have snowy (ie white) roofs anyway.
rootusrootus 5y ago
Isn't that only on commercial roofs, especially flat or low-pitch ones?
- auxym 5y ago
  It is for flat roofs only I believe. However, Montreal does have a lot of "plexes" and small apartment buildings with flat roofs.

xattt 5y ago

Where do solar panels fit into this if you have complete coverage of your roof?

krylon 5y ago

Has this had a measurable impact? (honest question, I like the idea very much.)

arboghast 5y ago
So when I moved to Montreal in 2016 I bought a 2 floors condo built before the new law was passed (2005 I believe). Above the second floor it had gravel roof I think, I’m not sure what it was but it was very hot in the summer (not so much on the first floor). After replacing it with elastomer, temperature definitely went down a little bit on the thermostat but I personally don’t feel much of a difference. This could be because, in the morning, the sun is facing the large windows which warms the inside even more. Anecdotal, of course. Regardless, roof had to be changed. But the AC is definitely ON when it’s 25C and above regardless of the roof type.

ipaddr 5y ago

Wouldn't this be a net negative with more heating days than cooling days to worry about?

mgbmtl 5y ago
Montreal has more days where heat is a problem (ex: for elderly people), than when cold is a problem. There are a lot of efforts put into reducing heat zones, from too much asphalt, not enough trees, etc. (I once ran for borough council :-) Since 2010, most Quebec building standards have also been updated pretty massively. I don't have references, but where I live, we had 1" insulation in the walls, and now the minimum requirement for new buildings is 1.5". Doors and windows tech have improved a lot too in the past 10-15 years. Overall, as I went through upgrades, our heating bills went down pretty significantly, but AC usage keeps going up.
1over137 5y ago
Many of the "heating days" would have snowy (ie white) roofs anyway.

rootusrootus 5y ago

Isn't that only on commercial roofs, especially flat or low-pitch ones?

auxym 5y ago
It is for flat roofs only I believe. However, Montreal does have a lot of "plexes" and small apartment buildings with flat roofs.